Frontal Hemodynamic Responses to high Frequency yoga Breathing in schizophrenia: A Functional near infrared spectroscopy (FNIRS) Study.

Abstract

Objective: Frontal hemodynamic responses to high frequency yoga breathing technique - Kapālabhāti (KB) were compared in patients of schizophrenia (n =16; 13 males, 3 females) and age-gender-education matched healthy controls (n =16; 13 males, 3 females) using functional near-infrared spectroscopy (fNIRS). Materials and Methods: Both the groups enrolled into the study after obtaining written informed consent. The diagnosis was confirmed by a psychiatrist using DSM IV. All patients except one received atypical anti-psychotics (one was on typical). They had obtained a stabilized state as evidenced by a steady unchanged medication from their psychiatrist for past 3 months or longer. Both the groups had no previous exposure to KB practice, which involves rapid breathing consisting of active expiration with the help of abdominal muscles and passive automatic inspiration. They learnt KB, among other yoga procedures, in a residential yoga retreat and the training was achieved over 2 weeks. A chest pressure transducer was used to monitor the frequency and intensity of the practice. The frontal hemodynamic response in terms of changes in the oxygenated hemoglobin (oxyHb), deoxygenated hemoglobin (deoxyHb) and total hemoglobin (totalHb) concentration was tapped for 5 min before, 1min during and for 5 min after KB. Eight sensors on each side over the frontals acquired the hemodynamic response. This was obtained in quiet room using a 16 channel functional near-infrared system (FNIR100-ACK-W, BIOPAC Systems, Inc, U.S.A.). Average of the eight channels for each side (right and left frontals) was obtained for the three sessions. The changes in the levels of oxyHb, deoxyHb and blood volume for the three sessions were analyzed using paired samples t test for both the groups. Results: During KB, healthy controls showed significant increase in oxyHb and totalHb from the baseline in bilateral pre-frontal cortices; right hemisphere (oxyHb, p = 0.007; totalHb, p = 0.013) and left hemisphere (oxyHb, p = 0.003; totalHb, p = 0.002). Schizophrenia patients on the other hand showed significant fall in deoxyHb from the baseline in right pre-frontal cortex (p = 0.008) during the practice of KB. Post KB, deoxyHb increased (p = 0.042) and blood volume decreased (p=0.013) significantly from the baseline in healthy controls in right hemisphere. Conclusion: Patients suffering from schizophrenia show reduced pre-frontal activation during KB practice as compared to healthy controls. This hypo-frontality of schizophrenia patients in response to KB may be used clinically to support the diagnosis of schizophrenia in future.