THE STUDY OF MODIFICATIONS IN THE SPEED O F BRAIN FLOW-INDUCED IN THEMIDDLE CEREBRAL-ARTERY BY ACUTE STRESS BY TRANSCRANIAL DOPPLER ULTRASONOGRAPHY

Background: The behavior of brain flow on acute stress has not been pr eviously evaluated. Transcraneal Doppler ultrasonography (TD) is a blo odless method to evaluate the speed of cerebral flow in the arteries o f the Willis polygon. The present study was designed to analyze the ch anges which occur in the same during two situations of acute stress. M ethods: The mean speed of cerebral flow (MS) and the pulsation rate (P R) of the right and left middle cerebral artery (MCA) were measured ba sally and following a mental stress test (calculation) and physical st ress (cold test) by TD and through the temporal window. Twenty-five he althy volunteers (18 women and 8 men) with a mean age of 27.8 +/- 7.3 years were studied. Results: In response to mental stress an increase was observed in MS in both the right MCA (10 +/- 8.6 cm/sec) and the l eft MCA (10.4 +/- 8.7 cm/sec) with a decrease in the MCA (0.14 +/- 0.2 3 in the right MCA, 0.14 +/- 0.18 cm/sec in the left MCA). In response to the cold test an increase in MS (7.3 +/- 7.5 cm/sec in the right M CA, 14.8 +/- 14.7 cm/sec in the left MCA) was also observed with a dec rease in the PR (0.2 +/- 0.2 in the right MCA and 0.2 +/- 0.16 in the left MCA). No significant differences were observed in the changes ind uced in the right or left artery or in those induced by the mental or cold tests.Conclusions: These results suggest that the acute stress pr oduces an increase in cerebral flow in the arteries of the Willis poly gon.