Final answer:
The term for non-goal-directed involuntary movements in movement disorders is chorea, which is characterized by brief, irregular muscle contractions and should not be confused with ataxia that involves loss of voluntary movement coordination.
Step-by-step explanation:
The term used to describe non-goal-directed involuntary movements seen in movement disorders is chorea. Chorea consists of brief, irregular contractions that are not repetitive or rhythmic, but appear to flow from one muscle to the next. These movements are typically found in disorders like Huntington's disease and are distinct from the coordinated, voluntary movements that are affected in cerebellar disorders like ataxia, which is characterized by a loss of coordination in voluntary movements and can also involve sensory deficits that affect balance, proprioception, and equilibrium.