Incremental rate of prefrontal oxygenation determines performance speed during cognitive Stroop test: the effect of ageing

• Published in: The journal of physiological sciences Vol. 68; no. 6; pp. 807 - 824
• Main Authors: Endo, Kana, Liang, Nan, Idesako, Mitsuhiro, Ishii, Kei, Matsukawa, Kanji
• Format: Journal Article
• Language: English
• Published: Japan Springer 01.11.2018; BioMed Central; Springer Japan
• Subjects: Age Factors; Aged; Aging; Aging - physiology; Attention - physiology; Cognition - physiology; Cognitive ability; Comparative analysis; Executive Function - physiology; Female; Geriatrics; Hemoglobin; Humans; Infrared spectroscopy; Language; Male; Middle Aged; Original Paper; Oxygenation; Oxyhemoglobins - metabolism; Prefrontal cortex; Prefrontal Cortex - blood supply; Reaction Time - physiology; Spatial distribution; Spectroscopy, Near-Infrared; Stroop Test; Young Adult; Japan; Congruent word-reading test; Incongruent Stroop test; Cognitive function; Multichannel near-infrared spectroscopy; Prefrontal oxygenation
• ISSN: 1880-6546; 1880-6562
• DOI: 10.1007/s12576-018-0599-3

Cognitive function declines with age. The underlying mechanisms responsible for the deterioration of cognitive performance, however, remain poorly understood. We hypothesized that an incremental rate of prefrontal oxygenation during a cognitive Stroop test decreases in progress of ageing, resulting in a slowdown of cognitive performance. To test this hypothesis, we identified, using multichannel near-infrared spectroscopy, the characteristics of the oxygenated-hemoglobin concentration (Oxy-Hb) responses of the prefrontal cortex to both incongruent Stroop and congruent word-reading test. Spatial distributions of the significant changes in the three components (initial slope, peak amplitude, and area under the curve) of the Oxy-Hb response were compared between young and elderly subjects. The Stroop interference time (as a difference in total periods for executing Stroop and word-reading test, respectively) approximately doubled in elderly as compared to young subjects. The Oxy-Hb in the rostrolateral, but not caudal, prefrontal cortex increased during the Stroop test in both age groups. The initial slope of the Oxy-Hb response, rather than the peak and area under the curve, had a strong correlation with cognitive performance speed. Taken together, it is likely that the incremental rate of prefrontal oxygenation may decrease in progress of ageing, resulting in a decline in cognitive performance.