Cerebral Blood Flow Velocity Responses to an Acute Cognitive Challenge in Healthy Adults

Abstract

Cerebral blood flow velocity responses to hypercapnia are blunted by the cyclooxygenase inhibitor indomethacin (INDO). We hypothesized that INDO would also attenuate middle cerebral artery blood flow velocity (MCAv) responses to an acute cognitive challenge. We evaluated the MCAv responses to an acute cognitive challenge in 20 healthy young (20‐35 yrs) and older (56‐76 yrs) healthy adults, including 10 men and 10 women before and 90 minutes after INDO administration. The cognitive challenge consisted of 2 blocks of the Stroop color word test: easy (3 colors) and difficult (8 colors). Mean arterial pressure (MAP), end‐tidal CO2, and MCAv were monitored throughout the protocol. There were no differences in MAP or end tidal CO2 between trials. Indeed, MCAv was lower during INDO than baseline for both the easy (50±4 vs. 68±4 cm/s; p<0.01) and difficult (49±3 vs. 66±3 cm/s; p<0.001) cognitive challenges. Additionally, there was an Age x Sex interaction for the increase in MCAv during the easy cognitive task, with older men having a greater increase than older women (15±5 vs. ‐1±5%, respectively; p<0.05). This interaction was not statistically significant for the difficult cognitive task or during the INDO trial. In conclusion, similar to hypercapnia, the cyclooxygenase inhibitor INDO blunts cerebral blood flow velocity responses to an acute cognitive challenge.Funded by NIH grant HL 118154