Parkinson’s Disease 101

Parkinson’s disease (PD) is the second-most-common neurodegenerative brain disorder after Alzheimer’s. In his 1817 “Essay on Shaking Palsy,” James Parkinson first described PD as a disease.

Now, 200 years later, PD is known to affect an estimated one million people in the US, with about 60,000 new cases diagnosed each year. The cause of PD is still unknown, but genetic and environmental factors are thought to contribute. No test has yet been developed to diagnose PD. Instead, it is diagnosed clinically based on the patient’s history of symptoms and a physical exam conducted by a neurologist or movement disorder specialist. PD is a chronic and progressive illness, but patients can live long, meaningful, and happy lives if they exercise routinely and take their medications on schedule.

PD seems to affect men more than women. Some studies have shown that African Americans and Asians are less likely than Caucasians to develop PD, although the reasons are not clear. Otherwise, the disease knows no social, ethnic, economic, or geographic boundaries. Many people live with symptoms of PD for several years and visit multiple physicians before a diagnosis is made. Early symptoms can be subtle and may even come and go. Frequently, a loved one is the first to notice subtle problems with movement.
PD symptoms are due to a deficiency of dopamine, a neurochemical in the brain that is essential for initiating and executing fast and smooth muscle movements. It’s also important in preserving mood, cognition, and energy. In PD patients, dopamine-generating neurons in the brain are dying at a much faster rate than the normal aging process. When 60-80% of dopamine-containing neurons have died, symptoms appear, including tremors, muscle rigidity or stiffness, slowness of movements, and shuffling when walking. Non-movement-related symptoms include smaller handwriting, less facial expression, acting out dreams, constipation, urinary incontinence, dizziness, depression, anxiety, hallucinations, delusions, and fatigue. The PD experience is unique to every patient, and no one ever develops all of the symptoms.

Most PD medications temporarily replenish or mimic dopamine, so they are often called dopaminergic drugs. These medications improve speed and coordination of movement, reduce muscle rigidity, and reduce tremors. Although dopaminergic medications don’t cure or slow the progression of PD, they are effective in treating the movement-related symptoms. Routine exercise is the only known method of slowing the progression of PD. Dallas Area Parkinsonism Society, a local nonprofit, offers over 30 exercise classes per week in various areas around the metroplex, as well as patient and caregiver support groups. Their monthly educational programs often feature academic and practicing physicians with topics of interest to people affected by PD. You can read their newsletter at

Editorial Note: Article written by Drs. Nirav Pavasia, MD and Aashoo Mentreddi, MD. Movement disorder specialists at Neurology Consultants of Dallas and volunteer members of the Dallas Area Parkinsonism Society Medical Advisory Board.