Internal carotid artery blood flow response to cognitive task is similar between young and older adults

Abstract

Previous studies reported that the increase in the middle cerebral artery blood flow velocity during cognitive task was greater in older adults than in young adults, suggesting age‐related differences in cerebral blood flow responses to cognitive task. However, previous studies utilized transcranial Doppler ultrasound and thereby information regarding arterial diameter, blood volume flow, and vascular conductance was lacking. On the other hand, Doppler ultrasonography can assess blood volume flow in the internal carotid artery (ICA), which provides the blood supply to a large portion of the cerebral cortex. To date, it remains to be determined whether ICA blood flow response to cognitive task is different between young and older adults. The present study examined the ICA blood flow and blood pressure (BP) responses to 20 s of task switching in 6 young (30 ± 3 yr) and 6 older (66 ± 3 yr) subjects. The ICA blood flow and BP did not change significantly during task switching in young subjects. In older subjects, significant ICA blood flow response was not found, while BP increased (p<0.05) slightly and transiently during the first 10 s of the task. In both subjects, vascular conductance of the ICA was unaltered during task switching. Our present findings suggest that the ICA blood flow response to task switching was similar between young and older subjects.Support or Funding InformationGrant‐in‐Aid for Research Activity start‐up from the Japan Society for the Promotion of Science (19K24333)