Meditation practices, rooted in ancient traditions, are being studied for their potential mental and physical health benefits, particularly regarding brain effects. This article reviews the use of electroencephalogram (EEG) as a tool to study meditation in healthy individuals, describing EEG signal processing techniques applied to meditation research up to April 2020. It examines the limitations and assumptions of these techniques, highlighting good practices and discussing how technical specifications can impact the interpretation of outcomes. The article aims to promote more rigorous approaches to evaluating meditation by focusing on technical features rather than subjective experiences.
During focused attention meditation, experienced practitioners suppress long-range temporal correlations (LRTC) of neuronal oscillations relative to eyes-closed rest, with remarkable consistency across frequency bands and scalp locations. This suppression is absent in meditation-naïve controls. The ability to reduce LRTC during meditation increased after one year of additional training and was associated with the subjective experience of absorption—fully engaging one's attentional resources. Sustained practice also affected normal waking brain dynamics, as reflected in increased LRTC during an eyes-closed rest state, indicating that brain dynamics are altered beyond the meditative state. The framework of critical brain dynamics appears promising for understanding neuronal mechanisms of meditative states.