Parkinson’s disease (PD) impacts people in different ways. Not everyone will experience all the symptoms of PD; even if people do, they won’t necessarily experience the symptoms in quite the same order or at the same intensity.
While symptoms and disease progression are unique to each person, knowing the typical stages of Parkinson’s can help you cope with changes as they occur. Some people experience the changes over 20 years or more. Others find the disease progresses more quickly.
It is difficult to accurately predict the progression of Parkinson’s. Following a diagnosis, many people experience a good response to medications, such as levodopa. This optimal timeframe can last many years and varies for everyone.
However, as the disease progresses, people with Parkinson’s often need to work alongside their doctor to adjust levodopa dosages. In this timeframe, they may experience new or worsening movement symptoms and fluctuations, levodopa-induced dyskinesia, swallowing problems, freezing of gait, falls and imbalance.
People with young-onset PD are more prone to levodopa-induced dyskinesia and changes in movement (called motor fluctuations), while those diagnosed later in age may experience more cognitive changes and non-movement symptoms.
Motor fluctuations can become an issue five to 10 years after diagnosis. Postural instability (trouble with balance and falls) typically occurs after about 10 years.
5 Stages
In 1967, Hoehn & Yahr defined five stages of PD based on the level of clinical disability. Clinicians use it to describe how motor symptoms progress in PD. On this scale, stages 1 and 2 represent early-stage, 2 and 3 mid-stage, and 4 and 5 advanced-stage PD.
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During this initial stage, the person has mild symptoms that generally do not interfere with daily activities. Tremor and other movement symptoms occur on one side of the body only. Changes in posture, walking and facial expressions occur.
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Symptoms start getting worse. Tremor, rigidity and other movement symptoms affect both sides of the body or the midline (such as the neck and the trunk). Walking problems and poor posture may be apparent. The person is able to live alone, but daily tasks are more difficult and lengthier.
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Considered mid-stage, loss of balance (such as unsteadiness as the person turns or when he/she is pushed from standing) is the hallmark. Falls are more common. Motor symptoms continue to worsen. Functionally the person is somewhat restricted in his/her daily activities now, but is still physically capable of leading an independent life. Disability is mild to moderate at this stage.
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At this point, symptoms are fully developed and severely disabling. The person is still able to walk and stand without assistance, but may need to ambulate with a cane/walker for safety. The person needs significant help with activities of daily living and is unable to live alone.
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This is the most advanced and debilitating stage. Stiffness in the legs may make it impossible to stand or walk. The person is bedridden or confined to a wheelchair unless aided. Around-the-clock care is required for all activities.
Recently, the Movement Disorder Task Force also recognized three stages in early PD.
Learn about more Parkinson's symptoms:
Preclinical Phase
The degeneration of the dopamine producing neurons has already begun, but no clinical symptom is evident yet.
Prodromal Phase
Some symptoms are present, but they are insufficient for the clinician to make a diagnosis of PD.
Clinical Phase
Parkinsonian symptoms have manifested and are clearly recognizable.
Rating Scales
Doctors use clinical rating scales to characterize the movement and non-movement symptoms of PD, how severe they are, and their impact on a person’s daily activities. Clinical scales also help doctors track the progression of PD and are used in clinical trials. In addition to the Hoehn and Yahr Scale described above, examples of widely used clinical scales for PD include:
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A commonly used and validated tool originally developed in the 1980s by a Parkinson’s Foundation researcher. It contains four parts:
- Mentation, behavior and mood
- Activities of daily living
- Motor examination
- Complications of therapy
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A revision and expansion of the UPDRS, published in 2008. It is a more comprehensive scale developed to evaluate the various aspects of PD. The four components included in this scale are:
- Non-movement aspects of experiences of daily living
- Movement aspects of experiences of daily living
- Movement examination
- Movement complications
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Used to evaluate abnormal involuntary movements (dyskinesia) that occur with advancing PD.
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Uses percentages to assess a person’s level of functional independence to complete daily chores.
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A 39-item self-reported questionnaire assessing PD-specific health related functioning and well-being across eight quality of life dimensions. There is also a short-form version derived from the PDQ-39, the PDQ-8.
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A patient-based screening tool designed to draw attention to the presence of non-movement symptoms in people with PD.
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A 30-item rater-based scale to measure the severity and frequency of a wide range of non-movement symptoms across nine dimensions in people with PD.
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They may provide invaluable insights on motor fluctuations in relation to medication intake. Increasingly, clinicians and researchers are exploring new kinematic sensor technologies to help detect and measure motor symptoms and fluctuations.
Theory of PD Progression: Braak’s Hypothesis
Researchers believe a combination of genetic and environmental factors cause Parkinson’s. In 2003, Heiko Braak, MD, hypothesized that an unknown pathogen (a bacteria, virus or other microorganism that causes disease) in the gut could be the cause of PD.
This was followed by a more extensive hypothesis, stating that PD starts in two places: the neurons of the nasal cavity and the neurons in the gut. This is now known as Braak’s hypothesis. In this theory, the pathogen enters the body via the nose and/or gets swallowed and reaches the gut. The pathogenic products thus come into contact with the olfactory (smell) and/or enteric (gut) neurons, triggering the aggregation of an abnormal protein called α-Synuclein. The aggregated α-Synuclein (called Lewy body) then spreads toward the central nervous system (namely the brain), and eventually arriving in and causing the degeneration of the dopaminergic neurons in the area of the brain called the substantia nigra.
This theory is supported by evidence that non-movement symptoms, such as a loss of sense of smell, sleep disorders and constipation, may appear several years ahead of movement symptoms. For this reason, researchers focus on these non-motor symptoms to detect PD as early as possible and to look for ways to stop its progression.
Page reviewed by Dr. Jun Yu, Movement Disorders Fellow at the University of Florida, a Parkinson’s Foundation Center of Excellence.
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