Parkinson's disease (PD) is a devastating and complex disease that interferes with movement more and more as time goes on. The main symptoms of Parkinson's are tremors or trembling of a limb, especially when the body is at rest, slow movement, an inability to move, rigid limbs, a shuffling gait, and stooped posture. It also produces a wide range of other problems for patients: problems with swallowing and chewing, speech impairments, urinary problems or constipation, excessive sweating and other skin problems, depression and other emotional changes, and difficulties with sleep.

No one can predict which of these symptoms will affect a particular patient, and the intensity of the symptoms varies from person to person. None of these secondary symptoms is fatal, although swallowing problems can cause choking.

The progression of symptoms in Parkinson's may take 20 years or more. In some people, however, the disease progresses much more quickly. Below is one commonly used system for describing how the symptoms of Parkinson's disease progress.

Hoehn and Yahr Staging of Parkinson's Disease

Stage One

  • Signs and symptoms on one side only
  • Symptoms tend to be mild
  • Symptoms are inconvenient but not disabling
  • The condition usually appears as a tremor of one limb
  • Friends have noticed changes in posture, locomotion and facial expression

Stage Two

  • Symptoms are bilateral, affecting both sides of the body
  • Symptoms start to interrupt the activities of daily living, with minimal disability
  • Posture and gait are vaffected

Stage Three

  • Significant slowing of body movements
  • Early impairment of equilibrium on walking or standing
  • Generalized dysfunction that is moderately severe

Stage Four

  • Severe symptoms
  • The person can still walk to a limited extent
  • Rigidity and bradykinesia
  • The person is no longer able to live alone
  • Tremor may be less than earlier stages

Stage Five

  • Cachectic stage
  • Invalidism is 100%
  • The person cannot stand or walk
  • Requires constant nursing care

Another commonly used scale is the Unified Parkinson's Disease Rating Scale (UPDRS). This much more complicated scale has multiple ratings that measure mental functioning, behavior, and mood; activities of daily living; and motor function. Both the Hoehn and Yahr scale and the UPDRS are used to measure how individuals are faring and how much treatments are helping them.


The National Institute of Neurological Disorders and Stroke (NINDS) conducts and supports research on brain and nervous system disorders.