title: The age at onset of Alzheimer's disease and an intracranial area measurement. A relationship.
abstract: OBJECTIVE
  To examine the possibility that premorbid brain size may influence the age at onset of symptoms of Alzheimer's disease (AD).
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  Outpatients attending a memory disorders clinic in a tertiary referral center.
  
  
  METHODS
  Twenty-eight female patients with the diagnosis of probable AD, selected for the availability of informant derived estimates of age at onset of symptoms and computed tomographic scans of the head satisfying angulation criteria.
  
  
  METHODS
  An average intracranial area of two adjacent computed tomographic scan sections appropriately angled was used as a correlate of premorbid brain size. Strict intracranial volume measurement was not performed.
  
  
  RESULTS
  Age at onset of symptoms of AD correlated positively (r = .48, P = .009) with our measure of premorbid brain size. There was no confounding by education, height, or ethnicity.
  
  
  CONCLUSIONS
  Premorbid brain size may be an important determinant of the age at onset of symptoms of AD. Epidemiologic studies of AD may need to assess the relationship between brain size and putative risk factors, eg, low educational attainment, since there is evidence that brain size is not distributed uniformly across populations.
authors: Gertrude H. Sergievsky Center, Columbia University, New York, NY.
authors: P W
authors: PW
authors: Schofield
authors: R E
authors: RE
authors: Mosesson
authors: Y
authors: Y
authors: Stern
authors: R
authors: R
authors: Mayeux
mesh_terms: D017668:Age of Onset; D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed