[Current status and future perspectives of near-infrared spectroscopy: clinical applications and neurocognitive findings].

Near-infrared spectroscopy (NIRS) is a noninvasive neuroimaging tool that can measure local hemodynamic changes in the brain. Over the past decade, the technical advantage offered by multichannel NIRS has provided various new findings on higher cerebral function of the human brain. These findings have improved our knowledge of cognitive neuroscience, neurology, psychiatric medicine, rehabilitation medicine, and pharmacology. The present review illustrates such new findings and introduces a general trend of studies with NIRS and its clinical applications. In particular, new findings on early brain development and the organization of connectivity associated with language acquisition in the first year of life have been highlighted. Finally, some issues and concerns mostly stemming from the technical limitations of NIRS have been pointed out and discussed in view of current progress, so that future NIRS studies are more fruitful and reliable.