Parkinson’s disease: Could an EEG test help predict cognitive decline?

Health News

Over 10 million people globally have Parkinson’s disease.
There is currently no cure for Parkinson’s, which affects a person’s cognitive abilities and ability to perform everyday tasks.
Researchers from the University of Iowa Carver College of Medicine say that an EEG test could help doctors predict cognition problems in people with Parkinson’s disease.

More than 10 million people around the world have Parkinson’s disease — a neurological disease affecting movement and cognition.

There is currently no cure for Parkinson’s and researchers are still unclear as to what causes the condition.

Now, researchers from the University of Iowa Carver College of Medicine have discovered a way to predict thinking problems, including dementia, in people with Parkinson’s using a widely available technology called electroencephalography (EEG).

Researchers believe that EEG tests could help improve the diagnosis of cognitive decline in people with Parkinson’s, and lead to new biomarkers that could be used to target therapies to treat the disease’s cognitive symptoms.

This study was recently published in the Journal of Neurology, Neurosurgery & Psychiatry.

What is an EEG test?

An electroencephalogram (EEG) is a medical test used to measure the electrical activity in the brain. It can also be used to detect any abnormalities in a person’s brain waves.

An EEG is a noninvasive test that uses small electrodes placed on the scalp. The electrodes pick up the electrical activity in the brain and display them as visual patterns on a computer screen. The visual patterns are then interpreted by a neurologist to check for any issues.

An EEG can be used to diagnose a variety of diseases, including:

epilepsy
sleep disorders
Alzheimer’s disease (AD)
brain tumor
brain damage from a head injury
stroke
encephalitis (swelling of the brain)

Parkinson’s: EEG test predicts cognitive decline

For this study, the researchers recruited 100 people with Parkinson’s disease with varying cognitive abilities, from healthy to dementia. They also included 49 control participants.

All study participants completed three different tasks commonly used to assess a person’s cognitive control. While doing the tasks, each participant wore a single EEG electrode that measured the strength of their brain waves.

“When people receive instruction, it triggers a brain wave that oscillates at four times [per] second,” Dr. Nandakumar Narayanan, PhD, associate professor of neurology at the University of Iowa Carver College of Medicine and senior author of the study, explained to Medical News Today.

Upon analysis, the research team found that diminished cognitive ability was correlated to reduced strength of low-frequency brain waves while doing a task. And scientists reported that importantly, it did not matter which task they were doing during the EEG test.

Dr. Narayanan said they were “blown away” by the study’s outcomes.

“Most people think EEG is too blurry, but what we found is all cognitive tasks require patients to pay close attention to instructions,” he detailed. “It was that neural mechanism that is impaired in Parkinson’s disease.”

Additionally, Dr. Narayanan commented they have high hopes that this might be used to develop markers for cognitive symptoms of Parkinson’s disease, and even other diseases as well.

“It has advantages (over) traditional paper-and-pen testing because it can run continuously, can be repeated, and capture fluctuations throughout the day or in response to medication or brain stimulation,” he continued. “This marker can be used to avoid cognitive side effects, or excitingly, find new therapies.”

Cognitive decline in Parkinson’s disease

Although most early signs of Parkinson’s are physical and affect motor function, there are some cognitive signs as well. These can include:

confusion
inability to focus
trouble speaking or communicating
memory issues
problems with tasks and problem-solving
slowed thinking
difficulty with depth perception

Dr. Narayan said his team chose to focus their research on cognitive decline in Parkinson’s disease because the motor symptoms of the disease are readily apparent, but Parkinson’s patients can also have cognitive symptoms.

“In fact, cognitive dysfunction affects about 80% of Parkinson’s patients at some point in their disease,” he told MNT.

“These symptoms are devastating for patients and their families (and) can lead to loss of independence and employment, as well as transfer to a nursing home. Critically, most healthcare providers aren’t trained to recognize these symptoms, and there are few objective, reliable tests — so they are often missed.”

And Dr. Narayanan said they decided to use EEG for their study as it is a 100-year-old technology that is inexpensive and ubiquitous.

“You can even wear EEG electrodes while at home, driving, or sleeping. While it doesn’t have great spatial resolution, it has excellent temporal resolution and gives you a dynamic snapshot of brain activity. We thought that we could use this to learn something about Parkinson’s disease. This is one of the largest EEG studies of Parkinson’s disease that I am aware of.”

— Dr. Nandakumar Narayanan, PhD, neurology professor and senior study author

New possibilities for Parkinson’s treatment

After reviewing this study, Dr. Jean-Philippe Langevin, a neurosurgeon and director of the Restorative Neurosurgery and Deep Brain Stimulation Program for Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, CA, told MNT he thought this was exciting research that opened the door to new possibilities.

“The technology that they use is pretty rudimentary, so it’s something that’s readily available,” he explained.

“And even though it was relatively simple in terms of experiments and set-up, they still were able to find a significant reduction in (the) power of certain signals inside the brain in those patients who were affected with cognitive dysfunction.”

“The reason why I think it’s exciting is because it’s something that could be relatively easy to monitor in our patients with Parkinson’s disease. The technology could be easily deployed. Something that can be tracked and monitored over time. And I think that could allow us to investigate new therapies (and) new medications.”

— Dr. Jean-Philippe Langevin, neurosurgeon

MNT also spoke with Dr. Daniel Truong, a neurologist and medical director of the Parkinson’s and Movement Disorder Institute at MemorialCare Orange Coast Medical Center, about this study.

“The study’s findings (are) intriguing and exciting, as it provides insights into the relationship between mid-frontal delta[and]theta rhythms and cognitive dysfunction in Parkinson’s disease,” he explained.

“This new information could potentially contribute to a better understanding of the underlying mechanisms of cognitive impairment in the disease.”

Dr. Truong added that the results of the study “confirm the importance of assessing cognitive function and investigating potential biomarkers for cognitive problems in Parkinson’s disease.”

“The measurement of mid-frontal delta [and] theta rhythms may aid in diagnosing cognitive dysfunction in Parkinson’s disease. Additionally, it may start thinking about potential treatment implications, such as exploring neurostimulation techniques or cognitive rehabilitation programs targeting the identified rhythms,” Dr. Truong concluded.

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