Introduction

Geriatric Essentials

• The most common movement disorders in the elderly are essential tremor and Parkinson's disease.
• Even mild movement disorders may lead to functional impairment in elderly people with other medical problems.
• Many drugs used to control the symptoms of movement disorders have CNS adverse effects (eg, hallucinations, confusion).
• If embarrassing or disabling symptoms occur, patients can be taught techniques to compensate and help preserve their independence, social interaction, and mental health.

Movement disorders result in abnormal movement, either decreased movement (hypokinesia) or in excessive, abnormal, involuntary movements (hyperkinesias). Dyskinesia refers to hyperkinesias secondary to drugs. Most movement disorders are caused by abnormalities in extrapyramidal structures (basal ganglia and substantia nigra), in the cerebellum, or in connecting pathways. Movement disorders are sometimes referred to as extrapyramidal disorders. Although knowledge of the fundamental anatomic, physiologic, and pathogenetic bases of many movement disorders is incomplete, available information about their biochemical pathophysiology often suggests an approach to drug treatment.

The basal ganglia contain high levels of neurotransmitters, notably acetylcholine, dopamine, and -aminobutyric acid (GABA). Normal function appears to depend on a balance between the various neurotransmitters; changes in their production, transport, release, action, or degradation can alter this balance. In general, dopamine deficiency, cholinergic hyperactivity, or both lead to decreased movement and rigidity (eg, in parkinsonism). Dopamine hyperactivity, cholinergic hypoactivity, or both result in excessive voluntary or abnormal involuntary movements (eg, in choreas).

Identifying the type of movement disturbance helps classify the disorder and eliminates some possible causes. Decreased or slow purposeful movements, especially when accompanied by rigidity, suggest hypokinetic, usually parkinsonian disorders. Excessive voluntary or abnormal involuntary movements suggest hyperkinetic disorders (see Figure 46-1 and Table 46-1).

This topic was last updated June 2006.