Age dependency of changes in cerebral hemoglobin oxygenation during brain activation: a near-infrared spectroscopy study.
We used near-infrared spectroscopy (NIRS) to study noninvasively the influence of aging on changes in the local concentration of oxygenated hemoglobin ([HbO2]), reduced hemoglobin ([HbR]), and total hemoglobin ([HbT] = [HbR] + [HbO2]) during activation of brain function. Young subjects (n = 12; age, 28 +/- 4 years) performing calculation tasks showed an increase in [HbO2] [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 years) showed a significantly lower mean increase (p < 0.05) in [HbO2] and [HbT] levels (1.21 +/- 1.38 and 0.72 +/- 1.41, respectively). Regression analysis supports the hypothesis of an age-dependent decline in the activation-induced local increase in [HbO2] (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 is a promising approach for studying changes in Hb oxygenation during brain activation in physiological aging.
Hock
C
C
Department of Psychiatry, University of Munich, Germany.
Müller-Spahn
F
F
Schuh-Hofer
S
S
Hofmann
M
M
Dirnagl
U
U
Villringer
A
A
D000328:Adult; D000375:Aging / Q000378:metabolism*; D001921:Brain / Q000502:physiology*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007259:Infrared Rays; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D010100:Oxygen / Q000378:metabolism*; D012044:Regression Analysis
D006454:Hemoglobins; D010100:Oxygen