EEG Spectral Analysis of Relaxation Techniques

Abstract

The acute central nervous system effects of relaxation techniques (RT) have not been systematically studied. We conducted a controlled, randomized study of the central nervous system effects of RT using spectral analysis of EEG activity. Thirty-six subjects were randomized to either RT or a music comparison condition. After listening to an RT audiotape or music audiotapes daily for 6 weeks, the acute central nervous system effects of RT and music were measured using power spectral analysis of alpha and theta EEG activity in all cortical regions. RT produced significantly greater increases in theta activity in multiple cortical regions compared to the music condition. These findings are consistent with widespread reductions in cortical arousal during RT. They extend previous findings and suggest that theta, and not alpha, EEG may be the most reliable marker of the central nervous system effects of RT. These findings demonstrate that RT produce greater reductions in central nervous system activity than a credible comparison condition. The findings suggest that RT represent a hypoactive central nervous system state that may be similar to Stage 1 sleep and that RT may exert their therapeutic effects, in part, through cerebral energy conservation/restoration.

Characterization of EEG patterns in brain-injured subjects and controls after a Snoezelen® intervention

“…In addition, a general increase of EEG activity in theta frequency band has been reported in several researches, independently of the particular meditation technique (for a review, see [35]). Other study proved that relaxation produces significantly greater increases in theta activity in multiple cortical regions compared to listening to music [36]. This neurophysiologic pattern (increase in theta activity) agrees with our IAF results.…”

“…Previous relaxation researches have reported both a global increase and decrease of EEG power for slow and fast rhythms, respectively [36][37][38]. These studies confirm that a decline in MF can be associated with relaxation states.…”

“…The patterns of changes observed using MF, IAF, SampEn and LZC parameters did not necessarily imply that Snoezelen ® 15 therapy produces neural repair in participants. However, we hypothesize that the changes described in this study are related with higher levels of psychophysiological relaxation of the participants, since similar EEG alterations have been described during different relaxation strategies [35][36][37][38][39][40][41]. Nevertheless, other results (e.g.…”

“…As we mentioned previously, several relaxation studies agree with these results. For instance, a slowing of the EEG activity has also been observed during relaxation and meditation states [35][36][37][38].…”

Spectral EEG Features of a Short Psycho-physiological Relaxation

“…The increased power of the alpha and theta frequencies [5,7,8,3,9] and interhemispheric synchronization, especially frontal alpha coherence [1], are usually considered to be neurophysiological indicators of a state of sensorimotor and mental rest.…”