Movement disorder has largely replaced the older term ‘Extrapyramidal disease’. A few movement disorders do arise outside the basal ganglia eg. myoclonus from the brain stem, cortex, or spinal cord, and painful legs/moving toes arise from the peripheral nervous system.
This large group of complex, sometimes bewildering, neurological disorders, is often highly treatable. However, an accurate diagnosis is mandatory before one can think of effective therapy. In this era of neurodiagnostic high–technology, there remains no way to diagnose an involuntary movement other than visual inspection. Words fail to express the subtle nuances which distinguish between various types of movements, and one can learn this art well only by examination of affected patients or videotapes. This article is an attempt to outline a clinical approach to the diagnosis of the common movement disorders.
Types of movement disorders Movement disorders essentially have either less movement (hypokinesia) or excessive movement (hyperkinesia). Sometimes, there is a combination of both.
The Akinetic–Rigid syndromes Hypokinesia bradykinesia or akinesia: Poverty of movement in speed or amplitude without any weakness or paralysis.
- Pure parkinsonism: Akinesia or rest tremor associated with rigidity and/or deficits in postural reflexes.
- Parkinsonism plus: Parkinsonism along with other signs eg.
- Vertical gaze paresis: Progressive supranuclear palsy.
- Apraxia due to Corticobasal ganglionic degeneration.
- Autonomic failure, Ataxia: OPCA.
The Hyperkinetic Dyskinetic syndromes Hyperkinesias or Dyskinesias A wide variety of abnormal, excessive involuntary movements further characterized according to their regularity, velocity and duration, as well as anatomical distribution, tremors, tics and stereotypies are regular and predictable movements while chorea flows irregularly from one body part to another without a predictable pattern. Myoclonus, clonictics and some tremors are rapid while dystonias and athetosis are slow and sustained, often with a twisting component.
Finally, several hyperkinesias have a tendency to involve certain body regions for example akathisia almost always affects the legs. Tics tend to be most prominent in the face, eyes and neck and dystonic movements occur in all body regions, but are particularly common in the neck muscles.