Parkinson’s disease (PD) is a brain disease that affects movement and coordination. Neurons (nerve cells) in a part of the brain called the substantia nigra die. This leads to a loss of muscle control.
Other conditions share certain PD symptoms, but have different causes. These conditions are called atypical Parkinsonism or atypical Parkinsonian syndromes.
Atypical Parkinsonism includes several conditions similar to PD. Among them are:
- Lewy body dementia (LBD)
- multiple system atrophy (MSA)
- progressive supranuclear palsy (PSP)
- corticobasal degeneration (CBD)
Each of these atypical Parkinsonian syndromes occur in less than 1 percent of the general population:
- LBD: 400 cases per 100,000 people
- MSA: 5 to 10 cases per 100,000 people
- PSP: 5 to 10 cases per 100,000 people
- CBD: 1 case 100,000 people
PD symptoms vary from person to person. Some people have a tremor, usually on one side of the body. Others with PD have muscle freezing or balance difficulties. You might have PD symptoms that are mild for years. Someone else may have symptoms that worsen quickly.
Atypical Parkinsonian syndromes each have their own set of symptoms:
- LBD: Thinking and memory decline. Hallucinations and difficulty staying alert are signs that usually show up early.
- MSA: Walking and balance problems are especially common with this condition. You may also have symptoms related to the autonomic nervous system (ANS), which is the part of the nervous system that controls functions like digestion and circulation. These include:
- PSP: Problems with walking and balance, eye movement, speech, and thinking skills are among the main symptoms of this disorder.
- CBD: The main symptoms of this condition include slow movements, difficulty with spontaneous movements, muscle rigidity, severe tremors, and abnormal posture or positioning of your limbs.
Symptoms of PD and atypical Parkinsonism are sometimes identical. This is why testing and imaging are so important in making an accurate diagnosis. Atypical Parkinsonism is sometimes diagnosed initially as PD.
One of the main differences between the two conditions is that atypical Parkinsonism symptoms tend to come on earlier than with PD. Problems with balance, muscle freezing, thinking skills, speech, and swallowing show up sooner. They also progress faster if you have atypical Parkinsonism.
PD symptoms often appear first on one side of the body. With atypical Parkinsonism, signs are usually present on both sides at the beginning.
Another key difference between PD and atypical Parkinsonism is what’s happening in the brain. If you have PD, you lose neurons that make the brain chemical dopamine. It helps control movement. However, your brain still has dopamine receptors. Those receptors allow the drug levodopa (Sinemet) to be synthesized into dopamine.
If you have an atypical Parkinsonian syndrome, however, you may be losing your dopamine receptors. Levodopa won’t be as effective in controlling your symptoms.
Atypical Parkinsonian syndromes each have their own causes. Scientists still don’t know why people develop PD or atypical Parkinsonism. PD and conditions such as MSA may have a genetic component. Research also suggests that exposure to some environmental toxins may be to blame.
Certain brain changes define each condition:
- LBD: An unusual buildup of alpha-synuclein protein in brain cells.
- PSP: A buildup of tau protein in the brain’s frontal lobe, cerebellum, substantia nigra, and brain stem.
- MSA: An abnormal buildup of alpha-synuclein protein that can affect the substantia nigra, cerebellum, and ANS.
- CBD: A tau protein buildup that usually affects one side of the body and makes movement difficult.
Diagnosing atypical Parkinsonism starts with a review of all your symptoms and your medical history.
A neurological exam will also be part of the evaluation. Your doctor might observe you walking across the room, sitting down, standing up, and performing other basic movements. They’ll look for problems with balance and coordination. Your doctor may also do some simple tests of your arm and leg strength.
You may take some tests of your mental ability, such as repeating back lists of numbers or answering questions about current events.
Your doctor may order imaging tests of the brain. Some commonly used tests include:
- Positron emission tomography (PET) scan: A radioactive dye called a tracer reveals signs of disease or injury to the brain.
- Magnetic resonance imaging (MRI) scan: A magnetic field and radio waves create images of the inside of your body.
- DAT-SPECT: A type of computed tomography (CT) scan checks the movement of dopamine in the brain.
No cures currently exist for atypical Parkinsonism. The goal of treatment is to manage symptoms for as long as possible. The appropriate medication for each disorder depends on your symptoms and how you respond to treatment.
For LBD, some people find relief from symptoms with cholinesterase inhibitors. These drugs increase the activity of neurotransmitters that affect memory and judgment.
For PSP, levodopa and similar drugs that act like dopamine are helpful for some people.
Participating in physical or occupational therapy can also help with most of these conditions. Being physically active may also help relieve symptoms.
Perhaps the most serious complication from any of these conditions is dementia. You may first develop mild cognitive impairment (MCI), which may not interfere too much with your daily activities. If your thinking skills and memory gradually decline, you may need the assistance of family, a home health aide, or an assisted living facility.
Because these conditions affect balance and coordination, fall risk becomes an important concern. Having PD or atypical Parkinsonism means avoiding falls and fractures. Make your home safer by getting rid of throw rugs, lighting hallways at night, and installing grab bars in the bathroom.
Atypical Parkinsonian syndromes are progressive diseases. That means their symptoms will continue to worsen over time. While no cures exist for these disorders, there are treatments that can help to slow their progression. It’s critical that you take your medications exactly as prescribed by your doctor. If you’re ever unsure about your treatment, call your doctor’s office.
PD and atypical Parkinsonism affect each person differently. Those differences include the type and severity of symptoms, as well as life expectancy. Research reported in American Family Physician found that women who are diagnosed with PD at age 70 or older live an average of 11 more years. Men 70 and older diagnosed with PD live an average of about 8 more years. People with atypical Parkinsonism have a shorter life expectancy.
These estimates can vary greatly, depending on your overall health. The healthier you are when you’re diagnosed, the better your chances of living longer with atypical Parkinsonism.