Pathophysiology and Clinical Assessment of Parkinsonian Symptoms and Signs

In his 1817 ‘‘An Essay on the Shaking Palsy,’’ James Parkinson recorded many features of the condition that now bears his name (1). Parkinson emphasized the tremor at rest, flexed posture, festinating gait (Fig. 1), dysarthria, dysphagia, and constipation. Charcot and others later pointed out that the term paralysis agitans used by Parkinson was inappropriate, because in Parkinson’s disease (PD) the strength was usually well preserved and many patients with Parkinson’s disease did not shake. Although traditionally regarded as a motor system disorder, PD is now considered to be a much more complex syndrome involving the motor as well as the nonmotor systems. For example, oily skin, seborrhea, pedal edema, fatigability, and weight loss are recognized as nonspecific but nevertheless typical parkinsonian features. The autonomic involvement is responsible for orthostatic hypotension, paroxysmal flushing, diaphoresis, problems with thermal regulation, constipation, and bladder, sphincter, and sexual disturbances. The involvement of the thalamus and the spinal