Neuropsychiatric symptoms impact associations between plasma neurofilament light and cognition in individuals with Lewy body pathology, but not in Alzheimer’s disease.

Lewy body disease (LBD) is one of the most prevalent causes of dementia following Alzheimer’s disease (AD). Plasma neurofilament light chain (NfL) is a marker of neuroaxonal degeneration associated with cognitive decline in LBD, AD, and other neurodegenerative disorders. Neuropsychiatric symptoms are often present in both LBD and AD and can affect quality of life and cognitive performance. Therefore, we investigated whether the association between plasma NfL and cognition was moderated by the severity of neuropsychiatric symptoms in LBD and AD.