Disease Progression

Progression of Symptoms

Parkinson’s disease typically starts on one side of the body in the arms and legs and does spreads to the other side over time. Axial symptoms are present later in disease and represent symptoms in the middle of the body as noted below. Note that balance problems are not experienced with early disease.

Parkinson's Disease Stages

Hoehn and Yahr is a staging system commonly used in research.

Stage Symptoms
Unilateral (one side of body), Minimal problems
Unilateral and Axial (middle of body)
Bilateral (both sides of body) or Axial without balance problems
Bilateral with mild postural instability (easily recovers)
Bilateral disease: mild to moderate disability with impaired postural reflexes; physically independent
Severely disabling disease; still able to walk or stand unassisted
Wheelchair or Bed Bound

Parkinson's Treatment Stages

Another way to stage Parkinson’s disease is by response to treatment usually referred to by Early, Mid and Advanced Stage.
You can learn more about these stages in the section Stages of PD.

Early Stage

In mild or early stage PD, levodopa or dopamine enhancing medications effectively improve motor symptoms throughout the day. Movements are often controlled with little to no variability (variability is called fluctuation) in response to each dose. Sometimes tremor or dystonia can be difficult to treat even when medication improves other movement symptoms.

Mid or Moderate Stage

In this stage, medication doses continue to improve symptoms such as tremor, rigidity, slow movement, shuffling and posture. However, the time that each medication dose is effective becomes shorter; often not lasting from one dose to the next, an effect referred to as end of dose wearing off.  When the benefits of medication wear off between doses the medication must be increased or taken more often. Dyskinesia can occur as medications are increased. Dyskinesia are involuntary (unintentional) or jerky motions caused by dopamine medication. Dyskinesia typically occur when medication levels (levodopa) are at their peak, but can also occur when medications levels are wearing off. Like dyskinesia, dystonia (abrupt muscle spasm, contraction or twisting) can occur at peak dose or when the dose is wearing off.


Advanced Stage

At this stage, advanced symptoms such as falling, poor balance, gait freezing, speech and swallowing problems typically do not improve with more medication.


This is very important to understand as growing disability prompts many people to seek more medicine or even DBS due to frustration and this frustration increases one’s desperation to ‘try-anything’.  Un-necessary treatment, risk and side effects can occur. Rehabilitation therapy can be very helpful when symptoms refractory to medication and surgery such as imbalance, freezing of gait, speech or swallowing problems increase.