Worldwide, it is estimated that four to six million people suffer from Parkinson’s disease, an incurable neurological disorder that progressively affects a person’s speech, mood, thinking, and movement, such as causing tremors. The condition is caused by a loss of function of nerve cells called neurons in the brain, including those that release a chemical called dopamine.
When levels of dopamine and other brain chemicals are too low, a person can develop a variety of symptoms, including difficulty with movement, speech, mood, and thinking. Even early on, Parkinson’s disease can cause nonmotor symptoms, including anxiety, depression, constipation, a reduced sense of smell, urinary incontinence, dizziness when standing, fatigue, and sleep disorders.
As the disease progresses, a person may experience hallucinations or cognitive impairment. Parkinson’s disease can occur at any age, but it most commonly affects people older than 50. The condition is likely to be caused by a combination of genetic and environmental factors.
Pesticide exposure and drinking well water, for example, have been associated with an increased risk of Parkinson’s disease. Often, a diagnosis of Parkinson’s disease can be made during an appointment with a movement disorders specialist and is based only on symptoms. Further testing is usually not necessary. However, sometimes doctors order imaging studies, such as an MRI scan, to help confirm the diagnosis.