Normative Data of Nerve Conduction Studies in the Upper Limb in Kuwait: Are They Different from the Western Data?

Objective: To establish the normal electrophysiological data for the median, ulnar and radial nerves and to compare our results with the Western data published in the literature. Methods: Nerve conduction studies were performed prospectively in the upper limbs of 50 carefully screened healthy individuals between the ages of 16 and 56 years using standardized technique. Results: The median motor distal latency (DL) was 3.1 (0.3) ms, amplitude 11.01 (2.8) mV, conduction velocity (CV) 56.5 (3.5) m/s. The ulnar motor studies gave DL of 2.4 (0.3) ms, amplitude 9.2 (2.2) mV, CV 60.4 (5.0) m/s. Sensory studies for the median nerve were: DL of 2.3 (0.3) ms, amplitude 63.3 (18.9) ÌV for men and 79.3 (28.8) ÌV for women and CV 56.6 (7.6) m/s. For the ulnar nerve (DL) 2.0 (0.23) ms, amplitude 54.5 (18.4) ÌV for men and 63.9 (16.8) ÌV for women and CV 51.7 (5.3) m/s. The radial sensory studies were DL 1.95 (0.3) ms, amplitude 18.7 (5.5) ÌV and CV 52.3 ms. Only gender showed a statistically significant effect on the sensory nerve action potential for the median (p = 0.04) and ulnar nerves (p = 0.07). Conclusion: Normative conduction parameters of commonly tested nerves in the upper limb were established in our EMG lab in Kuwait. The mean motor nerve conduction parameters for the median and ulnar nerves compare favourably with the existing literature data. However, for the sensory nerves, higher value for the nerve action potential amplitude was demonstrated in the study. Gender was shown to have a significant effect on the sensory amplitude of the median and ulnar nerves. Received: June 24, 1997 Revised: August 21, 1997 Dr. Dia Shehab Department of Medicine, Faculty of Medicine PO Box 24923 Safat 13110 (Kuwait) Tel. +965 531 9596, Fax +965 533 8907 ABC Fax + 41 61 306 12 34 E-Mail [email protected] www.karger.com © 1998 S. Karger AG, Basel 1011–7571/98/0073–0203$15.00/0 Accessible online at: http://BioMedNet.com/karger D ow nl oa de d by : 54 .7 0. 40 .1 1 10 /3 1/ 20 17 1 :4 1: 09 A M 204 Med Principles Pract 1998;7:203–208 Shehab Introduction Nerve conduction studies are routinely performed in electrodiagnostic medicine as an important method to evaluate peripheral nerve function. They help in the diagnosis, prognosis, extent and distribution of peripheral nerve injury. Many studies have been published from the Western countries regarding normative data for the nerves of the upper and lower limbs [1–6]. To the best of our knowledge no study has been performed in the Middle East. For the last two decades, the electrophysiology laboratory has been using standard values used by the US, Canada and Europe to diagnose different neurological problems. We were therefore interested to obtain a set of data in healthy adults in order to establish reference values for our EMG laboratory and to compare our values with other published data in the literature. For the upper limb, the median ulnar and radial nerves are the three most commonly tested nerves with published normative data. A number of factors need to be considered when establishing normative electrophysiological data. These are standardized measurements, temperature control, height, and age of normal healthy individuals. Some studies considered one or more of these factors, while Hennessey et al. [1] have looked at all these factors in their study of the median and ulnar nerves. This paper provides normative electrophysiological data for the median, ulnar and radial nerves in carefully screened healthy adult individuals using standard distances and temperature control. Subjects and Methods Fifty healthy individuals, aged 16–56 years (x = 34.9), were included in the study. These included 32 women (x = 32.6) and 18 men (x = 39). All individuals were screened, and inclusion criteria were young adults with no history of systemic or neuromuscular diseases, normal neurological examination and normal laboratory findings including blood sugar level, electrolytes and renal function. A standardized questionnaire was used to exclude those with a history of systemic or neuromuscular diseases. The following individuals were excluded: those individuals above age 60, those with a history of alcohol abuse or medications that might affect the results, and those with a history of diabetes, hypothyroidism and systemic diseases. None of the individuals were taking any medication at the time of the study. A simple neurological examination was performed including muscle power testing, muscle stretch reflexes and sensation including superficial and deep sensory testing. Room temperature was 25 °C and skin temperature at the palm of the individual was recorded immediately before the study using temperature probe No. 92E 46515 for the Nicolet Viking II machine. The study was performed when the temperature of the skin was between 32 and 35°C as was suggested by Denys [7]. The study was performed with the subject sitting comfortably in the upright position. A standardized technique was used to obtain and record action potentials for motor and sensory studies [2, 6, 8]. Motor and sensory studies were performed on the ulnar and median nerves, both proximally and distally along the forearm. The radial sensory nerve was examined distally along the forearm. The ground electrode was placed on the dorsum of the hand between stimulating and active electrodes. Standardized techniques were used to obtain and record action potentials. For sensory studies, the radial, median and ulnar nerves were examined antidromically. The active ring electrode was placed over the 1st, 3rd and 5th digit to record responses along the radial, median and ulnar nerves, respectively. The reference electrode was placed about 4 cm distal to the active electrode. Median nerve stimulation was performed at 13 cm proximal to the active electrode and medial to the flexor carpi radialis tendon. For the ulnar sensory nerve stimulation was performed 10 cm proximal to the active electrode and posterior to the flexor carpi ulnaris tendon. Radial nerve stimulation was performed 10 cm proximal to the active electrode along the lateral border of the radius. For motor studies, ulnar and median nerves were examined orthodromically. The active electrodes were placed over the motor point of the abductor pollicis brevis for the median nerve, and over the abductor digiti minimi for the ulnar nerve. The reference electrode was placed 4 cm distally over the 1st metacarpophalangeal joint for the median nerve and over the 5th metacarpophalangeal joint for the ulnar nerve. Distal D ow nl oa de d by : 54 .7 0. 40 .1 1 10 /3 1/ 20 17 1 :4 1: 09 A M