Parkinson's disease is a neurodegenerative disorder. Everyone who is diagnosed with PD will experience it differently. This disease causes a lot of movement-related symptoms such as tremors, rigidity, postural instability, bradykinesia, and hypokinesia. As well as some non-movement-related symptoms such as depression, anxiety, apathy, hallucinations, and other cognitive impairments.

There are five stages that a person with Parkinson's disease will go through. This scale is called the Hoehn & Yahr scale. It was developed in 1967 by Margaret M. Hoehn and Melvin D Yahr. Over the years, it has been modified through research. Today physicians use this scale to describe the motor symptoms that one might experience with PD. The five stages of Parkinson’s disease are separated by severity. Stages one and two are often labeled as the early stages. Stages two and three are mild stages, and stages four and five are considered advanced stages. 
 

Stage one is where a person will typically experience mild symptoms. Often, these symptoms do not interfere with daily life. Tremors and other movements occur only on one side of the body, typically. People will often experience changes in their facial expressions as well as changes in posture and walking.

Stage two is when the symptoms typically worsen. Both sides of the body are now affected. The tremors that are caused by Parkinson’s disease worsen and become more intense. As changes in walking and posture begin to increase, it will cause some daily activities to become more difficult.

Stage Three is considered the mid-stage. During this stage, a person will start to experience a loss of balance which often results in more frequent falls. Motor symptoms continue to worsen and intensify. Most people in this stage are still able to live independently. However, their daily activities continue to become more difficult.

Stage Four is where the symptoms fully develop. A person at this stage is no longer able to live alone and will require assistance with daily living. They will still be able to walk, however, most will require a cane or a walker for assistance and safety.

Stage Five is the most debilitating. He or she has become bed-reddened due to the stiffness in their legs. They are no longer able to stand or walk. People in this stage of Parkinson’s will require round-the-clock care.

Sources
Yu, Jun. “Stages of Parkinson’s | Parkinson’s Foundation.” Www.parkinson.org, 2022, www.parkinson.org/understanding-parkinsons/what-is-parkinsons/stages.
Hoehn, M. M., and M. D. Yahr. “Parkinsonism: Onset, Progression, and Mortality.” Neurology, vol. 17, no. 5, 1967, pp. 427–427., https://doi.org/10.1212/wnl.17.5.427.