For many individuals living with Parkinson's disease and those in its "prodromal" or early stages before movement impairment, there is a distressing gap between how they feel their brain is working and what clinical tests show. Patients often report, "I feel like my thinking is getting worse," only to be told their objective cognitive scores are perfectly normal.
A new study led by experts at Boston University, published in the journal Neuropsychology, is the first to examine "global" metacognition, a term to describe how accurately people judge their everyday cognitive abilities, by directly comparing self-reported cognitive concerns with objective neuropsychological performance.
Using data from 468 people diagnosed with Parkinson's disease, and 817 people in the prodromal stages of Parkinson's, the researchers found that more negative metacognitive bias was strongly linked to elevated depression and trait anxiety (i.e., the relatively stable aspects of anxiety) in both groups. Importantly, among people with Parkinson's disease, many cognitive worries appeared to reflect a negative metacognitive bias that increased over a 12-month period rather than reflecting a measurable cognitive impairment, and this bias remained strongly related to trait anxiety. While these findings are new in the Parkinson's disease literature, senior author on the paper, Dr. Joseph DeGutis, Associate Professor of the Department of Psychiatry, BU School of Medicine and Adjunct Research Associate Professor of BU's Department of Psychological and Brain Sciences, has previously found similar associations between negative metacognitive bias and depression and anxiety in other clinical populations.
The researchers suggest that targeting anxiety and depression may help recalibrate these global self-assessments and consequently improve the quality of life of people with Parkinson's disease, while giving clinicians a clearer way to interpret cognitive complaints early in the disease course. There is currently no cure for cognitive impairment associated with Parkinson's disease and other neurodegenerative conditions, but there are pharmacological treatments for depression and anxiety, as well as non-pharmacological treatments like cognitive-behavioral therapy that are known to work well in people diagnosed with Parkinson's disease.
"Previous metacognition studies have focused on moment-to-moment or task-specific judgments, such as whether someone thinks they answered a specific question correctly or how they performed on a single test," said Nishaat Mukadam (M.A. '22), a PhD candidate in BU's Psychological & Brain Sciences and lead author on the paper. "By shifting the focus to broader, real-world self-evaluations, we provide a more functional and clinically meaningful understanding of how people perceive their cognitive health."
Mukadam and the research team led by Dr. Alice Cronin-Golomb, Professor of BU's Department of Psychological & Brain Sciences, and Dr. DeGutis hope that their study findings can help inform future research in several areas by looking at interventions, such as treatment of depression and anxiety, and possibly metacognitive training, to understand whether these interventions can improve negative metacognitive bias and reduce subjective cognitive concerns in people with Parkinson's disease and those in very early stages of the disease; and by using neuroimaging to investigate the neural correlates of metacognitive bias.
"The findings from this study are a good reminder that subjective cognitive concerns should not be dismissed. By investigating the underlying causes and treating them, we can improve quality of life by helping people with Parkinson's regain their confidence," said Dr. Cronin-Golomb.
