Brain Wave Recordings Could Predict Cognitive Outcomes in Parkinson's

A brief period of data collection using a head-mounted electrode could be enough to predict whether people with Parkinson’s disease will develop thinking problems such as dementia during the course of their disease.

That’s the conclusion of a new study produced by a team at the University of Iowa. They hope that the findings may help to improve how cognitive difficulties in the condition are diagnosed and could lead to new biomarkers and therapies for an understudied facet of Parkinson’s.

The study is published in the Journal of Neurology, Neurosurgery & Psychiatry.

Nandakumar Narayanan, associate professor of neurology at the UI Carver College of Medicine is senior author of the new study. “Cognitive decline, including dementia, is a significant and underappreciated symptom of Parkinson’s disease. Around 30% of patients can have cognitive symptoms at the beginning of the disease, and up to 80% will have cognitive problems at some point in their disease,” says Narayanan. “Furthermore, although we have quite a few effective treatments for the motor symptoms of Parkinson's, including medical therapies and deep brain stimulation, we have very few treatments for the cognitive aspects of Parkinson's disease.” 

EEG insights

The new publication details Narayanan and colleagues’ efforts to measure brain waves in a cohort of 100 patients with Parkinson’s disease. This group had a full range of cognitive presentations including those with dementia. The team recruited 49 additional participants who did not have Parkinson’s as controls.

The team recorded their volunteers’ brain waves using a technique called electroencephalography (EEG). This measured delta and theta waves from regions at the front of the participants’ brains. The cohort completed three cognitive tasks that are used to assess cognition. While they were undertaking these tasks, a single EEG electrode on the top of their heads assessed the strength of the low-frequency delta and theta waves.

The team found that when a patient was required to engage in thinking, there was a strong link between cognitive dysfunction and reduced delta and theta wave strength, regardless of the type of task being undertaken. “Surprisingly, the effect was seen simply because the patient was required to pay attention to a cue and respond. I think this is the deep insight into why Parkinson’s patients have cognitive problems: they fail to engage these basic response processes in the brain,” Narayanan explains.  

Importantly, the team suggests that this finding might mean that “cueing” people with Parkinson’s to perform a cognitive or motor task could enhance their performance in the task. This may lead to improvements in how occupational and speech therapists organize assessments and rehab for people with the condition.

EEG’s many uses

What makes these findings particularly useful is EEG’s low cost and high utility.

“Traditional methods for diagnosing cognitive problems often involve time-consuming pen and paper tests and require a neurologist to administer and interpret the tests. In addition, because these traditional tests can be ‘learned,’ they cannot be used repeatedly over time for the same patient,” says Narayanan, who also is a neurologist with UI Health Care and a member of the Iowa Neuroscience Institute. “In contrast, EEG can be done continuously over several hours or days. It can be applied in nursing homes or patients' homes, and it gives you a richly featured description of a patient's cognitive status.” 

Once cognitive impairments are diagnosed, EEG could prove useful in exploring how medications, neurotechnology-based therapies and even novel Parkinson’s treatments improve symptoms.

Narayanan and the team now want to look at why these brain waves are linked to impaired cognition and explore in what other ways EEG can help assess and even treat people with Parkinson’s.

Reference: Singh A, Cole RC, Espinoza AI, Wessel JR, Cavanagh JF, Narayanan NS. Evoked mid-frontal activity predicts cognitive dysfunction in Parkinson’s disease. J Neurol Neurosurg Psychiatry. Published online June 1, 2023. doi:10.1136/jnnp-2022-330154h

This article is a rework of a press release issued by the University of Iowa. Material has been edited for length and content.