Sensory nerve abnormalities in brachial plexopathy.
Sensory nerve action potential (SNAP) amplitude should be abnormal in brachial plexopathies (BP) which cause axonal degeneration in distal segments. Fifty-six patients with BP were identified. In diffuse BP, 22/25 (88%) showed low amplitude or absent median or ulnar SNAP. Three of 5 patients with upper trunk BP had low amplitude or absent SNAP (1 median, 1 radial, 1 lateral antebrachial cutaneous). Seventy-five percent of patients with lower trunk/medial cord BP had low amplitude or absent SNAP (8/24 median, 18/24 ulnar). Overall, 82.5% of patients had low amplitude or absent SNAP when a sensory nerve in the distribution of signs was studied. Testing multiple sensory nerves to include symptomatic regions enhances the diagnostic yield of SNAP in BP.
Rubin
M
M
Department of Neurology and Neuroscience, New York Hospital-Cornell Medical Center, New York 10021.
Lange
D J
DJ
D000200:Action Potentials / Q000502:physiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001917:Brachial Plexus / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D010523:Peripheral Nervous System Diseases / Q000503:physiopathology