title: The pathophysiology of prospective memory failure after diffuse axonal injury--lesion-symptom analysis using diffusion tensor imaging.
abstract: BACKGROUND
  Prospective memory (PM) is one of the most important cognitive domains in everyday life. The neuronal basis of PM has been examined by a large number of neuroimaging and neuropsychological studies, and it has been suggested that several cerebral domains contribute to PM. For these activation studies, a constellation of experimental PM trials was developed and adopted to healthy subjects. In the present study, we used a widely used clinical PM assessment battery to determine the lesions attributable to PM failure, with the hypothesis that lesion-symptom analysis using diffusion tensor imaging (DTI) in subjects with diffuse axonal injury (DAI) can reveal the neuronal basis of PM in everyday life.
  
  
  RESULTS
  Fourteen DAI patients (age: range of 18-36, median 24) participated in this study. PM failure was scored in the range of 0-6 using three sub-tests of the Rivermead Behavioural Memory Test. The PM scores of DAI patients were in the range of 2-6 (median 4.5, inter-quartile range 2.25). The severity of axonal injury following DAI was examined using fractional anisotropy (FA), one of the DTI parameters, at voxel level in each subject. We then obtained clusters correlated with PM failure by conducting voxel-based regression analysis between FA values and PM scores. Three clusters exhibited significant positive correlation with PM score, the left parahippocampal gyrus, left inferior parietal lobe, and left anterior cingulate.
  
  
  CONCLUSIONS
  This is the first lesion-symptom study to reveal the neuronal basis of PM using DTI on subjects with DAI. Our findings suggest that the neuronal basis of PM is in the left parahippocampal gyrus, left inferior parietal lobe, and/or left anterior cingulate. These findings are similar to those of previous activation studies with loading experimental PM tasks.
authors.affiliation: Hiroshima Higher Brain Function Center, Hiroshima Prefectural Rehabilitation Center, 295-3, Taguchi, Saijo, Higashi-Hiroshima, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Kondo
authors.forename: Masaharu
authors.initials: M
authors.lastname: Maruishi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ueno
authors.forename: Kozue
authors.initials: K
authors.lastname: Sawada
authors.forename: Yukari
authors.initials: Y
authors.lastname: Hashimoto
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Ohshita
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Takahashi
authors.forename: Toshiho
authors.initials: T
authors.lastname: Ohtsuki
authors.forename: Masayasu
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D000293:Adolescent; D000328:Adult; D016880:Anisotropy; D001369:Axons / Q000473:pathology / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D020833:Diffuse Axonal Injury / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging / Q000379:methods; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D009483:Neuropsychological Tests / Q000592:standards; D011446:Prospective Studies; D055815:Young Adult