WORLD PARKINSON’S DISEASE DAY

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Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor and non-motor systems. The motor symptoms, collectively called parkinsonism, include tremors, slowness in initiating movement (bradykinesia), rigidity, and difficulty maintaining balance (postural instability). Non-motor symptoms such as autonomic nervous system failures (dysautonomia), sleep abnormalities, decreased ability to smell (anosmia), and behavioral changes or neuropsychiatric problems, such as cognitive impairment, psychosis, and anxiety, may appear at any stage of the disease. Symptoms typically develop gradually and non-motor issues become more prevalent as the disease progresses.

Parkinson's disease has no single cause: rather, genetic and environmental factors interact to affect critical cellular processes. Parkinson's disease involves the gradual decay and loss of dopamine-producing neurons in a brain region called the substantia nigra and other related cell groups in the brainstem. Misfolded proteins, such as alpha-synuclein, aggregate to form clumps called Lewy bodies, if not cleared from cells by cellular degradation systems. Protein accumulation stimulates the release of pro-inflammatory molecules by the microglia, a protective response that can cause neuroinflammation, further neuronal damage, and disruption of metabolic systems, if remaining chronic.

Diagnosis is primarily based on signs and symptoms, typically motor-related, identified through neurological examination. Medical imaging techniques such as PET scanning can support the diagnosis. PD typically manifests in individuals over 60, with about one percent affected. In those younger than 50, the condition is termed "early-onset PD".

No cure for PD is known, and treatment focuses on alleviating symptoms. Initial treatment typically includes levodopa, MAO-B inhibitors, or dopamine agonists. As the disease progresses, these medications become less effective and may cause involuntary muscle movements. Diet and rehabilitation therapies can help improve symptoms. Deep brain stimulation is used to manage severe motor symptoms when drugs are ineffective. Little evidence exists for treatments addressing non-motor symptoms, such as sleep disturbances and mood instability. Life expectancy for those with PD is near-normal, but is decreased for early-onset.

Parkinson's disease is a neurodegenerative disease affecting both the central and peripheral nervous systems, characterized by the loss of dopamine-producing neurons in the substantia nigra region of the brain.  It is classified as a synucleinopathy due to the abnormal accumulation of the protein alpha-synuclein, which aggregates into Lewy bodies within affected neurons.

The loss of dopamine-producing neurons in the substantia nigra causes movement abnormalities, leading to the categorization of Parkinson's as a movement disorder.  In 30% of those with PD, disease progression leads to cognitive decline, resulting in Parkinson's disease dementia (PDD). Alongside dementia with Lewy bodies, PDD is one of the two subtypes of Lewy body dementia. 

The four cardinal motor symptoms of Parkinson's—slowed movements (bradykinesia), postural instability, rigidity, and tremor—are called parkinsonism.  Parkinsonism is not exclusive to Parkinson's disease and can occur in other conditions,including HIV infection and recreational drug use.  Neurodegenerative diseases that feature parkinsonism, but have distinct differences are grouped under the umbrella of Parkinson-plus syndromes, or alternatively, atypical parkinsonian disorders.