Neuro Asia Care ~ Neurosurgery Specialist Clinic ~ Singapore


Brief explanation of terms used

Hoehn and Yahr Scale

This is a 5-stage clinical scale used to classify the severity of Parkinson disease based on motor symptoms.

Stage 1: Mild

  • Symptoms
    • Stage 1 Parkinson is the mildest form and symptoms may not be noticeable. If they are, they may be only seen on one side of the body, typically in the form of a mild tremor, rigidity, or slowness of movement. Symptoms are unlikely to interfere with daily life and tasks at this stage.
  • Diagnosis
    • Because the symptoms are so mild, it may not cross the individual’s mind to seek medical attention, and even if they do, a doctor may not be able to make a correct diagnosis.

Stage 2: Early

  • Progression
    • Each person experiences Parkinson disease differently. Symptoms and progression will not be the same as someone else’s. The progression from stage 1 to stage 2 may happen as quickly as within months or as long as several years.
  • Symptoms
    • At stage 2, symptoms start to appear on both sides of your body, or at the midline without usually affecting your balance. Individuals may start to experience one or more of the following symptoms:
      • Changes in facial expressions
      • Decreased blinking
      • Speech abnormalities (e.g., soft voice, fading volume after speaking loudly, slurring speech)
      • Muscle stiffness leading to neck or back pain, stooped posture and general slowness in daily activities
      • Tremors
  • Diagnosis
    • Diagnosis is easier if tremor is present. Sometimes, if the only symptoms are slowness or lack of spontaneous movement, it may be misinterpreted as signs of aging.

Stage 3: Middle

  • Symptoms
    • Symptoms reach a turning point here. Individuals will likely experience most, if not all, of the symptoms of stage 2. 
    • Muscle movement and reflexes become noticeably slower
    • Balance and coordination problems make falls more common at this stage. 
    • However, many people still remain independent in daily activities without requiring much assistance in dressing and other self-care tasks.
  • Diagnosis
    • Diagnosis of Parkinson disease is generally quite clear at stage three.

Stage 4: Advanced

  • Progression from stage 3 to 4 is usually marked by the loss of independence to perform daily activities.
  • Individuals will experience great difficulty standing on their own, and may require a walker or assistive device.
  • Living alone is not safe, possibly dangerous, as they will require some form of assistance with daily care.

Stage 5: Severely advanced

  • Stage 5 is the most debilitating stage characterised by confinement to a bed or wheelchair. Around-the-clock assistance becomes a necessity, to reduce the risk of falling and all daily activities. 
  • Also, at this stage, individuals may start to experience hallucinations or delusions.
  • While the symptoms worsen over time, some people never reach stage 5.