Nerve conduction topography in geriatric hand assessment

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J Rehabil Res Dev. 2005 Nov-Dec;42(6):821-8.

Nerve conduction topography in geriatric hand assessment.

Ferdjallah M, Wertsch JJ, Ahad MA, Phongsamart G, McGill KC.

Department of Electrical and Computer Engineering, University of

Tennessee, Knoxville, TN.

Motor nerve conduction is a noninvasive clinical test used to

diagnose nerve problems such as carpal tunnel syndrome or peripheral

neuropathy.

Current techniques use a single-site recording over a superficial

muscle. This traditional approach does not account for the electrical

contributions from the other muscles innervated by the nerve being

stimulated, which need to be considered with thumb carpometacarpal

(CMC) degenerative joint disease (DJD) because these electrical

contributions may change the anatomic relationship of the thenar

muscles.

This study recorded from 15 sites over the thenar eminence during

motor nerve conduction studies of the median nerve of 12 young

subjects with normal thenar anatomy and 25 elderly subjects with

thumb CMC DJD. The maximum compound muscle action potential (CMAP)

values did not occur in the same electrode position for the two

groups, and traditional single-site recording would have resulted in

smaller amplitudes and longer latencies for the elderly than the

values noted with the multiple-site recordings.

This pilot study of nerve conduction topography mapping with multiple-

site recording illustrates that single-site studies may be misleading

and supports further exploration of multichannel grid electrodes for

topographic display and analysis of the CMAP.