Abnormal movements most obvious when the patient initiates a movement. When the patient is totally relaxed, usually in the supine position, a full range of motion and decreased muscle tone may be found. Dyskinetic patients are sub-divided into two sub-groups. Hyperkinetic or choreoathetoid children show purposeless, often massive involuntary movements with motor overflow (i.e., the initiation of a movement of one extremity leads to activation of other muscle groups). The dystonic group manifest abnormal shifts of general muscle tone induced by movement. Typically, these children assume and retain stereotyped abnormal and distorted postures. Both types of dyskinesia may occur in the same patient.
See Cerebral palsy, Choreiform movements, Dystonia, Extrapyramidal system, Muscle tone, Spasticity