Dr James Eyerman aslo wrote and paper on the the 

Abstract Objectives: critical review of etiological theories of phenomena reported in Holotropic Breath-work [HB].

Method: literature on Holotropic Breathwork, hyperventilation syndrome, polyvagal theory, SARs theory, classical mytho-poetic traditions, the role of music, anomalous experiences and healing, and classical psycho-spiritual explanatory models are reviewed.

Discussion: physiological and neurophysiological models, transpersonal, and cognitive psychological models, ethno-epistemological problems and methodological concerns are reviewed. Narrative logic versus stochastic models is ex-amined.

Conclusions: voluntary over-breathing and music provide access to non-ordinary states through the putative effects of vagal toning and sonic integration. Cognitive processes may play a role in permit-ting the anomalous internal narrative experiences.