title: Comparison of alterations in cerebral hemoglobin oxygenation in late life depression and Alzheimer's disease as assessed by near-infrared spectroscopy.
abstract: BACKGROUND
  Patients with Alzheimer's disease (AD) often present with apathy symptoms resembling the decreased motivation observed in depressed patients. Therefore, differentiating the initial phase of AD from late life depression may be difficult in some cases. Near-infrared spectroscopy (NIRS) is a functional neuroimaging modality that uses near-infrared light to measure changes in hemoglobin concentration on the cortical surface during activation tasks. The objective of this study was to investigate differences in brain activation associated with late life depression and with AD by means of NIRS.
  
  
  METHODS
  NIRS was performed in 30 patients with depression, 28 patients with AD, and 33 healthy controls, all aged 60 years or older. During two tasks, a verbal fluency task and a visuospatial task, changes in oxygenated hemoglobin concentration in the frontal and parietal cortices were investigated.
  
  
  RESULTS
  In the visuospatial task, cortical activation was lower in the depressed group than in the AD group, and significant differences were observed in the parietal cortex.
  
  
  CONCLUSIONS
  NIRS can detect differences in brain activation between patients with late life depression and those with AD. NIRS is a promising tool for the differential diagnosis of late life depression and AD.
authors.affiliation: Department of Psychiatry, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan. hisashi@shinshu-u.ac.jp.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kito
authors.forename: Akiko
authors.initials: A
authors.lastname: Ryokawa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kinoshita
authors.forename: Daimei
authors.initials: D
authors.lastname: Sasayama
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Sugiyama
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ogihara
authors.forename: Takehiko
authors.initials: T
authors.lastname: Yasaki
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hagiwara
authors.forename: Shin
authors.initials: S
authors.lastname: Inuzuka
authors.forename: Tohru
authors.initials: T
authors.lastname: Takahashi
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Genno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nose
authors.forename: Tokiji
authors.initials: T
authors.lastname: Hanihara
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Washizuka
authors.forename: Naoji
authors.initials: N
authors.lastname: Amano
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D001921:Brain / Q000378:metabolism / Q000503:physiopathology*; D003866:Depressive Disorder / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D003937:Diagnosis, Differential; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019265:Spectroscopy, Near-Infrared
chemical_list: D006454:Hemoglobins