Receptors in focal reflex myoclonus.

The findings in a patient with focal reflex or action myoclonus suggest that the cortical somatosensory evoked response and the long loop reflex of the finger flexor muscles evoked by extension of the index finger at the volar surface of the distal phalanx occur largely through stimulation of touch or pressure receptors with evidence of a lesser contribution by joint receptors or muscle stretch receptors. Touch or pressure in the absence of movement is an adequate stimulus, whereas muscle stretch by itself is not.