Aperiodic EEG features of cognition: a systematic review

A defining feature of electroencephalography (EEG) data is its 1/f-like spectral structure, whereby power decreases as frequency increases. The nonoscillatory, aperiodic activity underlying this structure has regained attention as an index of cortical excitation-inhibition balance or neural noise, though its precise link to cognition remains unclear. Accordingly, this PRISMA-compliant systematic review examined 45 studies on aperiodic EEG features and cognition in healthy adults (∼18-65 years), organized across cognitive domains, which included processing speed, attention, perception, memory, working memory, executive functions, learning, language, and complex/naturalistic tasks. The aperiodic exponent showed consistent associations: steeper spectra correlated with inhibitory control, conflict resolution, and encoding; flatter spectra with sensory engagement, cognitive flexibility, and recall. Evidence from resting-state and task-based EEG indicates that aperiodic activity reflects both stable, trait-like neural efficiency and flexible, state-dependent adaptability. These findings support the functional relevance of aperiodic parameters and call for methodological standardization to guide future research.