Neurological conditions are the leading cause of non-traumatic disability worldwide, and the prevalence of Parkinson’s disease (PD) is increasing more rapidly than other neurological disorders. PD is the most common form of parkinsonism, a term reflecting a group of neurological disorders with Parkinson’s disease-like movement problems such as rigidity, slowness, and tremor. Less common parkinsonisms include other neurodegenerative diseases (multisystem atrophy, progressive supranuclear palsy), drug-induced parkinsonism (usually due to psychoactive medications), and vascular parkinsonism. It is estimated that 6.1 million people globally had a PD diagnosis in 2016, 2.4 times higher than in 1990. The increased prevalence has been attributed to improved methods to detect and diagnose the disease, greater awareness of it, aging populations with longer life expectancy, and possibly increased environmental exposures (e.g. pesticides, solvents, and heavy metals) associated with industrialization. It is estimated that this year will see 930,000 people living with a Parkinson’s disease diagnosis in the U.S.
PD is uncommon in individuals under the age of 50 and increases in prevalence with age,
peaking between the ages of 85 to 89 years. It is more common in men. Most cases are idiopathic (no known cause), but there are known genetic and environmental causative factors. Diagnosing the disease is usually based on the patient’s history and physical examination. Brain imaging with MRI can be helpful. While primarily a disorder of movement, PD has a number of non-motor symptoms. Most common of these non-motor symptoms is rapid eye movement (REM) sleep behavior disorder. REM sleep is the deepest and most restorative stage of sleep. It is also where dreams are most vivid. REM sleep and its vivid dreams are normally accompanied by atonia (paralysis). In REM sleep behavior disorder, atonia is absent, causing the individual to flail the arms or legs, scream, cry out and otherwise behave in ways that may cause injury to the individual or a roommate, all while remaining in a deep sleep. REM sleep behavior disorder is seen in up to 50% of those with PD and may appear before motor symptoms do. Other non-motor symptoms include anosmia (loss of smell), constipation, incontinence, depression, micrographia (tiny handwriting), and excessive daytime sleepiness.
There are slower- and faster-progressing forms of PD. Treatment is initially based on the use of medications that improve the function of chemicals in the brain called neurotransmitters (i.e. dopamine). These medications include carbidopa-levodopa combinations, dopamine agonists, and monoamine oxidase (MAO) inhibitors. Those who do not respond to these medications have a poorer prognosis, as do those individuals whose initial symptoms include cognitive impairment (dementia). Those who do respond to treatment may manage to keep symptoms controlled and continue to live a useful, functional life, for at least a few additional years. Physical, occupational, and balance therapy is helpful as well. Recently, when conventional treatments fail, electrical brain stimulation by use of an implanted electrode has shown promise.
Most people with PD die from the same causes as age-matched individuals, however those who live with PD for many years may die from PD-related causes like aspiration pneumonia and complications from a fall.
By Peter Galvin, MDBLOG COMMENTS POWERED BY DISQUS