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Updated: Nov 18, 2025
Functional Transcranial Doppler Ultrasound for Monitoring Cerebral Blood Flow
Published on: March 15, 2021
Effect of occipitoatlantal decompression on cerebral blood flow dynamics as evaluated by Doppler ultrasonography
Bryan Roberts1, Andrew E Makar1, Ryan Canaan1
1Kirksville College of Osteopathic Medicine , A.T. Still University , Kirksville , MO , USA.
Insights
Occipitoatlantal decompression (OAD) significantly increased blood flow in major cranial arteries in healthy adults. This osteopathic manipulative treatment may improve cerebral blood flow, though the exact mechanism requires further investigation.
Area of Science:
- Neurology
- Vascular Biology
- Osteopathic Medicine
Background:
- Osteopathic manipulative treatment is known to alleviate headache symptoms, but its precise physiological mechanisms remain largely unexplored.
- Understanding the impact of specific osteopathic techniques on vascular function is crucial for elucidating treatment efficacy.
Purpose of the Study:
- To quantitatively assess changes in intracranial and extracranial blood flow following occipitoatlantal decompression (OAD) using Doppler ultrasonography.
- To compare the vascular effects of OAD with a sham intervention in healthy participants.
Main Methods:
- A randomized, single-blinded, crossover study involving healthy osteopathic medical students.
- Participants received either OAD or a sham touch intervention, followed by the alternative intervention after one week.
- Blood flow parameters, including peak systolic velocity (PSV) and end-diastolic velocity (EDV), were measured in the middle cerebral artery (MCA), internal carotid artery (ICA), and vertebral artery (VA) at multiple time points pre- and post-intervention.
Main Results:
- Occipitoatlantal decompression (OAD) led to a significant increase in end-diastolic velocity (EDV) in the MCA, ICA, and VA (p<0.001).
- No significant changes in EDV were observed after the sham intervention (p>0.05).
- Post-treatment EDV was consistently higher for all measured arteries after OAD compared to sham treatment (p<0.001).
Conclusions:
- Occipitoatlantal decompression (OAD) demonstrably enhances blood flow in major cranial arteries, suggesting a potential mechanism for its therapeutic effects in headache disorders.
- The observed increase in EDV may be attributed to parasympathetic stimulation or reduced external vascular pressure.
- Further research is warranted to fully elucidate the neurovascular mechanisms underlying OAD's impact on cerebral circulation.
Context:
Osteopathic manipulative treatment reduces symptoms in patients with headache disorders, but the underlying mechanisms are unclear.
Objective:
To evaluate blood flow in the intracranial and extracranial vasculature before and after occipitoatlantal decompression (OAD) using Doppler ultrasonography.
Methods:
Healthy, first-year osteopathic medical students from A.T. Still University's Kirksville College of Osteopathic Medicine participated in a randomized, single-blinded, two-period, two-treatment crossover study. The participants were randomly assigned to 1 of 2 treatment interventions: OAD or sham touch. After one week, participants returned to have the other intervention performed. Blood flow parameters-peak systolic velocity (PSV) and end-diastolic velocity (EDV)-in the middle cerebral artery (MCA), internal carotid artery (ICA), and vertebral artery (VA) were evaluated before, immediately after, 5 minutes after, and 10 minutes after treatment. Differences in PSV, EDV, heart rate (HR), and blood pressure (BP) for both interventions were analyzed for the four time points using mixed-effects models.
Results:
Thirty healthy medical students (11 men, 19 women; mean age, 24 years) participated in this study. EDV increased after OAD in the MCA, ICA, and VA (all p<0.001); no change occurred after sham touch (all p>0.05). EDV was greater for all post-treatment timepoints after OAD in the MCA, ICA, and VA than after sham touch (all p<0.001). Although baseline PSV in the MCA measured before treatment was different between treatment interventions (p=0.01), no difference was found between interventions at any post-treatment time point (all p>0.59). Changes in PSV in the ICA and VA and for HR and BP did not depend on treatment intervention (p>0.06).
Conclusion:
Increases in EDV occurred in major cranial arteries after OAD but not after sham touch, indicating that OAD improves blood flow to the brain. The exact mechanism of this increase is unknown; however, it can be explained by either parasympathetic stimulation through the secretion of vasodilating neurotransmitters or by a decrease in external tissue pressure on ICA and VA, with the resulting flow causing further dilation in the MCA.
