Parkinson's Disease Quiz: Test Your Medical IQ

Parkinson's disease (PD) isn't just seen in people of advanced age. While it does tend to affect people over age 60 more often, in about 5% to 10% of cases, "early onset" PD can begin in people as young as age 40.

The progression of PD is different for everyone, however, those who develop it at earlier ages seem to have a more severe progression. Life expectancy for people with Parkinson's disease is about the same as the average population, but complications from the disease in the later stages can lead to fatal outcomes from choking, pneumonia, and falling.

Parkinson's disease (PD) is a movement disorder that is degenerative and chronic, and symptoms continue and generally worsen over time. The National Institute of Neurological Disorders and Stroke (NINDS) estimates about 50,000 people are diagnosed with PD each year in the U.S. The cause of PD is unknown. There is currently no cure, but there are several treatment options available to manage symptoms including medications and surgery.

The body's central nervous system (CNS) controls the five senses. The CNS is made up of your brain and spinal cord. The brain is what interprets our external environment, houses our thoughts and ideas, and controls our body movements. It acts like a central computer for our five senses, interpreting information from our eyes (sight), ears (sound), nose (smell), tongue (taste), and skin (touch), as well as other sensations from internal organs such as the stomach.

The spinal cord is the connection from the body to the brain, transmitting the signals our body receives to the brain, which then interprets them to make sense of our world. When the spinal cord is injured, this interrupts that communication.

There are several common symptoms of Parkinson's disease, though severe headaches are not one of them.

PD is diagnosed when a person has one or more of the four most common motor (motion) symptoms of the disease that include resting tremor, slow movement (bradykinesia), rigidity, and difficulty balancing when standing (postural instability). There are other secondary motor and non-motor symptoms that also occur with PD. Symptoms may be experienced differently by each person and the progression of the disease is different for everyone as well. For example, some people may have tremor as a primary symptom, while another may not have tremors but may have postural instability.

Parkinson's disease is the result of the loss of the brain chemical dopamine. When nerve cells, called neurons, in an area of the brain that controls movement become impaired and/or die, the amount of dopamine they normally produce decreases. This loss of dopamine causes the movement problems seen in people with PD.

Currently there are no laboratory tests that can diagnose Parkinson's disease. This can make it difficult to accurately diagnose because PD resembles other movement disorders.

In order to diagnose PD, a physician will take a complete medical history and perform a neurological exam. Additional testing may be done simply to rule out other neurological conditions that may resemble Parkinson's.

There are five stages of Parkinson's disease, described with the most commonly used Hoehn and Yahr scale:
- Stage one: Symptoms such as tremors or shaking on one side of the body
- Stage two: Tremors or shaking one or both sides of the body; possible imbalance
- Stage three: Noticeable balance impairment and slowing of motion
- Stage four: Severe symptoms, disability; patient likely needs assistance
- Stage five: Patient may be bedridden or wheelchair bound; needs constant care

Another scale that may be used to describe symptoms of Parkinson's disease is called the Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS). It is a four-part scale that measures motor movement in PD: non-motor experiences of daily living, motor experiences of daily living, motor examination, and motor complications.

About one-quarter to one-third of people with Parkinson's disease will develop cognitive difficulties such as problems with memory, judgment, language, reasoning, and other mental skills. In later stages of PD, patients may develop Parkinson's disease dementia (PDD).

There is no cure for dementia associated with Parkinson's, but some medications may help with the symptoms.

Lewy bodies are abnormal protein deposits found in the brain. Researchers do not know exactly why Lewy bodies form or what role they may play in Parkinson's disease, but they seem to be linked to certain types of dementia associated with both PD and Alzheimer's disease. Lewy body dementia is a degenerative disease and symptoms range from parkinsonian symptoms such as bradykinesia, rigidity, tremor, and shuffling walk, to symptoms similar to those of Alzheimer's disease (memory loss, poor judgment, and confusion). Symptoms may fluctuate, even from day to day. In later stages patients may develop hallucinations.

Parkinson's disease affects both men and women, though about 50% more men are affected than women. The reasons for this are unclear but there are theories that estrogen may cause women to develop the disease less frequently, and when they do, they seem to get a milder form of it.

The National Institute of Neurological Disorders and Stroke estimates about 50,000 people are diagnosed with PD each year in the U.S. However, this number may be higher due to the fact that many people in the early stages of PD assume their symptoms are due to aging and do not seek medical attention. Complicating the diagnosis is that symptoms of Parkinson's resemble other diseases and there is no one definitive test to diagnose it.

There does not seem to be a way to predict or prevent Parkinson's disease. Current research is investigating a biomarker – some kind of biological abnormality that would be present in patients with PD – that would be able to be detected from testing. This could help doctors identify people who are at-risk for developing Parkinson's and thus find treatments to stop the disease process in the early stages or slow the progression.

There are rare cases of genetically inherited PD where researchers can test for these genetic biomarkers to determine a person's risk for developing the disease.