Median and Ulnar Sensory Nerve Conduction Study in Five Digits

ABSTRACT

OBJECTIVE: To establish the reference values of the sensory conduction for all the digits in the hand, conduction studies were performed using the standard technique. METHOD: One hundred hands of fifty neurologically healthy adults with mean age of 45 years (range, 23~69) were tested. Depending on ages, the 50 adults were devided into three groups group 1, 20~45 years old; group 2, 46~60 years old; group 3, 61~ years old. Antidromic sensory nerve conduction techniques using a fixed distance were performed. The onset latency and baseline to peak amplitude of the sensory nerve action potentials (SNAPs) were measured. During the test, the skin temperature of the hand was maintained at 34 degrees C or above. These variables from SNAPs were compared according to age, gender, side, and recording digits. RESULTS: Comparison of the median and ulnar SNAPs between age groups revealed longer onset latency and smaller amplitude in the elderly group. The amplitude of SNAPs was larger in females than in males and the left side than the right side. Comparison of the latencies and amplitudes between the second and third digits showed no significant difference statistically. Also, the latencies and amplitudes of the median and ulnar nerves recorded from the fourth digits showed no significant difference statistically. CONCLUSION: Based on these results, the reference values for sensory conductions from all the digits were obtained. These values would be helpful in evaluation of CTS or unspecified finger pain or upper extremity neuropathy.