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This study investigates isokinetic muscle strength at elbow flexor and extensor by rehabilitation after medial collateral ligament reconstruction in the elbow joint. Isokinetic elbow flexor and extensor strength were evaluated in 6 groups of subjects as follows: control group without throwing disorders(18), MCL pre-operative group(11), MCL post-operative 4 months group(8). MCL post-operative 6 months group(7), MCL post-operative 8 months group(7), and MCL post-operative 14 months group(5). Isokinetic tests were performed concentrically flexion and extension at 60 deg/sec for the throwing elbow. The muscle strength of flexion, extension and flexion/extension ratios in the elbow joint was compared between each group. Test results for 6 group comparisons of muscle strength demonstrated a significant difference in flexor values between the control group and MCL post-operative 4 months group. Competition level muscle strength was not attained at postoperative 4 months. However, there was no significant difference in elbow muscle strength between the control group and the postoperative group at postoperative 6 months, upon starting a throwing program. Competition level muscles strength was attained at postoperative 6 months. [ABSTRACT FROM AUTHOR]

We measured the isokinetic peak torque of shoulder rotators in baseball players with elbow throwing disorders. Isokinetic shoulder rotational strength was evaluated in 4 groups of subjects as follows: control group: without throwing disorders (18), MCL group: with elbow medial collateral ligament injury (15), OA group: with elbow osteoarthrosis (8), and UND group: with elbow ulnar nerve disorder (11). Isokinetic: tests were performed concentrically internal and external rotation at 60 deg/sec for the throwing shoulders. Test results for 4 group comparisons of peak torque for the throwing shoulders demonstrated a significant difference in external rotator values between the control group and MCL group, UND group at shoulders. The MCL group and UND group had lower values compared with the control group. This is a characteristic finding baseball players with elbow throwing pain in the medial aspect. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate whether shoulder external rotator muscle fatigue affected the shoulder joint force during pitching. Two college baseball pitchers participated in this study. All subjects gave informed consent. All subjects threw multiple fastball pitches off an indoor throwing mound positioned at a regulatory distance from the home plate. They performed shoulder external rotator exercise until distress and threw some pitches before and after shoulder external rotator fatigue. The method of data collection involved the use of four 60-Hz digital video cameras. An Ariel APAS system was used to manually digitize the locations of the ball and 7 body landmarks for each subject. The DLT method was used to obtain three-dimensional coordinate data for the ball and each body landmark. Data were subsequently analyzed relative to three phases of the pitching motion: late cocking, acceleration, and follow through. Joint force at the shoulder joint was calculated according to the method of Feltner and Dapena and expressed in terms of anatomically relevant shoulder joint reference frame. T-tests revealed that the peak values of shoulder joint force changed significantly between before and after shoulder external rotator fatigue in intrapersonal data. Peak shoulder anterior shear force during the follow through phase significantly increased in both subjects. There was no significant difference in peak shoulder compression force and medial/lateral force. The fatigue of the shoulder rotators affected the shoulder joint anterior shear force at the follow through phase during pitching. [ABSTRACT FROM AUTHOR]

This study investigated whether different overground conditions affected the impact shock and muscle activity of the lower leg during running. Six healthy, male long-distance runners participated in this study. All subjects gave informed consent. No subjects had any disorders or injuries in the lower leg. The subjects underwent two trials : one was grass condition running (grass running) and, the other was asphalt condition running (asphalt running). Subjects ran at 5.0m/s across two different overground surfaces. During running, a piezoelectric accelerometer was used to measure the peak impact shock (G) of the distal antero-medial aspect in the right tibia, and muscle activity of two lower leg muscles (Tibialis anterior and Gastrocnemius) was recorded for the right leg. The data of the peak impact shock and the ratio of muscle activity to peak impact shock were analyzed. The peak impact shock during road running was significantly higher than during grass running (p<0.05). The ratio of muscle activity to peak impact shock in Gastrocnemius during grass running significantly increased (p<0.05). We concluded that grass running was at lower risk of causing overuse running injuries, and more likely to contribute to strengthening the lower leg muscle than road running. [ABSTRACT FROM AUTHOR]

Background: This study quantified thumb movement in patients with trapeziometacarpal osteoarthritis and carpal tunnel syndrome and examined the characteristics of each disorder using three-dimensional motion analysis., Methods: Twenty-three hands of 23 patients with trapeziometacarpal osteoarthritis, 88 hands of 73 patients with idiopathic carpal tunnel syndrome, and 29 hands of 20 healthy volunteers were included in this study; three-dimensional thumb kinematics were measured during the circumduction task using a retroreflective surface-based marker method., Findings: Trajectory of thumb tip reduced in both patient groups compared to healthy controls, with carpal tunnel syndrome exhibiting the flattening shape. Trapeziometacarpal osteoarthritis patients had decreased range of motion in all directions at the trapeziometacarpal joint, while maintaining flexion-extension at the metacarpophalangeal and interphalangeal joints. Carpal tunnel syndrome patients showed reduced motion particularly in metacarpophalangeal and interphalangeal flexion-extension. Joint contribution analysis revealed decreased trapeziometacarpal involvement and increased compensatory metacarpophalangeal and interphalangeal movements in trapeziometacarpal osteoarthritis, while carpal tunnel syndrome showed impaired metacarpophalangeal abduction., Interpretation: This study provides novel insights into the distinct kinematic characteristics of trapeziometacarpal osteoarthritis and carpal tunnel syndrome, offering potential for improved screening and assessment of thumb motor impairments in these conditions., Evidence Level: Diagnostic LEVEL III., 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 © 2025 Elsevier Ltd. All rights reserved.)

Introduction: Hand use recovery after a distal radius fracture (DRF) depends on whether the injured hand is dominant or not, which can affect laterality and influence functional outcomes. This study aimed to investigate how the injured side impacts changes in laterality and its relationship to functional outcome, aiming to contribute to the development of future hand therapy strategies., Methods: Patients with DRF were prospectively recruited. Triaxial accelerometers were wrist-mounted to collect data at 1, 4, 8, and 12 weeks postoperatively and examine the laterality index (LI), total hand use time, and total vector magnitude. Correlations between LI and functional outcomes were assessed at each time point., Results: 42 patients participated in this study. Among them, 19 and 23 had injured dominant (DI) and injured non-dominant (non-DI) hands, respectively. The LI showed a faster restoration of symmetry in the DI group than in the non-DI group at 8 and 12 weeks postoperatively. Moderate correlations between LI and functional outcomes were observed in wrist joints and grip strength in the DI and non-DI groups, respectively, at all time points., Discussion: The change in LI in the DI group was considered recovery, as it was identical to the symmetry observed in healthy adults. Additionally, the non-DI group was considered to have adapted to a pattern of predominant use of the dominant hand. The correlation between LI and some functional outcomes appeared to depend on hand use patterns, specifically whether the injured hand was dominant or not. These findings underscore the importance of tailoring interventions., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2025.)

Background: Conventional myoelectric prostheses (myo-prostheses) training involves repetitive grasping and manipulation training, which requires considerable training time. It is necessary to develop a short and efficient myo-prostheses training. This study aimed to verify the immediate and sustained effects of action observation and motor imagery (AOMI) using virtual reality (VR) on myo-prostheses control and clarify the effect of visual feedback of electromyogram (EMG) signals during AOMI using VR., Study Design and Methods: We evaluated 24 healthy right-handed individuals wearing a myo-prostheses simulator in their dominant hands. We divided participants into 3 groups: VR video observation with EMG presentation during manipulation (VR+), VR video observation without EMG presentation (VR), and control group. We evaluated prosthetic control skills using the Grasp Force Adjustment Test (GFAT) and Bowknot task immediately before and after AOMI and 1 week later. In addition, we evaluated the level of immersion during AOMI., Results: The rate of change in the GFAT 1 week after the intervention was significantly greater in the VR+ (P < 0.05, d = 1.32) and VR (P < 0.01, d = 2.34) groups than in the control group. Immersion was significantly higher in the VR+ and VR groups than in the control group. The condition and time required for GFAT had significant effects, although the post-hoc test showed no significant difference between VR+ and VR groups., Conclusions: AOMI using VR had sustained effects on motor learning of myo-prosthetic control despite EMG presentation. Therefore, AOMI, using VR, manipulates prostheses once learned, and it might be used for future training of myo-prosthetic control., (Copyright © 2024 International Society for Prosthetics and Orthotics.)

Aim Older inpatients have reduced physical function and walking ability with a higher risk of falls after being discharged home. Gait variability can assess ambulation and is strongly related to the risk of falls. However, the clinical factors affecting gait variability in inpatients have not been identified. The purpose of this study was to investigate the predictive factors affecting gait variability in older inpatients. Methods A total of 42 older orthopedic inpatients with fractures of the hip, spine, and other segments and 18 healthy volunteers as the control group were enrolled in this study. Inpatients wore tri-axial accelerometers for a 10m walk before discharge. Gait variability was assessed by the coefficient of variation (CV) based on five consecutive stride times. Clinical assessment of muscle strength, joint mobility, balance, pain, and activities of daily living were also evaluated. Results The CV in inpatients was higher than that in healthy elderly. Quadriceps muscle strength, ankle dorsiflexion range of motion, and balance described the CV. When model 2 (adjusted R 2 = 0.473) was compared with model 1 (adjusted R 2 = 0.293), the quadriceps muscle strength and ankle dorsiflexion range of motion had a major effect on CV, while balance had not a greater influence than these two factors when compared with model 3 (adjusted R 2 = 0.537). Conclusions Poor knee extension strength, balance, and restriction of ankle dorsiflexion mobility have influenced gait variability in older inpatients., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. The Institutional Review Board in Shimura Hospital issued approval 19. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: This study was supported by the Yuumi Memorial Foundation for Home Health Care. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Xu et al.)

This study explains the role of muscle coordination in chopstick manipulation and investigates the effects of object width and weight on intrinsic and extrinsic hand muscle activity when picking up objects with chopsticks. Surface electromyography was used to measure the activity of the intrinsic and extrinsic hand muscles when picking up objects of varying widths and weights using chopsticks. The results revealed coordinated muscle activity patterns in the intrinsic and extrinsic hand muscles and coordination between them during chopstick manipulation. Object widths varying between 1 and 3 cm did not significantly affect muscle activity; however, object weight influenced muscle activity during both chopstick closing and object grasping, with greater muscle activity in the 40 g condition than in the 10 g condition. Intrinsic hand muscles were found to be involved in object grasping, regardless of object weight. These findings suggest that object weight should be considered when practicing picking up objects with chopsticks in scenarios resembling daily dining, to prevent excessive muscle activity during rehabilitation., (Copyright © 2024 SFCM. Published by Elsevier Masson SAS. All rights reserved.)

The present study examined the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on short-latency afferent inhibition (SAI), as indirect biomarker of cholinergic system activation. 24 healthy adults underwent intermittent taVNS (30 s on/30 s off, 30 min) or continuous taVNS at a frequency of 25 Hz (15 min) along with earlobe temporary stimulation (15 min or 30 min) were performed in random order. The efficiency with which the motor evoked potential from the abductor pollicis brevis muscle by transcranial magnetic stimulation was attenuated by the preceding median nerve conditioning stimulus was compared before taVNS, immediately after taVNS, and 15 min after taVNS. Continuous taVNS significantly increased SAI at 15 min post-stimulation compared to baseline. A positive correlation (Pearson coefficient = 0.563, p = 0.004) was observed between baseline SAI and changes after continuous taVNS. These results suggest that 15 min of continuous taVNS increases the activity of the cholinergic nervous system, as evidenced by the increase in SAI. In particular, the increase after taVNS was more pronounced in those with lower initial SAI. This study provides fundamental insight into the clinical potential of taVNS for cholinergic dysfunction., (© 2024. The Author(s).)

Trapeziometacarpal osteoarthritis (TMC-OA) reduces the range of motion (ROM) of the thumb. However, the kinematic change achieved through surgical treatment remains unclear. Therefore, to quantify the kinematic change following TMC-OA surgery, we performed a three-dimensional motion analysis of the thumb using an optical motion capture system preoperatively and 1 year postoperatively in 23 patients with TMC-OA scheduled for arthrodesis (AD) or trapeziectomy with suspensionplasty (TS). Eighteen hands of nine healthy volunteers were also included as controls. Both procedures improved postoperative pain and Disability of the Arm, Shoulder and Hand scores, and AD increased pinch strength. The ROM of the base of the thumb was preserved in AD, which was thought to be due to the appearance of compensatory movements of adjacent joints even if the ROM of the TMC joint was lost. TS did not improve ROM. Quantifying thumb kinematic changes following TMC-OA surgery can improve our understanding of TMC-OA treatment and help select surgical procedures and postoperative assessment., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Tanaka et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Some individuals extend the three ulnar fingers when performing a precision pinch. The aim of the present study was to investigate the mechanisms and effect of the extension of the ulnar fingers during a pinch. When performing a pulp pinch task with the ulnar fingers in two positions (extension and flexion), 27 participants maintained 5% of their maximum force. The mean pinch force, force variability and time taken to reach the targeted force (reaching time) were calculated. Muscle activity was simultaneously measured, using surface electromyography, for nine muscles: the flexor pollicis brevis; abductor pollicis brevis; flexor pollicis longus; first lumbrical; first dorsal interosseous; flexor digitorum superficialis of the index finger; extensor indicis; and extensor digitorum of the index and ring fingers. No significant differences in the mean pinch force or force variability were found. However, the reaching time was significantly shorter (approximately 20% reduction) in the extension position and the activities in the flexor pollicis brevis, first lumbrical, extensor indicis and extensor digitorum of the ring finger were significantly higher. These findings suggest that extending the ulnar fingers during pinching enhances the activity of key muscles involved in the movement and allows for more rapid force exertion., Competing Interests: Declaration of conflicting interestsThe authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

We analysed the relationship between motor dysfunction of the thumb and the clinical parameters of carpal tunnel syndrome using three-dimensional motion analysis. This single-centred, prospective study included 65 hands in 51 patients with idiopathic carpal tunnel syndrome and 30 healthy hands. Three-dimensional thumb kinematics were acquired using a motion capture system with a retroreflective surface-based marker method. The trajectory area of thumb tip, adduction and abduction of the trapeziometacarpal joints and metacarpophalangeal joints were correlated with the clinical parameters. There was no significant correlation between the results of motion analysis values and patient-reported outcomes measures. Thumb movement disorder associated with carpal tunnel syndrome affected specific activities of daily living based on the pinching movements, such as 'writing' and 'buttoning clothes' among the patient-reported outcome measure items. Level of evidence: III., Competing Interests: Declaration of conflicting interestsThe authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Medial meniscus extrusion (MME) is associated with knee osteoarthritis (OA) progression because of increased loading stress in the medial compartment of the knee. Using a lateral wedge insole (LWI) decreases loading stress and immediately reduces MME., Objective: To investigate whether the wearing duration of LWI affects the midterm response to MME and is associated with knee OA progression., Study Design: Cohort study., Methods: Twenty-three patients with knee OA who were conservatively treated with LWI were classified according to the duration of the LWI wear per day: less than 5 h (short-duration group) or over 5 h (long-duration group). MME was evaluated in the single-leg standing position by ultrasound. Knee OA progression and limb alignment were evaluated radiographically. These evaluations were performed thrice: at the initial office visit as a baseline without LWI (time 0), with LWI (LWI-time 0), and 1 year after intervention with LWI (LWI-1 year)., Results: In both groups, the MMEs at LWI time 0 were significantly decreased compared with those at time 0. In the long-duration group, this reduction in MME was maintained 1 year after the intervention compared with time 0 (time 0: 3.9 ± 0.9, LWI-1 year: 2.6 ± 1.1), but this improvement was not observed in the short-duration group (time 0: 3.8 ± 1.7, LWI-1 year: 3.6 ± 1.7). In addition, three of four patients demonstrated OA progression, and varus alignment had significantly progressed compared with that at time 0 in the short-duration group. However, the long-duration group showed OA progression only in one patient and maintained limb alignment., Conclusions: The duration of wearing LWI affects the midterm reduction of MME and knee OA progression while maintaining limb alignment., (Copyright © 2024 International Society for Prosthetics and Orthotics.)

Background: Transcranial static magnetic stimulation (tSMS) is a non-invasive brain stimulation technique that place a strong neodymium magnet on scalp to reduce cortical excitability. We have recently developed a new tSMS device with three magnets placed close to each other (triple tSMS) and confirmed that this new device can produce a stronger and broader static magnetic field than the conventional single tSMS. The aim of the present study was to investigate the effect of the conventional single tSMS as well as triple tSMS over the unilateral or bilateral motor association cortex (MAC) on simple and choice reaction time (SRT and CRT) task performance., Methods: There were two experiments: one involved the conventional tSMS, and the other involved the triple tSMS. In both experiments, right-handed healthy participants received each of the following stimulations for 20 min on different days: tSMS over the unilateral (left) MAC, tSMS over the bilateral MAC, and sham stimulation. The center of the stimulation device was set at the premotor cortex. The participants performed SRT and CRT tasks before, immediately after, and 15 min after the stimulation (Pre, Post 0, and Post 15). We evaluated RT, standard deviation (SD) of RT, and accuracy (error rate). Simulation was also performed to determine the spatial distribution of magnetic field induced by tSMS over the bilateral MAC., Results: The spatial distribution of induced magnetic field was centered around the PMd for both tSMS systems, and the magnetic field reached multiple regions of the MAC as well as the sensorimotor cortices for triple tSMS. SD of CRT was significantly larger at Post 0 as compared to Pre when triple tSMS was applied to the bilateral MAC. No significant findings were noted for the other conditions or variables., Discussion: We found that single tSMS over the unilateral or bilateral MAC did not affect performance of RT tasks, whereas triple tSMS over the bilateral MAC but not over the unilateral MAC increased variability of CRT. Our finding suggests that RT task performance can be modulated using triple tSMS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Matsumoto, Watanabe, Ito, Horinouchi, Shibata, Kurumadani, Sunagawa, Mima and Kirimoto.)

Several reports have demonstrated the effectiveness of neurorehabilitation, such as mirror therapy or virtual reality, in treating phantom limb pain (PLP). This case study describes the effect of virtual reality training (VRT) on severe, long-term PLP and upper limb activity on the amputated side in a patient who underwent digit amputation 9 years prior. A woman in her 40 s underwent amputation of 2-5 fingers 9 years prior due to a workplace accident. She experienced persistent pain in the palms of her hand near the amputation sites. A single case design (ABA'B') was applied. Periods A and A' were set as periods without VRT intervention, and Periods B and B' were set as periods with VRT intervention. Periods A, B, A', and B' lasted 4, 10, 8, and 10 weeks, respectively. VRT was a task during which visual stimulation and upper limb movements were linked. The task consisted of catching a rolling ball in the display with a virtual hand, operated with both hands using a controller. VRT was performed once every 2-4 weeks for 30 min. Pain intensity was assessed using the short-form McGill Pain Questionnaire-2. Bilateral upper limb activity was measured continuously for 24 h using a triaxial accelerometer attached to the right and left wrist joints. The pain intensity was 147/220 points during Period A, 128 points during Period B, 93 points during Period A', and 100 points during Period B', showing a gradual decrease. Upper limb activity occurred mainly on the intact side during Periods A and B, whereas the activity on the amputated side increased 2-fold after Period A', and both upper extremities were used equally. Virtual reality training resulted in reduced pain intensity and increased activity in the upper limb. VRT may have induced reintegration of the sensory-motor loop, leading to a decrease in the PLP intensity. The upper limb activity on the amputated side may have also increased with the pain reduction. These results suggest that VRT may be valuable in reducing severe, long-term PLP., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Yoshimura, Kurumadani, Hirata, Senoo, Hanayama, Sunagawa, Uchida, Gofuku and Sato.)

Objectives: The effect of metacarpophalangeal joint position and finger joint movement speed on lumbrical muscle activity remains unproven and was examined in this study., Material and Methods: Twenty-four healthy adults performed flexion-extension movements of the index finger in different metacarpophalangeal joint positions (extension or flexion) and movement speeds (60, 120, 240, and 360 beats per minute). The activities of the first lumbrical, first dorsal interosseous, and extensor digitorum muscles were evaluated using surface electromyography, and compared with those during finger joint extension., Results: The metacarpophalangeal joint positions affected only lumbrical muscle activity, which was greater during extension. Further, finger movement speed affected the lumbrical and extensor digitorum muscle activities, which increased with increasing movement speeds., Conclusion: The present study suggests that position and movement speed can influence the lumbrical muscle activity during metacarpophalangeal joint extension. These findings may help expound lumbrical function and develop suitable strategies for inducing lumbrical muscle activity., (Copyright © 2023 SFCM. Published by Elsevier Masson SAS. All rights reserved.)

Although placing surface electrodes on small muscles by palpation is difficult, ultrasound guidance may enable electrode placement on the small muscles. This study aimed to examine whether ultrasound guidance is helpful for placement of electrodes on a small muscle, such as the hand lumbrical muscle. Twelve dominant hands of 12 healthy right-handed adults were included in this study. The first lumbrical muscle belly of the hands was identified using ultrasound guidance with a string navigation technique for placing surface electrodes. This technique was designed to identify the location of the center of the muscle belly under ultrasound imaging using a string. After the electrodes were placed on the muscle belly using this technique, the surface electromyographic signals of the first lumbrical, first dorsal interosseous, and adductor pollicis muscles were recorded. The activity of the lumbrical muscle could be separately measured of the first dorsal interosseous and adductor pollicis muscles. This technique has the potential to enable surface electromyography of small muscles for which placement of surface electrodes by palpation is challenging., 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 © 2023 Elsevier Ltd. All rights reserved.)

Background: Lateral thrust seen in people with medial compartment knee osteoarthritis can cause dynamic knee instability and poor postural control during gait cycles. A lateral wedge insole can reduce the lateral thrust and may have a favorable effect on gait variability, which in turn may indicate gait instability improves. The aim of this study was to investigate the effect of lateral wedge insole on gait variability in knee osteoarthritis patients., Method: We involved 15 symptomatic knee osteoarthritis patients who were provided with lateral wedge insole and 13 healthy asymptomatic volunteers as the control group. The gait variability was evaluated as the coefficient of variation of stride, stance, and swing duration based on acceleration monitoring using a wearable sensor. The lateral thrust was estimated as the lateral acceleration peak on the shank sensor. These measurements were performed without lateral wedge insole (baseline), immediately with lateral wedge insole (T0) at the initial office visit and one month after intervention (T1)., Result: Our data showed that the stance duration coefficient of variation and lateral thrust at T1 in the knee osteoarthritis group, were significantly decreased compared to the baseline values and these values were identical to those in the control group., Conclusion: The lateral wedge insole reduces dynamic knee instability and could improve gait variability in medial compartment knee osteoarthritis., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2023 Yosuke Ishii et al.)

Background: Phantom limb pain (PLP) is a frequent painful sensation in amputees, and motor imagery (MI) is a useful approach for the treatment of this type of pain. However, it is not clear regarding the best MI modality for PLP., Objectives: The purpose of this study was to investigate the relationship between the PLP and MI modality in upper limb amputees., Study Design: Observational study., Methods: Eleven patients who underwent unilateral upper limb amputation participated in this study. The MI modality (kinesthetic and visual) and PLP intensity were evaluated using the Kinesthetic and Visual Imagery Questionnaire (KVIQ)-20 and a visual analog scale. MI ability was also assessed during the hand mental rotation task. We examined the correlation between MI modalities, ability, and pain intensity., Results: The total KVIQ kinesthetic score was negatively correlated with pain intensity (r = -0.71, P < 0.01): the more vivid the kinesthetic imagery, the weaker the pain. In particular, the reduction in pain intensity was associated with strong kinesthetic imagery of opposing movements of the deficient thumb (r = -0.81, P < 0.01). The KVIQ visual score and MI ability were not associated with pain intensity., Conclusions: Our data showed that the reduction of PLP could be associated with the kinesthetic modality of MI but not with visual modality or MI ability. In other words, it was suggested that the more vivid the sensation of moving muscles and joints in the defect area, the lower the PLP intensity. To reduce PLP, clinicians may prefer interventions using the kinesthetic modality., (Copyright © 2022 International Society for Prosthetics and Orthotics.)

The Kapandji test is a simple method to score thumb opposition; however, the position of the interphalangeal joint of the thumb during this test has not been described. We aimed to quantitatively examine the effect of the thumb interphalangeal joint position on movements of the trapeziometacarpal joint during thumb opposition using the Kapandji test. The Kapandji test was carried out in 20 healthy participants during thumb interphalangeal joint extension and flexion. Movements of the joints and the activity of thenar muscles were recorded using motion capture and electromyography, respectively. We found that interphalangeal joint extension increased the trapeziometacarpal joint movement and thenar muscle activity compared with interphalangeal joint flexion, which contributed to thumb opposition at Kapandji Positions 0-6. These findings suggest the position of the thumb interphalangeal joint affects the trapeziometacarpal joint during thumb opposition, and assessment of thumb opposition using the Kapandji test is best done with the thumb interphalangeal joint in extension.

Muscle activities of the elbow flexors, especially the brachialis muscle (BR), have been measured with intramuscular electromyography (EMG) using the fine-wire electrodes. It remains unclear whether BR activity can be assessed using surface EMG. The purpose of this study was to compare the EMG patterns of the BR activity recorded during elbow flexion using surface and fine-wire electrodes and to determine whether surface EMG can accurately measure the BR activity. Six healthy men were asked to perform two tasks-a maximum isometric voluntary contractions (MVICs) task and an isotonic elbow-flexion task without lifting any weight. The surface and intramuscular EMG were simultaneously recorded from the BR and the long and short heads of the biceps brachii muscle (BBLH and BBSH, respectively). The locations of the muscles were identified and marked under ultrasonographic guidance. The peak cross-correlation coefficients between the EMG signals during the MVICs task were calculated. For the isotonic elbow-flexion task, the EMG patterns for activities of each muscle were compared between the surface and the fine-wire electrodes. All cross-correlation coefficients between the surface EMG signals from the muscles were lower than 0.3. Furthermore, the EMG patterns of the BR activity were not significantly different between the surface and the fine-wire electrodes. The BR has different EMG pattern from the BBLH and the BBSH. The BR activity, conventionally measured with intramuscular EMG, can be accurately accessed with surface EMG during elbow flexion performed without lifting any weight, independent from the BBLH and BBSH activities., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Date, Kurumadani, Nakashima, Ishii, Ueda, Kurauchi and Sunagawa.)

Introduction/aims: The treatment of entrapment neuropathies, such as carpal tunnel syndrome or cubital tunnel syndrome, has significant challenges that have yet to be solved. To a large extent, the success of the treatment of peripheral nerve damage is dependent on brain plasticity during the recovery process. Recently, noninvasive brain stimulation procedures, such as transcranial direct current stimulation (tDCS), to modulate brain activity have been developed. This study aimed to determine whether tDCS can improve artificially induced ischemic sensory disturbances in the finger., Methods: Ten right-handed, healthy volunteers, with an average age of 25.5 years, participated in this study. A rubber bandage at the base of the right index finger was used to induce a regional sensory disturbance for 30 minutes. An anodal tDCS was applied over their left M1 area 15 minutes into the session. The current perception threshold (CPT) in the index and little finger pad was evaluated using the PainVision system and used as a measure of the sensory threshold., Results: In the index finger, the CPT increased significantly with time, a finding that was absent after tDCS application., Discussion: It has been reported that anodal tDCS over M1 primarily modulates the functional connectivity of sensory networks, and our findings demonstrate that it improved ischemia-induced sensory disturbances. Modulating the central nervous system using tDCS represents a potential avenue for treating entrapment neuropathies., (© 2021 Wiley Periodicals LLC.)

Background: Vascular disorders in throwing athletes can occur from the thoracic outlet to the fingertips. The occurrence of these disorders around the shoulder is well known, and treatment options have been established for them. However, the occurrence of vascular pathology in the digital arteries in elite baseball pitchers is unclear, and treatment options have not yet been established. We hypothesized that asymptomatic professional baseball pitchers often have existing pathological changes in their digital blood flow; therefore, we quantitatively measured the blood flow in the index finger using ultrasonography and compared the results to those of non-baseball players., Methods: Seven asymptomatic professional baseball pitchers (pitcher group) and 11 healthy volunteers (control group) were included. The flow velocity, flow volume and vessel resistance index of the ulnar digital artery of the index finger were measured just distal to the proximal interphalangeal joint using pulsed wave Doppler in two positions: 1) with the proximal interphalangeal (PIP) joint relaxed (10-15° flexed) and 2) with the PIP joint passively extended (0-5°)., Results: The mean flow velocity and flow volume were lower in the extended position than in the relaxed position in both groups. In the dominant hand, which was the throwing hand in the pitcher group, the mean flow velocity and the flow volume in the relaxed position were significantly lower in the pitcher group than in the control group. The vessel resistance index in the relaxed position of the dominant hand was significantly higher in the pitcher group than in the control group. In the nondominant hand, there was no significant difference in any parameter between the two groups., Conclusions: Asymptomatic professional baseball pitchers may have a pathological change in digital blood flow in the throwing hand. As treatment options for this condition have not yet been established, it is of utmost importance to carry out periodic examination and prevention before the condition progresses to the symptomatic end stage., Competing Interests: Declaration of competing interest The authors declare no potential conflict of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2020 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Previous studies have reported qualitative characteristics of myelopathy hand, but few studies have reported quantitative kinematic parameters of this condition. Our purpose of this study was to quantitatively evaluate the abnormal finger movements in patients with cervical compressive myelopathy (CCM) (termed myelopathy hand) and to understand the characteristics of myelopathy hand during the grip and release test (GRT) using gyro sensors. Sixty patients with CCM (severe: n = 30; mild-to-moderate: n = 30) and sixty healthy adults (age-matched control: n = 30; young control: n = 30) were included in this study. All participants performed the GRT. The index and little fingers' and the wrist's movements during the GRT were recorded using three gyro sensors. The number of cycles, switching time-delay, time per cycle, and peak angular velocity were calculated and compared between groups. Patients with severe CCM had the lowest number of cycles and longest switching time-delays, followed by patients with mild-to-moderate CCM, the age-matched control group, and the young control group. The time per cycle and the peak angular velocities of fingers in participants with severe CCM were significantly lower than those in participants with mild-to-moderate CCM; however, there were no significant differences between the control groups. The peak angular velocities of fingers were significantly lower during extension motions than during flexion motions in participants with CCM. Participants with CCM have lower peak angular velocities during finger movement. Finger extension also is impaired in participants with CCM. Abnormal finger movements and the severity of myelopathy in participants with CCM can be assessed using gyro sensors., Competing Interests: The authors have declared that no competing interests exist.

Purpose: This study aimed to investigate the association between the severity of medial meniscus extrusion (MME) under weight bearing and pain in patients with early-stage knee osteoarthritis (OA)., Methods: Twenty-eight patients with symptomatic early-stage knee OA (Kellgren and Lawrence grade ≤ 2) who visited our outpatient clinic between 2016 and 2018 were included in this cross-sectional study (mean age: 58.0 ± 11.6 years, female: n = 10). MME was evaluated under weight-bearing conditions using ultrasonography. Patients were divided into two groups according to the severity of MME under weight bearing: those with MME ≥ 3 mm were assigned to the severe group, whereas those with MME < 3 mm were assigned to the mild group. The knee injury osteoarthritis outcome score (KOOS) system was used to evaluate knee pain. The incidence of bone marrow lesions (BMLs) was evaluated using magnetic resonance images., Results: The KOOS pain score was significantly lower in the severe group than in the mild group (P < 0.05). The incidence of BMLs was significantly higher in the severe group (69%) than in the mild group (7%) (P < 0.001)., Conclusion: Patients with early-stage knee OA who have greater MME under weight-bearing have more intense knee pain and a higher incidence of BMLs., (© 2021. The Japan Society of Ultrasonics in Medicine.)

This study quantified recovery of thumb motion in patients with carpal tunnel syndrome after carpal tunnel release using three-dimensional motion analysis with a retroreflective surface-based marker method. Eighteen hands from 14 patients who underwent carpal tunnel release for idiopathic carpal tunnel syndrome were included. The angular movements of the three joints of the thumb, the path length of the thumb tip and the area enclosed by the perimeter path of the thumb tip were measured during circumduction. The range of joint movement, including abduction/adduction of the trapeziometacarpal joint, and flexion/extension of the interphalangeal and metacarpophalangeal joints and the path length of the thumb tips, improved significantly 1 year after surgery. The quantification of thumb kinematics helps to better understand motor dysfunction in carpal tunnel syndrome, assess the severity of the condition and decide on treatment. Level of evidence: IV.

Background: Medial meniscus extrusion (MME) leads to symptomatic knee osteoarthritis (OA) due to increased mechanical stress. MME increases with weight-bearing, and the difference in MME between non-weight-bearing and weight-bearing status (ΔMME) is a factor that causes greater MME. The lateral wedge insole (LWI) is an ideal approach for decreasing the amount of ΔMME associated with the reduction of medial loading stress in the early stage of knee OA. However, the effect of the LWI for 3 months on the ΔMME and its response to OA stage have not been elucidated., Objective: To investigate the effects of the LWI for 3 months on MME and the ΔMME in each stage of OA., Methods: Participants were divided into three groups: no intervention with the LWI (control group; n = 9) and intervention with the LWI in early OA (early OA group: Kellgren-Lawrence (K/L) stage = 2, n = 17) and late OA (late OA group: K/L stage > 2, n = 13). MME was evaluated using ultrasound, and the ΔMME was obtained as the difference in MME from non-weight-bearing and weight-bearing conditions. These measurements were performed at two time points: the initial office visit as a baseline and post-3 months., Results: The weight-bearing MME and ΔMME values post-3 months were significantly decreased compared with those at baseline in the early OA group but not in the control or late OA groups., Conclusions: The use of the LWI for 3 months decreased weight-bearing MME and ΔMME values, and its effectiveness was more pronounced in the early stage of knee OA., 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 © 2020 Elsevier B.V. All rights reserved.)

This study evaluated factors affecting sensory restoration after thumb reconstruction using a wrap-around flap in 21 thumbs in patients aged 11 to 50 years old. The patients were followed from 12 to 94 months after surgery. Static and moving 2-point discrimination of the reconstructed pulp was measured and analysed using multiple regression analysis. According to the univariate and multivariate analyses, the preoperative period, the number of nerve coaptations, and the duration of follow-up all significantly affected sensory recovery. Sensory recovery with more than three coaptations was significantly better than those with less than three coaptations, and the number of nerve coaptations was one of the primary factors influencing sensory recovery. We conclude from this study that the wrap-around flap should be performed soon after injury and that surgeons should try to coaptate three or more nerves to enhance sensory recovery. Level of evidence: IV.

Background: Regular body-powered (BP) prosthesis training facilitates the acquisition of skills through repeated practice but requires adequate time and motivation. Therefore, auxiliary tools such as indirect training may improve the training experience and speed of skill acquisition. In this study, we examined the effects of action observation (AO) using virtual reality (VR) as an auxiliary tool. We used two modalities during AO: three-dimensional (3D) VR and two-dimensional (2D) computer tablet devices (Tablet). Each modality was tested from first- and third-person perspectives., Methods: We studied 40 healthy right-handed participants wearing a BP prosthesis simulator on their non-dominant hands. The participants were divided into five groups based on combinations of the different modalities and perspectives: first-person perspective on VR (VR1), third-person perspective on VR (VR3), first-person perspective on a tablet (Tablet1), third-person perspective on a tablet (Tablet3), and a control group (Control). The intervention groups observed and imitated the video image of prosthesis operation for 10 min in each of two sessions. We evaluated the level of immersion during AO using the visual analogue scale. Prosthetic control skills were evaluated using the Box and Block Test (BBT) and a bowknot task (BKT)., Results: In the BBT, there were no significant differences in the amount of change in the skills between the five groups. In contrast, the relative changes in the BKT prosthetic control skills in VR1 (p < 0.001, d = 3.09) and VR3 (p < 0.001, d = 2.16) were significantly higher than those in the control group. Additionally, the immersion scores of VR1 (p < 0.05, d = 1.45) and VR3 (p < 0.05, d = 1.18) were higher than those of Tablet3. There was a significant negative correlation between the immersion scores and the relative change in the BKT scores (Spearman's r s  = - 0.47, p < 0.01)., Conclusions: Using the BKT of bilateral manual dexterity, VR-based AO significantly improved short-term prosthetic control acquisition. Additionally, it appeared that the higher the immersion score was, the shorter the execution time of the BKT task. Our findings suggest that VR-based AO training may be effective in acquiring bilateral BP prosthetic control, which requires more 3D-based operation.

Background: Lateral thrust is known to be risk factors for knee osteoarthritis progression. Medial meniscus extrusion is also known to be risk factors for knee osteoarthritis progression; moreover, the amount of change in medial meniscus extrusion from non-weight bearing to weight bearing is an important factor for the progression of knee osteoarthritis. This study aimed to investigate the correlation between lateral thrust and the change in medial meniscus extrusion., Methods: In total, 44 knees from 44 patients (mean age, 68.9 years) with knee osteoarthritis were divided into two groups according to the Kellgren-Lawrence grade: early-stage osteoarthritis (Kellgren-Lawrence = 2) and severe osteoarthritis (Kellgren-Lawrence = 3 or 4). The lateral thrust during gait, represented as the lateral acceleration peak immediately after heel strike, was recorded by an inertial sensor. The amount of change in medial meniscus extrusion, which was the difference between weight-bearing (unipedal standing) and non-weight-bearing (supine) conditions, was evaluated using ultrasonography., Results: The mean value of the lateral acceleration peak in the severe osteoarthritis group was higher than that of the early-stage osteoarthritis group (p < 0.05). The non-weight-bearing and weight-bearing medial meniscus extrusion in the severe OA group were significantly higher than those of the early-stage osteoarthritis group (p < 0.001). However, the amount of change in medial meniscus extrusion in severe osteoarthritis group was significantly lower than in the early-stage osteoarthritis group (p < 0.05). The amount of change in medial meniscus extrusion showed a significant correlation with the lateral acceleration peak in the early-stage osteoarthritis group (r = 0.56, p < 0.001). On the other hand, there was no significant correlation in the severe osteoarthritis group., Conclusion: The lateral thrust shows a positive correlation with the amount of change in medial meniscus extrusion by weight bearing in patients with early-stage knee osteoarthritis., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Studies show that transcranial direct current stimulation (tDCS) can modulate somatosensory processing, but optimum parameters for tDCS effects on hand sensibility remain in question. We aimed to test the effects of anodal tDCS (atDCS) and cathodal tDCS (ctDCS) compared with sham tDCS (stDCS) of primary motor (M1) and sensory (S1) cortices on healthy subjects' hand sensibility. In this single-blind clinical trial, 30 randomized healthy volunteers received six tDCS sessions over 6 weeks: one session each of atDCS, ctDCS and stDCS over M1, and one session each of atDCS, ctDCS and stDCS over S1. Current perception threshold (CPT) was assessed using an objective quantitative analysis device (PainVision) at baseline, immediately (T0) and 30 min (T30) after each intervention. Our results showed that both atDCS and ctDCS of S1 and M1 significantly increased CPT. M1 ctDCS at T30 had the greatest effect of all M1 and S1 stimulation conditions (mean difference: 32.94%, Z: 3.12, effect size: 1.82, P < 0.001 The largest effect at S1 was for atDCS at T30 (mean difference: 29.87%, Z: 2.53, effect size: 1.72, P < 0.001. Our results are consistent with tDCS' modulatory effects on hand sensation, especially M1 ctDCS and S1 atDCS.

Background: Previous studies have indicated that the kinematics of the knee joint affect the trunk and pelvis during gait. However, the factors that influence trunk movement in knee osteoarthritis patients during gait after surgery remain unclear., Objective: To examine the effect of total knee arthroplasty (TKA) on trunk movement during gait by comparing knee osteoarthritis patients with healthy controls., Methods: Fourteen medial knee osteoarthritis patients who underwent initial unilateral TKA and 11 controls participated in this study. Knee and hip joint flexion and trunk and pelvic tilts during gait were acquired using a three-dimensional motion analysis system. Knee joint range of motion, pain, and kinematic data were collected preoperatively and 1 year postoperatively for knee osteoarthritis patients., Results: Knee extension limitation and pain significantly improved postoperatively compared with preoperative stages. Preoperatively, the peak anterior trunk tilt during the stance phase was significantly larger in osteoarthritis patients than in controls. The peak anterior trunk tilt during the stance phase was significantly smaller postoperatively than at preoperative stages., Conclusions: These results suggest that after TKA, the trunk movements of knee osteoarthritis patients were approximately equal to those of controls, with improvement in clinical outcomes such as knee extension limitation and pain.

The purpose of this study was to examine motor imagery ability in patients with peripheral nerve disorder using the hand mental rotation task. Five patients with left total avulsion brachial plexus palsy (BPP) and 16 healthy age-matched adults participated in this study. The mean±SD time from the injury was 103.6±49.7 months. Participants performed a hand mental rotation task as the motor imagery task; outcome measures included the reaction time from cognizing hand stimuli to the judgment of hand laterality (right or left) and the error rate. Patients also completed the Hand 20 questionnaire to assess the use of their affected limb. Log-transformed reaction times of the affected limb in patients with BPP were significantly higher than those of the unaffected limb and the left-sided limb of the healthy participants. Log-transformed reaction times of the unaffected limb in patients were significantly higher than those of the right-sided limb in healthy participants. Log-transformed error rate did not differ between patients and healthy participants. According to the results of the Hand 20 questionnaire, patients with BPP hardly used their affected limb because of severe sensory-motor dysfunction. Motor imagery ability of the affected and unaffected limbs in patients with complete BPP may be decreased owing to long-term disuse. These findings suggest that long-term disuse in those with severe peripheral nerve disorders could affect motor imagery ability of both the affected and unaffected limbs.

Background: Lumbar alignment of posterior or anterior tilts affects the exacerbation and remission of symptoms of lumbar spinal stenosis patients. This study aimed to clarify the correlation between spinal and pelvic movements during gait and the aggravation of low back pain after gait loading in lumbar spinal stenosis patients., Methods: A total of 29 patients with lumbar spinal stenosis completed leg and low back pain assessments and gait analysis before and after gait loading tests. Patients were divided into leg and low back pain change (n = 8), leg pain only change (n = 12), and non-change (n = 9) groups based on the differences of leg and low back pain between before and after the tests. Peak kinematic values of the anterior tilts of the trunk, thoracic spine, lumbar spine, and pelvis during the stance phase were obtained via three-dimensional gait analysis., Results: In the leg and low back pain change group, the anterior lumbar and pelvic tilts were larger after than before the tests; however, in the leg pain only change and non-change groups, only the anterior lumbar tilt was larger after than before the tests. Anterior lumbar tilt before and after the tests negatively correlated with the aggravation of low back pain, and an increase in the anterior pelvic tilt positively correlated with the aggravation of low back pain., Conclusions: In lumbar spinal stenosis patients, smaller anterior lumbar tilt and larger anterior pelvic tilt during gait loading may affect the aggravation of low back pain by gait loading. Increasing in lumbar lordosis during gait might be one of the factors leading to low back pain in lumbar spinal stenosis patients., (Copyright © 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

The aim of this study was to investigate the effect of finger-tip touch on the somatosensory cortex under mirror imaging conditions. Magnetoencephalographic recordings of somatosensory-evoked field responses to mechanical tactile stimulation of the index finger in both hands were obtained for the right-handed healthy participants as part of the following mirror or nonmirror tasks. Both hands were screened and mechanical stimuli were delivered to the right index finger pulp. A mirror was placed in front of the patient with the right hand facing the reflective surface, as if it were the left side (mirror task). Another task comprised the screening of right hands behind a partition, after which mechanical stimuli were delivered to the right index finger pulp without a mirror (nonmirror task). The same tasks for the left hand were also examined. The estimated current dipoles were identified and analyzed. In the measurements following all the tasks, the equivalent current dipoles (ECDs) were estimated in the corresponding contralateral primary somatosensory area (cSI). The other ECDs were estimated in the secondary somatosensory area both contralateral (cSII) and ipsilateral (iSII) to the stimulus side. The amplitudes of ECDs in the cSII area following the left index stimuli in the mirror task were significantly larger than those in the nonmirror task (P=0.043). The mirror effect on the somatosensory cortex in this study may be small, but a positive variation was shown in the form of a response to the actual stimulation in the hand opposite to the hand which was hidden behind the mirror.

Background: It is known that a lateral wedge insole (LWI) decreases medial loading stress in the knee. Medial meniscus pathology, such as a degenerative tear or a root tear, leading to malfunction and medial meniscus extrusion (MME), is a critical condition that leads to severe osteoarthritis (OA). However, the effect of LWI on MME is still unknown. The objective of this study was to investigate the effect of LWI use on MME in knee OA using ultrasonography., Methods: Thirty-one knees from 18 patients with knee OA diagnosed radiographically were allocated to the OA group (mean age, 73.6years; sex M:F, 2:16). Twenty-two knees from 11 volunteers without knee OA were also enrolled as an age-matched control group. MME was evaluated using ultrasonography with the patients in three positions: supine, standing without LWI, and standing with LWI., Results: In both groups, the mean values of the MME increased significantly when patients were in the standing position compared to the supine position. In the OA group, MME significantly decreased with LWI use. There was no significant difference in MME between use and non-use of an LWI in the control group., Conclusions: The LWI could significantly decrease MME in patients with knee OA., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Introduction: In recent operative cases of anterior interosseous nerve palsy (AINP), hourglass-like fascicular constrictions have been reported. We prospectively investigated the ultrasonographic history of these lesions to better understand the role of this lesion in AINP., Methods: Seven patients who were diagnosed with idiopathic AINP based on classic clinical findings and had hourglass-like fascicular constrictions found on ultrasonography were included. All but 1 patient selected surgery, and we followed up all patients clinically and with ultrasonography., Results: In the 5 patients treated surgically in whom paralysis recovered to a level greater than M4, postoperative ultrasonography revealed less constriction. The other patient experienced little recovery after surgery, and the severe constriction remained. In a conservatively treated patient, the paralysis recovered completely, and upon ultrasonography, the constriction had lessened., Conclusions: Although the mechanism is still unknown, hourglass-like fascicular constriction lessened with relief of motor weakness both in operatively and conservatively treated patients. Muscle Nerve 55: 508-512, 2017., (© 2016 Wiley Periodicals, Inc.)

Previous studies have shown that motor-related areas are activated when individuals perform the hand mental rotation task (HMRT), which is used as a motor imagery task. Transcranial direct current stimulation (tDCS) is a noninvasive method of cortical stimulation, and anodal tDCS enhances the excitability of target regions. The aim of this study was to investigate the effect of tDCS during the HMRT. Eighteen healthy, right-handed participants in this study performed the HMRT before (pre) and immediately after (post) anodal or sham tDCS. Both anodal and sham tDCS were applied to the left scalp over the hand-knob area for 10 min with a current intensity of 1 mA. Reaction times and error rates were analyzed and compared. As main results, reaction times were significantly shorter for postanodal tDCS than for preanodal tDCS (P<0.01) or postsham tDCS (P<0.05). No significant differences in reaction times were observed between presham and postsham tDCS. These findings indicate that anodal tDCS during the HMRT can enhance task performance.

Somatosensory evoked fields in response to compression (termed as Co) and decompression (termed as De) of glabrous skin (D1, thumb; D2, index finger; D5, little finger) were recorded. Although estimated equivalent current dipoles (ECDs) following stimulation of D1 and D5 were larger, but not significantly larger, in decompression than in compression, those of D2 were significantly larger (P = 0.035). The ECDs were located in the postcentral gyrus in the order of D5De, D2De, and D1De medially, posteriorly, and superiorly in decompression but not in compression (z-value, F = 2.692, P = 0.031). The average distance of ECDs between D1 and D5 was longer in decompression (12.8 ± 1.6 mm) than in compression (9.1 ± 1.6 mm). Our data suggest that the cortical response for the commonly used digit D2 is functionally different from those for other digits (D1 and D5) that the somatotopic variability is greater in compression., (Copyright © 2012 Wiley Periodicals, Inc.)

We studied somatosensory-evoked fields elicited by mechanical versus electrical stimuli to index finger of healthy participants. Mechanical stimulation was index pulp compression and decompression by using nonmagnetic mechanical stimulator. Electrical stimulation was three times of sensory threshold and delivered to index pulp by using ball-shaped electrodes. Mechanical/electrical stimuli evoked contralateral primary somatosensory cortical responses in all respective participants. Compressive stimuli evoked ipsilateral primary sensorimotor cortical responses in all respective participants, with dipole strengths less than contralateral primary somatosensory cortical responses of compressive stimuli. Mechanical/electrical stimuli evoked secondary somatosensory (SII) cortical responses bilaterally; electrical-stimuli SII dipole strengths were relatively stronger than compressive-stimuli SII responses. It is concluded that the use of mechanical stimulation may improve our understanding of functional sensory cortical responses compared with electrical stimulation.

Objective: The present study investigated the effect of joint immobilization on corticomotoneuronal excitability to only intracortical input from a hierarchical level above the primary motor cortex., Methods: Motor evoked potentials (MEPs) and H-reflexes in the flexor carpi radialis muscle were elicited from 8 orthopedic patients with splints and 8 healthy volunteers. Each patient was examined on the day of splint removal (disuse stage) and 2 months after that day (recovery stage). Both potentials were recorded under 3 conditions: at rest, while imagining motor movement (during motor imagery), and during 10% of maximum voluntary contraction (10% MVC)., Results: In the patient group, the amplitude of surface electromyography during voluntary maximum wrist flexion was lower at the disuse stage than at the recovery stage, although the supra-maximum M-wave amplitude did not change between stages. Compared to both the patient group at the recovery stage and the control group, patients at the disuse stage recorded significantly lower MEPs, but only during motor imagery. In contrast, the H-reflex amplitudes were not significantly changed under any of the 3 conditions for both patients and control., Conclusions: The present results indicated a strict parallelism between motor execution (the reduction of electromyography during mvc after immobilization) and motor imagery (the reduction of MEP-amps after immobilization). This parallelism suggests that a functional reorganization or decreased excitability in the cerebral cortex area involved in executing movement likely decreases the motor capability to produce voluntary muscular output after immobilization.