Grant Hercules, Bhambhani Yagesh, Singhal Anthony, Haennel Robert, Warren Sharon
Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada.
Department of Occupational Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada.
J Am Soc Hypertens. 2015 Oct;9(10):811-820. doi: 10.1016/j.jash.2015.07.010. Epub 2015 Aug 1.
Prefrontal (PFC) cerebral vasoreactivity may be altered in hypertension but has not been studied during postural change and carbon dioxide (CO2) rebreathing. In this study, a dual procedure of 5% CO2 rebreathing with positional change (standing to supine and reverse) was performed on normotensive (N = 24) and essential hypertensive males (N = 16) (18-55 years) to assess reliability of PFC responses using functional near infrared spectroscopy. The groups (matched on age levels, N = 13) were also compared on their hemodynamic reactivity (change of oxyhemoglobin or total hemoglobin as a function of change in end tidal CO2). Test-retest reliability within one session and 7 days later was moderate to high (intraclass correlation coefficient = .63-.901) in both normotensive and hypertensive groups for all hemodynamic measures; whereas reliability of reactivity measures for oxyhemoglobin and total hemoglobin was moderate (intraclass correlation coefficient = .68-.762). Functional near infrared spectroscopy-measured PFC hemodynamic responses are highly reproducible in normotensive and adult essential hypertensive males.
