The Impact of Chiropractic Adjustments on Intracranial Blood Flow: A Pilot Study
Robert M. Scott DC, Ph.D, Christopher L. Kaufman Ph.D., Donald R. Dengel, Ph.D.
Journal of Vertebral Subluxation Research ~ May 21, 2007 ~ Pages 1-8
Background: A limited number of studies have addressed the impact of extracranial vascular blood flow and positional changes of the cervical spine. Fewer have addressed the specific effects of chiropractic adjustments and vertebral artery blood flow via Doppler Ultrasound techniques. Identifying the effects on blood flow may prove helpful in identifying the relationship of flow to mechanism of action and subsequent application of chiropractic care to vascular health and the onset of disease.
Objective: To investigate the effect of a single chiropractic adjustment on middle cerebral artery blood flow and radial artery blood pressure response.
Design and Setting: A randomized controlled study involving 20 healthy chiropractic students. Data were analyzed utilizing a two-group repeated measures ANOVA with 6 levels followed by a post hoc multiple comparison analysis.
Results: A transient but significant change in middle cerebral artery blood flow occurred in subjects receiving a chiropractic adjustment. Peak flow was reached within one minute of receiving the adjustment and returned to baseline values by minute five. A single cervical adjustment had no effect on systolic or diastolic blood pressure.
Conclusion: This Doppler study looked at the effect of a chiropractic adjustment on intracranial blood flow. The results indicate that asymptomatic subjects experience small, transient increase in blood flow immediately following an adjustment.
Key Words: Chiropractic Adjustment, Blood Flow, Transcranial Doppler Ultrasound, Blood Pressure, Subluxation