Imagine the healthy American population as a bell curve. People with Parkinson’s disease would be toward the flat part of the curve, says Peter Schmidt, chief information officer at the National Parkinson Foundation. And if Parkinson’s disease patients constitute another bell curve, people with a variety of conditions that initially mimic Parkinson’s — and are collectively classified as atypical Parkinsonism syndromes — form the flat part of that curve.

Parkinson’s disease afflicts an estimated 1 million people in the U.S., with far fewer (no more than 10,000) suffering from the spectrum of disorders that mimic Parkinson’s disease. But about a quarter of people with those disorders are misdiagnosed with Parkinson’s disease. And their prognosis is usually worse, characterized by rapid deterioration and shorter longevity. Both Parkinson’s disease and Parkinsonism involve a loss of neurons in the basal ganglia region of the brain, but in Parkinonism, the loss of neurons is more far-reaching, to other parts of the brain as well, McFarland says.

“For many of these atypical disorders, the average lifespan is five to 10 years. The disability comes more quickly,” says Nikolaus McFarland, an assistant professor of neurology at the University of Florida College of Medicine. “Unfortunately, to date, we don’t really have a blood test or brain imaging scan that helps us distinguish these patients,” McFarland continues, adding that the “challenge of the next decade” is to identify those tests and treatments.

Parkinsonism: the “Grab-Bag” Term

The masked face. The tremor. The slowed movements. The tell-tale signs of Parkinson’s disease — except when it’s not. Many people go years before they are properly diagnosed, and that usually comes after the drugs used to treat Parkinson’s have not worked.

Actual Parkinson’s disease has four cardinal features, McFarland says: a resting tremor (which goes away when you move), rigidity, slowed movements and an abnormal gait. So if yours are different, you need to probe why.

“If they don’t respond to the classic medications, it’s a red flag to look at other disorders,” says McFarland, who is also a movement disorders specialist at UF’s Center for Movement Disorders and Neurorestoration. “I might be the third, fourth or fifth neurologist taking a crack at what the diagnosis is. People go doctor shopping and don’t get the right answer.”

Just as not all geriatricians or general practitioners are equipped to treat Parkinson’s disease, even though they may diagnose it, not all neurologists can properly treat the atypical Parkinsonism syndromes. So patients who suspect they have one should be proactive about seeking out a movement disorder specialist, says Jim Beck, vice president of scientific affairs at the Parkinson’s Disease Foundation. The Foundation has a helpline people can call to find the nearest specialist: 1-800-457-6676.

The Conditions

The most recognizable syndrome, at least to the public eye, may be what George H.W. Bush has: vascular Parkinsonism, which is essentially clotting in the brain caused by mini strokes, Beck says. Some other conditions include:

— Lewy body disease. This is characterized by the early onset of dementia and cognitive dysfunction. People can also have hallucinations, which makes treatment difficult, since anti-psychotics used to treat hallucinations can worsen other Parkinsonism symptoms, McFarland says.

— Progressive supra-nuclear palsy. Patients have early dementia, eye movement problems and a tendency to fall, McFarland says. They don’t have the resting tremor typical of Parkinson’s disease patients, but they do have stiffness and slowness, he adds, and they don’t respond to dopamine replacement therapy.

— Corticobasal degeneration. One of the rarest conditions on the Parkinsonism spectrum, patients typically lose function on one side of their body, McFarland says, and they can develop alien limb syndrome, in which a limb does what it wants. They can also develop speech problems and jerky body movements.

— Drug-induced Parkinsonism. Certain drugs, namely anti-psychotics, but also anti-nausea medications and some seizure medications, can cause Parkinsonism, McFarland says. Most Parkinsonism symptoms disappear after people stop taking the medications.

— Multiple system atrophy. People with this condition sometimes look like they have problems with coordination; they may have problems with bowel and bladder function, McFarland says, adding that sometimes when they stand up, their blood pressure may drop, and they faint. Men may develop erectile dysfunction, and women, urine retention.

Taking Matters Into Your Own Hands

Distinguishing these disorders from Parkinson’s disease is difficult, and the proper diagnosis is often not made until patients’ symptoms have progressed. For that reason, McFarland suggests people with symptoms of these disorders seek out Parkinson’s disease support groups.

“See if your symptoms match theirs. If you see that yours are different, that’s where I would ask the doctor: ‘Are you sure I have Parkinson’s disease, or [could it be] another disorder?'”

Brain scans and MRIs are getting better at identifying the distinguishing hallmarks of these conditions, and the Food and Drug Administration-approved DaTscan shows abnormal distribution of dopamine in the brain. Still, McFarland continues, “In Parkinson’s disease, we know exactly where the brain degenerates. For the atypical [disorders], the degeneration is much more widespread.” He adds that identifying the patterns of brain dysfunction characterized by each disorder may help spot them earlier.

At the moment, however, treatments for these disorders remain limited to physical therapy, occupational therapy and exercise, Schmidt says, adding that these are the same treatments (plus medications) used for Parkinson’s disease patients.

And while it can be important for patients with Parkinsonism disorders to seek out support groups specific to their condition, advocacy for research money should fall under the same umbrella, Schmidt adds. “I always say the Parkinson’s community is stronger at driving research dollars if it is unified,” he says. “Work to understand the basal ganglia can help everyone.”

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Do You Have Parkinson’s Disease or a Parkinsonism? originally appeared on usnews.com