The origin of fasciculations in motoneuron disease.

The collision technique was used to determine the origin of distal fasciculations in 25 motor units from 9 patients with amyotrophic lateral sclerosis and 6 with other diseases involving motoneurons. Fasciculations originated in the nerve proximal to the knee or elbow in 15 and distally in 2; multiple sites of origin were found in 8 motor units. The origin was not related to the presence or absence of electromyographic evidence for collateral sprouting or lesions in descending suprasegmental pathways.