Sensory Nerve Action Potential Latency Research Articles

Do Socioeconomic Factors Affect Symptom Duration and Disease Severity at Presentation for Cubital Tunnel Syndrome?

Socioeconomic factors have been implicated in delayed presentation for compressive neuropathies of the upper extremity. Our article seeks to elucidate the effect of socioeconomic factors on self-reported symptom duration and objective disease severity at presentation for cubital tunnel syndrome. This retrospective cohort study included 207 patients with surgical management of cubital tunnel syndrome at 2 institutions between June 1, 2015, and March 1, 2020. Exclusion criteria included age under 18 years, revision surgery, lack of preoperative electrodiagnostic studies, and concurrent additional surgeries. Response variables were self-reported symptom duration, time from presentation to surgery, McGowan grade, and electrodiagnostic measures. Explanatory variables included age, sex, white race, diabetes mellitus, depression, anxiety, and the Distressed Communities Index. Symptom duration was associated with nonwhite race, and time from presentation to surgery was associated with insurance provider. More clinically severe disease was associated with older age, male sex, and not having carpal tunnel syndrome. Nonrecordable sensory nerve action potential latency was associated with older age, higher body mass index, male sex, diabetes mellitus, and unemployment. Nonrecordable conduction velocities were associated with older age, and having fibrillations at presentation was associated with older age, male sex, and unemployment. Economic distress is not associated with self-reported symptom duration, time from presentation to surgery, or presenting severity of cubital tunnel syndrome. White patients presented with shorter self-reported symptom duration. Insurance type was associated with delay from presentation to surgery. Older age and male sex were risk factors for more clinically severe disease at presentation.

The Rise Slope of the Compound Sensory Nerve Action Potential in Normal and Pathological Human Nerves

ABSTRACT In spite of the diagnostic importance of the early phase of the sensory nerve action potential (SNAP), reliable electrodiagnostic metrics for this part of the recorded waveform are lacking. The average rise slope of the SNAP appreciates the steepness of the initial negative deflection of the waveform, which might be a useful metric for the first part of the potential. Sural nerve sensory neurography was performed in patients with various axonal neuropathies, and median nerve sensory studies were carried out in patients with carpal tunnel syndrome. Age-matched healthy individuals served as controls. The rise slope was compared to conventional SNAP parameters such as conduction velocity, latency, duration, and rise time. Overall, 537 sensory studies were prospectively analyzed. The rise slope of the sural SNAP demonstrated superior classification performance in terms of sensitivity (92.5%), specificity (97%), and area under the receiver operating characteristic curve (0.986), as compared to conventional SNAP parameters. Its diagnostic power was similarly excellent in median nerve studies, whereas here a slightly better classification performance was obtained by SNAP latency and conduction velocity. The average rise slope appears to do justice to the tight interplay between amplitude and rise time of the initial negative spike deflection, outperforming many conventional measures. This composite metric proved high diagnostic potency in particular with regard to axonal sensory nerve dysfunction.

Electrophysiological Changes in Patients with Carpal Tunnel Syndrome after Open Carpal Tunnel Release

Objective: Carpal tunnel syndrome (CTS) is the most common peripheral neuropathy affecting the upper limbs. Various treatment methods exist for this disease, but only a few reports have compared the effects of various treatments using objective indicators. This study analyzed the changes in electrophysiological parameters after carpal tunnel release.Methods: In patients planning to undergo surgical treatment for CTS, electrophysiological studies, including nerve conduction studies and electromyography (EMG), of both upper extremities were performed before and 6 to 8 weeks after mini-open transverse carpal ligament release and median nerve neurolysis.Results: After surgical intervention, the onset latency and amplitude of the sensory nerve action potential (SNAP) and the onset latency of the compound muscle action potential (CMAP) of the median nerve improved. Additionally, the grade of abnormal spontaneous activity in needle EMG of the abductor pollicis brevis (APB) and the severity of the electrodiagnostic study results significantly decreased after the intervention compared to the initial evaluation.Conclusion: This study shows that the onset latency of SNAP and CMAP, the amplitude of SNAP of the median nerve, and EMG findings in the APB can be useful electrodiagnostic parameters for postoperative monitoring in CTS patients.

The effects of head posture on nerve conduction studies in patients with ankylosing spondylitis.

Ankylosing spondylitis (AS) is a chronic inflammatory disease which effects cervical posture of patients. The aim of this study was to evaluate AS patients according to the degree of cervical disorder and was evaluate them electrophysiologically, functionality, and disease parameters. Our study comprised 64 AS patients and 30 healthy controls. The head posture of patients was evaluated by craniovertebral angle (CVA) measurement. Nerve conduction of bilateral median, radial, ulnar, and medial antebrachial cutaneous (MAC) nerves were studied in all patients. The most important nerve conduction differences in AS patients who have severe forward head posture (FHP) were decrease in sensory nerve action potential (SNAP) amplitude and compound muscle action potential amplitudes of median nerves, a decrease in the SNAP amplitude of ulnar nerves, a delay in the F response latency of ulnar nerves, and prolongation in the SNAP latency of the MAC nerve. The FHP disorder that develops in AS patients may have electro physiological effects, similar to those of thoracic outlet syndrome In addition, the functional status of these patients is worsened as severity of FHP increases.

Effectiveness of Lavendula stoechas essential oil in treatment of mild to moderate carpal tunnel syndrome: A randomized controlled clinical trial

In this study, we investigated the effectiveness of topical Lavender (Lavendula stoechas) essential oil on pain intensity, isometric pinch strength, specific parameters of electro-diagnosis study (EDS), symptom severity and functional status of patients with mild to moderate carpal tunnel syndrome (CTS). Forty-eight patients with mild to moderate CTS were enrolled in this randomized placebo-controlled trial. Group A was treated with night wrist splint and topical Lavender oil ointment. Group B was treated with night wrist splint and a placebo ointment. Patients were evaluated at baseline and after 40 days of intervention with Boston CTS questionnaire (BCTQ), Visual Analog Scale (VAS) for pain, pinch grip strength (PGS), power grip (PG), median compound motor action potential latency (MCMAPL) and median sensory nerve action potential latency (MSNAPL). At the end of the study period, both groups improved significantly in terms of BCTQ, VAS, isometric pinch powers, and EDS parameters. However, group A showed significantly greater improvements in BCTQ (mean difference: 0.39 ± 0.31 VS. 0.6 ± 0.35; P = 0.03), VAS (3.37 ± 1.86 VS. 1.33 ± 2.07; P = 0.001), and PGS (0.73 ± 0.63 VS. 0.27 ± 0.54; P = 0.01) than group B. No significant differences in PG, MCMAPL and MSNAPL were seen between the two groups. This study was the first trial of topical Lavender oil used in patients with CTS. The results of this study suggested that splinting therapy combined with topical Lavender oil is more effective than splinting and placebo in treatment of mild to moderate CTS.

Evaluating degree of symptom improvement, safety and the change of electrophysiological findings after ultrasound versus landmark guided steroid injection in treatment of carpal tunnel syndrome

To evaluate the degree of symptom improvement, safety and the change of electrophysiological findings after ultrasound (US)-guided versus landmark (LM)-guided local steroid injection in treatment of carpal tunnel syndrome (CTS). Fifty-two patients with moderate or moderate to severe CTS were recruited in this study. The subjects were randomly assigned into each US-guided or LM-guided steroid injection group and received 40 mg methylprednisolone. After 4 weeks and 12 weeks, the patients were evaluated using Boston questionnaire and electrophysiologic parameters. All variables including symptom/functional scores and electrophysiological findings improved significantly in both groups after 4 weeks (all P < 0.05) except CMAP amplitude in LM-guided group. However, LM-guided group showed a regress with all variables after the 12-week period compared with the 4-week period, these improvements persisted at the week 12 after treatment in the US-guided group ( P < 0.05) except Functional Status Scale (FSS) and Sensory Nerve Action Potential (SNAP). The improvement in the Compound Muscle Action Potential (CMAP) amplitude in the US-guided group at the week 12 was higher than in the LM-guided group ( P < 0.05); however, SNAP amplitude and SNAP Nerve Conduction Velocity (NCV) had improved significantly in the LM-guided group. Significant differences were not observed between groups with respect to Symptom Severity Score (SSS), FSS, SNAP latency, and CMAP latency in 4 or 12 weeks after treatment ( P > 0.05). symptom severity, functional status and all electrophysiologic parameters improved significantly in both groups and generally no statistical significant difference was observed between two groups.

Neurodynamic evaluation and nerve conduction studies in patients with forward head posture.

Forward head posture (FHP) is one of the most frequently seen problems. The aim of this study was to evaluate the neurodynamic tests and peripheral nerve conductions of upper extremity in patients with FHP. The study population included 100 patients with upper extremity and neck problems and 34 healthy individuals as a control group. Craniovertebral angle measurement was used to determine forward head posture. Stretch tests for radial, ulnar and median nerves were performed. Nerve conductions of bilateral median, radial, ulnar and medial antebrachial cutaneous (MAC) nerves were examined in all patients included in the study. The most significant nerve conduction differences in moderate-to-severe FHP patients were a decrease in the sensory nerve action potential (SNAP) and compound muscle action potential (CMAP) amplitudes of median nerves, a decrease in the SNAP amplitude of ulnar nerves, a delay in the F response latency of ulnar nerves and prolongation in the SNAP latency of the MAC nerve. FHP makes patients more prone to peripheral entrapments.

F101. Effect of gender on nerve conduction studies parameters in healthy individuals

Introduction Nerve conduction studies (NCS) are electrodiagnostic tests which are used to evaluate the ability of the conduction of the motor and sensory nerves. Nerve conduction studies assist in the evaluation of neuromuscular diseases by providing a physiologic assessment of the peripheral nerve, muscle, neuromuscular junction, dorsal root ganglion cell and anterior horn cell. Among the various factors affecting nerve conduction gender has effect on latency, amplitude and conduction velocity of motor and sensory nerves. Methods The study was conducted on 50 (m = 25; f = 25) age matched healthy individuals of 18–24 age group. The compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) were recorded in Department of Physiology, Kathmandu University School of Medical Sciences. Results Males had higher CMAP amplitude, longer latencies and duration. SNAP latencies and duration were longer in males whereas amplitude was higher in females. Conclusion Gender has definite effects on NCS variables and the effects are not similar in motor and sensory nerves.

Ultrasonography Predictive Factors of Response to Local Steroid Injection in Patients with Carpal Tunnel Syndrome.

Background:The aim of this study is to determine the predictive value of ultrasonography for results of local steroid injection in patients with carpal tunnel syndrome (CTS).Materials and Methods:This prospective cohort study was conducted during a 1-year period in outpatient clinics of rehabilitation and physical medicine including 35 patients with moderate and severe CTS who receive ultrasonography-guided local steroid injection. The Boston self-assessment questionnaire and electrodiagnosis parameters were recorded at baseline, 1 month, and 3 months after therapy. We also recorded the baseline ultrasonography parameters to determine the predictors of outcome.Results:The sensory severity score and functional status scale along with electrodiagnosis parameters decreased significantly at 1 month (P < 0.001) and remained unchanged after 3 months. Volar bulging was negatively associated with sensory nerve action potential latency (r = −0.392; P = 0.020). Cross-sectional area (CSA) of maximal swelling (MS; r = 0.409; P = 0.015), CSA at 2-cm of MS (r = 0.563; P < 0.001), and CSA at 12-cm of MS (r = 0.521; P = 0.001) correlated positively with compound muscle action potential (CMAP) amplitude while maximal swelling/12-cm MS ratio (r = −0.439; P = 0.008) and maximal swelling/2-cm MS ratio (r = −0.342; P = 0.045) correlated negatively. CSA at 12-cm of MS also correlated positively with CMAP amplitude nerve conduction velocity (r = 0.436; P = 0.010).Conclusion:Volar bulging, CSA of maximal swelling, CSA of MS at 2-cm, and CSA of MS at 12-cm are among the ultrasonographic predictors of response to local steroid injection in patients with CTS.

Effectiveness of Lavendula stoechas essential oil in treatment of mild to moderate carpal tunnel syndrome: A randomized controlled trial

Study DesignRandomized controlled trial. IntroductionCarpal tunnel syndrome (CTS) is the most common entrapment neuropathy of the upper extremity. To date, no previous study has evaluated the efficacy of topical Lavendula stoechas (Lavender) oil in CTS patients. Purpose of the StudyTo investigate the effectiveness of topical Lavender essential oil in pain intensity, isometric pinch strength, electrophysiological features, and functional status of patients with mild to moderate CTS. MethodsForty eight patients with mild to moderate CTS were enrolled in this randomized placebo-controlled trial. Group A was treated with night wrist orthotic and topical lavender oil ointment. Group B was treated with night wrist orthotic and a placebo ointment. Patients were evaluated at baseline, and after 40 days of intervention with Boston CTS questionnaire (BCTQ), visual analog scale (VAS) for pain, pinch grip strength, power grip, median compound motor action potential latency, and median sensory nerve action potential latency. ResultsAt the end of the study period, both groups improved significantly in terms of BCTQ, VAS, isometric pinch powers, and electrodiagnosis study parameters. However, group A showed significantly greater improvements in BCTQ (mean difference, 0.39 ± 0.31 vs 0.6 ± 0.35; P = .03), VAS (3.37 ± 1.86 vs 1.33 ± 2.07; P = .001), and pinch grip strength (0.73 ± 0.63 vs 0.27 ± 0.54; P = .01) than group B. No significant differences in power grip, median compound motor action potential latency, and median sensory nerve action potential latency were seen between the 2 groups. ConclusionThis study was the first trial of topical lavender oil used in patients with CTS. Wrist orthotic combined with topical lavender oil was more effective than orthotic and placebo in treatment of mild to moderate CTS. Level of Evidence1b.

Impact of height on sensory nerve conduction

Background: Change in height of the limb not only increases the length of nerve but also causes gradual tapering of nerve with decrease in fiber diameter and myelination. Aim and Objectives: To study the correlation of height with the nerve conduction study (NCS) variables, i. e., latency, duration, amplitude, and conduction velocity of sensory nerve action potential (SNAP) of the sensory nerves of the upper and lower limbs. Materials and Methods: This is cross-sectional study including 37 participants. After taking consent their age, sex, height, weight, and body mass index were noted. NCS test was carried out for median, ulnar, and sural sensory nerves. Pearson’s correlation coefficient was calculated. P < 0.05 (*) means difference is statistically significant while P < 0.01 (**) is highly significant difference. Results: Height showed a significant positive correlation with the SNAP latencies of all the sensory nerves: Median sensory (r = 0.704, P < 0.01), ulnar sensory (r = 0.350, P < 0.05), and sural (r = 0.392, P < 0.05). The SNAP duration and amplitude of ulnar and median sensory nerve were negatively correlated with height while that of sural sensory nerve showed insignificant positive correlation with height. However, a significant negative correlation was seen with the SNAP conduction velocity of median sensory (r = −0.740, P < 0.01) and sural sensory (r = −0.701, P < 0.01) nerve. For ulnar sensory nerve, correlation of height and conduction velocity (r = −0.220) was negative but not statistically significant. Overall, height had an inverse correlation with conduction velocity and positive correlation with latency of SNAP. Conclusion: Clinical recognition of this height effect is important as one should not label an individual with mild increase/decrease in peripheral nerve conduction velocity as abnormal which may be solely related to height.

Test-retest reliability of transcarpal sensory NCV method for diagnosis of carpal tunnel syndrome.

Background:Carpal Tunnel Syndrome (CTS) is the most frequent entrapment neuropathy affecting the upper extremity. There are a variety of electrodiagnostic methods available for documenting median neuropathy in CTS. In some studies, determining the sensory NCV across the palm-wrist segment has been introduced as the most sensitive diagnostic procedure for CTS. The aim of this study was to investigate the test-retest reliability of transcarpal median sensory NCV method for the diagnosis of CTS.Materials and Methods:Twenty-three patients with clinical symptoms of CTS were tested two times by two different practitioners in one session and again by the first practitioner after one week. Stimulation of the median nerve was performed in the wrist and palm, with a conduction distance maximum of 7 cm, reliabilities of median nerves sensory nerve action potential latencies with stimulation at wrist and palm (W-SNAP, P-SNAP) and its transcarpal NCV were assessed with intraclass correlation coefficient (ICC).Results:Comparison of the obtained values, which were done by two practitioners in one session showed ICC of W-SNAP latency, P-SNAP latency and transcarpal NCV of 0.93, 0.88 and 0.87, respectively and values that were done by one practitioner in two sessions with one-week interval showed ICC of 0.60, 0.50 and 0.47, respectively.Conclusion:Our findings suggest excellent interpractitioner test-retest reliability of transcarpal median sensory NCV method for diagnosing CTS.

Sensory Nerve Conduction and Somatosensory Evoked Potentials of the Trigeminal Nerve in Horses with Idiopathic Headshaking

Idiopathic headshaking (HSK) in horses is a distressing disorder in which the etiology and pathophysiology are unknown. Differences in sensory function of the trigeminal nerve exist between healthy and affected horses. Six healthy mature geldings and 6 mature geldings with idiopathic HSK. Prospective study. Sensory nerve action and somatosensory evoked potentials studies were performed. The stimulus site comprised the gingival mucosa dorsal to the maxillary canine. A pair of recording electrodes was placed along the sensory pathway of the trigeminal complex at the infraorbital nerve (R1), maxillary nerve (R2), spinal tract of trigeminal (R3), and somatosensory cortex (R4). Sensory nerve action potential latency (ms), amplitude (μV), duration (ms), area under the curve (μVms), and conduction velocity (m/s) were calculated. Threshold for activation of the infraorbital branch of the trigeminal nerve was significantly different between 5 affected (≤ 5 mA) and 6 control horses (≥ 10 mA). After initiation of an action potential, there were no differences in all parameters measured and no differences between left and right sides. A horse with seasonal HSK tested during a time of no clinical manifestations showed a threshold for activation similar to control horses. This study confirms involvement of the trigeminal nerve hyperexcitability in the pathophysiology of disease. Further, results might support a functional rather than a structural alteration in the sensory pathway of the trigeminal complex that can be seasonal. The horse could serve as a natural animal model for humans with idiopathic trigeminal neuralgia.

A study of interpolation method in diagnosis of carpal tunnel syndrome

Context:The low correlation between the patients’ signs and symptoms of carpal tunnel syndrome (CTS) and results of electrodiagnostic tests makes the diagnosis challenging in mild cases. Interpolation is a mathematical method for finding median nerve conduction velocity (NCV) exactly at carpal tunnel site. Therefore, it may be helpful in diagnosis of CTS in patients with equivocal test results.Aim:The aim of this study is to evaluate interpolation method as a CTS diagnostic test.Settings and Design:Patients with two or more clinical symptoms and signs of CTS in a median nerve territory with 3.5 ms ≤ distal median sensory latency <4.6 ms from those who came to our electrodiagnostic clinics and also, age matched healthy control subjects were recruited in the study.Materials and Methods:Median compound motor action potential and median sensory nerve action potential latencies were measured by a MEDLEC SYNERGY VIASIS electromyography and conduction velocities were calculated by both routine method and interpolation technique.Statistical Analysis Used:Chi-square and Student's t-test were used for comparing group differences. Cut-off points were calculated using receiver operating characteristic curve.Results:A sensitivity of 88%, specificity of 67%, positive predictive value (PPV) and negative predictive value (NPV) of 70.8% and 84.7% were obtained for median motor NCV and a sensitivity of 98.3%, specificity of 91.7%, PPV and NPV of 91.9% and 98.2% were obtained for median sensory NCV with interpolation technique.Conclusions:Median motor interpolation method is a good technique, but it has less sensitivity and specificity than median sensory interpolation method.

Application of latent period of sensory nerve action potential in the ring finger for early diagnosis of carpal tunnel syndrome

目的 寻找诊断轻度腕管综合征(carpal tunnel sydrome,CTS)电生理的敏感诊断指标.方法将临床症状、体征符合CTS,而正中神经末端运动动作电位潜伏期正常的患者38例为CTS组,取年龄、性别相匹配的健康人46名为对照组.采用顺向法分别测定2组指4(环指)正中神经和尺神经感觉动作电位的潜伏期(Lat),并比较其差值.结果环指正中神经和尺神经感觉动作电位潜伏期差值的异常率为91％(≥0.4ms).刺激环指后16例患者腕部正中神经处记录到双峰电位,对照组则未见.结论环指正中神经和尺神经感觉动作电位潜伏期之差≥0.4ms,即可诊断为轻度CTS.在怀疑轻度CTS时,该法最敏感,可作为常规的电生理检查方法。

Effect of Fluidotherapy on Superficial Radial Nerve Conduction and Skin Temperature

Cross-sectional study. The purpose of this study was to examine the effects of the superficial heating modality, Fluidotherapy, on skin temperature and on sensory nerve action potential (SNAP) conduction latency and amplitude of the superficial radial nerve in healthy individuals. Fluidotherapy is a dry, superficial heating modality, which also provides tactile stimulation through the bombardment of air-fluidized cellulose particles. Previous literature has documented a direct relationship between skin temperature and neural conduction velocity; however, there is an absence of published research examining the effects of Fluidotherapy, and of tactile stimulation specifically, on neural conduction. Twenty-one subjects between the ages of 22 and 31 years (mean+/-SD, 25.5+/-0.7 years) and without prior history of diabetes, alcoholism, renal or metabolic dysfunction, current pregnancy, or heat sensitivity were invited to participate. Subjects completed an upper quarter screening exam and medical history form prior to participation. One group underwent heat (46.7 degrees C-48.9 degrees C) and tactile stimulation, a second group underwent tactile stimulation alone, while a third served as controls. Dependent variables were assessed at 3 intervals: before the intervention, immediately after the intervention, and 20 minutes after the intervention. All interventions were 20 minutes in length. A mixed 2-way analysis of variance indicated a significant interaction between time of neural conduction velocity assessment and treatment group for the dependent variables of sensory nerve action potential latency (P< .001) and skin temperature (P< .001). Appropriate post hoc tests were performed for simple effect comparisons. An inverse linear relationship existed between skin temperature and latency (r2 = .65; Pearson product coefficient, -.81). Fluidotherapy treatment, which combines the effects of heat and tactile stimulation, significantly elevated superficial skin temperature, while tactile stimulation alone and no treatment (control group) did not bring about a temperature change. As the superficial skin temperature increased, there was a concomitant decrease in the distal sensory latency of the superficial radial sensory nerve action potential. These results should be an important consideration for the clinician using superficial heating modalities.

Automated sensory nerve conduction testing using fuzzy logic.

Nerve conduction studies continue to be an important tool in the evaluation of peripheral nerve disorders but have come under increased scrutiny because of heightened cost control in health care service delivery. In selected clinical settings, automated nerve conduction studies may be a useful clinical tool replacing conventional testing, but existing instruments are limited and have not generally been accepted into clinical practice. Further advancements in nerve conduction automation may be possible by incorporating expert system approaches into nerve conduction measurement and control algorithms. Using fuzzy logic techniques to duplicate the reasoning strategies of experienced electrodiagnostic clinicians, a software controller was developed to automatically perform sensory nerve conduction studies. The fuzzy logic system successfully performed 88% of 97 sensory studies in a mixed group of normal and patient populations. Sensory nerve action potential latency and amplitude measures obtained with automated testing were the same as determined by clinicians. Failures were related to design limitations of the controller, noise, and artifact. The high negative predictive value and sensitivity of fuzzy logic based testing suggest that its utility is in minimizing the need for unnecessary conventional electrodiagnostic studies in patients with normal nerve function. Fuzzy logic appears to be a useful approach to nerve conduction automation that can model expert reasoning and judgment.

The lateral femoral cutaneous nerve: nerve conduction technique.

In 58 subjects without signs or symptoms of peripheral nerve disorders, an antidromic sensory nerve conduction study was performed on the lateral femoral cutaneous nerve. Anatomic dissections were performed on two cadavers to reveal the course of the nerve and to localize the optimal stimulation and recording sites. Mean sensory nerve action potential latency was measured at 1.7 msec (SD = 0.23) with a mean amplitude of 10.5 microV (SD = 4.0). The optimal localization of recording and stimulating surface electrodes and nerve conduction technique procedures are discussed. Reliable electrophysiologic criteria, according to age and body mass index, are obtained.

Neuropathy associated with Brescia-Cimino arteriovenous fistulas.

We performed a clinical and electrophysiologic study of median and ulnar nerve function to determine the frequency of neuropathy in 21 patients who had unilateral Brescia-Cimino arteriovenous fistulas and who were undergoing maintenance hemodialysis. Seven patients had symptomatic median or ulnar neuropathy in the arm with the fistula, and abnormalities of motor and/or sensory nerve conduction were found in all of these patients. Of the 14 asymptomatic patients, nine had electrophysiologic evidence of median and/or ulnar neuropathy in the arm with the fistula. Evidence of subclinical median or ulnar neuropathy was also found in the contralateral extremity in 11 of the 21 subjects. Statistically significant differences were found for median and ulnar sensory nerve action potential latencies and motor conduction velocities and for the median distal motor latency between the arms with and without fistulas in the group as a whole, and the mean interarm differences for these values were statistically significant.

Nerve Conduction Study in Healthy Individuals: a Gender Based Study

Background: Nerve conduction study (NCS) assesses peripheral nerve functions and has clinical implication. Objective: To study effect of gender on NCS variables in healthy adults. Settings and Design: Department of Physiology, B.P. Koirala Institute of Health Sciences, Dharan, Nepal. Material and Method: The study was done in 34 (m=19, 32±11 years; f=15, 32±12 years) consenting healthy adults. The compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) were recorded. Statistical analysis: The effect of gender on NCS variables was analyzed using Mann Whitney U test. Results: Male vs. female: males had increased CMAP and F-wave latencies (ms) in all tested motor nerves. CMAP duration (ms) was longer in males (p&lt;0.05) in all tested motor nerves: right median (5.9±1.3 vs. 4.92±0.65), left median (5.54±0.91 vs. 4.72±0.57), right ulnar (5.55±1.01 vs. 4.56±0.59), left ulnar (5.71±0.97 vs. 4.64±0.51), right tibial (6.58±0.95 vs. 5.95±0.71), and left tibial (6.98±1.31 vs. 6.21±0.78). Females showed higher sural SNAP amplitude (µV) (23.26±9.23 vs. 15.94±8.42). SNAP duration (ms) was longer in males: right ulnar (1.16±0.19 vs. 1.03±0.06). SNAP latencies (ms) were also longer in males: right sural (2.61±0.44 vs. 2.21±0.36). Males had greater height (165.9±4.74 vs. 149.3±7.24) and weight (60.4±7.2 vs. 53±7.2).Conclusion: Gender has definite effects on NCS variables. Males had higher CMAP amplitude, longer latencies and duration. SNAP latencies and duration were longer in males whereas amplitude was higher in females. Without adjustment for these factors, the sensitivity and specificity of NCS will decrease when using the same reference data in patients with different gender. Keywords: compound muscle action potential; gender; nerve conduction study; sensory nerve action potential DOI: 10.3126/hren.v8i3.4210Health Renaissance, September-December 2010; Vol 8 (No.3);169-175