Parkinson's disease (PD also known as idiopathic or primaryparkinsonism, hypokinetic rigid syndrome/HRS, or paralysis agitans) is adegenerative disorder of the central nervous system. Early in the course of the disease, the most obvious symptoms are movement-related these include shaking, rigidity, slowness of movement and difficulty with walking and gait.
Later, thinking and behavioral problems may arise, with dementia commonly occurring in the advanced stages of the disease, whereas depression is the most common psychiatric symptom. Other symptoms include sensory, sleep and emotional problems. Parkinson's disease is more common in older people, with most cases occurring after the age of 50.