Repeated self-administered EEG recordings enable longitudinal measurement of brain activity at home

Mobile electroencephalography (EEG) offers new opportunities to investigate brain activity outside the laboratory, but the quality and reliability of self-administered recordings remain important concerns. Here, we evaluated whether repeated at-home recordings using a four-channel consumer EEG device could provide meaningful electrophysiological measurements and characterized the stability of these measures across sessions. Five participants completed repeated recordings across multiple days, including resting-state measurements and an auditory oddball task performed with and without concurrent cognitive load. The recordings captured established spectral signatures of physiological state and task demands, including increased alpha activity during eye closure and changes in theta activity associated with cognitive load. Auditory stimulation elicited clear event-related responses, while exploratory multivariate decoding distinguished standard from target tones across recording sessions. Measurement stability varied across electrophysiological features, and aggregating repeated sessions improved the consistency of individual-level estimates. For example, split-half reliability of the auditory N1-like response increased from r = .22 with one session to r = .76 with seven sessions per half. By demonstrating the feasibility of repeated self-administered EEG measurements, this study provides a step toward investigating how brain activity varies both between individuals and within individuals over time in everyday environments.