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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 mm2) or "clear" (MNCSA ≥ 13 mm2) 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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.

To assess whether patients with acute inflammatory demyelinating polyneuropathy (AIDP) associated with SARS-CoV-2 show characteristic electrophysiological features. 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. 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. 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. [ABSTRACT FROM AUTHOR]

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 [ABSTRACT FROM AUTHOR]

Zusammenfassung Die Untersuchung der distal motorischen Latenz ist Standard zur Diagnose der Karpaltunnelsyndroms. Obwohl einfach auszuführen birgt sie einige Fehler. Die gilt es zu erkennen und zu vermeiden. Dazu dienen Standard Operating Procedures (SOPs), die die Untersuchung sehr detailliert beschreiben und damit deren Sicherheit erhöhen. Summary The examination of the distal motor latency is standard for the diagnosis of carpal tunnel syndrome. Although simple to run, it contains some errors. They must be recognized and avoided. Standard Operating Procedures (SOPs) are used to describe the investigation in a very detailed manner and thus increase their safety. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The result of an electromyography (EMG) test may be influenced by many factors. A fundamental effect on nerve impulse conduction has a skin temperature. Its reduction leads to a reduced conduction velocity and distal latency prolongation. Therefore the methodology recommends the skin temperature between 32-36 °C and below this value the examination cannot be considered valid. In case of insufficient skin temperature, the patients' limbs are necessary to be heat up first. If heat up is not possible an emergency solution is applied by the correction of observed distal latency values of 0.3 ms or of 0.1 ms for every degree under the standard temperature. The aim of this study was to compare the measurement results of the distal motor latency (DML) of median nerves at the lack of skin temperature and after heating hands at standard temperature. The further goal was to verify the reliability of the DML measurement results after applying the above corrections during the screening EMG within occupational medicine examinations. DML measurement of median nerves in wrist area was realized by the EMG TruTrace 2 device, which also includes a device for continuous measurement of skin temperature. In total 40 persons were examined - first at room temperature, when the skin temperature of hands did not reached 32 °C, and retested after heating hands up to the standard temperature 33-36 °C. DML values were compared by a paired t-test and evaluated on the 5% level of significance. The data analysis was conducted using the software STATA v.13. In comparison with the DML results after heating up to the standard temperature the DML values at room temperature were significantly prolonged (p < 0.001) that led to false positive results in 55 % of the findings. Conversely, if correction 0.3 ms/1 °C was applied the resulting DML values significantly decreased (p < 0.001) and thus led to false negative results. Neither the correction 0.1 ms/1 °C has not been confirmed, as reliable especially in persons with borderline, and abnormal findings, whose results showed statistically significant differences (p < 0.05). In conclusion, it can be summarized that a lack of compliance with the standard skin temperature during the DML testing poses a significant risk of false positive findings. The study results did not confirm the reliability of the corrections which use in practice may be a significant source of errors, especially in the case of abnormal or borderline findings. Although the abnormal findings of the EMG screening are verified by a neurologist examination, the standard methodology including recommended skin temperature is necessary to be respected during the screening test. Compliance with those conditions lead to a minimization of errors in tests and interpreting the results. [ABSTRACT FROM AUTHOR]

Background: Studies have shown slow healing of peripheral nerve injury in elderly patients. Carpal tunnel syndrome (CTS) is the most frequent compressive mononeuropathy, affecting mostly older people and females. Few studies have assessed electrophysiological differences between younger and older patients. We aimed to evaluate age-dependent differences in electrophysiological parameters preoperatively and postoperatively over a 100-day postoperative period. Method: This retrospective study included 258 hands of patients who underwent conventional open-technique carpal tunnel syndrome surgery. Patients with paresthesia in the median nerve distribution or with impaired sensation or abnormal findings in sensory and motor median nerve conduction studies were enrolled. The age dependence of the preoperative values of distal motor latency, amplitude of the compound motor action potential and sensory conduction velocity was estimated using regression analysis. Results: Statistically significant age dependence was found for the preoperative distal motor latency, compound motor action potential, amplitude and sensory conduction velocity. The repair of segmental demyelination was nearly twice as slow in the older group, at a 5 % significance level, even when comparing groups with the same preoperative distal motor latency. Conclusions: Analysis of preoperative nerve conduction parameters indicates that surgery for carpal tunnel syndrome is performed later in older patients. [ABSTRACT FROM AUTHOR]

Highlights: [•] Polyneuropathy associated with IgM monoclonal gammopathy is an immune-mediated polyneuropathy clinically characterized by symmetrical, distal polyneuropathy with predominant sensory ataxia. [•] Many cases of IgM-related neuropathy with a clinical phenotype not fitting the classic sensory-ataxic form have been described in literature. [•] Present findings suggest that demyelinating abnormalities in nerve conduction studies are more often associated with classical forms while axonal impairment occurs more often in atypical phenotypes. [ABSTRACT FROM AUTHOR]

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.)

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Summary: Objective: This paper describes a new electrode placement for recording compound muscle action potentials (CMAPs) of the first dorsal interosseous muscle (FDI) to determine the distal motor latency (DML) and study nerve conduction of the ulnar nerve across the wrist. Methods: The DML to the FDI was evaluated bilaterally in 90 subjects after stimulation 1cm proximal to the distal wrist crease and at the palm. The CMAP was recorded with a pair of disposable surface electrodes fixed over the FDI and wrist. Results: The CMAP never exhibited a positive initial deflection, with a gain of 0.5mV per division. DML to the FDI was 2.65±0.26ms (mean±SD), and CMAP amplitude was 14.7±3.3mV. A prolonged DML was taken as 3.4ms (mean+3standard deviation [SD]). Conclusions: This new electrode placement offers more reproducible results for determining the DML to the FDI as it provides the shortest DML, and the tightest SD values. Significance: This result is obtained through the respect of fundamental rules for CMAP recording, as it shows no positive wave at the onset of the CMAP of the FDI. Its use should improve the diagnosis of ulnar nerve lesions at the wrist and more especially of the deep motor branch. [ABSTRACT FROM AUTHOR]

Abstract: Nerve conduction slowing in amyotrophic lateral sclerosis (ALS) is usually caused by loss of fast motor axons. We studied the frequency, extent, and distribution of prominently prolonged distal motor latencies in ALS. We reviewed results of median, ulnar, and tibial nerve conduction studies in 91 patients with ALS, 24 with lower motor neuron disorders, and 36 with axonal neuropathy. Coincidental carpal tunnel syndrome was found for 4 (4.4%) of the ALS patients who were excluded from analyses. Markedly prolonged distal latencies (>125% of the upper limit of normal) were found only in the median nerve of ALS patients (9%), and in none of the disease controls. Excitability studies suggested membrane depolarization in some ALS patients. Our results show that approximately 10% of ALS patients shows prominently prolonged median distal latency, which cannot be explained by axonal loss and carpal tunnel lesion. The distal nerve conduction slowing may partly be caused by membrane depolarization possibly due to motor neuronal degeneration in ALS. We suggest that recognition of the pattern of distal motor axonal dysfunction predominant in the median nerve is clinically important, and could provide additional insights into the pathophysiology of ALS. [Copyright &y& Elsevier]

Abstract: Objective: To evaluate the diagnostic value of second lumbrical and interossei distal motor latency difference (2LIDMLD) in diagnosing CTS of different electro-physiological grades of CTS. Methods: 2LIDMLD was standardized in 120 hands of healthy controls. Subjects with clinically diagnosed CTS and CTS with incidental polyneuropathy were prospectively evaluated with 2LIDMLD in addition to other standard diagnostic tests. Sensitivities of these tests were compared in patients with CTS of varying grades of severity and CTS associated with polyneuropathy. Results: Two hundred and fifty hands of 130 patients met the clinical criteria for CTS. Sensitivity and specificity of 2LIDMLD, palm–wrist distal sensory latency difference (PWDSLD), and median distal motor latency (MDML) were 85.60% and 96.67%, 68.80% and 96.10%, 60.80% and 97%, respectively. Sensitivity of 2LIDMLD in mild CTS was similar to that of PWDSLD. In severe CTS, and CTS with polyneuropathy, 2LIDMLD was the most sensitive test. It was the only test of localizing value in 16% of hands with severe CTS, when all other methods failed due to absent median motor and sensory responses. Conclusions: 2LIDMLD is a sensitive, specific for diagnosis of all grades of CTS. It is an accurate and reliable method that helps especially in diagnosis of severe CTS and CTS associated with polyneuropathy, when other standard localized tests fail. Significance: The second lumbrical is relatively less affected in severe carpal tunnel syndrome and median to ulnar comparison, using 2LIDMLD, appears to be a reliable and a valuable technique in the localization of severe CTS and CTS associated with polyneuropathy, especially when the median sensory or motor responses are absent on routine conduction studies. [Copyright &y& Elsevier]

Objectives: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder, characterized by a selective progressive degeneration of the motor system. Electromyography is essential for the diagnosis of ALS. The measurement of motor conduction of peripheral nerves is of major importance to recognize other possible causes of progressive muscle wasting. However, there are also pathologic changes in nerve conduction studies in ALS patients. Methods: In this study we analysed the values of distal motor latency (DML), compound muscle action potential (CMAP) and motor nerve conduction velocity (MNCV) in 95 patients with definite ALS. Results: We found slight slowing of MNCV and moderate to strong reduction of CMAP and a prolongation of DML. We found no significant correlation between MNCV and CMAP. Discussion: The main finding of the present work was the negative correlation between DML and CMAP. It is interpreted as a very distal axonal damage as the main reason for prolongation of DML in ALS patients. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Median nerve entrapment neuropathy at the wrist can be accompanied by slowed motor conduction within the forearm. Existing studies conflict regarding a correlation between the severity of the entrapment neuropathy in carpal tunnel syndrome (CTS) and slowing of median motor nerve conduction velocity (MNCV) in the forearm. Here, it was asked if there is a correlation between markers of CTS severity and median forearm MNCV, and if there is an explanation for the preceding conflicting results. Methods: Median MNCV in the forearm was correlated with neurophysiologic markers of severity of a median neuropathy at the wrist in 91 hands from 64 patients with clinical and electrodiagnostic evidence of CTS. Results: Median MNCV within the forearm segment was negatively correlated with the median nerve distal motor latency (r =−0.64, P <0.001, n =91) and positively correlated with the CMAP amplitude of the abductor pollicis brevis muscle (r =0.45, P <0.001, n =91). These correlations only occurred in patients with a prolonged median distal motor latency. Previous investigations that failed to find such correlations used variable or non-standardized methods or analyzed smaller numbers of patients. Conclusions: Slowing of median MNCV in the forearm is related to the severity of the entrapment of median motor fibers at the wrist. Significance: Slowed forearm median MNCV can be a marker of motor nerve injury at the wrist. [Copyright &y& Elsevier]

Abstract: Objective: Distal motor latency (DML) is shortened when the anode is held distally instead of the cathode by increasing the stimulus intensity. The objective of this study was to clarify the mechanism responsible for this shortening. Methods: In seven healthy subjects, compound muscle action potential (CMAP) was obtained from the thenar muscle by bipolar stimulation of the median nerve at the wrist, and the intensity at which the first motor units were stimulated was defined as the threshold. Bipolar stimulation with extended interpole distance was employed to identify the generating site of the CMAP and F-wave. Results: The shortening of DML was dependent on the stimulus intensity and threshold. For the low threshold condition, the CMAP generating site was replaced from the proximal cathodal pole to the distal anodal pole by increasing the stimulus intensity. The generating site of the F-wave remained at the proximal cathodal pole irrespective of stimulus intensity. Conclusions: Replacement of the generating site results in the shortening of DML. When the F-wave is recorded after being induced by anode distal stimulation, CMAP should not be simultaneously evaluated. Significance: This study clarified the generation sites of CMAP and the F-wave when induced by anode distal stimulation. [Copyright &y& Elsevier]

There is debate whether the terminal latency index (TLI) is a sensitive marker for polyneuropathy with anti-myelinassociated-glycoprotein antibodies (anti-MAGP). We examined 6 patients with an anti-MAGP and 6 patients with a chronic inflammatory demyelinating polyneuropathy (CIDP). The electroneurographic features studied were: distal compound motor action potential (CMAP), distal motor latency (DML), motor conduction velocity (MCV) elbow to wrist (distal MCV), MCV axilla to elbow (proximal MCV), MCV distal/proximal, terminal latency index (TLI), residual latency (RL), F-wave, and modified F ratio.We found significant differences between anti-MAGP and CIDP for DML and for RL.No significant differences were found for TLI and the other measures. The TLI values were not significant probably because our patients had a longer duration of disease,which supports the hypothesis of a distal to proximal progression of conduction slowing over time. We propose that a residual latency >4.0 and a distal motor latency >7.0 are strongly suggestive for an anti- MAGP. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to compare the results of our endoscopic management of carpal-tunnel syndrome caused by long-term haemodialysis to that with no apparent cause (idiopathic). We have operated on 551 hands in 370 patients using the Universal Subcutaneous Endoscope system under local anaesthesia without a pneumatic tourniquet on an out-patient basis since 1986. Ninety-six hands in 64 patients who suffered from carpal-tunnel syndrome from long-term haemodialysis and 85 hands in 52 patients who suffered from carpal-tunnel syndrome for no apparent cause were statistically analysed using complete pre- and postoperative electrophysiological and clinical studies for periods of time ranging from over 6 months to 4.8 years (mean 16.9 months). Electrophysiological and clinical results showed that our endoscopic management in long-term haemodialysis patients is effective, safe and yields the same results as in patients who suffered from carpal-tunnel syndrome for no apparent cause. [ABSTRACT FROM PUBLISHER]

Surgical decompression of the median nerve is a standardized treatment for carpal tunnel syndrome. After surgery a clinical and neurophysiological improvement is observed also on severe cases. We report 4 cases of carpal tunnel syndrome (CTS) in the hands of 3 patients with prolonged median wrist-thenar distal motor latency (longer than 10 ms, normal values < 4.0 ms) and absence of digit-wrist sensory responses. In these patients surgery caused complete loss of median nerve function. Such a marked increase of median distal motor latency (DML) is rare (0.6% in 500 CTS hands consecutively examined in our laboratory) and suggests the presence of a chronic condition with severe disruption of the myelin. On the basis of these anecdotal observations, we suggest that patients with median DML of 10 ms or more be considered at high risk for CTS surgery failure. [ABSTRACT FROM AUTHOR]

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.

Abstract: Background: With increase in type 2 diabetes mellitus patients the complications of diabetes are being seen more frequently. Patients with diabetic neuropathy often present with distressing symptoms such as pain and burning sensation in the feet. Tarsal tunnel syndrome with electrophysiological changes may be a causative or contributing factor. The present study was designed to assess the presence and features of tarsal tunnel syndrome in diabetes mellitus patients. Method: In this study a group of 10 normal volunteers were selected who had no neurological complaints or foot trauma. Another group of 33 patients having longstanding diabetes mellitus with complaints of pain, burning sensation and paraesthesia in the feet were selected for electrophysiological tests and median plantar nerve was studied. Results: In the present study we observed that 15 (45%) of diabetic cases showed abnormal findings e.g., prolonged distal motor latency, decreased amplitude of M-response, low or absent sensory response suggesting tarsal tunnel syndrome. Conclusion: This study shows that the tarsal tunnel syndrome may be present in a significant number of diabetic patients with subjective neuropathic symptoms in the feet. The tarsal tunnel syndrome should be kept in mind during the diagnostic workup and management of diabetes mellitus. [Copyright &y& Elsevier]

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: 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.