TCD study of hemodynamic changes in PCA response to photic stimulation

摘要

Obiectives:During visual stimulation,the elevated metabolism rate will couple wity increase of blood flow velocity(BFV) in posterior cerebral artery(PCA),This strudy with TCD was aimed to investigate whether the coupling might change according to the different vasoneuronal conditions.Methods:Ninety-nine volunteers including 24 hypertension(HT) patients and 2 patients suffering from both HT and diabetes mellitus (DM) were enrolled in this trial.BFV and pulse indexes(PI) in P2 segments of PCA on both sides were mon-itored during visual stimulation.Results:In all subjects,Mean BFV increased and PI went down in response to visual stimulation.The percentages of changtes(△V and △P) of both mean BFV and PI were larger in young group(<55 years old)than in old one(≥55 years old),There was significant positive correlation be-tween △V and △P.Multivariated regression analysis did not show HT and DM,but age related to △V(△P).We did not find significant difference of △V(△P) between left and right sides,Conclusions:Blood flow ve-locity in PCA P2 segment increased due to decreased cerebrovascular resistance during visual stimulation and the response weakened with aging of the patient.