Attention-induced frontal brain activation measured by near-infrared spectroscopy

In eight right-handed healthy males aged 9.6-12.9 years, changes in the frontal cerebral concentrations of oxygenated, deoxygenated, and total hemoglobin, as well as in tissue oxygenation index and cytochrome oxidase aa(3) were measured by near-infrared spectroscopy. The males were evaluated using a trail-making test with four test cycles interrupted by relax breaks. During the first cycle of this task, a significant increase in deoxygenated hemoglobin was documented in the left frontal region. In the extended course of the test, a significant increase in oxygenated and total hemoglobin was observed on both sides, indicating an increase in cerebral blood volume. However, only on the left side was an increase in deoxygenated hemoglobin documented. In children, changes in cerebral oxygenation induced by a cognitive task could be measured by near-infrared spectroscopy. In a short and extended attention task, a lateralized increase in oxygen consumption was documented by an increase in deoxygenated hemoglobin. In an extended attention task, an increase in oxygenated and total hemoglobin was recorded additionally in both frontal brain regions, indicating a compensatory increase in cerebral perfusion. Further studies are required to examine the significance of this technique in testing differences in children with neurobehavioral disabilities.