title: Developmental changes in frontal lobe function during a verbal fluency task: a multi-channel near-infrared spectroscopy study.
abstract: OBJECTIVE
  Near-infrared spectroscopy (NIRS) is commonly used to investigate continuous changes of brain activation and has excellent time resolution. Verbal fluency task (VFT) is widely used as a neuropsychological test of frontal lobe function. The aim of this study was to investigate normal developmental change in frontal lobe function during VFT performance using multi-channel NIRS, specifically focusing on oxygenation hemoglobin (oxyHb) changes.
  
  
  METHODS
  The subjects were 9 adults and 37 childrens who were all healthy right-handed volunteers. Children were divided into four age groups (group A, 6-8 years; group B, 9-11 years; group C, 12-14 years; group D, 15-18 years). The [oxyHb] changes were measured with 22 channels of NIRS during VFT. We defined the frontopolar region as the region of interest for analysis, and calculated the Z-score to compare the data between groups.
  
  
  RESULTS
  The task performance changed with age. There were significant differences between group A and other groups. The Z-score of [oxyHb] also significantly increased with age, when comparing adults to groups A and B. The task performances decreased with time in all groups. In contrast, [oxyHb] only continued to increase in the adult group.
  
  
  CONCLUSIONS
  The verbal retrieval functions begin to mature in early adolescence and continue to grow up to adulthood.
authors: Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Japan. Electronic address: orrery_2@yahoo.co.jp.
authors: Tomoko
authors: T
authors: Tando
authors: Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Japan.
authors: Yoshimi
authors: Y
authors: Kaga
authors: Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Japan.
authors: Sayaka
authors: S
authors: Ishii
authors: Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Japan.
authors: Kakuro
authors: K
authors: Aoyagi
authors: Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Japan.
authors: Fumikazu
authors: F
authors: Sano
authors: Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Japan.
authors: Hideaki
authors: H
authors: Kanemura
authors: Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Japan.
authors: Kanji
authors: K
authors: Sugita
authors: Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Japan.
authors: Masao
authors: M
authors: Aihara
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging; D000704:Analysis of Variance; D001931:Brain Mapping; D002648:Child; D002657:Child Development / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000254:growth & development* / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D019265:Spectroscopy, Near-Infrared; D014705:Verbal Behavior / Q000502:physiology*
chemical_list: D006454:Hemoglobins
keywords: Development; Frontal lobe function; Near-infrared spectroscopy; Retrieval; Verbal fluency task