FEATURED ARTICLE • PHYSIOTHERAPY & REHABILITATION
Parkinson’s Disease — Study Material
Motor features, pathophysiology, assessment and physiotherapy rehabilitation
1. What is Parkinson’s Disease?
Parkinson’s disease (PD) is a progressive neurological disorder that primarily affects movement. It is associated with dysfunction and progressive loss of dopaminergic neurons in the substantia nigra, leading to reduced dopamine availability in the basal ganglia.
Major motor features include:
- Bradykinesia — slowness of movement
- Resting tremor
- Rigidity
- Postural instability
Non-motor problems may also occur, including sleep disturbance, constipation, mood changes, cognitive impairment, speech difficulties and swallowing problems.
2. Main Motor Symptoms
Bradykinesia
Bradykinesia is one of the most important clinical features. Patients may have difficulty initiating movement, turning in bed, standing from a chair, walking, dressing, writing and performing fine motor tasks. Movements may become progressively smaller and slower.
Resting Tremor
A resting tremor typically occurs when the limb is relaxed and may decrease during purposeful movement. It often begins asymmetrically, although not every patient develops a prominent tremor.
Rigidity
Rigidity is increased resistance to passive movement. It can contribute to reduced joint movement, stooped posture, difficulty turning, reduced arm swing and musculoskeletal discomfort.
Postural Instability
Impaired balance and postural responses can contribute to falls, difficulty turning, difficulty negotiating obstacles and reduced confidence during walking.
3. Parkinsonian Gait
Gait abnormalities may include:
- Shortened step length
- Reduced walking speed
- Reduced arm swing
- Shuffling
- Festination
- Difficulty initiating gait
- Turning difficulty
- Freezing of gait
Freezing of gait is particularly important in physiotherapy. The person may suddenly feel that the feet are stuck to the floor, especially during gait initiation, turning or passing through narrow spaces.
4. Postural Changes
- Forward head posture
- Increased thoracic kyphosis
- Trunk flexion
- Flexed hips and knees
- Reduced trunk rotation
These changes can affect balance, walking, reaching, transfers and functional activities.
5. Pathophysiology
Parkinson’s disease is primarily associated with progressive loss of dopamine-producing neurons in the substantia nigra pars compacta, a region of the midbrain. These neurons normally release dopamine into the striatum, where dopamine helps regulate basal-ganglia circuits responsible for movement.
5.1 Loss of Dopaminergic Neurons
In Parkinson’s disease, dopaminergic neurons progressively degenerate. This produces reduced dopamine availability in the striatum and disrupts normal basal-ganglia function.
↓ Dopaminergic neurons → ↓ dopamine in the striatum
5.2 Basal Ganglia Circuit Dysfunction
Dopamine normally facilitates movement through the direct pathway and reduces movement suppression through the indirect pathway. With dopamine loss, facilitation of movement decreases while inhibitory influence on movement increases. The overall result is increased inhibition of thalamocortical motor activity, contributing particularly to bradykinesia and difficulty initiating movement.
5.3 Why Rigidity Occurs
Altered basal-ganglia activity affects the normal regulation of muscle activity. This can produce increased muscle tone, resistance to passive movement, reduced reciprocal movement and difficulty relaxing muscles. Clinically, this appears as rigidity.
5.4 Why Resting Tremor Occurs
The exact mechanism of Parkinsonian resting tremor is complex and is not explained by dopamine deficiency alone. Abnormal activity within basal-ganglia, thalamocortical and cerebellar-related networks is thought to contribute. Not every person with Parkinson’s disease develops a prominent tremor.
5.5 Postural Instability
As Parkinson’s disease progresses, changes may affect neural systems involved in postural control, balance, automatic movement, gait and anticipatory postural adjustments. Reduced automatic postural responses can result in impaired balance and increased fall risk.
5.6 Alpha-Synuclein and Lewy Bodies
Another important pathological feature is abnormal accumulation of the protein alpha-synuclein inside neurons. These abnormal protein aggregates are associated with Lewy bodies and Lewy neurites. Their relationship with neuronal degeneration remains an important area of Parkinson’s disease research.
5.7 Other Pathological Mechanisms
- Mitochondrial dysfunction
- Oxidative stress
- Neuroinflammation
- Abnormal protein handling
- Impaired cellular waste/protein clearance
- Synaptic dysfunction
These mechanisms may contribute to progressive neuronal damage and disease-related dysfunction.
6. Pathophysiology Flow Chart
Neurodegenerative processes
↓
Loss of dopaminergic neurons in substantia nigra pars compacta
↓
↓ Dopamine in the striatum
↓
Basal ganglia circuit dysfunction
↓
Abnormal thalamocortical motor activity
↓
Impaired movement regulation
↓
Bradykinesia + rigidity + tremor + gait/postural problems
Physiotherapy connection: Understanding this pathway helps explain why Parkinson’s rehabilitation focuses on large-amplitude movement, external cueing, gait training, balance training, strengthening, aerobic exercise, flexibility and functional practice rather than treating tremor alone.
7. Physiotherapy Assessment
Important assessment areas include:
- History: onset/progression, medication schedule, falls, freezing, pain, fatigue, sleep and physical activity
- Observation: posture, tremor, bradykinesia, rigidity, movement initiation and gait
- Physical examination: ROM, strength, flexibility, balance, coordination, endurance and gait
- Functional assessment: bed mobility, sit-to-stand, walking, turning, stairs and transfers
- Appropriate outcome measures such as the MDS-UPDRS and functional mobility, gait and balance measures
8. Physiotherapy Management
Aerobic Exercise
Walking, treadmill training, cycling, stationary cycling and other appropriately selected cardiovascular activities can improve physical fitness and functional capacity.
Strength Training
Strengthen lower limbs, upper limbs and trunk. Examples include sit-to-stand, supported squats, step-ups and resistance-band exercises.
Flexibility and Mobility
Focus on trunk rotation, hip mobility, shoulder mobility, chest flexibility and lower-limb flexibility.
Balance Training
May include static and dynamic balance, weight shifting, reaching, turning, stepping strategies and appropriately selected dual-task activities.
Gait Training
Address step length, walking speed, arm swing, turning, initiation, obstacle negotiation and freezing.
9. External Cueing
External cues may help overcome difficulties with movement initiation and gait.
- Visual cues: floor lines or foot-placement targets
- Auditory cues: metronome, rhythmic counting or music/rhythm
- Verbal cues: “Take a big step,” “Lift your feet,” or “Turn slowly”
10. Freezing of Gait — Practical Strategy
A simple strategy is: Stop → regain posture → shift weight → use a cue → initiate a large step.
Triggers may include turning, doorways, crowded environments, starting to walk and changing direction.
11. Functional Training
- Sit-to-stand
- Bed mobility
- Turning
- Reaching
- Walking
- Stair climbing
- Transfers
- Community mobility
The overall goal is to maintain independence and participation.
12. Falls Prevention
- Balance and gait training
- Strengthening
- Environmental modification
- Appropriate walking aids when required
- Education and freezing strategies
- Footwear assessment
- Safe transfer practice
13. Exercise Safety
Exercise should be individualized according to cardiovascular status, balance, fall risk, fatigue, disease severity, medication effects, cognitive status and other medical conditions.
14. Medication and Physiotherapy Timing
Symptoms can fluctuate during the day. The therapist should ask about medication timing, ON and OFF periods, dyskinesia and freezing episodes. This information can help plan assessment and exercise sessions appropriately.
15. Non-Motor Symptoms
- Depression and anxiety
- Apathy
- Cognitive changes
- Sleep problems
- Constipation
- Urinary problems
- Speech difficulties
- Swallowing difficulties
- Fatigue
16. Multidisciplinary Management
- Neurologist
- Physiotherapist
- Occupational therapist
- Speech and language therapist
- Dietitian
- Nurse
- Mental-health professional when appropriate
- Social/support services
17. Key Physiotherapy Goals
- Maintain mobility
- Improve movement
- Improve balance
- Prevent falls
- Preserve independence
- Improve gait and functional mobility
- Maintain range of motion
- Improve strength and endurance
- Address posture
- Develop strategies for freezing
- Promote safe physical activity
Educational Clinical Case Study
Illustrative case: An older adult with Parkinson’s disease presents with bradykinesia, a short-stepped shuffling gait, difficulty turning, occasional freezing at doorways, reduced arm swing and impaired balance.
Physiotherapy assessment: Assessment would consider gait, turning, balance, transfers, strength, range of motion, functional mobility, falls history, fatigue, cognitive status and the timing of medication-related ON/OFF periods.
Rehabilitation focus: The supplied material supports large-amplitude movement, external cueing, gait training, balance work, strengthening, aerobic activity and functional practice. Freezing may be addressed with the sequence: stop, regain posture, shift weight, use a cue, then initiate a large step.
Educational note: This is an illustrative learning case, not a patient record or individualized treatment prescription.