Nerve Conduction Studies in the Upper Limb in the Malwa Region-Normative Data

Abstract

Objective: To establish the normal electrophysiological data for the median and the ulnar nerves in normal healthy adults in the Malwa region of Punjab, India. Methods:Nerve conduction studies were performed prospectively in the upper limbs of 100 carefully screened, healthy individuals of either sex, who were between the ages of 20 and 60 years, by using a standardized technique. Results:Motor studies: The median distal latency (DL) in men was 3.4 (0.2) ms, the amplitude (CMAPA) was 10.80 (2.8) mV, the conduction velocity (MNCV) was 55.6 (2.5) m/s and the F-wave (min latency) was 27.57±2.54(21.5-34.2). In the ulnar nerve , the motor DL was 2.34 (0.25) ms, the amplitude (CMAPA) was 9.8(2.6) mV, MNCV was 63.4 (3.0) m/s and the F-Wave(min latency) was 26.29±2.12(21.6-34.7). In the sensory studies, the median nerve DL was 2.0(0.35) ms, SNCV was 53.4±3.0 m/s and the amplitude (SNAPA)was 59.3 (16.4) µV for men and it was 68.7(28.4) µV for women. For the ulnar nerve in men, the DL was 1.85(0.25)ms, SNCV was 55.5 (4.1) m/s and the amplitude(SNAPA) was 55.5 (18.4) µV for men and it was 64.9 (16.8) µV for women. Only the gender showed a statistically significant effect on the sensory nerve action potential for the median (p < 0.04) and the ulnar nerves (p < 0.041) . Conclusion:The normative conduction parameters of the commonly tested nerves in the upper limb were established in our EMG lab. The mean motor nerve conduction parameters for the median and the ulnar nerves correlated favourably with the existing literature data. However, for the sensory nerves, a higher value for the nerve action potential amplitude was demonstrated in this study.

Influence of gender on nerve conduction parameters of median and ulnar nerves in healthy individuals

“…Garg R et al [14] in their study of upper limb in malwa region had found that sensory nerve action potential ISSN-2321-127X…”

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“…Males have significantly lower SNAP amplitudes of median and ulnar nerves, which match Stetson et al's 11 observations in the same nerves, 11, this difference may be explained by thicker subcutaneous tissue (finger circumference) among males, which result in a greater distance between the surface electrode and the digital nerves, hence causing diminished SNAP amplitudes. 11,19 Sensory peak latencies (SPL) were also measured along with SDLs and as shown in Table 3, SPLs are more sensitive to gender comparisons. SDLs were employed in this paper because they are a good indication of the fastest nerve fibers.…”

“…3,11,21 Most of our values were similar to four other similar published studies. 2,3,5,8,13,21,22,23 However, there were some differences, which could be attributed to different NCS techniques, machine settings, and demographic characteristics. A notable dissimilarity was in the CMAP and the SNAP amplitudes because some studies used peak-to-peak measurement and others used baseline-to-negative peak measurements.…”

“…NCS is considered an extension of the clinical assessment of a patient being evaluated for suspected peripheral neuropathy and it has been used extensively in research as well as in clinical practice. [1][2][3][4] NCS examination involves electrically stimulating the peripheral nerves and recording the motor and sensory responses from the targeted muscles or nerves, respectively. NCS data interpretation is influenced by some technical and physiological factors, such as fixed measurements, skin temperature, height, Body Mass Index (BMI), gender and age; In addition to the nerve diameter and degree of myelination.…”

“…NCS data interpretation is influenced by some technical and physiological factors, such as fixed measurements, skin temperature, height, Body Mass Index (BMI), gender and age; In addition to the nerve diameter and degree of myelination. 2,3,[5][6][7][8] It is clearly required, in a clinical setting, to have standardized data acquired from a sample population that represents, as nearly as possible, the demographic and ethnic features of the examined patients. 2,3 In the context of developing normative data for nerve conduction studies among healthy Omani adults for our Neurophysiology laboratory, we aimed also to examine the influence of gender on our data.…”