Understanding Parkinson's Disease: Definition, Causes, and Symptoms

Parkinson's Disease is one of the neurodegenerative disorders that causes individuals to experience brain dysfunction and a decline in brain control. This disease is a chronic and progressive neurological disorder that typically affects individuals aged ≥ 65 years. Parkinson's Disease is pathologically characterized by the loss or decrease of dopamine produced by a part called the substantia nigra.¹ According to several studies, Parkinson's Disease has a much higher incidence in older individuals. However, there is a possibility that Parkinson's Disease can affect younger individuals, referred to as "early onset" (between the ages of 20-40) and "juvenile onset" (under 20 years old).² The prevalence of Parkinson's Disease reaches 160 cases per 100,000 population with an incidence of approximately 20 cases per 100,000 population.³ In Indonesia, the estimated incidence of Parkinson's Disease is around 10 individuals per year, with a temporary estimate of 200,000-400,000 patients, where males outnumber females with a ratio of 3:2.⁴

The symptoms of Parkinson's Disease initially appear in approximately 5-10% of cases before the age of 40, but on average, it affects individuals at the age of 65, making age one of the important risk factors for developing Parkinson's Disease. Late-onset is the most common type of Parkinson's Disease, and the risk of developing this condition increases with age.⁵ Parkinson's Disease is characterized by tremors, muscle rigidity, akinesia/bradykinesia (reduced movement speed), postural instability (e.g., stooped posture, small steps, slightly lowered head), stiff facial expression, weakened movements, short steps, reduced arm swinging, postural imbalance, and frequent falls. Non-motor symptoms include incontinence, dementia, depression, dysphagia, sleep disorders, constipation, etc. By taking careful medical history & physical examination, in general Parkinson’s disease can be clinically diagnosed. However, additional diagnostic tests may be performed to evaluate Parkinson's Disease comprehensively especially to rule out other differential diagnosis.

Other than Idiopathic Parkinson’s Disease, severe and repeated head trauma can increase the risk of damage to neurons or damage to the substantia nigra, which produces dopamine. Therefore, many studies suggest that head trauma is one of the risk factors for developing Parkinson's Disease.⁶ Stroke can also cause parkinsonism. It can occur during a stroke or as a result of a stroke lesion. During a stroke, small blood vessels in the middle or posterior cerebral artery regions may experience decreased blood supply due to vessel blockage. This can occur in the substantia nigra. Since stroke generally occurs suddenly, the onset of Parkinson's symptoms in these patients can also happen in sudden Additionally, there are other additional symptoms, such as asymmetrical limb weakness (affecting only one side of the body).⁷

Reference :

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5. U.S. National Library of Medicine. (2012). Parkinson Disease. [diakses 8 September 2019]. Available from: https://ghr.nlm.nih.gov/condition/parkinson-disease#statistics
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