Resting EEG spectral slopes are associated with age-related differences in information processing speed

Background Previous research has shown the slope of the EEG power spectrum differentiates between older and younger adults in various experimental cognitive tasks. Here, we extend that work, assessing the relation between the EEG power spectrum and performance on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), a widely-used neuropsychological instrument that assesses a broad range of cognitive domains. Methods Forty-four participants (21 younger adults, 23 older adults) completed the RBANS with EEG data collected at-rest. Using spectral parameterization, we tested the mediating effect of the spectral slope on age-related differences in subsequent cognitive task performance. Results Older adults performed reliably worse on the RBANS overall, and on the Attention and Delayed Memory domains. However, evidence of mediation was only found for the Coding subtest, a measure of information processing speed. Conclusions We found some evidence that the slope of the resting EEG power spectrum mediated age-related differences in cognition. These effects were evident only in tasks requiring speeded processing, whereas this effect was not statistically significant for delayed memory, even though age-related differences were present.