dyskinesia means difficulty in performing voluntary movement,
such as lifting an arm or nodding the head. (In contrast,
movements such as eyeblinks or reflex responses are considered
involuntary, since they occur without conscious intent.)
Patients experiencing dyskinesia may have
trouble initiating movements, including the motor movements
of mouth and larynx needed for speaking and the facial movements
needed to display facial expression.
Dyskinesia is a symptom of Parkinson's
disease and other motor disorders.
by Catherine E. Myers. Copyright © 2006 Memory Loss and the Brain