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Abstract: The randomised clinical current study was planned to determine the comparative effects of isometric and isotonic global neck muscles strengthening exercises on pain, range of motion, strength, function and quality of life in patients with chronic mechanical neck pain. The study comprised 22 patients with chronic mechanical neck pain. The subjects were randomly divided into two interventional groups, with group A receiving isometric exercises and group B receiving isotonic exercises. Numeric Pain Rating Scale, Neck Disability Index, goniometer, dynamometer and Short Form-36 questionnaire were used for data collection. Isometric and isotonic exercise groups showed significant improvement (p<0.05) in terms of decreasing pain and functional disability, and increasing range of motion and strength. Intergroup comparison showed no significant differences (p>0.05), indicating similar efficacy of isometric and isotonic global neck muscles strengthening exercises., Trial Registration Number: This study was registered at ClinicalTrials.gov ID: NCT05865951.

Background: Pain is a common non-motor symptom in patients with cervical dystonia (CD), severely impacting their quality of life. The pathophysiology of CD is incompletely understood but it involves altered processing of proprioceptive and pain signals., Objectives: The purpose of this proof-of-concept study was to determine if vibro-tactile stimulation (VTS)-a non-invasive form of neuromodulation targeting the somatosensory system-can modulate neck pain in people with CD., Methods: In a multi-center study, 44 CD patients received VTS to sternocleidomastoid and/or trapezius muscles for up to 45 min under 9 different stimulation conditions that either targeted a single or a pair of muscles. The primary outcome measure was a perceived pain score (PPS) rated by participants on a 100-point analogue scale., Results: During VTS, 29/44 (66%) of participants experienced a reduction in PPS of at least 10% with 17/44 (39%) reporting a reduction in pain of 50% or higher. After VTS cessation, 57% of participants still reported a 10% or higher reduction in PPS. Effects were significant at the group level and persisted for up to 20 min post-treatment. No distinct optimal stimulation profiles were identified for specific CD phenotypes. Clinical markers of disease severity or duration did not predict the degree of VTS-induced pain reduction., Conclusion: This proof-of-concept study demonstrates the potential of VTS as a new non-invasive therapeutic option for treating neck pain associated with CD. Further research needs to delineate optimal dosage and long-term effects., (© 2024. The Author(s).)

Objective: This study aims to evaluate the effects on bite force and muscle thickness of the botulinum toxin (BoNT) injection for patients with sleep bruxism (SB) by comparing injections into the masseter muscle only and both the masseter and the anterior belly of the digastric muscle (ABDM) in a clinical trial., Methods: Twelve SB patients received BoNT-A injections using US-guided techniques into the masseter muscle only (Group A), while the remaining 12 SB patients received injections into both the masseter and ABDM (Group B). Bite force and muscle thickness were measured before injection, as well as 1 and 2 months after injection., Results: The bite force and masseter muscle thickness decreased in both Group A and Group B before injection, and at 1 and 2 months after injection. However, there was no significant difference (p > .05, repeated measures analysis of variance) between the two groups, and there was also no significant difference in ABDM thickness (p > .05, repeated measures analysis of variance)., Conclusion: This study is the first to assess the short-term effects of BoNT injected into ABDM for SB control. Results show no influence on SB reduction, suggesting the need for further research on BoNT's effectiveness in controlling intense ABDM contractions during sleep and assessing suprahyoid muscle potential impact on rhythmic masticatory muscle activity occurrence., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Background: We analyzed cervical sagittal parameters and muscular function in different cervical kyphosis types., Methods: This cross-sectional study enrolled subjects with cervical spine lordosis (cervical curvature < -4°) or degenerative cervical kyphosis (cervical curvature > 4°), including C-, S-, and R-type kyphosis. We recorded patients' general information (gender, age, body mass index), visual analog scale (VAS) scores, and the Neck Disability Index (NDI). Cervical sagittal parameters including C2-C7 Cobb angle (Cobb), T1 slope (T1S), C2-C7 sagittal vertical axis (SVA), spino-cranial angle (SCA), range of motion (ROM), and muscular function (flexion-relaxation ratio (FRR) and co-contraction ratio (CCR) of neck/shoulder muscles on surface electromyography). Differences in cervical sagittal parameters and muscular function in subjects with different cervical spine alignments, and correlations between VAS scores, NDI, cervical sagittal parameters, and muscular function indices were statistically analyzed., Results: The FRR of the splenius capitis (SPL), upper trapezius (UTr), and sternocleidomastoid (SCM) were higher in subjects with cervical lordosis than in subjects with cervical kyphosis. FRR SPL was higher in subjects with C-type kyphosis than in subjects with R- and S-type kyphosis ( P < 0.05), and was correlated with VAS scores, Cobb angle, T1S, and SVA. FRR UTr was correlated with NDI, SCA, T1S, and SVA. FRR SCM was correlated with VAS scores and Cobb angle. CCR was correlated with SCA and SVA., Conclusion: Cervical sagittal parameters differed among different cervical kyphosis types. FRRs and CCRs were significantly worse in R-type kyphosis than other kyphosis types. Cervical muscular functions were correlated with cervical sagittal parameters and morphological alignment., Competing Interests: The authors declare that they have no competing interests., (© 2024 Wang et al.)

Background and Objectives : It has been seen that jaw opening is associated with neck extension and jaw closing is associated with neck flexion. This natural association between the jaw and neck can be used as a novel approach to treat chronic non-specific neck pain, although the effects of this concept have never been previously evaluated as a treatment strategy. This article intends to study the effects of integrating jaw opening and closing movements along with active neck exercises versus active neck exercises alone in the management of chronic non-specific neck pain. Materials and Methods : A total of 80 patients, aged 20 to 50, with chronic non-specific neck pain were included in a double-blind randomized controlled trial, conducted at the Sindh Institute of Physical Medicine and Rehabilitation, Karachi, Pakistan from 2018 to 2022. The patients were divided into two groups: Group A patients were assigned jaw movements with active neck exercises, while Group B patients were assigned only active neck exercises. Both groups were assigned isometric strengthening exercises and self-resisted strengthening exercises for cervical spine muscles as a home plan. The study used various outcome measures, including the numerical pain rating scale (NPRS), neck disability index (NDI), neck flexion endurance (NFE), neck extension endurance (NEE), the neck proprioception error (NPE): neck flexion proprioception error (NFPE), neck extension proprioception error (NEPE), neck right rotation proprioception error (NRRPE), and neck left rotation proprioception error (NLRPE), with measurements taken at week 1 and week 6, respectively; the mean differences between the groups were measured using a two-way repeated ANOVA. Results : The experimental group showed better improvements compared to the control group, NPRS (73%), NDI (57%), NFE (152%), NEE (83%), NFPE (58%), NEPE (65%), NRRPE (65%), and NLRPE (62%), with a significant difference ( p < 0.05). Conclusions : Active neck extension and flexion movements combined with jaw opening and closing are more effective in reducing pain and disability, improving neck muscles endurance and normalizing neck proprioception in patients with chronic neck pain.

Background: Recent studies revealed the connection between the endurance of neck muscles and pain, neck awareness, and fear of movement in patients with chronic neck pain in literature., Objectives: To investigate the association between cervical, scapular, trunk, and upper extremity muscles' endurance and neck pain, disability, neck awareness, and kinesiophobia in patients with chronic neck pain., Design: Cross-sectional, observational study., Methods: Thirty-six patients with chronic neck pain (aged 18-65 years) were included in the study. Endurance tests were performed for 9 muscles/muscle groups in the cervical and scapular region, upper limb, and trunk. Pain severity, neck disability, neck awareness, and fear of movement were measured by Visual Analog Scale (VAS), Neck Disability Index (NDI), Fremantle Neck Awareness Questionnaire (FreNAQ), and Tampa Scale of Kinesiophobia (TSK), respectively., Results: Negative, weak-to-moderate relations were found between VAS (at rest and during activity) and the endurance of muscles evaluated in the cervical and scapular regions, upper extremity, and trunk as well as between NDI and endurance of the same muscles, similar to the relations between FreNAQ scores and the endurance of the cervical flexor, anterior trunk flexor, and upper extremity muscles ( p  < 0.05). No relation was found between the endurance of the muscles and TSK ( p  > 0.05)., Conclusions: Since the decrease in upper extremity, scapular region, and trunk muscles' endurance may contribute to neck pain and disability, and decrease neck awareness in patients with chronic neck pain; the evaluation of muscular endurance of upper body and trunk should also be considered., Clinical Trials: NCT05121467.

Background: Dropped head syndrome (DHS) is followed by severe cervical extension muscle weakness that results in chin-on chest deformity. However, maintaining a neutral cervical position can be temporarily possible, and the diagnosis of DHS might sometimes be difficult. The purpose of the present study is to examine a novel clinical test (DHS test) as the diagnostic utility for objective evaluation that focuses on cervical extension condition in the prone position., Methods: One hundred subjects were diagnosed with isolated neck extensor myopathy (INEM)-DHS at our hospital (17 men and 83 women, mean age 75.0 ± 8.5 years), and 62 subjects were enrolled as age-matched controls. The DHS test consisted of three examinations; the first was "Ceiling gazing test" in standing position, the second was horizontal gazing in "Sphinx prone position test", and the third was horizontal gazing in "Hands and knees prone position test". We investigated the sensitivity and specificity of the DHS test for DHS., Results: The patients showing positive in the INEM-DHS group were 63/100 in Ceiling gaze test, 73/100 in the Sphinx prone position test, and 91/100 in the Hands and knees prone position test. In the control group, 0/62 patients presented positive in the Ceiling gaze test, 4/62 in the Sphinx prone position test, and 0/62 in the Hands and knees prone position test. Sensitivity and specificity of the DHS test were 63.0%/100%, 73.0%/93.5%, and 91.0%/100% in the Ceiling gaze test, Sphinx position prone position test, and Hands and knees prone position test, respectively., Conclusion: The prone position cervical extension test (DHS test) would be useful as a novel objective diagnostic tool for INEM-DHS., Competing Interests: Declaration of competing interest All authors declare that there are no personal or professional conflicts of interest related to the preparation and publication of this manuscript., (Copyright © 2023 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

The mobile phone is essential in daily life, especially during the pandemic. Prolonged use can cause postural issues, leading to common neck pain. This study aims to determine the correlation between mobile phone use duration, addiction, neck muscle endurance, and neck pain in university students. The study included 62 participants (30 female, 32 male) aged 18-35 years. Inclusion criteria required participants to have experienced neck pain at least twice in the past year and to have no other concomitant issues, as well as to volunteer for the study. Demographic information and daily mobile phone usage time were collected. Neck pain was assessed with the Visual Analogue Scale, smartphone addiction with the Smartphone Addiction Scale, and cervical muscle endurance was evaluated. Correlation analysis reveals a moderate relationship between neck pain severity (NPS) and cervical extensor muscle endurance (CEME), a strong relationship between NPS and cervical flexor muscle endurance (CFME), as well as a strong relationship among daily phone usage time (DPUT), CFME, and NPS, with a moderate relationship between DPUT and CEME. Participants were divided into two groups based on their DPUT, revealing that those who used their phone for four hours or more showed significantly higher levels of pain (p < 0.05) and reduced endurance in cervical flexor muscles. Our study found a strong correlation between neck pain, muscle endurance, and daily phone usage. Participants using their phones for more than four hours daily reported increased neck pain and decreased muscle endurance. We suggest integrating phone usage duration into neck pain assessments, promoting ergonomic practices, and offering detailed usage guidelines for users., (© 2024. The Author(s).)

A whiplash injury can alter neck muscle function, which remains years after the injury and may explain why symptoms such as persistent pain and disability occur. There is currently limited knowledge about dynamic neck muscle function in chronic whiplash-associated disorders (WAD), and about the extent to which altered muscle function can improve after rehabilitation. Ultrasound can detect mechanical neck muscle function by measuring real-time deformation and deformation rate in the muscles. This method was used for five dorsal neck muscles in participants with chronic WAD versus matched controls in resistant neck rotation. We obtained real-time, non-invasive ultrasound measurements using speckle tracking, multivariate analyses, and mixed-design ANOVA analyses. The results showed altered deformation in the three deepest neck muscle layers, with less deformation area in the WAD group compared to controls in rotation to the most painful side at baseline. Participants in the WAD group performed three months of neck-specific exercises, resulting in improved deformation in the deep neck muscles in WAD and with a similar deformation pattern to controls, and the significant group differences ceased. We reveal new and important insights into the capability of ultrasound to diagnose altered neck muscle function and evaluate an exercise intervention., (© 2024. The Author(s).)

Background: Myofascial Trigger Points (MTrPs) play a significant role in the pathogenesis of Tension Type Headache (TTH). Abnormal cranio-cervical posture has been linked to various types of headaches. However, the correlation between MTrPs sensitivity, cervical postural alignment, and clinical measures of headache has not been extensively studied in patients with TTH., Objectives: To investigate the relationship between MTrPs sensitivity in cervical and pericranial muscles, cervical postural abnormality, and clinical headache parameters in patients with TTH. Furthermore, to investigate the effect of sex on the examined variables and their association with headache type (episodic vs chronic TTH)., Methods: A total of 72 patients with TTH of both sexes were enrolled in this study. Headache frequency and disability as clinical measures of headache, pressure pain threshold (PPT) of bilateral upper trapezius (UT) and suboccipital (SUB) muscles, cervical lordosis angle (CA), and anterior head translation (AHT) were measured., Results: Pericranial MTrPs sensitivity did not demonstrate any correlation with clinical headache parameters or cervical postural abnormality. However, there was a significant correlation between the frequency of headaches and the level of disability ( r  = 0.32, P  < 0.05). In addition, episodic TTH was more prevalent in females who exhibited greater AHT and MTrPs sensitivity of both bilateral UT and right SUB muscles than males., Conclusions: There was no correlation found between the frequency of headaches and the level of disability with measures of cervical posture alignment or MTrPs sensitivity in individuals with TTH.. Based on findings, Clinicians should consider sex differences when assessing patients with TTH.

Objective: To evaluate neck muscle coactivation across different levels of mental workload during simulated flight tasks., Background: Neck pain (NP) is highly prevalent among military aviators. Given the complex nature within the flight environment, mental workload may be a risk factor for NP. This may induce higher levels of neck muscle coactivity, which over time may accelerate fatigue, increase neck discomfort, and affect flight task performance., Method: Three counterbalanced mental workload conditions represented by simulated flight tasks modulated by interstimulus frequency and complexity were investigated using the Modifiable Multitasking Environment (ModME). The primary measure was a neck coactivation index to describe the neuromuscular effort of the neck muscles as a system. Additional measures included perceived workload (NASA TLX), subjective discomfort, and task performance. Participants ( n = 60; 30M, 30F) performed three test conditions over 1 hr each while seated in a simulated seating environment., Results: Neck coactivation indices (CoA) and subjective neck discomfort corresponded with increasing level of mental workload. Average CoAs for low, medium, and high workloads were: .0278(SD = .0232), .0286(SD = .0231), and .0295(SD = .0228), respectively. NASA TLX mental, temporal, effort, and overall scores also increased with the level of mental workload assigned. For ModME task performance, the overall performance score, monitoring accuracy, and resource management accuracy decreased while reaction times increased with the increasing level of mental workload. Communication accuracy was lowest with the low mental workload but had higher reaction times relative to increasing workload., Conclusion: Mental workload affects neck muscle coactivation during combinations of simulated flight tasks within a simulated helicopter seating environment., Application: The results of this study provide insights into the physical response to mental workload. With increasing multisensory modalities within the work environment, these insights may assist the consideration of physical effects from cognitive factors.

Video head impulse tests (video-HITs) are commonly used for vestibular evaluation; however, the results can be contaminated by various artifacts, including technical errors, recording problems, and participant factors. Although video-HITs can be used in patients with Parkinson's disease (PD), the effect of neck rigidity has not been systematically investigated. This study aimed to investigate the effect of neck rigidity on video-HIT results in patients with PD. We prospectively recruited 140 consecutive patients with PD (mean age ± standard deviation = 68 ± 10 years, 69 men) between September 2021 and April 2024 at Korea University Medical Center. The video-HIT results were compared with those of 19 age- and sex-matched healthy participants. Neck rigidity was stratified as a subdomain of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale motor part (MDS-UPDRS-III). In 59 patients, the vestibulo-ocular reflex (VOR) gain was overestimated in at least one canal plane (58/140, 41%), mostly in the anterior canal (AC, n = 44), followed by the horizontal (HC, n = 15) and posterior canals (PC, n = 7). VOR gain overestimation was also observed in patients with no (18/58, 35%), subtle (20/58, 34%), or mild (17/58, 29%) neck rigidity. Multivariable logistic regression analysis showed that VOR overestimation was positively associated with neck rigidity (odds ratio [OR] [95% confidence interval] = 1.51 [1.01-2.25], p = 0.043). The head velocities of patients decreased during head impulses for the AC (p = 0.033 for the right AC; p = 0.014 for the left AC), whereas eye velocities were similar to those of healthy participants. Our findings suggest that neck rigidity may be a confounder that can contaminate video-HIT results. Thus, the results of video-HITs, especially for the AC, should be interpreted with the context of head velocity during head impulses in patients with neck rigidity., (© 2024. Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To compare the effects of a neck-specific exercise programme with internet support and 4 physiotherapist sessions (NSEIT) and the same neck-specific exercises supervised by a physiotherapist (NSE) on neck muscle endurance and cervical range of motion., Design: Randomized controlled trial., Patients: A total of 140 participants with chronic whiplash-associated disorders grade II or grade III were randomly assigned to the NSEIT or NSE groups., Methods: Outcomes were changes in active cervical range of motion, cranio-cervical flexion test, neck muscle endurance, and neck pain, at 3- and 15-month follow-ups., Results: There were no significant differences between the NSEIT and NSE groups. There was a significant group-by-time inter-action effect in active cervical range of motion flexion/extension where the NSEIT group improved to 3-month follow-up, but the NSE group did not. Both groups were significantly improved over time in all other outcomes (p < 0.001) at 3- and 15-month follow-ups, with effect size between 0.64 and 1.35 in active cervical range of motion, cranio-cervical flexion test, dorsal neck muscle endurance, and neck pain, and effect size between 0.22 and 0.42 in ventral neck muscle endurance., Conclusion: Both NSE and NSEIT led to improved neck function. Depending on the patients' needs, either NSE or NSEIT could be used as treatment for patients with chronic whiplash-associated disorders.

Background: Text neck syndrome is an overuse condition that has become a global problem for all ages who use smartphones. Although therapeutic approaches are used to manage text neck syndrome, relatively little evidence exists on efficacy. This study aimed to investigate the effects of proprioceptive neuromuscular facilitation (PNF) techniques on individuals with text neck syndrome., Methods: Thirty-eight participants with text neck syndrome were randomly allocated to either the experimental or control group. Both groups performed the program including cervical range of motion, strengthening, and posture correction exercises for 6 weeks, 3 days a week, once a day for 10 repetitions. In the experimental group were included in a PNF program 3 days a week for 6 weeks. In the program, contract-relax and replication techniques were used. Pain intensity, cervical range of motion, cervical muscles' endurance, posture, and disability were assessed. Outcome measures were assessed at baseline and after 6 weeks., Results: Pain intensity, neck muscle endurance tests, posture, and disability scores significantly improved in both groups (P < .05). The cervical range of motion values in all directions were significantly increased only in the experimental group (P < .05). The improvements in pain intensity, neck muscle endurance tests, posture, and disability scores were greater in the experimental group compared with the control group (P < .05)., Conclusion: PNF could be used effectively to reduce neck pain and disability level and enhance cervical range of motion, cervical muscles' endurance, and posture in individuals with text neck syndrome., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: To investigate whether a combination of dry-needling treatments and upper extremity neuromuscular reeducation exercises can significantly improve neck pain and/or headache-related disability, joint position error, cervical range of motion, and pain pressure threshold in individuals suffering from cervicogenic headache (CGH)., Methods: This study is a quasi-experimental design. Seven participants met the inclusion criteria and received dry needling to three muscles that reproduced the participant's headache symptoms and completed the Neck Disability Index (NDI), Headache Disability Inventory (HDI), Visual Analog Scale (VAS), and Numeric Pain Rating Scale (NPRS). Participants performed an exercise regimen designed to address strength and mobility of cervical and scapulothoracic musculature., Results: There were significant improvements seen in cervical range of motion and neck pain-related disability (NDI) during the 4-week treatment period., Conclusion: Dry needling and neuromuscular re-education (NMR) exercises could be effective components of treatment for individuals suffering from CGH to reduce disability and pain.

Abstract: Medical provider's ability to detect, diagnose, and treat sport-related concussion has greatly improved in recent years. Although more is known about the biomechanical forces involved in concussion, it is still uncertain whether there are preventative measures athletes can take to prevent a sport-related concussion from occurring. The objective of this review was to determine if either neck size or neck strength is related to a decreased risk of sustaining a sport-related concussion. A literature review was conducted on Google Scholar and Ovid MEDLINE for pertinent articles. Findings indicate that isometric neck strength, but not neck size, has been shown to be a predictor for sport-related concussion prevention. Formal neck strengthening programs are feasible and lead to decreased sport-related concussion risk. Additionally, there may be greater opportunity to increase neck strength in amateur athletes compared to professional. In conclusion, cervical strengthening programs have been shown to be feasible and beneficial for athletes to decrease their risk of sustaining a sport-related concussion, though the optimal duration, intensity, and frequency has yet to be determined., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: The objectives were to compare forward head posture (FHP) in natural and corrected head postures between patients with nonspecific neck pain (NSNP) and controls and to clarify the relationship between natural and corrected head posture angle differences and deep cervical flexor function. This study aimed to provide useful evidence for postural assessment and treatment in patients with NSNP., Methods: In this cross-sectional study, 19 patients with NSNP reporting a pain score of 3-7 for at least 3 months and 19 participants with no neck pain within the previous 12 months were recruited. To evaluate FHP, the cranial rotation and vertical angles were measured using lateral head and neck photographs. The craniocervical flexion test was used to evaluate deep cervical flexor activation and endurance. We evaluated the head and neck alignment in natural and corrected head postures and the relationship between the degree of change and deep cervical flexor function., Results: FHP in the natural head posture did not differ between groups. In the corrected head posture, FHP was significantly smaller in the NSNP group than in the control group. In the NSNP group, the cranial rotation and vertical angles were significantly different between the natural and corrected head postures, and the angle difference correlated significantly with deep cervical flexor function., Conclusions: Patients with NSNP show hypercorrection in the corrected head posture, which may be correlated with deep cervical flexor dysfunction. Further investigation into the causal relationship between hypercorrection, deep neck flexor dysfunction, and neck pain is required., Competing Interests: Declaration of Competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The study examined how neck muscle imbalance and plagiocephaly affect the lying and rolling activities in 118 infants aged 4 to 6 months with postural torticollis. Outcome measures included age, sex, cervical movement, and plagiocephaly severity. Neck muscle function was assessed with the Muscle Function Scale (MFS), and infant motor abilities in lying and rolling were evaluated through the corresponding dimensions of the Gross Motor Function Measure (GMFM). Multiple regression analysis showed that a better MFS score of the affected neck was significantly associated with improved lying and rolling activities in the GMFM ( p  < .01), and importantly, the interaction between the plagiocephaly and the MFS scores of the affected neck muscle in these activities was found to be significant ( p  < .05). These results highlight the need for early intervention in infants with torticollis to address muscle imbalance and plagiocephaly, crucial for early motor development (KCT0008367).

Introduction: Cervical dystonia is defined by excessive contraction of muscles that produce abnormal postures and movements of the head, neck, and sometimes the shoulders. Many affected individuals also have pain, local muscle hypertrophy, and/or abnormally increased EMG activity. However, abnormal movements are considered the defining feature., Cases: Three cases are described suggesting that some features of cervical dystonia may occur without abnormal movements. In these cases, the only clinical features are pain, local muscle hypertrophy, or abnormal EMG activity. These features may occur years before abnormal movements emerge, or they may occur coincidentally with dystonia affecting regions other than the neck. In some cases, some features associated with cervical dystonia may occur without any obvious abnormal movements., Conclusions: Some symptoms of cervical dystonia may occur without abnormal movements of the head or neck. The purpose of this report is not to question current diagnostic criteria for cervical dystonia, but to call attention to a phenomenon that deserves further attention. Such cases may be considered to have a pro-dromal form of cervical dystonia or a formes fruste of cervical dystonia. Whatever diagnostic label is applied, the phenomenon is important to recognize, because symptoms may be readily alleviated with botulinum toxin., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Disorder of consciousness (DOC) is a state of prolonged altered consciousness due to severe acquired brain injury (ABI). DOC can be differentiated into coma, unresponsive wakefulness syndrome (UWS), or minimally conscious state (MCS) depending on the behavioral features observed and their relationship to the level of consciousness. Spasticity is one of the most frequently reported medical comorbidities in DOC patients. Since there is a critical lack of spasticity-focused studies and, in turn, of target treatment, we designed this pilot prospective study to evaluate cervical spine muscle spasticity and its effect on rehabilitation outcome in a large cohort of patients followed from the post-acute phase to 6 months after severe ABI., Aim: To evaluate neck muscle spasticity and investigate its impact on neurological and functional outcome in a large cohort of adult patients with DOC followed from post-acute to 6 months after severe ABI., Design: Single-center prospective pilot study., Setting: Highly specialized inpatient neurorehabilitation clinic., Population: Patients with severe ABI admitted within 3 months after the acute event to our Neurorehabilitation Unit between May 21 st , 2019 and April 23 rd , 2020 for treatment of DOC as a part of their rehabilitation program., Methods: In this single-center prospective pilot study demographic data, etiology of ABI (traumatic versus non-traumatic), DOC evaluated with the revised Coma Recovery Scale (CRS-R), and neurological and functional outcome assessed respectively with the Glasgow Coma Scale (GCS) and Functional Independence Measure (FIM) were considered. During cervical examination, we assessed spasticity with the Modified Ashworth Scale (MAS), deviation of head alignment with a goniometer, and pain with the Nociception Coma Scale-Revised (NCS-R)., Results: Of the 48 patients, 41.7% were diagnosed with UWS and 58.3% were in a minimally conscious state (MCS). We found spasticity of neck muscles in 91.7% of patients, with no difference in severity (assessed with MAS) between UWV and MCS. The NCS-R score at cervical spine examination was lower in UWS than MCS. Spasticity was severer in patients with traumatic brain injury (TBI) compared to non-traumatic. At multiple linear regression analysis, younger age, hemisyndrome, and tetraparesis were independent predictors of severity of neck muscle spasticity in MCS. More severe spasticity was a predictor of worse neurological and functional outcome at discharge in UWS patients, independently of the other confounding variables at admission (e.g., age, severity of brain injury, functional assessment, and pain)., Conclusions: Spasticity of neck muscles frequently develops in patients with DOC and is more severe in those after TBI. UWV and MCS have different spasticity profiles as regards risk factors and neurological and functional outcome. Severity of neck muscle spasticity in UWV patients may represent an early indicator of worse neurological and functional outcome after inpatient rehabilitation., Clinical Rehabilitation Impact: Our findings could prompt clinicians to redefine the rehabilitation aims regarding spasticity and to estimate the functional outcome in patients undergoing intensive rehabilitation after severe ABI.

Background and Objectives : Physiotherapy approaches are used to eliminate the problems caused by cervicogenic headache (CHA), known as secondary headache associated with the structures of the upper cervical region. This study aimed to investigate the effects of cervical mobilization (CM) with clinical Pilates exercises (CPE) on pain, muscle stiffness and head-neck blood flow in CGH. Materials and Methods : A total of 25 patients participated in this randomized controlled study and were randomized into either the CM group or the CM+CPE group. All treatment methods were applied 3 days a week for 6 weeks. The outcome measure was headache intensity and frequency, the number of analgesics, muscle stiffness and vertebral artery (VA) and internal carotid artery (ICA) blood flow. Headache intensity was measured by a visual analogue scale, muscle stiffness by a myotonometer and blood flow by Doppler US. Evaluations were repeated after 6 weeks of treatment. Within-group comparisons were made by the Wilcoxon signed rank test, and between-group comparisons were made by the Mann-Whitney U test. Results : After treatments in the two groups, headache intensity and frequency and the number of analgesics decreased, the muscle stiffness of the suboccipital, upper trapezius and sternocleidomastoid (SCM) muscles decreased, and the blood flow of the ICA and VA increased ( p < 0.05). There was a significant difference between the groups in terms of headache intensity ( p = 0.025) and muscle stiffness in SKM ( p = 0.044) in favor of the CM+CPE group. Conclusions : Non-pharmacological treatment approaches have an important role in CHA related to the upper cervical region. This study suggests that it would be beneficial to add CM in combination with CPE to the non-pharmacological treatment of patients with CHA.

Objective: Muscle dysfunction caused by repetitive work or strain in the neck region can interfere muscle responses. Muscle dysfunction can be an important factor in causing cervical spondylosis. However, there has been no research on how the biomechanical properties of the upper cervical spine change when the suboccipital muscle group experiences dysfunction. The objective of this study was to investigate the biomechanical evidence for cervical spondylosis by utilizing the finite element (FE) approach, thus and to provide guidance for clinicians performing acupoint therapy., Methods: By varying the elastic modulus of the suboccipital muscle, the four FE models of C0-C3 motion segments were reconstructed under the conditions of normal muscle function and muscle dysfunction. For the two normal condition FE models, the elastic modulus for suboccipital muscles on both sides of the C0-C3 motion segments was equal and within the normal range In one muscle dysfunction FE model, the elastic modulus on both sides was equal and greater than 37 kPa, which represented muscle hypertonia; in the other, the elastic modulus of the left and right suboccipital muscles was different, indicating muscle imbalance. The biomechanical behavior of the lateral atlantoaxial joint (LAAJ), atlanto-odontoid joint (ADJ), and intervertebral disc (IVD) was analyzed by simulations, which were carried out under the six loadings of flexion, extension, left and right lateral bending, left and right axial rotation., Results: Under flexion, the maximum stress in LAAJ with muscle imbalance was higher than that with normal muscle and hypertonia, while the maximum stress in IVD in the hypertonic model was higher than that in the normal and imbalance models. The maximum stress in ADJ was the largest under extension among all loadings for all models. Muscle imbalance and hypertonia did not cause overstress and stress distribution abnormalities in ADJ., Conclusion: Muscle dysfunction increases the stress in LAAJ and in IVD, but it does not affect ADJ., (© 2024. The Author(s).)

Clinical management of whiplash-associated disorders is challenging and often unsuccessful, with over a third of whiplash injuries progressing to chronic neck pain. Previous imaging studies have identified muscle fat infiltration, indicative of muscle weakness, in the deep cervical extensor muscles (multifidus and semispinalis cervicis). Yet, kinematic and muscle redundancy prevent the direct assessment of individual neck muscle strength, making it difficult to determine the role of these muscles in motor dysfunction. The purpose of this study was to determine the effects of deep cervical extensor muscle weakness on multi-directional neck strength and muscle activation patterns. Maximum isometric forces and associated muscle activation patterns were computed in 25 test directions using a 3-joint, 24-muscle musculoskeletal model of the head and neck. The computational approach accounts for differential torques about the upper and lower cervical spine. To facilitate clinical translation, the test directions were selected based on locations where resistance could realistically be applied to the head during clinical strength assessments. Simulation results reveal that the deep cervical extensor muscles are active and contribute to neck strength in directions with an extension component. Weakness of this muscle group leads to complex compensatory muscle activation patterns characterized primarily by increased activation of the superficial extensors and deep upper cervical flexors, and decreased activation of the deep upper cervical extensors. These results provide a biomechanistic explanation for movement dysfunction that can be used to develop targeted diagnostics and treatments for chronic neck pain in whiplash-associated disorders., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background/purpose: Differential screening is a complex process in chronic pain conditions. There is significant uncertainty that surrounds the pathophysiology of many chronic pain syndromes that may lead to misdiagnosis and treatment failures. Such differential screening is even more challenging where there is regional overlapping from surrounding tissues. This case report chronicles the differential screening and treatment of a patient with sternocleidomastoid syndrome (SCMS) originally diagnosed as Eagle's syndrome (ES)., Case Description: A 55-year-old woman, referred to a physical therapist (PT) by an ear, nose and throat (ENT) physician with the diagnosis of ES. The patient complained of yearlong left-sided otalgia, blurred vision, excessive lacrimation, dysphagia, hyperesthesia on the left side of the face, unilateral temporal headaches, and both left mandibular and anterior neck pain., Outcomes: The PT examination revealed the patient did not exhibit hallmark findings for clinical confirmation of ES and instead demonstrated multiple signs consistent with SCMS., Discussion: Manual therapy techniques and therapeutic exercises resolved the patient's year-long chronic symptoms within 6 sessions.

Background: The impact of computer typing in a slump posture on pain, proprioception and muscle recruitment has not been extensively investigated. Therefore, the purpose of this study was to evaluate the extent of pain, proprioception and muscle activity resulting from computer typing in a slump posture in women who already suffer from chronic neck pain., Methods: This cross-sectional study was conducted between May 20 to July 10, 2021. A total of 15 female 42-(±4.96)-year-old office workers with chronic non-specific neck pain participated in this study. Before and after 60 min of computer typing in a slump posture, proprioception and pain were measured using an inclinometer and visual analog scale (VAS), respectively. The activity of the cervical erector spine (CES) and upper trapezius (UT) muscle was also measured before and after the slump-posture computer typing, in upright, forward, and slump postures. RESU: lts: Paired-samples t-tests showed that pain was increased and proprioception in all directions (flexion, extension, right and left lateral flexion, and right, and left rotation) was less accurate (P < 0.05) after 60 min computer typing. The CES and UT muscle activity were elevated more in the forward head and slump posture than in the upright posture (P < 0.05)., Conclusion: Sixty minutes computer typing in a slump posture increased neck pain, resulted in a decreased proprioception in the neck and was accompanied by an increased activity of the neck musculature., Competing Interests: Declaration of competing interest There are no known conflicts of interest associated with this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Movement System Impairment (MSI) classification and treatment effectively diagnose and treat the individual with neck pain. There is a lacuna in the current neck pain management guidelines addressing movement-specific mechanical diagnosis. MSI is based on the movement-specific mechanical diagnosis and kinesiopathologic model., Purpose: The present study aimed to investigate the effectiveness of the movement system impairment model among neck pain individuals., Methods: This study was designed as a randomized controlled trial. Eighty-two participants were screened for eligibility; Sixty individuals fulfilling the inclusion criteria were randomized into the experimental group (n = 30) and control group (n = 30). A total of 52 individuals completed the study, 26 in both groups. The experimental and the control group received treatment as recommended by the MSI model and clinical practice guideline (CPG) for neck pain with mobility deficits. All participants were assessed for pain intensity, cervical range of motion, deep cervical muscle strength, endurance, and disability at baseline and the end of 3rd week of treatment., Results: Significant differences were found in pain intensity, cervical range of motion, cervical muscle strength, endurance, and disability with both groups at the end of 10 sessions of treatment spread over three weeks (p < 0.05). However, the experimental group (MSI) demonstrated more clinical benefits than CPG based neck mobility deficits treatment., Conclusion: The movement system impairment model may effectively diagnose and treat neck pain in individuals with mobility deficits. Future research is warranted to establish its long-term effect., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: There is a lack of information about the optimal setup of multiple screen configurations in virtual reality (VR) office work., Objective: The objective of this study was to evaluate the effects of different screen configurations on neck flexion, rotation, neck muscle activity, and simulator sickness symptoms during Virtual Reality (VR) office work., Methods: Twelve participants (7 males; 21 to 27 years old) performed copy-paste and drag-drop tasks in three different screen configurations (single screen, primary-secondary screen, and double screen) in a randomized order. Optical motion capture system, electromyography (EMG) device, and simulator sickness questionnaire (SSQ) were used to measure the users' responses., Results: Neck rotation angles, muscle activities, and VR sickness were significantly affected by the screen configurations (p < 0.021). The primary-secondary screen showed the highest right rotation angle (median: -33.47°) and left sternocleidomastoid (SCM) muscle activities (median: 12.57% MVC). Both single (median: 22.42) and primary-secondary (median: 22.40) screen showed the highest value of SSQ., Conclusions: The screen configurations in VR could be an important design factor affecting the users' physical demands of the neck and VR sickness symptoms. Asymmetric neck rotations caused by the primary-secondary screen conditions should be avoided.

Neck muscle weakness due to amyotrophic lateral sclerosis (ALS) can result in dropped head syndrome, adversely impacting the quality of life of those affected. Static neck collars are currently prescribed to hold the head in a fixed upright position. However, these braces are uncomfortable and do not allow any voluntary head-neck movements. By contrast, powered neck exoskeletons have the potential to enable head-neck movements. Our group has recently improved the mechanical structure of a state-of-the-art neck exoskeleton through a weighted optimization. To evaluate the effect of the structural changes, we conducted an experiment in which patients with ALS were asked to perform head-neck tracking tasks while using the two versions of the neck exoskeleton. We found that the neck muscle activation was significantly reduced when assisted by the structurally enhanced design compared to no assistance provided. The improved structure also improved kinematics tracking performance, allowing users to better achieve the desired head poses. In comparison, the previous design did not help reduce the muscle effort required to perform these tasks and even slightly worsened the kinematic tracking performance. It was also found that biomechanical benefits gained from using the structurally improved design were consistent across participants with both mild and severe neck weakness. Furthermore, we observed that participants preferred to use the powered neck exoskeletons to voluntarily move their heads and make eye contact during a conversation task rather than remain in a fixed upright position. Each of these findings highlights the importance of the structural design of neck exoskeletons in achieving desired biomechanical benefits and suggests that neck exoskeletons can be a viable method to improve the daily life of patients with ALS.

Objectives: To verify the rates of heat effectiveness generated by Carbon Nanotubes (CNT) in the resolution of dizziness in individuals diagnosed with Cervical Dizziness (CD)., Methods: Randomized clinical trial was performed and samples from volunteers diagnosed with CD, divided into a Study Group (SG) and Control Group (CG). Patches containing CNT with thermotherapeutic effect were used in SG and inert patches in the CG. Treatment was performed over 30 days and measures of pain, dizziness and asymmetry of cervical muscle tension were evaluated over 60 days., Results: Pain, dizziness and asymmetry of cervical muscle tension were reduced in the SG. The variables analyzed in this study did not change in the CG., Conclusion: Our results show that the therapeutic effect of heat was effective in the treatment of patients diagnosed with CD. We could also observe a clear interrelationship between pain and dizziness symptoms with the asymmetry of cervical muscle tension., Level of Evidence: 1B., (Copyright © 2023 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier España S.L.U. All rights reserved.)

Objective: To develop a multidimensional facial surface electromyographic (EMG) analysis for assessing bulbar involvement in amyotrophic lateral sclerosis (ALS)., Methods: Fifty-four linear and nonlinear features were extracted from the surface EMG recordings for masseter, temporalis, and anterior belly of digastric in 13 patients with ALS and 10 healthy controls, each performed a speech task three times. The features were factor analyzed and then evaluated in terms of internal consistency, relation to functional speech outcomes, and efficacy for patient-control classification., Results: Five internally consistent, interpretable factors were derived, representing the functioning of masseter, temporalis, digastric, antagonists, and agonists, respectively. These factors explained 40-43% of the variance in the functional speech outcomes and were ≥90% accurate in patient-control classification. The jaw muscle performance of individuals with ALS was characterized by (1) reduced complexity and coherence of antagonist muscle activities, and (2) increased complexity and irregularity of temporalis activity., Conclusions: Two important bulbar muscular changes were identified in ALS, related to both upper and lower motor neuron pathologies. These changes reflected (1) decreased motor unit recruitment and synchronization for jaw antagonists, and (2) a potential neuromuscular adaptation for temporalis., Significance: The surface EMG-based framework shows promise as an objective bulbar assessment tool., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

The purpose of this study was to investigate the effects of neck and shoulder pain (NSP) and the position of the head and neck on the intramuscular circulation of the cervical muscles such as the trapezius and levator scapulae muscles in young females. Ten NSP subjects (mean age: 20.9 ± 0.5 years) and ten non-NSP subjects (mean age: 20.6 ± 0.7 years) were recruited to this study. Near-infrared spectroscopy (NIRS) was used to non-invasively measure total haemoglobin (Total-Hb), oxygenated haemoglobin (Oxy-Hb), and deoxygenated haemoglobin (Deoxy-Hb) of the trapezius and levator scapulae muscles. The measurements of Total-Hb, Oxy-Hb, and Deoxy-Hb were taken in the neutral position, immediately after the maximally flexed (extended) position, and after 30 s in the maximally flexed (extended) position. In flexion, no significant main effect or interaction was observed with Total-Hb and Oxy-Hb. A significant interaction was observed with Deoxy-Hb (p < 0.01). There was no significant difference in the changes over time in the NSP group (p = 0.91). However, in the non-NSP group, a significant increase was noted at the neutral position to immediately after the maximally flexed position (p < 0.01) and at the end of maintaining the maximally flexed position (p < 0.01). In extension, no significant main effect or interaction was observed with Total-Hb and Oxy-Hb. A significant interaction was observed with Deoxy-Hb (p < 0.01). In the NSP group, no significant difference was observed in the changes over time (p = 0.91). In the non-NSP group, however, a significant decrease was observed from the neutral position to immediately after the maximally extended position (p < 0.01). The results of this study indicate that maintaining either maximal cervical flexion or extension may affect venous blood flow on non-NSP group. However, no effect on NSP group was observed due to existing diminished intramuscular circulation., (© 2022. Springer Nature Switzerland AG.)

Objective: The objective of this study was to synthesize the current evidence regarding the predictive ability of measures of physical function (PF) of the neck region and perceived PF on prognosis following a whiplash injury., Materials and Methods: Electronic databases were searched by 2 independent reviewers up to July 2020, including MEDLINE, EMBASE, CINAHL, PsycINFO, Scopus, and Web of Science as well as gray literature. Eligible studies were selected by 2 reviewers who then extracted and assessed the quality of evidence. Observational cohort studies were included if they involved participants with acute whiplash-associated disorders (WAD), followed for at least 3 months postinjury, and included objective measures of neck PF or self-reported measures of PF as prognostic factors. Data could not be pooled and therefore were synthesized qualitatively., Results: Fourteen studies (13 cohorts) were included in this review. Low to very low quality of evidence indicated that initial higher pain-related disability and higher WAD grade were associated with poor outcome, while there was inconclusive evidence that neck range of motion, joint position error, activity of the superficial neck muscles, muscle strength/endurance, and perceived functional capacity are not predictive of outcome. The predictive ability of more contemporary measures of neck PF such as the smoothness of neck movement, variability of neck motion, and coactivation of neck muscles have not been assessed., Discussion: Although initial higher pain-related disability and higher WAD grade are associated with poor outcome, there is little evidence available investigating the role of neck PF on prognosis following a whiplash injury., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background and Objectives: The main target of inspiratory muscle training (IMT) is to improve diaphragm function in patients with COPD who have inspiratory muscle weakness. Ventilatory demand is already increased during quiet breathing in patients with COPD, and whether threshold load imposed by IMT would active more accessory muscle remained to be determined. The purpose of this study was to examine diaphragm and sternocleidomastoid (SCM) activation during IMT with intensities of 30% and 50% maximal inspiratory pressure (P Imax )., Methods: Patients with COPD and a P Imax lower than 60 cmH 2 O were recruited for the study. Surface electromyography (EMG) was used to measure diaphragm and SCM activation, and group-based trajectory modeling (GBTM) was used to identify activation patterns during IMT. The generalized estimating equation (GEE) was then used to detect differences of variables between various breathing tasks. Statistical significance was established at p < 0.05., Results: A total of 30 patients with COPD participated in this study. All patients demonstrated significant increases in diaphragm and SCM activation during 30% and 50% P Imax of IMT than during quiet breathing (all p < 0.001). Diaphragm demonstrated two distinct patterns in response to IMT: low activation (n = 8) and high activation (n = 22) group using GBTM analysis., Conclusion: Diaphragm and SCM were substantially activated during IMT in patients with COPD who had inspiratory muscle weakness. Regardless of whether diaphragm activation was high or low, SCM was activated to a greater extent in response to IMT., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: To date, the histopathologic characteristics of dropped head syndrome (DHS) have not been reported sufficiently. The present study investigates the histopathology of biopsy specimens from the cervical paravertebral region in patients with DHS., Methods: Histopathological parameters were evaluated in biopsy specimens of the cervical paravertebral soft tissue from 15 patients with DHS., Results: Among the 15 cases of DHS examined, skeletal muscle was identified in 7 cases, all of which showed necrosis, microvessel proliferation and atrophy. The ligament was identified in 12 cases, 8 of which showed degeneration. The lag time between the onset of symptoms and the performance of a biopsy in all 8 cases, which showed degeneration was over 3 months. Microvessel proliferation in the ligament was observed in 1 of the 4 cases, in which the lag time between the onset of symptoms and the performance of a biopsy was less than 3 months (acute or subacute phase), and in 7 of the 8 cases, in which the lag time between the symptoms and the performance of a biopsy was over 3 months (chronic phase). Chronic inflammation in the ligament was identified in 1 of the 12 cases., Conclusions: The identification of necrosis, microvessel proliferation, and atrophy in the skeletal muscle of patients with DHS and the presence of ligament degeneration and microvessel proliferation in the chronic but not acute or subacute phases may suggest that persistent skeletal muscle damage of the cervical paravertebral region causes subsequent ligament damage in patients with DHS., (© 2021. The Author(s).)

Background: More than 40% of individuals with whiplash injury experience persistent neck pain and disability years later, called whiplash-associated disorders (WAD). A randomized controlled trial evaluated three exercise interventions in WAD and found that neck-specific exercise (NSE) and NSE with a behavioral approach (NSEB) significantly improve disability compared to prescribed physical activity (PPA). However, the relationship between neck-related function and disability is inconclusive and needs to be further investigated., Aim: The present study compares the effect of NSE, NSEB, and PPA on neck muscle endurance (NME), active cervical range of motion (AROM), grip strength, and pain intensity immediately before and after the physical tests, and neck disability in individuals who are below or above the cut-off for normative reference values regarding NME, AROM, and grip strength., Design: Follow-up to a multicenter randomized clinical trial., Setting: Primary healthcare centers and hospital outpatient services., Population: The selected population of this study included 216 patients with persistent WAD grades II and III., Methods: This is a secondary analysis including 12 months' follow-up. NME, AROM, grip strength, pain, and self-reported disability were recorded at baseline, 3, 6, and 12 months. Linear mixed models were used, and sub-group analyses evaluated by non-parametric tests., Results: NSE and NSEB resulted in greater improvements compared to PPA (P<0.01) in ventral (only males) and dorsal NME, AROM, and pain intensity during testing. We found no significant between-group differences in grip strength and no significant differences between the NSE and NSEB groups. Improvement in disability was seen at the 12-month follow-up of NSE and/or NSEB for individuals both below and above the cut-off reference values for NME and AROM. Individuals in the PPA group below the reference values for NME and AROM reported increasing disability at 12 months compared to baseline., Conclusions: The results suggest that neck-specific exercises (i.e., NSE, NSEB) improve clinical function and decrease disability in chronic WAD compared to PPA, but PPA can increase disability for patients with low neck-related function., Clinical Rehabilitation Impact: Higher neck-related function seems to be important for reduced disability in persistent WAD grades II and III. Neck-specific exercises could lead to higher neck-related function.

This study aimed to verify if migraine frequency or migraine-associated neck pain were associated with a reduction of normalized force and altered electromyographic activity during maximal cervical muscle isometric contractions. Additionally, it aimed to assess the correlation of normalized isometric force with years with migraine, headache frequency, headache intensity, migraine-related disability, and severity of cutaneous allodynia. The sample comprises 71 women with migraine (40/31 episodic/chronic, 42/18 with/without neck pain) and 32 women without headache. Cervical muscle isometric force in flexion, extension, and lateral flexion was assessed synchronized with the acquisition of superficial electromyography from the cervical muscles. Women with episodic migraine presented lower normalized isometric force in extension, flexion, and right and left lateral flexions than controls (P < 0.05). Women with migraine and neck pain exhibited lower cervical extension and right/left lateral-flexions normalized isometric force than controls (P < 0.05). No significant differences were observed in antagonist activity. Normalized isometric force in all directions showed weak to moderate correlations with the severity of self-reported symptoms of cutaneous allodynia (- 0.25 ≥ r ≥ - 0.39). No additional linear correlation with clinical migraine features was observed. In conclusion, cervical muscle weakness may be associated with episodic migraine and neck pain concurrent with migraine attacks without altered antagonist activity. Additionally, it may also be related to the severity of cutaneous allodynia., (© 2021. The Author(s).)

Chronic neck pain (CNP) incidence in the general population is high and contributes to a significant health problem. Kinesiophobia (fear of pain to movement or re-injury) combined with emotions and physical variables may play a vital role in assessing and managing individuals with CNP. The study's objectives are 1) to evaluate the relationship between kinesiophobia, neck pain intensity, proprioception, and functional performance; 2) to determine if kinesiophobia predicts pain intensity, proprioception, and functional performance among CNP individuals. Sixty-four participants with CNP (mean age 54.31 ± 9.41) were recruited for this cross-sectional study. The following outcome measures were evaluated: Kinesiophobia using the Tampa Scale of Kinesiophobia (TSK), neck pain intensity using the visual analog scale (VAS), cervical proprioceptive joint position errors (in flexion, extension, and rotation directions) using cervical range of motion (CROM) device and handgrip strength as a measure of functional performance using the Baseline® hydraulic hand dynamometer. Kinesiophobia showed a strong positive correlation with neck pain intensity (r = 0.81, p<0.001), a mild to a moderate positive correlation with proprioception joint position errors (JPE) in extension, rotation left and right directions (p<0.05), but no correlation in flexion direction (p = 0.127). Also, there was a moderate negative correlation with handgrip strength (r = -0.65, p<0.001). Regression analysis proved that kinesiophobia was a significant predictor of pain intensity, proprioception, and functional performance (p<0.05). This study infers that kinesiophobia in individuals with CNP predicts pain, proprioception, and functional performance. Kinesiophobia assessment should be considered in regular clinical practice to understand the barriers that can influence rehabilitation outcomes in CNP individuals., Competing Interests: No authors have competing interests.

Active neck musculature plays an important role in the response of the head and neck during impact and can affect the risk of injury. Finite element Human Body Models (HBM) have been proposed with open and closed-loop controllers for activation of muscle forces; however, controllers are often calibrated to specific experimental loading cases, without considering the intrinsic role of physiologic muscle reflex mechanisms under different loading conditions. This study aimed to develop a single closed-loop controller for neck muscle activation in a contemporary male HBM based on known reflex mechanisms and assess how this approach compared to current open-loop controllers across a range of impact directions and severities. Controller parameters were optimized using volunteer data and independently assessed across twelve impact conditions. The kinematics from the closed-loop controller simulations showed good average CORA rating to the experimental data (0.699) for the impacts following the ISO/TR9790 standard. Compared to previously optimized open-loop activation strategy, the average difference was less than 9%. The incorporation of the reflex mechanisms using a closed-loop controller can provide robust performance for a range of impact directions and severities, which is critical to improving HBM response under a larger spectrum of automotive impact simulations., (© 2021. Biomedical Engineering Society.)

Neuromuscular impairments are frequently observed in patients with chronic neck pain (CNP). This study uniquely investigates whether changes in neck muscle synergies detected during gait are sensitive enough to differentiate between people with and without CNP. Surface electromyography (EMG) was recorded from the sternocleidomastoid, splenius capitis, and upper trapezius muscles bilaterally from 20 asymptomatic individuals and 20 people with CNP as they performed rectilinear and curvilinear gait. Intermuscular coherence was computed to generate the functional inter-muscle connectivity network, the topology of which is quantified based on a set of graph measures. Besides the functional network, spectrotemporal analysis of each EMG was used to form the feature set. With the use of Neighbourhood Component Analysis (NCA), we identified the most significant features and muscles for the classification/differentiation task conducted using K-Nearest Neighbourhood (K-NN), Support Vector Machine (SVM), and Linear Discriminant Analysis (LDA) algorithms. The NCA algorithm selected features from muscle network topology as one of the most relevant feature sets, which further emphasize the presence of major differences in muscle network topology between people with and without CNP. Curvilinear gait achieved the best classification performance through NCA-SVM based on only 16 features (accuracy: 85.00%, specificity: 81.81%, and sensitivity: 88.88%). Intermuscular muscle networks can be considered as a new sensitive tool for the classification of people with CNP. These findings further our understanding of how fundamental muscle networks are altered in people with CNP., Competing Interests: The authors have declared that no competing interests exist.

Motor tics are sudden, rapid, recurrent, non-rhythmic movements. There is a lack of quantitative assessment methods for the motor tics despite severe neck complications. We aimed to provide an improved quantitative method for neck tic assessment in motor tic disorders. We recorded neck motor tics in patients with motor tic disorders and voluntary neck movements in healthy controls. The maximum peak angular velocities and angular accelerations were calculated. Motor tics were assessed in three orthogonal planes (yaw, pitch, and roll) separately, and compared between the patients with motor tic disorders and controls. Correlations between the maximum angular velocities/accelerations and tic counts were also assessed. In the pitch plane, motor tics of the patients showed higher angular velocities/accelerations than voluntary movements of the controls. Angular acceleration in the yaw, and roll planes showed positive correlations with tic count. Some of the observed tics were comparable to the movements experienced in contact sports. Our findings may aid in the identification of populations at a high risk for severe neck complications among motor tic disorder patients., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To identify how frequently the neck pain associated with migraine presents with a pattern of cervical musculoskeletal dysfunction akin to cervical musculoskeletal disorders, and to determine if pain hypersensitivity impacts on cervical musculoskeletal function in persons with migraine., Background: Many persons with migraine experience neck pain and often seek local treatment. Yet neck pain may be part of migraine symptomology and not from a local cervical source. If neck pain is of cervical origin, a pattern of musculoskeletal impairments with characteristics similar to idiopathic neck pain should be present. Some individuals with migraine may have neck pain of cervical origin, whereas others may not. However, previous studies have neglected the disparity in potential origins of neck pain and treated persons with migraine as a homogenous group, which does not assist in identifying the origin of neck pain in individuals with migraine., Methods: This cross-sectional, single-blinded study was conducted in a research laboratory at the University of Queensland, Australia. Persons with migraine (total n = 124: episodic migraine n = 106, chronic migraine = 18), healthy controls (n = 32), and persons with idiopathic neck pain (n = 21) were assessed using a set of measures typically used in the assessment of a cervical musculoskeletal disorder, including cervical movement range and accuracy, segmental joint dysfunction, neuromuscular and sensorimotor measures. Pain hypersensitivity was assessed using pressure pain thresholds and the Allodynia Symptom Checklist. People with migraine with diagnoses of comorbid neck disorders were excluded. Cluster analysis was performed to identify how participants grouped on the basis of their performance across cervical musculoskeletal assessments. Post hoc analyses examined the effects of pain hypersensitivity on musculoskeletal function, and if any symptoms experienced during testing were related to musculoskeletal function., Results: Two distinct clusters of cervical musculoskeletal function were found: (i) neck function similar to healthy controls (n = 108) and (ii) neck dysfunction similar to persons with neck pain disorders (n = 69). Seventy-six of the individuals with migraine (62 with neck pain and 14 without neck pain) were clustered as having normal cervical musculoskeletal function, whereas the remaining 48 with neck pain had cervical dysfunction comparable with a neck disorder. Musculoskeletal dysfunction was not related to pain hypersensitivity or symptoms experienced during testing., Conclusions: Neck pain when present with migraine does not necessarily indicate the existence of cervical musculoskeletal dysfunction. Skilled assessment without reliance only on the person reporting symptoms is needed to identify actual cervical dysfunction. Treatments suitable for neck musculoskeletal disorders would seem inappropriate for the individuals without cervical dysfunction. Future studies evaluating any potential effects of such treatments should only select participants with neck pain of cervical origin., (© 2021 American Headache Society.)

Objective: To evaluate the reliability and validity of clinical tests for measuring cervical muscle strength or endurance in participants with and without neck pain., Data Source: Systematic review and meta-analysis on reliability and validity. Literature search was conducted on January 28, 2020, using 5 databases: MEDLINE, Cumulative Index to Nursing and Allied Health, EMBASE, SPORTDiscus, and Scopus., Study Selection: We included studies that investigated the reliability or validity of clinical tests for measuring cervical muscle strength or endurance in participants with nonspecific chronic neck pain, with or without irradiation, or healthy participants. We included only those that were viable for daily practice and of low cost., Data Extraction: Data were extracted as follows: (1) author and year of publication, (2) demographic values and health condition, (3) reported clinical tests, (4) inclusion and exclusion criteria, (5) description of test, (6) interrater reliability, and (7) intrarater reliability. For validity studies we also extracted the (8) reference method and (9) validity estimates., Data Synthesis: Methodological quality was assessed with the Quality Appraisal of Diagnostic Reliability and the Guidelines for Reporting Reliability and Agreement Studies. Data on reliability and validity were extracted from included articles and then analyzed., Results: Thirty-one studies were included. Cervical flexor and extensor endurance test, craniocervical flexion test (CCFT), AND cervical muscle strength using a handheld dynamometer (HHD) showed moderate to good intra- and interrater reliability (intraclass correlation coefficients ranging from 0.64-0.90). Concurrent validity was measured by only 2 studies, which do not provide adequate evidence for a recommendation., Conclusions: The cervical flexor and extensor endurance tests, CCFT, and HHD for measuring cervical strength presented an acceptable interrater and intrarater reliability., (Copyright © 2021 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Background: Cervical mobilisations are used to treat people with neck pain but their mechanisms of action are unclear. One theorised reason for induced analgesia is effect on neck muscle activity., Objectives: To assess the effects of cervical mobilisations on muscle activity during active neck movements and whether changes in muscle activity are associated with changes in symptoms., Design: Double-blind randomised placebo controlled trial., Setting: Primary care., Participants: 40 patients (aged 19 to 80 years, 24 female) with non-specific neck pain., Interventions: One session of cervical mobilisations or motionless manual contact (placebo)., Main Outcome Measures: sternocleidomastoid (SCM), scalene (SCA), upper trapezius (UT) and erector spinae (ES) surface electromyography (SEMG) during active neck flexion, extension, side flexion and rotation was measured immediately before and after the intervention. Patients were classified as responders according to change in symptoms assessed using the Global Rating of Change Scale (GROC)., Results: Compared with placebo, patients receiving mobilisation showed an increase in contralateral UT and ES SEMG during rotation and contralateral and ipsilateral SCM, SCA and UT during side flexion (P<0.05), however changes were mostly associated with an increase in range and speed of movement. The only association with GROC was increased (5%) SEMG in the contralateral SCM during side flexion in the mobilisation group (P=0.013)., Conclusion: Cervical mobilisations caused increased neck SEMG, mostly due to increased movement range and speed. Change in muscle activity is unlikely to be a major mechanism of action of cervical mobilisations in symptomatic improvement with physiological neck movements. (ClinicalTrials.gov record number: 2016/066)., Clinical Trials Registry: ClinicalTrials.gov record number: 2016/066., (Copyright © 2019 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.)

There is a lack of studies comparing the effects of different exercise types in patients with thoracic hyperkyphosis. Twenty-four subjects were divided into three groups: corrective exercise, resistance exercise, and physical therapy. The groups performed their respective interventions, two times per week for three months. Clinical outcomes, including the value of Cobb's angle, cervical muscle strength and endurance, and the cross-sectional area of the cervical deep muscles were measured pre- and post-intervention. There was a significant difference in the changes in the thoracic Cobb's angle between the groups (P < 0.001). The corrective exercise group revealed a significantly superior increase in muscle strength and endurance between pre- and post-intervention (P < 0.012). There was a significant difference in the cross-sectional area of the cervical deep muscles included longus capitis and multifidus between the groups (P < 0.036 and 0.007, respectively). The corrective exercise group showed the most significant increase in cross-sectional area between pre- and post-intervention (P < 0.012). A corrective exercise program is a more effective intervention than traditional resistance exercise and physical therapy for improving the thoracic Cobb's angle, cervical muscle strength and endurance, and the cross-sectional area of the deep muscles in patients with thoracic hyperkyphosis.Trial registration: KCT0005292.

Background: Despite previous reports supporting cervical muscle weakness and altered motor control in migraine, the endurance under standardized submaximal loads has not been investigated. Therefore, this study aimed to assess the endurance and muscle activity of the cervical musculature during submaximal isometric contractions in women with migraine and those without headache., Methods: Cervical muscle endurance tests were performed for flexors and extensors at 25%, 50%, and 75% of the output force during maximal isometric contraction using the Multi-Cervical Rehabilitation Unit with customized biofeedback. Initial values and relative rates of changes in root mean square and median frequency were calculated using cervical muscle superficial electromyography., Findings: Women with chronic migraine presented significantly shorter flexor endurance time in all load tests than controls (25%, P = .001, 50%, P = .005; 75%, P = .013), while episodic migraine only differed from controls at 75% (P = .018). The frequency of neck pain and/or pain referred to the head after the endurance test was up 12% in the control group, 40% in the episodic migraine group and 68% of the chronic migraine group. Few differences between groups were observed in the electromyographic variables and none of them was related to a worse performance in the endurance tests., Interpretation: Cervical flexor endurance was reduced in women with chronic migraine when independent of the load, whereas it was reduced to 75% of the maximal force in those with episodic migraine. No difference in the electromyographic variables could be related to this reduced flexor endurance. Also, no differences were detected in extensors endurance., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Neck pain (NP) is a common work-related disorder, with high prevalence in the profession of teaching. The daily duties of a school teacher involve head-down postures while reading and writing, which expose them to the risk of developing NP. Deep cervical flexor (DCF) muscles have been reported to have lower endurance in patients with cervical impairment, which has additionally been associated with disability. There is limited evidence regarding the efficacy of training of DCF muscles in occupational NP. The objective of this study was to investigate the effects of DCF muscle training on pain, muscle endurance, and functional disability using pressure biofeedback in school teachers with NP., Methods: Sixty-five teachers (age, 25-45 years) with more than 5 years of teaching experience participated in this study. They were randomly divided into two groups: the experimental (E) and control (C) groups. In the E group, the subjects underwent DCF muscle training using pressure biofeedback in addition to conventional exercises for neck pain, while those in the C group underwent conventional exercises only. Pain, muscle endurance, and disability were measured at day 0 (before the treatment) and days 14 and 42 after the treatment. Endurance of DCF muscles was measured by the craniocervical flexion test using pressure biofeedback, pain intensity was measured using the numeric pain rating scale, and functional disability was assessed using the neck disability index questionnaire. This study was performed in accordance with CONSORT guidelines., Results: On day 0, there were no significant differences in the age, pain, muscle endurance, and disability levels between the groups. After initiating the intervention, although there were improvements in both groups, there was a statistically significant improvement in muscle endurance, pain, and disability in subjects who received additional training with pressure biofeedback., Conclusions: Besides increasing muscle endurance, specific training of DCF muscles in addition to conventional exercises can improve neck pain and functional disability. These results should be further correlated clinically. A dedicated time for exercises at school could help prevent the development of NP in teachers. This trial is registered with ClinicalTrials.gov NCT03537300 May 24, 2018 (retrospectively registered)., Competing Interests: The authors declare that they have no conflict of interest., (Copyright © 2021 Zaheen A. Iqbal et al.)

Background: The cervical flexion relaxation phenomenon (FRP) is a myoelectric silence of neck extensor muscles which occurs after a certain degree of flexion. Impaired flexion relaxation can impose the vertebral structures to excessive loading resulting from the persistence of muscular contraction., Objective: This study aimed to investigate the incidence or absence of FRP in cervical erector spinae (CES) and upper trapezius muscles in patients with chronic neck pain (CNP)., Methods: Twenty-five patients with CNP and 25 healthy volunteers were recruited. They accomplished cervical flexion and extension from a neutral position in four phases in the sitting position. The surface electromyography activity of both CES and upper trapezius muscles was recorded in each phase. Cervical flexion and extension movements were simultaneously measured using an electrogoniometer., Results: FRP in CES was observed in 84% and 36% of healthy subjects and CNP patients, respectively. Flexion relaxation ratio (FRR) in CES was lower in CNP patients than in healthy subjects (mean diff = 1.33; 95% CI: 0.75-1.91) (P< 0.001). Only in CNP patients, FRR in right erector spinea was significantly higher than that in the left erector spinea (P= 0.04)., Conclusions: FRP incidence in CNP patients was less than in healthy subjects. Moreover, this phenomenon begins later in CNP patients than in healthy subjects indicating prolonged activity of CES muscles during flexion in the CNP group. The difference between FRR in the right and left sides of erector spinea muscles can result in CNP.

Background: The aim of this study was to establish reference jitter values for the voluntary activated sternocleidomastoid (SCM) muscle using a concentric needle electrode (CNE)., Methods: The study included 39 healthy participants (20 female and 19 male) aged 18-77 y. Jitter was expressed as the mean consecutive difference (MCD) of 80-100 consecutive discharges. Filters were set at 1 and 10 kHz. The mean MCDs for all participants were pooled, and the mean value +2.5 SD was accepted as the upper limit for the mean MCD. The upper limit for individual MCD was calculated using +2.5 SD of the upper 10th percentile MCD for individual participants., Results: Mean age of the participants was 45 ± 14.5 y. Mean MCD was 16.20 ± 2.23 μs (range: 12-21 μs), and the upper limit of normal for mean MCD was 21.8 μs. The mean value for 823 individual jitters was 23.3 ± 4.61 μs (range: 6.6-36.9 μs), and the upper limit of normal for each individual jitter was 34.6 μs., Conclusions: The present findings indicate that upper normal limit for mean MCD is 22 μs and for individual data it is 35 μs., (© 2020 Wiley Periodicals LLC.)

Objective: The purpose of this study was to examine associations between the degree of central sensitization (CS) and remote muscle performance in people with chronic low back pain (CLBP)., Methods: The 2011 fibromyalgia (FM) criteria and severity scales (2011 FM survey) were used as a surrogate measure of CS to divide the participants into 2 groups: FM-positive CLBP and FM-negative CLBP. Measures related to central sensitization included the 2011 FM survey and pressure pain threshold of the thumbnail. Measures related to muscle performance included neck flexor muscle strength and endurance and plantar flexor muscle strength. Between-groups and correlation analyses were performed., Results: Sixty people with CLBP were enrolled (30 FM-positive, 30 FM-negative). There was no significant difference between the subgroups in age, sex, or pain duration (P > .05). The FM-positive CLBP group showed poorer neck flexor muscle endurance (P = .01) and plantar flexor muscle strength (P = .002) than the FM-negative CLBP group, whereas neck flexor muscle strength was not different between the groups (P = .175). Scores for FM and values for pressure pain thresholds of the thumbnail were associated with neck flexor muscle strength (respectively, r = -0.320, P = .013, and r = 0.467, P < .001), endurance (r = -0.242, P < .001, and r = 0.335, P = .009), and plantar flexor muscle strength (r = -0.469, P < .001, and r = 0.500, P < .001)., Conclusion: We found associations between the degree of CS and remote muscle strength and endurance, suggesting that poor remote muscle performance is possibly a clinical sign of CS in people with CLBP., (Copyright © 2020. Published by Elsevier Inc.)

Understanding the interactions between neural and musculoskeletal systems is key to identifying mechanisms of functional failure. Mammalian swallowing is a complex, poorly understood motor process. Lesion of the recurrent laryngeal nerve, a sensory and motor nerve of the upper airway, results in airway protection failure (liquid entry into the airway) during swallowing through an unknown mechanism. We examined how muscle and kinematic changes after recurrent laryngeal nerve lesion relate to airway protection in eight infant pigs. We tested two hypotheses: 1 ) kinematics and muscle function will both change in response to lesion in swallows with and without airway protection failure, and 2 ) differences in both kinematics and muscle function will predict whether airway protection failure occurs in lesion and intact pigs. We recorded swallowing with high-speed videofluoroscopy and simultaneous electromyography of oropharyngeal muscles pre- and postrecurrent laryngeal nerve lesion. Lesion changed the relationship between airway protection and timing of tongue and hyoid movements. Changes in onset and duration of hyolaryngeal muscles postlesion were less associated with airway protection outcomes. The tongue and hyoid kinematics all predicted airway protection outcomes differently pre- and postlesion. Onset and duration of activity in only one infrahyoid and one suprahyoid muscle showed a change in predictive relationship pre- and postlesion. Kinematics of the tongue and hyoid more directly reflect changes in airway protections pre- and postlesion than muscle activation patterns. Identifying mechanisms of airway protection failure requires specific functional hypotheses that link neural motor outputs to muscle activation to specific movements. NEW & NOTEWORTHY Kinematic and muscle activity patterns of oropharyngeal structures used in swallowing show different patterns of response to lesion of the recurrent laryngeal nerve. Understanding how muscles act on structures to produce behavior is necessary to understand neural control.