Aperiodic EEG features of cognition: A systematic review

A defining feature of electroencephalography (EEG) data is its 1/f-like spectral structure, wherein power decreases as frequency increases. This feature captures non-oscillatory activity, referred to as aperiodic activity, and has gained renewed attention as an indicator of neural mechanisms such as excitation-inhibition balance and neural noise, with a functional role in cognitive processing. However, despite its increasing use in cognitive neuroscience, the extent to which aperiodic EEG parameters reliably relate to cognitive functions remains unclear. Following PRISMA guidelines, this systematic review examined research exploring the relationship between aperiodic EEG features in cognitive processes in healthy adults, aged ~18–65. The results obtained from 45 studies are presented within three domains: (i) processing speed, perception, and attention, (ii) memory, working memory, and executive functions, and (iii) language, learning, and complex processes. Across studies, aperiodic EEG parameters, particularly the aperiodic exponent, showed relatively consistent associations with cognitive processing. Steeper spectra were typically observed during conditions requiring inhibitory control, conflict resolution, and encoding of information. Instead, flatter spectra accompanied sensory engagement, cognitive flexibility, and memory recall. Both resting-state and task-related measures indicated that aperiodic activity reflects a combination of stable, trait-like neural efficiency and flexible, state-dependent adaptability. The reviewed evidence supports the functional relevance of aperiodic EEG parameters as indices of cortical state regulation, reflecting shifts in excitation-inhibition balance, neural noise, and arousal. Future work should prioritize methodological standardization and extend investigations across developmental and clinical populations to clarify the generality and mechanistic basis of the aperiodic-cognition relationship.