When this occurs the patient shows disorder of movement because of fluctuation in the level of postural fixation. The patient adopts a succession of abnormal postures which may be quite grotesque. The condition is made more severe by excitement and emotional stress.
It is thought to be due to lesion within the basal ganglia and in particular in the putamen. In this instance the basal ganglia are failing in their ability to encourage adequate postural fixation and fluctuations therefore occur. Involuntary movements occasionally occur but the symptoms are always made worse by voluntary activity.
