ABSTRACT

This chapter reviews progress in the epidemiology of the following movement disorders: idiopathic Parkinson’s disease (PD), essential tremor, Huntington’s disease, tardive dyskinesia, tic disorders, and dystonias. The final section embraces all of the aforementioned disorders and is devoted to a discussion of therapeutic agents. PD is characterized clinically by cogwheel rigidity, akinesia, postural reflex impairment, and resting tremor, and pathologically by the loss of pigmented neurons, most prominently in the substantia nigra, with associated characteristic eosinophilic cytoplasmic inclusions. Essential tremor is similar to the physiologic tremor present in all persons, differing primarily by its increased amplitude and nearly continuous presence, so that the distinction between normal persons and those with mild essential tremor may be impossible to make in community surveys. All movement disorders are rare, and the design of clinical trials is limited by the small numbers of patients available at individual research centers.