Changes in midlatency auditory evoked potentials following two yoga-based relaxation techniques.

Practicing meditation while focusing on a sound or a symbol influenced midlatency auditory evoked potentials (MLAEPs). Cyclic meditation (CM) is a technique combining yoga postures with meditation while supine, which has influenced the P300 event-related potential. The effects of CM on MLAEPs have not been previously studied. The MLAEPs were studied before and after the practice of CM compared to an equal duration of supine rest (SR) in 47 male volunteers (group mean age 26.5 +/- 4.4 years), recorded from the vertex referenced to linked earlobes. The sessions were one day apart and subjects were randomly assigned to each session. The Pa wave peak latency and Nb wave peak latency significantly increased following CM compared to before CM (repeated measures ANOVA, post-hoc analysis with least significant difference, p<0.05). There was a significant increase in the peak amplitude of the Nb wave (p<0.05) compared to before CM. Post SR there was a significant increase in the peak latency of the Na wave (p<0.05) compared to before SR. In conclusion following CM the latencies of neural generators corresponding to cortical areas is prolonged, whereas following SR a similar change occurs at mesencephalic-diencephalic levels.