Research Updates – Transcranial Doppler ultrasound to assess cerebrovascular reactivity

Please be seated…

Transcranial Doppler ultrasound (TCD) allows measurement of blood flow velocities in the intracranial vessels, and until last year’s publication in PeerJ of “Transcranial Doppler ultrasound to assess cerebrovascular reactivity: reliability, reproducibility and effect of posture”, there was no agreement about whether the technique should be performed in sitting or lying postures.

Dr Michelle McDonnell—Neurological Physiotherapist at University of South Australia—and her colleagues demonstrated that cerebrovascular reactivity using transcranial Doppler ultrasound should be performed with participants sitting in order to maximize measurement reliability.

Dr McDonnell told us that her publication has definitively influenced her peers. “Since our publication in PeerJ, other authors have reported testing participants in sitting, due to our evidence that measurements of cerebrovascular reactivity are more reproducible in sitting, compared with lying”, she said. “Our peers have taken notice of our study and are reporting the reliability values we published”. Indeed, as can be seen, this article has already been cited several times and has a high proportion of download to views (indicating that a large proportion of readers are choosing to save the article for future study).

The reliability of the measurements taken in research is critically important, particularly to evaluate the effectiveness of an intervention. The technique that Dr McDonnell and her collaborators described is very useful for measuring changes in circulatory function in the cerebral vessels, a part of the body difficult to access non-invasively. They have provided evidence that assists researchers to apply the most appropriate methodology, which ultimately assists with the validity and reliability of results for studies using this technique.

Since her PeerJ publication, Dr McDonnell’s research has progressed quite well: “We continue to use this technique to investigate cerebral circulatory function in healthy adults, and those with disorders such as cognitive impairment and type 2 diabetes”, she told us. “Moreover, various dietary, medication, and lifestyle interventions may be able to improve endothelial function or microcirculation in the brain, and the ability to have reliable and accurate measurement of this is essential. So we are now also investigating the effect of foods such as pulses (legumes), a Mediterranean diet, and peanuts on cerebral vasculature and cognitive function”.

We hope to read more about this important research in future papers and we encourage any others working in this field to submit their work to PeerJ.