Altered states of Ganzfeld: A systematic review

The Ganzfeld experiment appears as a uniform and unstructured field that may measure altered states of consciousness. The experiment uses a dim light frequency projected on translucent eye covers combined with a static audio frequency emitted through a pair of headphones. Since altered states and alpha interactions appear in Ganzfeld studies, the hypothesis here states that they may be internally related. Therefore, the extraction filtered EEG data from combined stimulations of light and static sound for their implications on consciousness. The systematic search included PubMed, Scopus, Medline (OVID), and the Web of Science databases to gather data. Between January 2000 and January 2022, only four controlled trials studied the Ganzfeld-EEG stimulation. The results verify the role of alpha interactions during hallucination-like imagery. Furthermore, this review highlights a significant gap in Ganzfeld-induced altered states of consciousness research.