what are common early manifestations of parkinson's disease
Parkinson's disease Parkinson's disease (PD) is a long-term degenerative disorder of the central nervous system that mainly affects the motor system.[1] The symptoms generally come on slowly over time.[1] Early in the disease, the most obvious are shaking, rigidity, slowness of movement, and difficulty with walking.[1] Thinking and behavioral problems may also occur.[2] Dementia becomes common in the advanced stages of the disease.[2] Depression and anxiety are also common occurring in more than a third of people with PD.[2] Other symptoms include sensory, sleep, and emotional problems.[1][2] The main motor symptoms are collectively called "parkinsonism", or a "parkinsonian syndrome".[4][8]
Substantia nigra The substantia nigra is a basal ganglia structure located in the midbrain that plays an important role in reward and movement. Substantia nigra is Latin for "black substance", reflecting the fact that parts of the substantia nigra appear darker than neighboring areas due to high levels of neuromelanin in dopaminergic neurons.[1] It was discovered in 1784 by Félix Vicq-d'Azyr,[2] and Samuel Thomas von Sömmerring alluded to this structure in 1791.[3] Parkinson's disease is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta.[4]