Reference guide
What is Parkinson’s disease?
Parkinson’s disease is a long-term condition involving the nervous system. It is associated with changes in movement, including slowness, stiffness, and tremor. Symptoms and their pace of change vary widely from person to person.
This page is for general education. It cannot diagnose Parkinson’s disease or replace advice from a qualified healthcare professional.
Parkinson’s commonly begins later in adulthood, although earlier-onset forms also occur. A diagnosis is based on a person’s history and examination rather than one single test.
Symptoms of Parkinson’s disease
Symptoms may begin gradually. Some affect movement; others involve sleep, mood, speech, smell, thinking, or automatic body functions. Having one symptom does not by itself mean that someone has Parkinson’s disease.
Early or non-movement changes
- Reduced sense of smell
- Constipation
- Changes in sleep
- Smaller handwriting or changes in voice
- Lower mood or reduced facial expression
Movement-related symptoms
- Slowness of movement
- Muscle stiffness
- Tremor, often beginning on one side
- Changes in balance, walking, or arm swing
- Difficulty starting or stopping a movement
Other possible symptoms
Some people experience tiredness, pain, anxiety, depression, swallowing difficulties, changes in blood pressure, or problems with attention and memory. Symptoms differ between individuals and may change over time.
Causes and risk factors
The exact cause is not known. Parkinson’s disease appears to involve a combination of inherited susceptibility, ageing, and environmental influences. Researchers study changes in nerve cells and proteins, including alpha-synuclein, but these findings do not explain every individual case.
Risk is influenced by several factors, including age, family history, and some environmental exposures. A risk factor is not a prediction: many people with a risk factor do not develop Parkinson’s disease.
How stages are described
Clinicians may use scales such as the Hoehn and Yahr scale to describe how movement symptoms affect daily life. These stages are a broad framework, not a timetable. Progression is different for each person.
Early changes
Symptoms are usually mild and may be limited mainly to one side of the body.
Symptoms on both sides
Stiffness, slowness, or tremor may become more noticeable, while balance can remain relatively steady.
Balance becomes affected
Movement and balance difficulties can make everyday tasks harder, although independence may continue.
Greater assistance
Standing and walking may require support, and regular help with daily activities may be needed.
Advanced support needs
Marked movement difficulties can require extensive assistance and careful, coordinated care.
Diagnosis
A clinician usually reviews symptoms, medical and family history, medicines, and changes over time, then performs a neurological examination. Imaging or laboratory tests may be used to look for other explanations. There is no single routine test that confirms every case of Parkinson’s disease.
Treatment and everyday support
Treatment is individualised. Medicines may help movement symptoms, and options can include levodopa-based medicines, dopamine agonists, MAO-B inhibitors, or other treatments selected by a clinician. Medicines should not be started, stopped, or changed without professional guidance.
Physiotherapy, occupational therapy, speech and language therapy, regular safe activity, rest, and practical adjustments can support mobility, communication, swallowing, and independence. In selected situations, specialist procedures may be considered.
Food and daily habits
A balanced diet, enough fluids, regular movement, and a consistent sleep routine can support general health. Some medicines interact with food timing or protein intake, so dietary changes should be discussed with the treating team. No food or supplement has been proven to prevent Parkinson’s disease.
References
For current, detailed information, discuss symptoms and treatment choices with a qualified healthcare professional. Educational background reading is also available through the central nervous system guide, basal ganglia guide, and neurotransmitters guide.