Lower Aperiodic Activity is Associated with Reduced Verbal Fluency Performance Across Adulthood

Abstract

ABSTRACTAge-related cognitive decline associations with human electroencephalography (EEG) have previously focused on periodic activity. However, EEG is primarily made up of non-oscillatory aperiodic activity, which can be characterised with an exponent and offset value. In a secondary analysis of a cohort of 111 healthy participants aged 17 – 71 years, we examined the associations of the aperiodic exponent and offset with a battery of cognitive tests assessing processing speed and response inhibition, working memory, verbal learning and memory, psychomotor speed, and verbal fluency. Using Principal Component Analysis and K-Means Clustering, we identified clusters of electrodes that exhibited similar aperiodic exponent and offset activity during resting-state eyes-closed EEG. Robust linear models were then used to model how aperiodic activity interacted with age and their associations with performance during each cognitive test. Exponent by age and offset by age interactions were identified for the verbal fluency model where flatter exponents and smaller offsets were associated with poorer performance in adults as early as 30 years of age. Steeper exponents and greater offsets become increasingly related to verbal fluency performance and executive functioning in adulthood.SIGNIFICANCE STATEMENTThis study investigates aperiodic components of EEG activity and their association with cognitive function. Using data from 111 participants aged 17 to 71 years, we uncover that variations in aperiodic activity, specifically flatter exponents and smaller offsets, are significantly associated with poorer verbal fluency in adults as early as 30 years of age. Our findings highlight the importance of aperiodic activity and its association with lifespan models. Understanding how aperiodic EEG activity influences cognitive decline could inform future cognitive assessments and interventions for aging populations.