Cutaneomuscular reflex in a peripheral nerve lesion
Brezinova, V.
Electromyography and Clinical Neurophysiology 28(4): 183-189
1988
ISSN/ISBN: 0301-150X PMID: 2846263 Document Number: 323843
Cutaneomuscular reflex (CR), obtained during a mild isometric voluntary contraction of the abductor digiti minimi (ADM) muscle and electrical stimulation of the 5th digit, was replaced in 35 subjects with a normal ulnar nerve function, and in 20 patients with clinical and electrophysiological signs of an ulnar nerve lesion at elbow. A similar procedure using EMG activity of the abductor pollicis brevis (APB) muscle and stimulation of the index finger was carried out in 30 patients with a median nerve compression at wrist. In a normal nerve a CR was always elicited, containing 3 or more phases in 94% of the subjects, with average stimulus intensity of 6 mA. In the two groups of peripheral neuropathy patients a significantly higher stimulus intensity was needed (10 mA), a substantial proportion of patients (50% and 67%) had a CR with only two phases or less, and some patients (20% and 33%) failed to develop a CR at all. Out of 12 ulnar neuropathy patients with an absent ulnar sensory nerve action potential (SNAP) a CR was obtained in 9 (75%), out of 22 median neuropathy patients with absent median SNAP a CR was elicited in 14 (64%). The information about the peripheral sensory nerve function provided by a CR might be useful when conventional measurement of SNAPs fails because the patient is too tense or cannot tolerate a supramaximal stimulus.