Parkinson’s Disease is a progressive neurodegenerative disorder in which the brain’s ability to produce dopamine, an essential neurotransmitter, is damaged, leading to symptoms including tremors, shaking, rigidity, and difficulty with movement and speech, and for some, significant cognitive and emotional effects as well. These symptoms generally advance and worsen over the course of a patient’s life.
Anyone can develop the disease, although it is more prevalent in men than in women and in whites than in individuals of other races. In most cases, symptoms emerge after age 60, but for about 5 percent of those who develop Parkinson’s, it begins before the age of 50. Parkinson’s itself is not fatal, although its symptoms often lead to life-threatening complications; these complications are the 14th-leading cause of death in the United States, according to the federal Centers for Disease Control and Prevention.
According to the National Institutes of Health, the primary symptoms of Parkinson’s Disease are:
- Unintended, uncontrollable tremors or shaking in one or more limbs, which also occurs when the arm, leg, or hand is at rest.
- Muscle contraction, stiffness, and rigidity, often for long stretches of time.
- Slowed movements, also known as bradykinesia.
- Impaired coordination and balance, increasing risk of falls and other injuries.
Other symptoms include impaired speech, constipation or urinary problems, difficulty chewing or swallowing, and skin problems. And for many patients, Parkinson’s Disease also brings depression, emotional changes, hallucinations, and major or mild neurocognitive symptoms.
It is important to note that one person’s experience of living with Parkinson’s—the severity and particular set of symptoms, the speed of the disease’s progression, and whether it brings cognitive or emotional concerns along with it—can vary in significant ways from another’s.
The rate of Parkinson’s progression and accompanying symptoms can vary widely from patient to patient. Often, the first signs of Parkinson’s are mistaken for signs of normal aging, including sleep difficulty, constipation, and restless legs. (Rapid Eye Movement sleep behavior disorder, in which an individual reacts physically to their dreams, often occurs in people who are eventually diagnosed with Parkinson’s.)
Other symptoms may advance gradually and may include mild tremors, changes in gait, some difficulty with movement including smaller steps and reduced arm swinging, quieter speech, handwriting changes (typically, letters become smaller and less legible), and changes in affect—specifically, one’s face losing expression or animation. Often another person such as a partner, friend, relative, or primary-care physician notices changes before an individual is willing or able to do so.
Some, but not all, individuals with Parkinson’s Disease will experience memory and attention problems, and difficulty remembering and completing tasks that could affect their daily routines. Some individuals with more severe cognitive symptoms including substantial memory loss may eventually be diagnosed with the condition known as Parkinson’s dementia.
It’s quite common, although it is considered to be significantly underdiagnosed and undertreated. Some experts estimate that half of all patients will experience depression at some point. Specific symptoms of Parkinson’s, such as sleep difficulty and fatigue, echo those of depression. But even in Parkinson’s patients, depression is treatable, and should be treated, through increased movement or physical therapy, increased social support, medication, or psychotherapy.
They often do. While psychotic symptoms are more common in Lewy body dementia, they may also occur in Parkinson’s patients who do not have symptoms of dementia. Most commonly, these symptoms manifest as hallucinations—seeing (or hearing) a person or animal in the periphery of their vision. Initially, individuals are able to recognize these as hallucinations, but as their Parkinson’s symptoms progress, it can become more difficult to distinguish them from reality. Some medications used to treat Parkinson’s may cause or increase the incidence of psychotic symptoms even as they alleviate some movement symptoms. Complicating treatment of psychotic symptoms is the fact that many medications typically used to treat them in the general population block dopamine receptors in the limbic region of the brain, which can worsen physical symptoms.
The etiology of Parkinson's is not well understood. In a Parkinson’s patient, nerve cells in the brain region known as the basal ganglia, which control movement, are impaired or die. Neurons in this region are relied upon to produce dopamine, an essential neurotransmitter. When their production is limited, a person experiences the movement challenges typical of Parkinson’s, which progress over time. Researchers do not know for sure what causes the neurons to begin to die off but now generally believe it is a combination of genetic and environmental factors, including exposure to toxins.
There is no blood or laboratory test for Parkinson’s Disease. An individual who appears to be experiencing symptoms may see their doctor for referral to a neurologist who can conduct a neurological examination based on the Unified Parkinson’s Disease Rating Scale, which establishes baseline measures of core symptoms of the condition.
Parkinson’s symptoms are somewhat similar to other conditions including Lewy body dementia. One way a doctor can determine that a patient has Parkinson’s is by evaluating their response to medications commonly used to treat the disease. Magnetic resonance imaging (MRI) scans of the brain, a dopamine transporter (DaT) scan, or blood work may be prescribed either to confirm a diagnosis or to help rule out other medical conditions that may manifest with similar symptoms.
Not typically. Genetics plays a role in Parkinson’s, as some specific genetic variants may cause it, but that does not necessarily mean those variants are inherited within families. However, some research suggests that early-onset forms of the disease—in which symptoms emerge before age 50—are more likely to be hereditary.
Parkinson’s Disease is the second-most-common neurodegenerative disease, after Alzheimer’s Disease. Approximately 1 million people in the United States, and at least 10 million people worldwide, are estimated to be living with Parkinson’s Disease. As age is the greatest risk factor for the disease, its incidence is expected to continue to rise.
There is no cure for Parkinson’s Disease, although medication and therapy can help people find some relief from symptoms and ideally slow the progression of the condition. In addition to ameliorating symptoms of the disease, medications for Parkinson’s increase the level of dopamine in the brain and support other neurotransmitters that could help compensate for its absence.
The primary medication for Parkinson’s Disease is levodopa, which is converted to dopamine in the brain, enabling a patient to experience some relief from their symptoms. On its own, levodopa causes nausea, so it is combined with the drug carbidopa, which significantly lessens that side effect. Another primary side effect of levodopa is dyskinesia, or involuntary extraneous movements. (It’s a common misconception that dyskinesia is a symptom of Parkinson’s but it is instead a side effect of the drug.) Other side effects may include low blood pressure and restlessness.
Levodopa does not halt or slow the progression of Parkinson’s; it only addresses symptoms in the moment. Patients prescribed levodopa will generally take the drug for the rest of their lives.
Doctors may also prescribe medications such as amantadine and anticholinergics to directly address physical symptoms such as tremors, or to counteract dyskinesia brought on by levodopa.
Doctors may prescribe drugs known as dopamine agonists instead of, or in conjunction with, the oft-prescribed drug levodopa. Dopamine agonists do not convert to dopamine but instead stimulate brain regions typically influenced by dopamine, in effect tricking the brain into believing the neurotransmitter is present. Levodopa generally has a stronger effect on Parkinson’s symptoms, but agonists have fewer side effects and are less likely to bring on dyskinesia.
Researchers continue to explore the potential of surgical procedures for Parkinson’s. As of now, the primary procedure is deep-brain stimulation, in which electrodes are implanted into the brain and connected to a separate electrical device in the chest in order to stimulate specific regions of the brain controlling movement to address tremor, bradykinesia, and rigidity. Deep-brain stimulus is generally only used in patients who do not respond to levodopa or other medications.
As a progressive, incurable condition, Parkinson’s Disease can be a significant source of stress for an individual and their loved ones. After diagnosis, denial, hopelessness, and visions of a future filled with misery may rush in. But an understanding that the disease progresses gradually, and that each patient’s path of progression is unique, as well as a commitment to exercise, therapy, and medication adherence, can reassure families that, with their help, their loved one can maintain a high quality of life for many years.
Still, it is inevitable that the disease will bring changes to a household’s dynamics. Accepting that the Parkinson’s patient may need more time to perform basic tasks is important, as well as allowing that person to focus on their daily tasks of life by taking other chores off of their plate. Being flexible enough to be available to engage with the Parkinson’s patient during their “on” periods, if such exist, can also help to maximize one’s relationship with them and enhance both people’s mood and well-being.
A range of therapies can help people better manage symptoms, delay the progression of the disease, and cope with it on an emotional level. Physical, occupational, and speech therapy are all generally recommended, to address patients’ struggles with gait, voice, and cognition. Attention to diet, massage therapy, movement routines including yoga and tai chi, and especially exercises to support strength, balance, and coordination are all strongly recommended.