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The following is a summary of “Cold stimulation of the oral cavity redistributes blood towards the brain in healthy volunteers,” published in the February 2024 issue of Neurology by Hensel et al.
Researchers started a retrospective study to analyze cold stimulation effects on cerebral and cardiac hemodynamics.
They used transcranial Doppler sonography to assess changes in the resistance index, mean flow velocity, and flow index of middle cerebral arteries (MCA) post-ingestion of an ice cube. Extracranial duplex sonography assessed the average flow velocity and resistance index in the right internal carotid artery (ICA). They investigated variations in mean blood pressure, heart rate, root mean square of successive differences (RMSSD), and end-tidal carbon dioxide levels. These variations were compared with those under sham stimulation.
The results showed that compared to sham stimulation, cooling of the oral cavity led to significant changes in cerebral and cardiac hemodynamics. The cold stimulation resulted in a decrease in the resistance index in the MCA (-4.5% ±5.4%, P<0.0001) and the right ICA (-6.3% ±15.6%, P=0.001). This was accompanied by an increase in mean flow velocity in the MCA ( 4.1% ±8.0%, P<0.0001) and flow index (10.1% ±43.6%, P=0.008). Regarding cardiac effects, there was an increase in mean arterial pressure (1.8% ±11.2%, P=0.017) and RMSSD by (55% ±112%, P=0.048) while simultaneously decreasing the heart rate (-4.3% ±9.6%, P=0.0001).
Investigators concluded that oral cavity cooling significantly redirects blood flow toward the brain, impacting brain and heart function.