Glossary of Movement Disorder Terms

Symptoms of movement disorders can be confusing as some of them are similar. Each condition may be well characterized by its behavioral signatures that include: spatio-temporal and kinetic features, and frequency characteristics.

Ataxia: an unsteady and swaying walk, often with feet planted widely apart. Many symptoms of ataxia mimic those of being drunk, such as slurred speech, stumbling, falling, and incoordination (lack of synergy). These symptoms are caused by damage to the cerebellum.

Bradykinesia: slowness of movement. It is closely related to hypokinesia means decreased amplitude or range of movement. Bradykinesia is a prominent feature of parkinsonism (PD) due to the damage in basal ganglia. It is mild in the early disease stages but becomes more severe in the advanced stages of Parkinsonism.

Dysmetria: misjudging the distance to a target. A person with dysmetria will have problems reaching out and accurately touching a targeted object.

Chorea: involuntary, irregular, purposeless, non-rhythmic, abrupt, rapid, or unsustained movements that seem to flow from one body part to another. A characteristic feature of chorea is that the movements are unpredictable in timing, direction, and body parts affected. This is a typical symptom of Huntington's disease, another disease that impacts basal ganglia.

Dyskinesia: a general term for any abnormal involuntary movement (“tardive dyskinesia”). It is a term used for abnormal involuntary movements that begin after taking certain medications used to treat nausea or emotional problems. Tardive dyskinesia sometimes resembles chorea, dystonia, myoclonus, tics, or tremor. A variant of this, paroxysmal dyskinesias is movement that starts suddenly and then disappears after being present for seconds, minutes, or hours.

Dystonia: twisting movements and postures that tend to be sustained at the peak of the movement, often patterned and repetitive. Opposing muscles contract simultaneously to produce the sustained quality of dystonic movements. When dystonia first appears, the movements typically occur only with a voluntary movement of the affected body part. Common forms of focal dystonia affect the voice, eyelids, the neck, and the hand (e.g. writer’s cramp, musician focal dystonia).

Akathisia: means unable to sit still. When sitting, a person may caress their scalp, cross and uncross their legs, rock or squirm in their chair, get out of the chair often and pace back and forth, and even make noises such as moaning. When standing, a person with akathisia may involuntarily march in place.