Parkinsonism: Successive Clinical Stages

Untreated Parkinson disease may be divided into five stages. Stage 1 is characterized by mild unilateral disease. Tremor may be the only visible sign but other subtle findings, including slowness or rigidity, may be noted on examination. Gait is usually normal, but there may be mild decrease in arm swing on the most symptomatic side, and the upper limb may be carried slightly abducted at the shoulder and flexed at the elbow. Diminished facial expression, hypophonic speech, reduced manual dexterity, impaired rapid alternating movements, and micrographia with poorly formed letters may be present. As the disease advances to stage 2, there is bilateral involvement with postural changes. In this stage, the more classic phenotype is observed, with reduced facial mobility, stooped posture when standing, reduced arm swing on walking, and en bloc turning, Rapid alternating movements are impaired. Movements become slow and deliberate, and patients may complain of fatigue and weakness. Fatigue may be disabling in up to 75% of patients. The hand assumes the so-called striatal posture with dorsiflexed wrist, adducted fingers, flexed metacarpophalangeal and distal interphalangeal joints, and extended proximal interphalangeal joints. In some patients, a “striatal foot” may be present consisting of a varus position with clawing of toes. In stage 3 disease, retropulsion and propulsion reflect increasing impairment of postural reflexes and righting responses. Gait is festinating and shuffling. In this stage, the symptoms become increasingly pronounced, and the patient may require assistance in the activities of daily living. With further progression, a more advanced stage is reached (stage 4), with severe disability, rigidity, bradykinesia, and gait disturbances. Standing is unsteady; a slight push precipitates severe retropulsion, culminating in a fall if the patient is not caught or is left unattended. Eventually, the patient becomes markedly bradykinetic, rigid, and confined to a wheelchair or bed (stage 5). Drs. Melvin Yahr and Margaret Hoehn studied the natural progression of patients suffering with Parkinson disease and developed a staging scale that bears their names. This classification, known as the Hoehn and Yahr staging scale, emphasizes the disease by progression of symptoms; it is arbitrarily divided into five stages of disease progression, and although widely used, it provides only a crude estimate of disease severity.

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