Age-related effects on verbal and visuospatial memory are mediated by theta and alpha II rhythms

• Relative theta and alpha II power decrease with age.
• Verbal and visuospatial memory performances show a similar pattern of age-related decline.
• Oscillations in specific frequency bands explain age-related memory deficits.
• Fronto–central eyes-open theta power mediates the age-related effect on verbal memory.
• Parietal eyes-closed alpha II power mediates the age-related effect on visuospatial memory.

Both electrical brain activity during rest and memory functions change across the lifespan. Moreover, electrical brain activity is associated with memory functions. However, the interplay between all these effects has been investigated only scarcely. The present study investigated the extent to which the power of resting-state electroencephalographic (EEG) frequencies mediates the impact of aging on verbal and visuospatial memory. Seventy healthy participants with 22 to 83 years of age completed a visuospatial and verbal learning and memory test and provided eyes-open and eyes-closed resting-state EEG data. Robust age-related effects on behavioral and EEG data were observed. Mediation analyses showed that the relative power of the theta (4–8 Hz) frequency band in fronto–central locations partly explained the negative age-related effect on delayed recall in the verbal memory task. The relative power of the alpha II (10–12 Hz) frequency band in mainly parietal locations partly explained the negative impact of age on immediate and delayed recall in the visuospatial task. Results indicate that spontaneous brain activity carries specific information about aging processes and predicts the level of competence in verbal and visuospatial memory tasks.