Globally, more than 10 million people have Parkinson’s Disease. About 60,000 will be diagnosed with the disease in this country this year. While Parkinson’s has historically been associated with motor function symptoms like tremors, rigidity and a shuffling gait, several cognitive issues are also related to the disease.

We spoke with Dr. Stewart Factor, professor of neurology and director of the Movement Disorders Program at the Emory University School of Medicine. He will be one of the speakers at the Neuro Challenge’s Parkinson’s Expo on Saturday, April 13, at the Bradenton Area Convention Center, 1 Haben Blvd., Palmetto. Factor’s presentation is titled “Recognizing and Treating the Cognitive and Behavioral Symptoms of Parkinson’s Disease.” In this interview, he discusses Parkinson’s-related dementia, sleep disorders and why some hallucinations aren’t so bad after all.

Register for the Parkinson’s Expo at neurochallenge.org/expo.

What’s the most common cognitive symptom in Parkinson’s patients?

Dementia occurs in a pretty good portion of people with Parkinson's. Bear in mind that the biggest risk factor for developing dementia is age, whether they have Parkinson's or not. But we now know Parkinson’s is probably the second or third most common cause of dementia, behind Alzheimer's and multiple strokes.

Does dementia manifest differently depending on the cause?

There's so much overlap. But for those people who have pure Parkinson’s-related dementia, it's more related to frontal lobe problems, which would be called executive dysfunction, while Alzheimer's is more memory function, related to the temporal lobe. Alzheimer's patients can't make new memories. Parkinson’s patients can make them but can't find them—they have delayed recovery of the memory. And they have trouble with multitasking.

What other cognitive symptoms are related to Parkinson’s?

Some 40 to 50 percent of people with Parkinson’s have depression. And it's not because they're depressed that they have the disease. Some people develop depression as the first symptom of Parkinson’s, even before they ever get the motor symptoms.

Another cognitive symptom is psychosis—hallucinations and delusions—and there are multiple causes. People with Parkinson’s-related dementia have a pretty high frequency of hallucinations, whereas in Alzheimer's disease it's very low. But there's also a psychosis due to the drugs, and psychosis related to things like depression and anxiety.

The other cognitive symptom that has gotten a lot of press is impulse-control disorders: gambling, hypersexuality and pathological spending. These occur in a much smaller segment of Parkinson’s patients, maybe less than 20 percent, and they seem to be related more to certain medications. They can be very difficult to treat because people don't want to tell us about them.

Recently, TV commercials for Nuplazid are highlighting Parkinson’s hallucinations.

Nuplazid is the first antipsychotic specifically approved by the FDA for hallucinations in Parkinson's disease, but there are others that we have used for a long time now, including clozapine. I think it's kind of a dark commercial. When I was in training, there was a man, one of the first Parkinson's patients I took care of. I always remember him saying, “Well, don't treat my hallucinations because I kind of like them.” So, they're not all bad. When you have hallucinations, some of them are fleeting. Some of them are not troublesome. We don't always treat them, we just keep an eye on them.

What about sleep disorders and Parkinson’s?

There’s REM sleep behavior disorder, where people act out their dreams. A good percentage of people with Parkinson's start with that, sometimes as far back as 20 years before the motor symptoms occur. Other things are excessive daytime sleepiness and insomnia, what we call fragmented sleep, where people are waking up three, four or even more times per night.

What treatments are available for Parkinson’s cognitive symptoms?

We use some of the same drugs that were developed for Alzheimer's disease: Donepezil (Aricept) and another one called Rivastigmine (Exelon). There’s some data to suggest that they may be better for the cognitive change in Parkinson's than they are for Alzheimer's.

Is exercise still an important activity for managing Parkinson’s symptoms?

Physical exercise is important for the motor features, and mental exercise is important for the cognitive features. Doing crosswords and playing music is helpful.

What can we expect from Parkinson’s cognitive treatments in the next five years?

There are new drugs specifically for dementia and others for hallucinations that are being developed right now. There's a whole bunch of new things on the horizon. Five years in drug development time is a short time.  With a new drug that you're bringing to clinical these days, you're talking about a decade before they actually become available to the public.