Analysis of the check reflex

Abstract

The check reflex was elicited under standard conditions in 5 normal subjects and in 5 patients with a Gordon Holmes sign. Action potentials were recorded simultaneously from the biceps and triceps, and the latency of each muscular response was measured. Relaxation of the biceps, contraction of the triceps, and termination of the silent period were all delayed in patients with ataxia, who showed greater variance on all three measurements. The results were interpreted in the light of current views concerning the muscle spindles and their control.