title: Evaluation of changes in oxyhemoglobin during Shiritori task in elderly subjects including those with Alzheimer‧s disease.
abstract: BACKGROUND
  In recent years, as the prevalence of Alzheimer‧s disease (AD) has increased rapidly, demand has increased for early detection and treatment. Therefore, discovery and treatment intervention at the mild cognitive impairment stage are important. Dysfunction of the working memory is known to be conspicuously present in AD patients or mild cognitive impairment subjects from an early stage. Near-infrared spectroscopy (NIRS) is a method to measure hemoglobin concentration changes during an activation task. In the present study, we evaluated the cognitive function of elderly subjects, including those with AD, by means of NIRS.
  
  
  METHODS
  The subjects were divided into three groups-the AD group, the intermediate group, and the healthy group (HG)-based on assement of dementia using the Hasegawa‧s Dementia Scale-Revised, Mini-Mental State Examination, and Clinical Dementia Rating. The intermediate group was divided into two groups-the high score group (HSMG) and the low score group (LSMG)-based on Hasegawa‧s Dementia Scale-Revised and Mini-Mental State Examination scores. In this study, during Shiritori tasks using single-event-related NIRS, we analyzed oxyhemoglobin changes in an area, the peak amplitude, and latency, and compared them among four groups: AD group, HSMG, LSMG, and HG.
  
  
  RESULTS
  In the AD group, the area at left channel (Ch)9, 11, and 19, the area at right Ch22, and the peak ampulitude at left Ch11 and 19 and right Ch5,12, and 22 were significantly smaller than those in HSMG and HG. Furthermore, the latency of the AD group was significantly longer than that of HSMG and HG at all region of interests. However, no significant difference was observed between the AD group and LSMG.
  
  
  CONCLUSIONS
  These findings suggest that analysis of changes in oxyhemoglobin during Shiritori tasks may be a useful neuropsychological index for the early diagnosis of AD. Detailed studies will be conducted in LSMG to facilitate the early introduction of NIRS as a screening tool for cognitive impairment.
authors.affiliation: Department of Neuropsychiatry, Kurume University School of Medicine, Kurume, Japan.|Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Kurume, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Department of Neuropsychiatry, Kurume University School of Medicine, Kurume, Japan.|Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Kurume, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Shoji
authors.affiliation: Department of Neuropsychiatry, Kurume University School of Medicine, Kurume, Japan.|Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Kurume, Japan.
authors.forename: Kiichiro
authors.initials: K
authors.lastname: Morita
authors.affiliation: Department of Neuropsychiatry, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Inoue
authors.affiliation: Department of Neuropsychiatry, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Ishii
authors.affiliation: Department of Neuropsychiatry, Kurume University School of Medicine, Kurume, Japan.|Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Kurume, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Sato
authors.affiliation: Department of Neuropsychiatry, Kurume University School of Medicine, Kurume, Japan.|Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Kurume, Japan.
authors.forename: Yuuji
authors.initials: Y
authors.lastname: Yamashita
authors.affiliation: Department of Neuropsychiatry, Kurume University School of Medicine, Kurume, Japan.|Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Kurume, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Okawa
authors.affiliation: Department of Neuropsychiatry, Kurume University School of Medicine, Kurume, Japan.|Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Kurume, Japan.
authors.forename: Naohisa
authors.initials: N
authors.lastname: Uchimura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood*; D002560:Cerebrovascular Circulation; D003071:Cognition / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D010108:Oxyhemoglobins / Q000378:metabolism*; D011597:Psychomotor Performance / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared
chemical_list: D010108:Oxyhemoglobins
keywords: Alzheimer‧s disease (AD); Shiritori; intermediate group (MG); prefrontal cortex; single-event-related near-infrared spectroscopy; working memory