Exploring the Potential of a Questionnaire in Predicting Results of Nerve Conduction Studies in Patients with Suspected Carpal Tunnel Syndrome: Exploring a Clinician and Patient Complete Version

This evaluation of the Carpal Tunnel Questionnaire (CTQ) was designed to establish the validity and flexibility of its potential use both within a primary and secondary care setting. The questionnaire was originally designed to predict the positive and negative outcome of Nerve Conduction Studies (NCS) in those patients with suspected Carpal Tunnel Syndrome (CTS). Prior to being seen by the hand specialist patients who had been referred with suspected CTS where asked to complete the CTQ. These questionnaires were coded and filed by the clinic nurse. The hand specialist then completed the questionnaire with the patient preceding NCS. Questionnaires were scored subsequent to the appointment. Results for the hand specialist completed questionnaire showed an 80% specificity and 92% sensitivity regarding the ability of the CTQ to predict a positive NCS using a pre-determine cut-off score. The patient completed questionnaire showed a 70.67% specificity and 72% sensitivity. Using receiver operating characteristics a threshold score could be determined to achieve 100% sensitivity/specificity for both questionnaires. This questionnaire provides a useful addition in the assessment of patients with suspected carpal tunnel syndrome and could be used in a range of clinical settings although the scoring cut-off may need to be adapted depending on whether the questionnaire was completed by the clinician or patient. Using the questionnaire in a clinical setting would reduce the requirement for NCS by 60%, this would offer significant time and cost savings.

Preliminary Study on the Lesion Location and Prognosis of Cubital Tunnel Syndrome by Motor Nerve Conduction Studies

Background：To study lesions＇ location and prognosis of cubital tunnel syndrome （CubTS） by routine motor nerve conduction studies （MNCSs） and short-segment nerve conduction studies （SSNCSs,inching test）.Methods：Thirty healthy subjects were included and 60 ulnar nerves were studied by inching studies for normal values.Sixty-six patients who diagnosed CubTS clinically were performed bilaterally by routine MNCSs and SSNCSs.Follow-up for 1-year,the information of brief complaints,clinical symptoms,and physical examination were collected.Results：Sixty-six patients were included,88 of nerves was abnormal by MNCS,while 105 was abnormal by the inching studies.Medial epicondyle to 2 cm above medial epicondyle is the most common segment to be detected abnormally （59.09％）,P ＜ 0.01.Twenty-two patients were followed-up,17 patients＇ symptoms were improved.Most of the patients were treated with drugs and modification of bad habits.Conclusions：（1） SSNCSs can detect lesions of compressive neuropathy in CubTS more precisely than the routine motor conduction studies.（2） SSNCSs can diagnose CubTS more sensitively than routine motor conduction studies.（3） In this study,we found that medial epicondyle to 2 cm above the medial epicondyle is the most vulnerable place that the ulnar nerve compressed.（4） The patients had a better prognosis who were abnormal in motor nerve conduction time only,but not amplitude in compressed lesions than those who were abnormal both in velocity and amplitude.Our study suggests that SSNCSs is a practical method in detecting ulnar nerve compressed neuropathy,and sensitive in diagnosing CubTS.The compound muscle action potentials by SSNCSs may predict prognosis of CubTS.

Nerve conduction studies in patients with dermatomyositis or polymyositis

Background Involvement of peripheral nerves in dermatomyositis （DM） and polymyositis （PM） is less well known. In the present study we retrospectively analyzed the clinical and electrophysiological records of hospital inpatients with a diagnosis of DM or PM to investigate the association of DM/PM and peripheral neuropathy. Methods The data of inpatients diagnosed with DM or PM were collected in Peking Union Medical College Hospital, and 186 patients （118 patients with DM and 68 with PM） were retrospectively analyzed. Nerve conduction studies （NCSs） of the median nerve, ulnar nerve, posterior tibial nerve, and common peroneal nerve were examined simultaneously. Results There were 71 （38.2%） patients with abnormal NCS findings, 37 （19.9%） with pure motor involvement （decreased compound muscle action potential, CMAP）, and 34 （18.3%） with peripheral neuropathy. Of the 34 peripheral neuropathy patients, 14 （7.5%） had polyneuropathy, 1 （0.5%） had multiple mononeuropathy, 16 （8.6%） had carpal tunnel syndrome （CTS）, 1 （0.5%） had trigeminal sensory neuropathy, 1 （0.5%） had ulnar sensory neuropathy, and 1 （0.5%） had brachial plexus involvement. The prevalence of malignant disease （3/34, 8.8%）, other connective tissue diseases （CTDs） （7/34, 20.6%） and diabetes （6/34, 17.6%） was significantly greater in DM/PM patients with peripheral neuropathy （X2=15.855, P=0.000） compared with DM/PM patients without involvement of peripheral nerves （5/115, 4.3% and 7/115, 6.1%, respectively）. Conclusions Peripheral neuropathy in DM/PM often suggests a complication with cancer, other CTDs, diabetes or CTS. From a practical point of view, NCS for DM/PM may help find the underlying disorders.

Motor versus Sensory Nerve Conduction Monitoring of Median Nerve during Carpal Tunnel Surgery

Background/Aim: Carpal tunnel syndrome (CTS) is one of the most common compressive, canalicular neuropathies of the upper extremities, causing hand pain and impaired function. This clinical study was designed to compare the intraoperative median nerve distal motor latency (DML) versus the distal sensory latency (DSL) and sensory nerve conduction velocity (SNCV) during surgical treatment of CTS. Patients and Methods: A total number of 36 wrists in 30 patients with CTS diagnosed by preoperative median MNCS who underwent surgical intervention for median nerve release. Intraoperative measurements of motor distal latency (DML) and proximal latency, amplitude, and conduction velocity and distal sensory latency (DSL), amplitude, and conduction velocity of both the median and ulnar nerves before and after division of the flexor retinaculum (FR). Results: A significant decrease of the intraoperative median nerve distal motor latency (DML) after release (8.89 ± 0.93) in comparison with the preoperative median nerve DML (6.24 ± 1.06) with (p < 0.001*). But intraoperative distal sensory latency (DSL) and sensory nerve conduction velocity (SNCVM) show non-significant decrease (p = 0.161). Conclusion: Intraoperative monitoring of median nerve show rapidly improve Intraoperative motor nerve conduction than the sensory nerve conduction after release the FR during carpal tunnel surgery.

Acupuncture in diabetic peripheral neuropathy-neurological outcomes of the randomized acupuncture in diabetic peripheral neuropathy trial

BACKGROUND Diabetic peripheral neuropathy(DPN)is a common complication of diabetes mellitus and can lead to serious complications.Therapeutic strategies for pain control are available but there are few approaches that influence neurological deficits such as numbness.AIM To investigate the effectiveness of acupuncture on improving neurological deficits in patients suffering from type 2 DPN.METHODS The acupuncture in DPN(ACUDPN)study was a two-armed,randomized,controlled,parallel group,open,multicenter clinical trial.Patients were randomized in a 1:1 ratio into two groups:The acupuncture group received 12 acupuncture treatments over 8 wk,and the control group was on a waiting list during the first 16 wk,before it received the same treatment as the other group.Both groups received routine care.Outcome parameters were evaluated after 8,16 and 24 wk and included neurological scores,such as an 11-point numeric rating scale(NRS)11 for hypesthesia,neuropathic pain symptom inventory(NPSI),neuropathy deficit score(NDS),neuropathy symptom score(NSS);nerve conduction studies(NCS)were assessed with a handheld point-of-care device.RESULTSSixty-two participants were included.The NRS for numbness showed a difference of 2.3(P<0.001)in favor of theacupuncture group,the effect persisted until week 16 with a difference of 2.2(P<0.001)between groups and 1.8points at week 24 compared to baseline.The NPSI was improved in the acupuncture group by 12.6 points(P<0.001)at week 8,the NSS score at week 8 with a difference of 1.3(P<0.001);the NDS and the TNSc score improvedfor the acupuncture group in week 8,with a difference of 2.0 points(P<0.001)compared to the control group.Effects were persistent in week 16 with a difference of 1.8 points(P<0.05).The NCS showed no meaningfulchanges.In both groups only minor side effects were reported.CONCLUSION Study results suggest that acupuncture may be beneficial in type 2 diabetic DPN and seems to lead to a reductionin neurological deficits.No serious adverse events were recorded and the adherence to treatment was high.Confirmatory randomized sham-controlled clinical studies with adequate patient numbers are needed to confirmthe results.

Exploratory use of ultrasound to determine whether demyelination following carpal tunnel syndrome co-exists with axonal degeneration

Carpal tunnel syndrome （CTS） accompanied by secondary axonal degeneration cannot be clearly dis- criminated using the current cross-validated ultrasound severity classification system. This study aimed at exploring cut-off values of ultrasound parameters, including wrist cross-sectional area （W-CSA）, wrist perimeter （W-P）, ratio of cross-sectional area （R-CSA） and perimeter （R-P）, changes of CSA and P from wrist to one third distal forearm （△CSA＆AP） for differentiation. Seventy-three patients （13 male and 60 female） were assigned into group A （demyelination only, n = 40） and group B （demyelination with secondary axonal degeneration, n = 33） based on the outcomes of nerve conduction studies （NCS）. Receiver Operative Characteristics （ROC） curves were plotted to obtain sensitivity, specificity, and accuracy of cut- off values for all the ultrasound parameters. The overall identified cut-off values （W-CSA 12.0 mm2, W-P 16.27 mm, R-CSA 1.85, R-P 1.48, △CSA 6.98 mm2, △P 5.77 mm） had good sensitivity （77.1-88.6%）, fair specificity （40-62.2%） and fair-to-good accuracy （0.676-0.758）. There were also significant differences in demographics （age and severity gradation, P 〈 0.001）, NCS findings （wrist motor latency and conduction velocity, P 〈 0.0001; wrist motor amplitude, P 〈 0.05; distal sensory latency, P 〈 0.05; sensory amplitude, P 〈 0.001） and ultrasound measurements （W-CSA, W-P, R-CSA, R-P, △CSA＆△P, P 〈 0.05） between groups. These findings suggest that ultrasound can be potentially used to differentiate demyelinating CTS with sec- ondary axonal degeneration and provide better treatment guidance.

Neural plasticity secondary to carpal tunnel syndrome: a pseudo-continuous arterial spin labeling study

Conventional neuroimaging techniques cannot truly reflect the change of regional cerebral blood flow in patients with carpal tunnel syndrome.Pseudo-continuous arterial spinning labeling(pCASL)as an efficient non-invasive neuroimaging technique can be applied to directly quantify the neuronal activities of individual brain regions that show the persistent symptoms owing to its better spatial resolution and increased signal-to-noise ratio.Therefore,this prospective observational study was conducted in 27 eligible female carpal tunnel syndrome,aged 57.7±6.51 years.Psychometric tests,nerve conduction studies and pCASL neuroimaging assessment were performed.The results showed that the relevant activated brain regions in the cortical,subcrotical,and cerebral regions were correlated with numbness,pain,functionality,median nerve status and motor amplitude of median nerve(K=21–2849,r=–0.77–0.76,P<0.05).There was a tendency of pain processing which shifted from the nociceptive circuitry to the emotional and cognitive one during the process of chronic pain caused by carpal tunnel syndrome.It suggests the necessity of addressing the ignored cognitive or emotional state when managing patients with carpal tunnel syndrome.Approval for this study was obtained from the Institutional Review Board of The University of Hong Kong/Hospital Authority Hong Kong West,China(HKU/HA HKW IRB,approval No.UW17-129)on April 11,2017.This study was registered in Clinical Trial Registry of The University of Hong Kong,China(registration number:HKUCTR-2220)on April 24,2017.

Factors Associated with Peripheral Neuropathy in Type 2 Diabetes： Subclinical versus Confirmed Neuropathy

This study determined the prevalence of diabetic peripheral neuropathy(DPN) and subclinical DPN(s DPN) in patients with type 2 diabetes mellitus(T2DM) using nerve conduction study(NCS) as a diagnostic tool. We also investigated the factors associated with the development of s DPN and compared factors between the sD PN and confirmed DPN(cDPN). This cross-sectional study involved 240 T2DM patients who were successively admitted to the endocrinology wards of Wuhan Union Hospital over the period of January to December 2014. Data on the medical history, physical and laboratory examinations were collected. DPN was diagnosed using NCS. One-way ANOVA with least significant difference(LSD) analysis or chi-square tests was used to compare parameters among DNP-free, s DPN and c DPN patients. Independent factors associated with s DPN were determined using logistic regression. The results showed that 50.8% of the participants had DPN, and among them, 17.1% had sDPN. sDPN showed significant independent associations with age, height, HbA1c, presence of atherosclerosis and diabetic retinopathy. Patients with DPN differed significantly from those without DPN with respect to age, duration of disease(DOD), HbA1c, presence of atherosclerosis, diabetic retinopathy, nephropathy and hypertension. Patients with cDPN, relative to those with sDPN, had significantly longer DOD and higher prevalence of peripheral artery disease(PAD) and coronary artery disease(CAD). Our study suggests that a significant number of T2DM patients are affected by s DPN, and the development of this condition is associated with advanced age, tall stature, poor glycaemic control, presence of diabetic retinopathy and atherosclerosis. On the other hand, patients with cDPN tend to have a longer DOD and are more likely to suffer from PAD and CAD.

Effect of Elbow Position on Short-segment Nerve Conduction Study in Cubital Tunnel Syndrome

Background： The appropriate elbow position of short-segment nerve conduction study （SSNCS） to diagnose cubital tunnel syndrome （CubTS） is still controversial. The goal of this study was to determine the effect of different elbow positions at full extension and 70° flexion on SSNCS in CubTS. Methods： In this cross-sectional study, the clinical data of seventy elbows from 59 CubTS patients between September, 2011 and December, 2014 in the Peking University First Hospital were included as CubTS group. Moreover, thirty healthy volunteers were included as the healthy group. SSNCS were conducted in all subjects at elbow fhll extension and 70° elbow flexion. Paired nonparametric test, bivariate correlation, Bland-Altman, and Chi-squared test analysis were used to compare the effectiveness of elbow full extension and 70° flexion elbow positions on SSNCS in CubTS patients. Results： Data of upper limit was calculated from healthy group, and abnormal latency was judged accordingly. CubTS group＇s latency and compound muscle action potential （CMAP） of each segment at 70° elbow flexion by SSNCS was compared with lull extension position, no statistically significant difference were found （all P 〉 0.05）. Latency and CMAP of each segment at elbow full extension and 70° flexion were correlated （all P 〈 0 elbow （P - 0.43）, and the latency （P = 0.15） and the CMAP （P = 01）, except the latency of segment of 4 cm to 6 cm above 0.06） of segment of 2 cm to 4 cm below elbow. Bivariate correlation and Bland-Altman analysis proved the correlation between elbow full extension and 70° flexion. Especially in segments across the elbow （2 cm above the elbow and 2 cm below it）, latency at elbow full extension and 70° flexion were strong direct associated（r=0.83, P〈0.01;r=0.55, P〈0.01）,andsodidtheCMAP（r 0.49, P〈0.01;r=0.72, P〈0.01）.Therewasno statistically significant difference in abnormality of each segment at full extension as measured by SSNCS compared with that at 70° flexion （P 〉 0.05, respectively）. Conclusions： There was no statistically significant difference in the diagnosis of CubTS with the elbow at full extension compared with that at 70° flexion during SSNCS. We suggest that elbow positon at full extension can also be used during SSNCS.

The Clinical Value of the Self-Administered Kamath and Stothard’s Questionnaire in the Diagnostics of Carpal Tunnel Syndrome

The clinician-administered Kamath and Stothard’s questionnaire is a recommended tool for assessing Carpal Tunnel Syndrome (CTS). The authors investigated whether the self-administered Kamath and Stothard’s questionnaire (KSQ) can categorize the severity of CTS according to the Nerve Conduction Study (NCS) and predict the outcome of Carpal Tunnel Release (CTR). One hundred and forty-two consecutive patients were enrolled in this prospective study, who completed the KSQ and were referred for NCS. Symptom relief after CTR was considered as the reference standard. KSQ’s scores were compared with the severity of CTS confirmed by NCS and the effectiveness of the surgery, Sensitivity and Positive Predictive Value (PPV) of the KSQ was calculated. The sensitivity of KSQ in each NCS severity category (mild, moderate, and severe CTS) was low (11.9% - 50.0%), however, the sensitivity and PPV of KSQ in the moderate + severe CTS category was 88.9% and 95.5%. The KSQ score of 5 or greater was found to be correlated with a successful CTR (sensitivity 92.8%, PPV of 90.2%). The study revealed that the KSQ with a score of 5 or greater is able to distinguish the mild conditions from moderate and severe ones. The KSQ’s score of 5 or greater also can predict the successful outcome of CTR. The authors believe that in addition to reducing the duration and cost of diagnostics, the KSQ can also reduce patient appointments and clinic time. Application of the KSQ may be of paramount importance in the current Covid pandemic era.

Clinical neurophysiology and imaging of nerve injuries:preoperative diagnostic work-up and postoperative monitoring

Peripheral nerve injuries are a heterogeneous group of lesions that may occurs secondary to various causes.Several different classifications have been used to describe the pathophysiological mechanisms leading to the clinical deficit,from simple and reversible compression-induced demyelination,to complete transection of nerve axons.Neurophysiological data localize,quantify,and qualify(demyelination vs.axonal loss)the clinical and subclinical deficits.High-resolution ultrasound can demonstrate the morphological extent of nerve damage,fascicular echotexture(epineurium vs.perineurium,focal alteration of the cross-section of the nerve,any neuromas,etc.),and the surrounding tissues.High field magnetic resonance imaging provides high contrast neurography by fat suppression sequences and shows structural connectivity through the use of diffusion-weighted sequences.The aim of this review is to provide clinical guidelines for the diagnosis of nerve injuries,and the rationale for instrumental evaluation in the preoperative and postoperative periods.While history and clinical approach guide neurophysiological examination,nerve conduction and electromyography studies provide functional information on conduction slowing and denervation to assist in monitoring the onset of re-innervation.High-resolution nerve imaging complements neurophysiological data and allows direct visualization of the nerve injury while providing insight into its cause and facilitating surgical treatment planning.Indications and limits of each instrumental examination are discussed.

Efficacy and safety of Buyang Huanwu decoction(补阳还五汤)for diabetic peripheral neuropathy:a systematic review and Meta-analysis

OBJECTIVE:To evaluate the efficacy and safety of Buyang Huanwu decoction(BYHWD)in treating diabetic peripheral neuropathy(DPN).METHODS:Eight electronic databases,including China National Knowledge Infrastructure Database,Wanfang Database,China Science and Technology Journal Database,Chinese Biomedical Literature Database,Cochrane Library,Embase,Web of Science,and PubM ed,were searched for randomized controlled trials(RCTs)of BYHWD to treat DPN.We identified all RCTs related to BYHWD and those on the treatment of DPN with the combination of mecobalamin.RevMan software was used for the statistical analysis.RESULTS:Twenty-one RCTs with a total of 1945 patients were included.The methodological quality of the literature included was low.Meta-analysis showed that the efficacy of the treatment group was significantly better than that of the control group in the treatment of DPN with BYHWD[risk ratio(RR)=0.33,95%CI(0.27,0.40),Z=11.25,P<0.00001].The median nerve of median motor nerve conduction velocity(MNCV)[mean difference(MD)=4.16,95%CI(1.35,6.98)]and median sensory NCV(SNCV)[(MD=3.28,95%CI(2.35,4.22)]were improved in the treatment group.The MNCV in the common peroneal nerve[(MD=1.63,95%CI(0.39,2.87)]and SNCV[(MD=4.56,95%CI(3.16,5.97)]were significantly higher than those in the control group(P<0.01).Plasma viscosity[(MD=-0.15,95%CI(-0.20,-0.09),Z=5.17,P<0.01)],whole blood high shear[(MD=-0.83,95%CI(-1.56,-0.11),Z=2.26,P=0.02)]and whole blood low shear[(MD=-1.61,95%CI(-2.28,-0.94),Z=4.68,P<0.01)]decreased significantly after treatment.There was no significant difference in fasting blood glucose[(MD=-0.42,95%CI(-0.89,0.05),Z=1.76,P=0.08)]between the treatment and control groups;postprandial blood glucose[(MD=-0.62,95%CI(-1.19,0.05),Z=2.12,P=0.03)]decreased significantly.No significant difference was found in the blood lipid levels between the treatment and control groups,including triglycerides[(MD=-0.21,95%CI(-0.52,0.10),Z=1.34,P=0.18)]and cholesterol[(MD=-0.13,95%CI(-0.27,0.00),Z=1.92,P=0.06)].Of the 21 RCTs,only five reported adverse reactions,and four studies reported the length of follow-up.No serious adverse events were reported.None of the studies reported the quality of life and economic conditions.CONCLUSIONS:Our study suggests that BYHWD has a significant therapeutic effect on DPN.High-quality,largescale RCTs are needed to provide more reliable evidence.

Clinical Characteristics, Electrophysiology, and Skin Biopsy of 38 Peripheral Neuropathy Cases with Small Fiber Involvement of Various Etiologies

Background：In small fiber neuropathy （SFN）,thinly myelinated Aδ and unmyelinated C fibers are primarily affected,resulting in sensory and/or autonomic symptoms.Various etiologies have been shown to be associated with SFN.This study was aimed to analyze a variety of features in peripheral neuropathy （PN） with small fiber involvement.and to compare disease severity among patients with idiopathic PN,PN associated with impaired glucose tolerance （IGT）,and metabolic syndrome （MS） PN.Methods：Thirty-eight PN patients with small fiber involvement were enrolled from December 20,2013 to May 31,2016.Patients were divided into idiopathic PN,IGT-related PN,and MS-related PN groups.Detailed medical history and small fiber neuropathy were investigated,and symptom inventory questionnaire was conducted,as well as the visual analog scale.Nerve conduction studies and skin biopsies were also performed.The differences among the groups were analyzed using analysis of variance and Kruskal-Wallis test.Results：Eight patients were diagnosed with pure SFN.lntraepidermal nerve fiber density （I ENFD） weakly correlated with motor conduction velocity （MCV） （r =0.372,P =0.025）,and proximal （r =0.383,P =0.021） and distal （r =0.358,P 0.032） compound muscle action potential （CMAP） of the tibial nerve.IENFD also weakly correlated with MCV of the peroneal nerve （r=0.399,P =0.016）.IENFD was shown to be significantly different among all groups （x2 =9.901,P-0.007）.IENFD was significantly decreased （x2 =23.000,P=0.003） in the MS-related PN group compared to the idiopathic PN group.The MCV of the tibial nerve was significantly different among all groups （x2 =8.172,P 〈 0.017）.The proximal （F =4.336,P =0.021） and distal （F =3.262,P =0.049） CMAP of the tibial nerve was also significantly different among all groups.Conclusions：IENFD of patients included in the present study weakly correlated with various electrophysiological parameters.Small and large fibers are more involved in patients with MS-related PN than in patients with idiopathic PN.

Relevance of muscle biopsy for diagnosing multifocal motor neuropathy

Multifocal motor neuropathy （MMN） is a rare,.focal,inflammatory,demyelinating disease of the peripheral nerves with pure motor involvementJ MMN is clinically characterized by slowly progressive,asymmetric,distal,upper limb predominant weakness,in the absence of sensory disturbances） Weakness is usually multifocal and connected to a distinct motor nerve,such as the musculocutaneous nerve resulting in biceps weakness,the posterior interosseus nerve resulting in finger drop,the median,ulnar,or radial nerve resulting in dexterity problems or grip weakness,or the peroneal nerve resulting in a foot drop.Onset of clinical manifestations is between 20 and 50 years of age.The prevalence of MMN is reported as 1-2 per 100 000.2 MMN is three times more frequent in men as compared to women.

A clinical neurophysiology study of Hirayama disease

Background Hirayama disease is a rare disease characterized by juvenile-onset of asymmetric amyotrophy, of which etiology has not been clarified. The aim of our study was to investigate the clinical and neurophysiologic characteristics of Hirayama disease. Methods Neurophysiological tests, including nerve conduction studies （NCS）, F-wave and routine electromyography （EMG）, were performed in seventy-three patients with Hirayama disease. EMG was selectively performed on upper and lower extremities, sternocleidomast and thoracic paravertebral muscles according to the clinical features of the patients. Results Abnormal NCS parameters, including decreased compound muscle action potentials or delayed distal motor latency, were found in 34.2% （25/73） and 12.3% （9/73） of the patients, respectively. A total of 24.6% （18/73） of the patients showed decreased F-wave frequency. EMG demonstrated the presence of neurogenic lesions in all patients with spontaneous potentials, prolonged duration or augmentation of amplitude in motor unit potentials （MUPs）, or a single pattern of MUP recruitment. About 17.8% （13/73） of the patients showed neurogenic lesions, mostly in the C7-8 level of the cervical cord, only in the upper extremity of affected side, whereas 35.6% （26/73） of the patients possessed lesions in the upper extremities bilaterally. A total of 46.6% （34/73） of patients exhibited abnormalities in the lower extremities, sterno- cleidomast or thoracic paravertebral muscle. Changes in motor NCS were significantly correlated with muscle strength. Conclusions EMG detects diffused subclinical neurogenic lesion in a high proportion of patients with Hirayama disease. Results of our study challenge the hypothesis that Hirayama disease is a type of cervical myelopathy.