Parkinson’s disease is a chronic and progressive neurological condition characterised by symptoms of motor tremor, motor rigidity, and/or problems with balance.
Additional common features include cognitive impairment (such as problems with memory and slowness of thinking), fatigue, anxiety, low mood, and disturbed sleep1.
Parkinson’s disease is the second most common neurodegenerative disease in middle and older age, second only to Alzheimer’s disease.
It is estimated that at least 4.6 million people are affected by Parkinson’s disease globally, with this number expected to double by 20302.
The condition knows no boundaries in terms of gender, culture, or socioeconomic class. The economic cost of Parkinson’s disease was estimated at around $14.4 billion in the USA alone in 20103.
Pathology and functional impact of Parkinson’s disease
Classical understanding of the underlying brain pathology in Parkinson’s disease emphasises early loss of dopaminergic neurons in part of the basal ganglia called the substantia nigra.
These dopaminergic projections from the substantia nigra are heavily involved in the control of movement, accounting for why motor symptoms represent a core feature of the disorder.
Over time, abnormal protein aggregates – known as Lewy bodies – develop inside nerve cells4, not just in the substantia nigra but also in other brain regions including the cortex5.
This progressive pathological process is likely to account, at least in part, for the cumulative emergence of non-motor symptoms including cognitive impairment in patients.
Research and development in Parkinson’s disease
Comprehensive treatment of Parkinson’s disease should involve a multidisciplinary approach, including consideration of medications.
Currently available, licensed drug treatments for Parkinson’s disease do not significantly halt the underlying progression of disease, but rather provide symptomatic relief to maximise comfort, dignity, and independence.
First-line drug treatments enhance dopamine function in the brain4. Examples include levodopa and certain dopamine receptor agonists e.g. pramipexole, which tend to help most with alleviating bradykinesia and motor rigidity. Medications require close monitoring as side effects are relatively common with many existing treatments.
Neurologists and psychiatrists may also utilise a range of other medications in the comprehensive management of Parkinson’s disease, depending on the types of symptoms an individual presents with. For example, serotonin reuptake inhibitors can be used to treat depression as part of Parkinson’s disease, while stimulant medications can be used for fatigue occurring as part of the illness, while a cholinesterase inhibitor can be used for dementia-related cognitive impairment6.
The search for well-tolerated pharmacotherapies capable of stemming disease progression in Parkinson’s disease, and ameliorating cognitive dysfunction, continues, and represents a key unmet need.
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Robbins T.W., and Cools .R., (2014). Cognitive deficits in Parkinson's disease: a cognitive neuroscience perspective. Mov Disord.
Dorsey E.R., et al (2007). Projected number of people with Parkinson disease in the most populous nations, 2005 through 2030. Neurology.
Kalia L.V., and Lang A.E., (2015). Parkinson's disease. Lancet.
Kowal S.L., et al (2013). The current and projected economic burden of Parkinson's disease in the United States. Mov Disord.
- European Brain Council. Parkinson’s disease Fact Sheet 2011. http://www.europeanbraincouncil.org/pdfs/Documents/Parkinson's%20fact%20sheet%20July%202011.pdf
- Dorsey ER, Constantinescu R, Thompson JP, et al. Projected number of people with Parkinson disease in the most populous nations, 2005 through 2030. Neurology. 2007;68(5):384–386
- Kowal SL, Dall TM, Chakrabarti R, Storm MV, Jain A. The current and projected economic burden of Parkinson’s disease in the United States. Mov Disord. 2013;28(3):311–318
- Kalia, L.V., Lang, A.E., 2015. Parkinson's disease. Lancet 386, 896–912
- Braak H., Tredici K. Del, Rüb U., de Vos R.A.I., Jansen Steur E.N.H., Braak E. Staging of brain pathology related to sporadic Parkinson's disease. Neurobiol. Aging. 2003;24:197–211
- Rolinski M, Fox C, Maidment I, McShane R. Cholinesterase inhibitors for dementia with Lewy bodies, Parkinson’s disease dementia and cognitive impairment in Parkinson’s disease. Cochrane Database of Systematic Reviews.2012, Issue 3.