Novel method to classify hemodynamic response obtained using multi-channel fNIRS measurements into two groups: Exploring the combinations of channels

• Main Authors: Hiroko eIchikawa, Jun eKitazono, Kenji eNagata, Akira eManda, Keiichi eShimamura, Ryoichi eSakuta, Masato eOkada, Masami K Yamaguchi, So eKanazawa, Ryusuke eKakigi
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2014-07-01
• Series: Frontiers in Human Neuroscience
• Subjects: Autism spectrum disorders (ASD); Near-infrared spectroscopy (NIRS); Attention-deficit / hyperactivity disorder (ADHD); hemodynamic data; support vector machine (SVM); sparse modeling
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00480/full

Near-infrared spectroscopy (NIRS) in psychiatric studies has widely demonstrated that cerebral hemodynamics differs among psychiatric patients. Recently we found that children with attention attention-deficit / hyperactivity disorder (ADHD) and children with autism spectrum disorders (ASD) showed different hemodynamic responses to their own mother’s face. Based on this finding, we may be able to classify their hemodynamic data into two those groups and predict which diagnostic group an unknown participant belongs to. In the present study, we proposed a novel statistical method for classifying the hemodynamic data of these two groups. By applying a support vector machine (SVM), we searched the combination of measurement channels at which the hemodynamic response differed between the two groups; ADHD and ASD. The SVM found the optimal subset of channels in each data set and successfully classified the ADHD data from the ASD data. For the 24-dimentional hemodynamic data, two optimal subsets classified the hemodynamic data with 84% classification accuracy while the subset contains all 24 channels classified with 62% classification accuracy. These results indicate the potential application of our novel method for classifying the hemodynamic data into two groups and revealing the combinations of channels that efficiently differentiate the two groups.