Generalized and focal stimulus-sensitive muscle jerks often represent a form of abnormal startle response or reflex myoclonus. However, these movements may also occur as a psychogenic movement disorder. Indeed, psychogenic myoclonus or muscle jerks represent a common form of psychogenic movement disorder, accounting for 8.5% of patients with myoclonus and 20% of psychogenic movement disorders. Distinguishing between psychogenic myoclonus and other forms of myoclonus may be difficult. A number of characteristic features of psychogenic myoclonus/jerks have been proposed including (1) the inconsistent character of the movements which are incongruous with typical organic myoclonus, (2) obvious reduction of myoclonus with distraction, (3) exacerbation and relief with placebo and suggestion, (4) spontaneous periods of remission, (5) acute onset and sudden resolution, and (6) evidence for underlying psychopathology
KeywordsAcute Onset Variable Amplitude Generalize Body Longe Latency Repeated Stimulation
While supine, the patient exhibits a generalized body jerk characterized by hip and variable elbow flexion following loud claps. While sitting, with a more prolonged latency following a loud clap, she develops a sudden whole body jerk with milder hip flexion and bilateral arm flexion to head level.
Psychogenic myoclonus.mp4 (MP4 8,928KB)