C. Hock et al., AGE DEPENDENCY OF CHANGES IN CEREBRAL HEMOGLOBIN OXYGENATION DURING BRAIN ACTIVATION - A NEAR-INFRARED SPECTROSCOPY STUDY, Journal of cerebral blood flow and metabolism, 15(6), 1995, pp. 1103-1108
We used near-infrared spectroscopy (NIRS) to study noninvasively the i
nfluence of aging on changes in the local concentration of oxygenated
hemoglobin ([HbO(2)]), reduced hemoglobin ([HbR]), and total hemoglobi
n ([HbT] = [HbR] + [HbO(2)]) during activation of brain function. Youn
g subjects (n = 12; age, 28 +/- 4 years) performing calculation tasks
showed an increase in [HbO(2)] [mean (arbitrary units) +/- SD, 2.36 +/
- 1.07] and [HbT] (2.24 +/- 1.13) in the frontal cortex, while [HbR] (
-0.11 +/- 0.48) decreased. Elderly subjects (n = 17; age, 52 +/- 10 ye
ars) showed a significantly lower mean increase (p < 0.05) in [HbO(2)]
and [HbT] levels (1.21 +/- 1.38 and 0.72 +/- 1.41, respectively). Reg
ression analysis supports the hypothesis of an age-dependent decline i
n the activation-induced local increase in [HbO(2)] (y = -0.241x + 20.
062; r = -0.431, p < 0.05) as well as [HbT] (y = -0.346x + 22.496; r =
-0.568, p < 0.05). We conclude that NIRS isa promising approach for s
tudying changes in Hb oxygenation during brain activation in physiolog
ical aging.