Context: The use of cranial osteopathic manipulative medicine (OMM) to alter cerebral tissue oxygen saturation could play a role in the maintenance of cerebral homeostasis.

Objective: To examine the effects of cranial OMM on cerebral tissue oxygen saturation (S(CT)O(2)) and cardiac autonomic function in healthy adults.

Methods: Cranial OMM augmentation and suppression techniques and sham therapy were randomly applied to healthy adults. During cranial OMM and sham therapy, S(CT)O(2) of the prefrontal cortex was determined bilaterally by using near-infrared spectroscopy. Heart rate, blood pressure, and systemic arterial blood oxygen saturation (SaO(2)) were also measured. Power spectral analysis was applied to continuous 4-minute R-R intervals. Measurements were made during 2-minute baseline periods, during 4-minute applications of the techniques, and during 5-minute recovery periods.

Results: Twenty-one adults (age range, 23-32 y) participated in the present study. Differences in mean baseline measurements for the augmentation technique, suppression technique, and sham therapy were not statistically significant for heart rate, blood pressure, SaO(2), left S(CT)O(2), or right S(CT)O(2). During the suppression technique, there was a statistically significant decrease in both left (slope [standard deviation]= -0.33 [0.08] %/min, R(2)=0.85, P=.026) and right (slope [standard deviation]=-0.37 [0.06] %/min, R(2)=0.94, P=.007) S(CT)O(2) with increased cranial OMM time. However, neither the augmentation technique nor the sham therapy had a statistically significant effect on S(CT)O(2). Decreases in normalized low-frequency power of R-R interval variability and enhancements of its high-frequency power were statistically significant (P=.05) during cranial OMM and sham therapy, indicating a decrease in cardiac sympathetic influence and an enhanced parasympathetic modulation.

Conclusion: The cranial OMM suppression technique effectively and progressively reduced S(CT)O(2) in both prefrontal lobes with the treatment time.