title: Proposal of auxiliary diagnosis index for autism spectrum disorder using near-infrared spectroscopy.
abstract: Lack of a diagnostic index is a problem that needs to be overcome in the diagnosis of autism spectrum disorder (ASD), because this problem prevents an objective assessment based on biomarkers. This paper describes the development of a diagnostic index for ASD using near-infrared spectroscopy (NIRS). We investigated continuous prefrontal hemodynamic changes depending on reciprocal disposition of working memory and nonworking memory tasks using two-channel NIRS. NIRS signals in the prefrontal cortex were compared between high-functioning ASD subjects ([Formula: see text]) and typically developed (TD) subjects ([Formula: see text]). The brain activities of the TD subjects were related to experimental design. These results were not confirmed in brain activities of ASD subjects, although the task performance rate was almost equivalent. The brain activities of TD subjects and ASD subjects were evaluated using a weighted separability (WS) index obtained from the feature phase of oxy-hemoglobin and its differential value. Calculation of the [Formula: see text]-test (TD subject versus ASD subject) confirmed that WS was significant. This result showed that the proposed index was useful for evaluation of the brain activity of ASD subjects.
authors.affiliation: Nihon University , College of Industrial Technology, Department of Mechanical Engineering, 1-2-1 Izumi-cho Narashino-shi, Chiba 275-8575, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Yanagisawa
authors.affiliation: Nihon University , Graduate School of College of Industrial Technology, Department of Mechanical Engineering, 1-2-1 Izumi-cho Narashino-shi, Chiba 275-8575, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Nakamura
authors.affiliation: Nihon University , College of Industrial Technology, Department of Mechanical Engineering, 1-2-1 Izumi-cho Narashino-shi, Chiba 275-8575, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tsunashima
authors.affiliation: Bunkyo University , Institute of Education, School Education Course, 3337 Minami-Ogishima, Koshigaya, Saitama 343-851 Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Narita
keywords: autistic spectrum disorder; auxiliary diagnosis; near-infrared spectroscopy