Parkinson’s disease, a progressive, degenerative neurological disease, causes muscle tremors; slow movement, or bradykinesia; difficulty with movement and stiff muscles. These symptoms result due to damage to the areas of the brain that house cells producing the chemical messenger dopamine, a critical signal between nerves and muscles. Although typically diagnosed in older people, Parkinson’s disease can affect people as young as 18.
Age and Risk
The symptoms of Parkinson’s disease appear as debilitating brain changes that accumulate over time. The National Parkinson’s Foundation explains that symptoms first start to appear when damage affects 60 to 80 percent of dopamine-producing cells, preventing them from making adequate levels of dopamine. The cumulative and progressive nature of the damage means that the risk of diagnosis for Parkinson’s disease increases with advancing age.
Statistics
The Merck Manual cites 2007 statistics showing the increase in Parkinson’s with age. Only 0.4 percent of people under the age of 40 are affected, compared to about 1 percent of people under 65, and 10 percent of people age 80 or older. The Merck Manual cites the average age of onset at 57, while 2010 information from the National Parkinson’s Foundation puts it at 62.
Diagnosis
Diagnosis of Parkinson’s disease in the elderly can be difficult because some symptoms of the disease also occur as part of normal aging. In addition, the condition called parkinsonism shows many of the hallmark symptoms of Parkinson’s disease but can have other causes, including some conditions that affect the elderly more frequently like stroke and Lewy body dementia. The elderly often take multiple medications, some of which can cause parkinsonism.
Typical Parkinson's
With the average age of Parkinson’s disease onset at 57 to 62, and the slow-progressing nature of the condition, patients could expect to live with Parkinson’s disease for 20 years or more. Having Parkinson’s disease can complicate many common complaints of aging, such as problems with sleep, urination, constipation, and sexual function, difficulty with moving and lack of balance.
The primary medication for Parkinson’s disease, levodopa, typically controls symptoms well for two to five years, but then loses effectiveness, according to the Merck Manual. Some doctors therefore prefer to treat younger patients with other drugs first, saving levodopa for when the symptoms become more pronounced.
Early-Onset
When people under the age of 50 have Parkinson’s disease, it is classified as early onset or young onset Parkinson’s. The National Parkinson’s foundation estimates that about 50 percent of early onset causes result from an inherited mutation in the parkin gene. For early onset Parkinson’s disease to develop, the patient must inherit two faulty copies of the parkin gene, one from each parent.
