Cranial osteopathic techniques and electroencephalogram (EEG) alpha power: a controlled crossover trial

Osteopathic tradition in the cranial field (OCF) stated that the primary respiratory mechanism (PRM) relies on the anatomical links between the occiput and sacrum. Few studies investigated this relationship with inconsistent results. No studies investigated the occiput-sacrum connection from a neurophysiological perspective.

This study aims to determine whether the sacral technique (ST), compared to the compression of the fourth ventricle (CV4) technique, can affect brain alpha-band power (AABP) as an indicator of a neurophysiological connection between the occiput and sacrum.

Healthy students, 22-30 years old for men and 20-30 years old for women, were enrolled in the study and randomized into eight interventions groups. Each group received a combination of active techniques (CV4 or ST) and the corresponding sham techniques (sham compression of the fourth ventricle [sCV4] or sham sacral technique [sST] ), organized in two experimental sessions divided by a 4 h washout period. AABP was continuously recorded by electroencephalogram (EEG) of the occipital area in the first 10 min of resting state, during each intervention (active technique time) and after 10 min (post-active technique time), for a total of approximately 50 min per session. Analysis was carried out utilizing a repeated-measure ANOVA within the linear general model framework, consisting of a within-subject factor of time and a within-subject factor of treatment (CV4/ST).

Forty healthy volunteers (mean age ± SD, 23.73±1.43 years; range, 21-26 years; 16 male and 24 female) were enrolled in the study and completed the study protocol. ANOVA revealed a time × treatment interaction effect statistically significant (F=791.4; p<0.001). A particularly high increase in mean AABP magnitude was recorded during the 10 min post-CV4, compared to both the CV4 and post-sCV4 application (p<0.001). During all the times analyzed for ST and sST application, no statistically significant differences were registered with respect to the resting state.

The ST does not produce immediate changes on occipital AABP brain activity. CV4, as previous evidence supported, generates immediate effects, suggesting that a different biological basis for OCF therapy's connection between the head and sacrum should be explored.