Movement Disorders

Movement disorders are neurological conditions that affect the speed, fluency, quality, and ease of movement. Movement disorders occur as a result of damage or disease in a region located at the base of the brain (basal ganglia). The basal ganglia is comprised of clusters of nerve cells (neurons) that send and receive electrical signals and are responsible for involuntary movement. Movement disorders can result from the following: age-related changes, environmental toxins, genetic disorders (e.g., Huntington's disease, Wilson disease), medications (e.g., antipsychotic drugs), metabolic disorders (e.g., hyperthyroidism), Parkinson's disease, and stroke.

Mental and neurological disorders are highly prevalent worldwide with 450 million people estimated to be suffering from them. The Global Burden of Disease report drew the attention of the international health community to the fact that the burden of mental and neurological disorders has been seriously underestimated by traditional epidemiological methods that took into account only mortality but not disability rates. This report specifically showed that while the mental and neurological disorders are responsible for about 1 percent of deaths, they account for almost 11 percent of disease burden the world over. The study has demonstrated that magnitude and burden of neurological disorders are huge and that they are priority health problems globally. The extension of life expectancy and the aging of the general populations in both developed and developing countries are likely to increase the prevalence of many chronic and progressive physical and mental conditions including neurological disorders.

There is emerging awareness that movement disorders rank among the most common neurological diseases. However, the overall burden of these disorders in the general community is not well defined. Disorders of movement due to basal ganglia dysfunction are generally classified into two categories: those with too little movement (hypokinesias) and those with excess movement (hyperkinesias). Hypokinetic movement disorders include Parkinson's disease and atypical parkinsonian syndromes. Hyperkinesias include involuntary movements such as tremor, chorea, dystonia, tics, and myoclonus. Movement disorders are usually diagnosed by “pattern recognition.” The complex diagnostic process is essentially one of phenomenology first, neurologic examination second, and any supportive laboratory testing last.