Modern medicine understands Parkinson’s disease as a chronic progressive degenerative brain disease that occurs when dopaminergic neurons in a specific area of the brain, namely the substantia nigra of the midbrain, are gradually lost. Dopamine is an important neurotransmitter that smoothly and accurately coordinates our body’s movements, and when this dopamine becomes deficient, various motor dysfunctions appear.
Four major motor symptoms characterize Parkinson’s disease. First is bradykinesia, a phenomenon where movements slow down and their amplitude decreases. You can notice everyday actions such as walking or buttoning a shirt becoming markedly slow. Second, rigidity gives a feeling of stiffened, tight muscles; when moving the limbs, one may feel a ratcheting resistance like cogwheels. Third, tremor is a rhythmic shaking that appears mainly in the hands or feet at rest, which may temporarily disappear when tense or moving. Finally, postural instability makes it difficult to maintain body balance, leading to easy falls.
Dysarthria, where speech becomes slurred, is also an important symptom of Parkinson’s disease. It occurs as the movements of the facial, tongue, and pharyngolaryngeal muscles responsible for pronunciation become dull due to dopamine deficiency. It features a smaller voice, flat inflection, and unclear articulation. A faster speaking rate or drooling can also often accompany it. These speech symptoms make communication difficult for the patient, affect social life, and can lead to depression.
Parkinson’s disease does not present solely with motor symptoms; as it progresses, it is accompanied by various non-motor symptoms such as anosmia, constipation, REM sleep behavior disorder, depression, anxiety, and cognitive decline. Because these non-motor symptoms often appear much earlier than motor symptoms, they can serve as important clues for early diagnosis. Unlike Alzheimer’s disease, Parkinson’s disease tends to present with motor symptoms first and cognitive decline in the late stages of the disease, helping to distinguish between the two conditions. In brain tissue, the presence of abnormal protein deposits called Lewy bodies is characteristic, which is known to be closely related to disease progression. Receiving an accurate diagnosis early and beginning appropriate treatment and management is crucial for improving the patient’s quality of life.
