Parkinson's disease is a disorder of the central nervous system that causes a loss of cells in the part of the brain that controls movement. People with Parkinson’s disease experience a range of symptoms, including tremor (shaking), rigidity (stiffness), slowness of movement, and problems with balance and coordination. They may also have memory problems, depression, and sleep complaints. Parkinson's disease is both chronic and progressive, meaning that once it occurs it does not go away and symptoms generally get worse over time; the rate or speed of progression is different from person to person.
Parkinson’s disease can be idiopathic, meaning that it occurs with no known cause. In this case it probably develops by some interaction between a person's genes and their environment. It can also be secondary, occurring as a result of another disease, exposure to certain drugs, or as a result of repeated head trauma. According to the Parkinson's Disease Foundation, between 15 and 25 percent of people with Parkinson's have a relative with the disease, suggesting that for some people it may be inherited. Age is also a risk factor, with older people being more likely to develop Parkinson’s disease than younger people, according to the National Institute of Neurological Disorders and Stroke at the National Institutes of Health. Exposure to toxins may also play a role but the nature of that role is not well understood.
Sleep problems may be an early sign of Parkinson’s disease, even before motor symptoms have begun. Some of the common sleep problems for Parkinson’s patients include:
A recent study by UCLA researchers found an association between Parkinson's disease and narcolepsy, a disorder caused by the brain's inability to regulate sleep/wake cycles normally. The study revealed that patients with Parkinson's disease and those with narcolepsy both display a loss of orexin/hypocretin (Hcrt) cells in the brain and that loss of Hcrt cells