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Background: Nerve conduction studies (NCS) and ultrasound (US) remain imperfect compared with clinical diagnosis and/or diagnostic tools such as carpal tunnel syndrome-6 (CTS-6) for diagnosis of carpal tunne syndrome (CTS). One potential reason for the discrepancy between clinical diagnosis and testing is "borderline" case inclusion. This study aims to compare clinical outcomes after carpal tunnel release (CTR) between "borderline" and "clear" patients with CTS determined by NCS and US., Methods: This was a retrospective review of patients who underwent CTR. We collected NCS and US measurements of the median nerve cross-sectional area (MNCSA) at the carpal tunnel inlet, and the Boston Carpal Tunnel Questionnaire (BCTQ) scores comprised of the Symptom Severity Scale (SSS) and the Functional Status Scale (FSS). Ultrasound measurements defined patients as having "borderline" (MNCSA < 13 mm 2 ) or "clear" (MNCSA ≥ 13 mm 2 ) CTS., Results: The study included 94 unilateral patients with CTS. "Borderline" CTS was diagnosed in 58 patients (62%), and "clear" CTS was diagnosed in 36 patients (38%). No significant differences in BCTQ scores were found between groups. At greater than 6-month follow-up, the mean FSS was 1.44 and 1.45 for clear and borderline groups, respectively ( P = .97) and the mean SSS was 1.47 and 1.51, respectively ( P = .84). However, a significant difference between groups when comparing distal motor latency (DML) and distal sensory latency (DSL) existed. The mean DSL was 3.71 and 4.44 for the clear and borderline groups, respectively ( P = .02). The mean DML was 4.59 and 5.36 ( P = .048)., Conclusion: Categorizing CTS diagnosis into "borderline" and "clear" based on preoperative US and NCS testing did not correlate with BCTQ changes after CTR. It remains unclear whether the BCTQ is a valid postoperative assessment tool, despite its frequent use in literature., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: J.R.F.J. is an advisor for Integra LifeSciences. R.C.V. has no conflicts of interest.

The clinical manifestation of median nerve entrapment at the carpal tunnel level is known as carpal tunnel syndrome (CTS). Electroneurography (ENG) is considered the gold standard in CTS evaluation. We conducted a retrospective study and analyzed some clinical and demographic variables, relating them to the degree of neuropathy using ENG, to better understand the role of ENG in this very common disease. We studied 816 patients referred to our service for neurographic evaluation. Their symptoms were classified as compatible with CTS (cCTS) ( n = 646) and atypical for CTS (aCTS) ( n = 170). A blind ENG was performed on 797 patients. Patient characteristics were coded as variables and analyzed to study whether they could predict neuropathy severity (sensory and motor involvement or grade ≥ 3 in our classification). We found a correlation between typical symptomatology, age over 50 years, male gender, positivity of Phalen's maneuver and Tinel's sign, and a neuropathy grade ≥ 3. We also found a correlation with CTS in the contralateral hand if the other hand showed neuropathy, despite the lack of symptoms in this hand. We propose a practical algorithm for ENG referral based on clinical symptoms, demographic factors, and neurophysiological variables.

Background There are many physiological changes that accompany aging. Slowing of muscle contraction, alteration of muscle metabolism and neuromuscular junction, and reduction of nerve conduction velocity (NCV) are among these physiological changes. The present study was conducted to elucidate the effect of physiological factors like gender, height, and Body Mass Index (BMI) on motor and sensory nerve conduction study (NCS) of the upper limb and find out the normal data for healthy elderly subjects in central India. Methods A cross-sectional study among 382 healthy adult participants of central India aged 60 years and above. The study was carried out in the department of Physiology, Acharya Vinoba Bhave Rural Hospital, Wardha, India, from July 2017 to June 2022. An NCS was performed using the Neuron Spectrum 5 machine (Neurosoft, Ivanovo, Russia). A Microsoft Excel spreadsheet (Microsoft Corporation, Redmond, Washington, United States) was used to tabulate the information gathered. For statistical analysis, IBM SPSS Statistics for Windows, Version 22.0 (Released 2013; IBM Corp., Armonk, New York, United States) was used. Results All NCS parameters were greater in males as compared to females. As age advances, longer distal motor latency (DML) and F-wave minimum latency, decreasing amplitude, and slowing of conduction velocity (CV) were observed. As height increases, increasing DML and F-wave minimum latency, decreasing amplitude, and slowing of CV were observed. Higher BMI was found to be associated with lower amplitudes and slowing of CVs. Conclusion Age and height have a negative influence on amplitude and CV is a positive influence on DML and F-min latency. Higher BMI has a negative influence on amplitude and CV., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Taksande et al.)

Objective: To assess whether patients with acute inflammatory demyelinating polyneuropathy (AIDP) associated with SARS-CoV-2 show characteristic electrophysiological features., Methods: Clinical and electrophysiological findings of 24 patients with SARS-CoV-2 infection and AIDP (S-AIDP) and of 48 control AIDP (C-AIDP) without SARS-CoV-2 infection were compared., Results: S-AIDP patients more frequently developed respiratory failure (83.3% vs. 25%, P=0.000) and required intensive care unit (ICU) hospitalization (58.3% vs. 31.3%, P=0.000). In C-AIDP, distal motor latencies (DMLs) were more frequently prolonged (70.9% vs. 26.2%, P=0.000) whereas in S-AIDP distal compound muscle action potential (dCMAP) durations were more frequently increased (49.5% vs. 32.4%, P=0.002) and F waves were more often absent (45.6% vs. 31.8%, P=0.011). Presence of nerves with increased dCMAP duration and normal or slightly prolonged DML was elevenfold higher in S-AIDP (31.1% vs. 2.8%, P=0.000);11 S-AIDP patients showed this pattern in 2 nerves., Conclusion: Increased dCMAP duration, thought to be a marker of acquired demyelination, can also be oserved in critical illness myopathy. In S-AIDP patients, an increased dCMAP duration dissociated from prolonged DML, suggests additional muscle fiber conduction slowing, possibly due to a COVID-19-related hyperinflammatory state. Absent F waves, at least in some S-AIDP patients, may reflect α-motor neuron hypoexcitability because of immobilization during the ICU stay. These features should be considered in the electrodiagnosis of SARS-CoV-2 patients with weakness, to avoid misdiagnosis., Competing Interests: Declaration of Competing Interest The authors report no declarations of interest., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Studies suggest that low vitamin D levels are associated with carpal tunnel syndrome. We aimed to evaluate whether level of vitamin D receptor expression in the endothelial cells of the subsynovial connective tissue is associated with clinical features of carpal tunnel syndrome. We obtained the subsynovial connective tissue from 52 women with carpal tunnel syndrome during surgery and performed immunohistochemical analysis of vitamin D receptors in the endothelial cells of the subsynovial connective tissue. We explored correlation of vitamin D receptor expression with clinical features of carpal tunnel syndrome, such as age, symptom duration, symptom severity and electrophysiological severity. Diverse range of vitamin D receptor expression was observed. Vitamin D receptor expression was independently associated with distal motor latency. This suggests that vitamin D receptor expression may be associated with disease progression, as prolonged distal motor latency reflects severity of the disease. Further studies are necessary to explore the role of vitamin D and vitamin D receptors in patients with carpal tunnel syndrome., Level of Evidence: IV.

Purpose: The measurement of distal motor latency (DML) is an established method for diagnosing entrapment peripheral neuropathy. DML can also serve as an index for disease severity and prognosis. We considered that measuring DML could be useful in estimating the severity of spinal root impairment and predicting prognosis in patients with lumbar spinal stenosis (LSS). The purpose of this study was to investigate the efficacy of intraoperative direct electrical stimulation of the spinal root and the measurement of DML in LSS., Methods: In 39 patients with LSS, a total of 93 spinal roots were stimulated, and evoked electromyography was recorded at the leg muscles after decompression. DML was measured and its correlation with clinical severity, as evaluated by Zurich claudication questionnaire (ZCQ) and Short Form 36 (SF-36), was investigated., Results: For the stimulation of the L3, L4, and L5 spinal root, the mean DML (ms) were 6.8 (±1.4), 7.4 (±1.3), and 6.0 (±1.3) in gluteus medius, 9.3 (±1.5), 9.2 (±1.5), and 9.0 (±1.6) in biceps femoris, 9.7 (±1.0), 9.8 (±1.8), and 9.4 (±1.2) in vastus medialis, 16.1 (±1.0), 14.7 (±1.3), and 14.1 (±1.5) in tibialis anterior, and 16.4 (±1.4), 14.3 (±1.8), and 13.9 (±1.9) in gastrocnemius muscles. Statistically significant positive correlations were observed between DML and height. Preoperative symptom and function scores of ZCQ and postoperative bodily pain scores of SF-36 were significantly worse in the patients with prolonged DML., Conclusions: DML is thought to be useful for estimating the severity of spinal root impairment and for predicting the prognosis.

Objective: To elucidate the cutoff value for distal motor latency (DML) at which sensory nerve action potentials (SNAPs) are absent in carpal tunnel syndrome (CTS) patients., Method: We examined 157 hands in 129 patients with CTS retrospectively. We classified the patients according to whether SNAPs were successfully obtained. Group A consisted of hands with SNAPs, while Group B consisted of hands without SNAPs. The cutoff value for DML was determined by receiver-operating characteristic curve analysis. We enrolled 130 hands with CTS for the analysis, because measurements were successful in 130 hands for compound muscle action potentials and in 82 hands for SNAPs from a total of 157 hands investigated., Results: A significant correlation was observed between DML and SCV (P<0.0001, R*2=0.40). The most discriminative cutoff value for DML was 7.7ms, resulting in a sensitivity of 79.6% and specificity of 79.3%., Conclusion: Cases in which SNAPs are evoked despite a DML longer than 7.7ms should raise suspicion., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Pallido-pyramidal syndromes combine dystonia with or without parkinsonism and spasticity as part of a mixed neurodegenerative disorder. Several causative genes have been shown to lead to pallido-pyramidal syndromes, including FBXO7, ATP13A2, PLA2G6, PRKN and SPG11. Among these, ATP13A2 and PLA2G6 are inconsistently associated with brain iron deposition. Using homozygosity mapping and direct sequencing in a multiplex consanguineous Saudi Arabian family with a pallido-pyramidal syndrome, iron deposition and cerebellar atrophy, we identified a homozygous p.G53R mutation in C19orf12. Our findings add to the phenotypic spectrum associated with C19orf12 mutations., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Objective: We aim to draw clinical-neurophysiological correlations in our cohort of patients affected by IgM-related neuropathy to investigate whether neurophysiological parameters may help differentiate the classical phenotype from atypical forms., Methods: We retrospectively evaluated patients with IgM-related neuropathy referred to our Institute from 1990 to 2011. All patients underwent extensive laboratory, clinical and neurophysiological evaluation., Results: A classic sensory-ataxic form was observed in 20 of 34 patients, while an atypical phenotype (multiple mononeuropathy, polyneuropathy with predominant motor impairment, painful small-fibre neuropathy) was identified in the remaining 14 cases. Nerve conduction studies revealed in almost all cases a pattern typical of demyelination. A reduced terminal latency index and a prolonged distal motor latency of median nerve, as well as a prolonged distal motor latency and a reduced motor conduction velocity of peroneal nerve when recorded from extensor digitorum brevis, were significantly associated with classic sensory-ataxic phenotype. Conversely, a compound muscle action potential amplitude reduction of peroneal nerve from the tibialis anterior, was mostly associated with atypical forms., Conclusions: No clear electrophysiological differences between classical forms and atypical cases can be identified in IgM-related neuropathy. Still, we demonstrated that demyelinating abnormalities are more often associated with classical phenotypes, while axonal impairment occurs more often in atypical clinical patterns., Significance: Performing correlations between clinical and neurophysiological findings in IgM-related neuropathy may help to better understand different disease mechanisms in this heterogeneous form of inflammatory neuropathy., (Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: Workers exposed to vibrating tools may develop hand-arm vibration syndrome (HAVS). We assessed the somatosensory phenotype using quantitative sensory testing (QST) in comparison to electrophysiology to characterize (1) the most sensitive QST parameter for detecting sensory loss, (2) the correlation of QST and electrophysiology, and (3) the frequency of a carpal tunnel syndrome (CTS) in HAVS., Methods: QST, cold provocation tests, fine motor skills, and median nerve neurography were used. QST included thermal and mechanical detection and pain thresholds., Results: Thirty-two patients were examined (54 ± 11 years, 91% men) at the more affected hand compared to 16 matched controls. Vibration detection threshold was the most sensitive parameter to detect sensory loss that was more pronounced in the sensitivity range of Pacinian (150 Hz, x12) than Meissner's corpuscles (20 Hz, x3). QST (84% abnormal) was more sensitive to detect neural dysfunction than conventional electrophysiology (37% abnormal). Motor (34%) and sensory neurography (25%) were abnormal in HAVS. CTS frequency was not increased (9.4%)., Conclusion: Findings are consistent with a mechanically-induced, distally pronounced motor and sensory neuropathy independent of CTS., Significance: HAVS involves a neuropathy predominantly affecting large fibers with a sensory damage related to resonance frequencies of vibrating tools., (Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Objective: This study aims to investigate the involvement of the peripheral nervous system in Ehlers-Danlos syndromes/hypermobility type patients with particular attention to entrapment syndromes., Methods: We consecutively enrolled Ehlers-Danlos syndromes/hypermobility type patients. Patients underwent clinical, neurophysiological and ultrasound evaluations. Dynamic ultrasound evaluation was also performed in healthy subjects as control group., Results: Fifteen Ehlers-Danlos syndromes/hypermobility type patients and fifteen healthy subjects were enrolled. Most of patients presented tingling, numbness, cramps in their hands or feet. Clinical evaluation was normal in all patients. One patient was affected with carpal tunnel syndrome and one with ulnar nerve entrapment at elbow. One patient had an increased and hypoechoic ulnar nerve at elbow at ultrasound evaluation. Dynamic ultrasound evaluation of ulnar nerve at elbow showed, in patients, twelve subluxations and three luxations. In the control group dynamic evaluation showed one case of ulnar nerve luxation., Conclusion: Statistical analysis showed a significant difference in the occurrence of ulnar nerve subluxation and luxation between patients and control subjects., Significance: The study shows an inconsistency between symptoms and neurophysiological and ultrasound evidences of focal or diffuse nerve involvement. The high prevalence of ulnar nerve subluxation/luxation at elbow in Ehlers-Danlos syndromes/hypermobility type patients could be explained by the presence of Osborne ligament laxity., (Copyright © 2013. Published by Elsevier Ireland Ltd.)

This research used distal motor latency (DML) and vibration thresholds (VT) to evaluate 84 hand activity and wrist deviation combinations to determine the best association with carpal tunnel syndrome (CTS). Female volunteers, 2 healthy and 2 CTS diagnosed, were age matched and operated a keyboard for 4 hrs a day. Room temperature was 28°C(±2). Beginning DML and VT were taken with a relaxed neutral posture hand. The wrist was deviated in a randomly selected combination, and determinations were taken at 5-min intervals. The trial ended at 20 min or when discomfort was felt. The CTS conditions were discriminated by pain four times, DML once, and VT 14 times. Vibrometry was the most consistent CTS discriminator. The best VT results for wrist positions were obtained with wrist extension and extended extension, whereas the unclenched, clenched, and loaded power grip activities proved to be the most consistent hand activities.