Parkinson’s Disease

By: Alec Andoyan, PT, DPT

Summary of Parkinson’s Disease 

Parkinson’s Disease (PD) is a chronic, progressive neurodegenerative disorder that primarily affects movement while also impacting cognition, mood, sleep, and autonomic function. It is caused by the degeneration of dopamine-producing neurons in the substantia nigra of the basal ganglia, resulting in hallmark motor features such as bradykinesia, rigidity, resting tremor, and postural instability. Although PD is incurable, symptoms can be effectively managed through pharmacologic treatment and multidisciplinary rehabilitation, allowing individuals to maintain function and quality of life.

Parkinsonism is a broader clinical term used to describe a syndrome characterized by parkinsonian motor features (bradykinesia, rigidity, tremor, and postural instability), regardless of underlying cause. While idiopathic Parkinson’s Disease is the most common form of parkinsonism, other causes include atypical parkinsonian disorders (e.g., progressive supranuclear palsy, multiple system atrophy, corticobasal degeneration), drug-induced parkinsonism, and vascular parkinsonism. These conditions often differ from PD in disease progression, response to dopaminergic medication, and prognosis.

Distinguishing PD from other forms of parkinsonism is important for treatment planning, rehabilitation expectations, and long-term management, as atypical parkinsonian disorders typically demonstrate faster progression and reduced responsiveness to medication, requiring earlier emphasis on compensatory strategies and supportive care.

Signs and Symptoms

Motor Symptoms

  • Bradykinesia (slowness of movement)
  • Resting tremor (typically unilateral at onset)
  • Rigidity (lead-pipe or cogwheel)
  • Postural instability and impaired balance
  • Shuffling gait, reduced arm swing
  • Freezing of gait (FOG)

Non-Motor Symptoms

  • Cognitive impairment and dementia
  • Depression and anxiety
  • Sleep disturbances (REM sleep behavior disorder)
  • Autonomic dysfunction (orthostatic hypotension, constipation)
  • Speech and swallowing difficulties
  • Fatigue and apathy

Pathology and Onset

Parkinson’s Disease is associated with:

  • Loss of dopaminergic neurons in the substantia nigra
  • Presence of Lewy bodies (aggregates of alpha-synuclein protein)
  • Typically idiopathic, though genetic and environmental risk factors exist
  • Onset is usually gradual, most commonly occurring after age 60, though early-onset PD can occur before age 50.

Stages and Types

Hoehn and Yahr Stages

  • Stage 1: Unilateral involvement only
  • Stage 2: Bilateral involvement without balance impairment
  • Stage 3: Mild to moderate disease with postural instability
  • Stage 4: Severe disability but able to walk/stand with assistance
  • Stage 5: Wheelchair-bound or bedridden without assistance

Types

  • Idiopathic Parkinson’s Disease (most common)
  • Atypical Parkinsonism (e.g., PSP, MSA, CBD)
  • Drug-induced Parkinsonism

Important Terminology

  • Bradykinesia: Slowness and decreased amplitude of movement
  • Rigidity: Increased resistance to passive movement
  • Freezing of Gait: Sudden inability to initiate or continue walking
  • Dyskinesia: Involuntary movements often related to long-term levodopa use
  • ON/OFF periods: Fluctuations in medication effectiveness

Helpful Resources

Websites

Apps

YouTube / Video Resources

References 

  1. American Institutes for Research. (n.d.). Rehabilitation Measures Database (RehabMeasures).
  2. American Physical Therapy Association. (n.d.). Physical therapy guide to Parkinson disease.
  3. American Speech-Language-Hearing Association. (n.d.). Parkinson’s disease practice portal.
  4. Belafsky, P. C., Mouadeb, D. A., Rees, C. J., Pryor, J. C., Postma, G. N., Allen, J., & Leonard, R. J. (2008). Validity and reliability of the Eating Assessment Tool (EAT-10). Annals of Otology, Rhinology & Laryngology, 117(12), 919–924.
  5. Berg, K., Wood-Dauphinee, S., Williams, J. I., & Maki, B. (1992). Measuring balance in the elderly: Validation of an instrument. Physiotherapy Canada, 44(2), 49–54.
  6. Bohannon, R. W., & Williams Andrews, A. (2011). Normal walking speed: A descriptive meta-analysis. Physiotherapy, 97(3), 182–189.
  7. Goetz, C. G., Tilley, B. C., Shaftman, S. R., et al. (2008). Movement Disorder Society–sponsored revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS): Scale presentation and clinimetric testing results. Movement Disorders, 23(15), 2129–2170.
  8. Hoehn, M. M., & Yahr, M. D. (1967). Parkinsonism: Onset, progression, and mortality. Neurology, 17(5), 427–442.
  9. Jacobson, B. H., Johnson, A., Grywalski, C., et al. (1997). The Voice Handicap Index (VHI): Development and validation. American Journal of Speech-Language Pathology, 6(3), 66–70.
  10. Jankovic, J. (2008). Parkinson’s disease: Clinical features and diagnosis. Journal of Neurology, Neurosurgery & Psychiatry, 79(4), 368–376.
  11. Kalia, L. V., & Lang, A. E. (2015). Parkinson’s disease. The Lancet, 386(9996), 896–912.
  12. King, L. A., & Horak, F. B. (2013). On the Mini-BESTest: Scoring and reliability in Parkinson disease. Physical Therapy, 93(4), 571–581.
  13. Law, M., Baptiste, S., McColl, M., Opzoomer, A., Polatajko, H., & Pollock, N. (1990). The Canadian Occupational Performance Measure: An outcome measure for occupational therapy. Canadian Journal of Occupational Therapy, 57(2), 82–87.
  14. Mann, G., Hankey, G. J., & Cameron, D. (1999). Swallowing disorders following stroke and neurological disease. Dysphagia, 14(2), 84–94.
  15. McHorney, C. A., Bricker, D. E., Kramer, A. E., et al. (2002). The SWAL-QOL outcomes tool for oropharyngeal dysphagia. Dysphagia, 17(2), 97–114.
  16. Morris, S., Morris, M. E., & Iansek, R. (2001). Reliability of measurements obtained with the Timed “Up & Go” test in people with Parkinson disease. Physical Therapy, 81(2), 810–818.
  17. Nieuwboer, A., Rochester, L., Herman, T., et al. (2009). Reliability of the Freezing of Gait Questionnaire in Parkinson’s disease. Movement Disorders, 24(9), 1309–1314.
  18. Parkinson’s Foundation. (n.d.). Understanding Parkinson’s disease.
  19. Peto, V., Jenkinson, C., Fitzpatrick, R., & Greenhall, R. (1995). The development and validation of a short measure of functioning and well-being for individuals with Parkinson’s disease. Quality of Life Research, 4(3), 241–248.
  20. Platz, T., Brown, R. G., Marsden, C. D., et al. (1989). Motor execution and timing in Parkinson’s disease. Brain, 112(3), 639–658.
  21. Podsiadlo, D., & Richardson, S. (1991). The Timed “Up & Go”: A test of basic functional mobility for frail elderly persons. Journal of the American Geriatrics Society, 39(2), 142–148.
  22. Steffen, T., Seney, M., & McNeely, M. (2015). Mini-BESTest, Berg Balance Scale, and Timed Up and Go test in people with Parkinson disease: Responsiveness and MCID. Journal of Neurologic Physical Therapy, 39(3), 119–128.
  23. Tomlinson, C. L., Patel, S., Meek, C., et al. (2012). Physiotherapy intervention in Parkinson’s disease: Systematic review and meta-analysis. BMJ, 345, e5004.
  24. Yorkston, K. M., Beukelman, D. R., Strand, E. A., & Bell, K. R. (1999). Management of motor speech disorders in children and adults (2nd ed.). Pro-Ed.

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