title: Cognitive impairment in late-onset depression. Limited to a decrement in information processing resources?
abstract: BACKGROUND
  While cognitive dysfunction in late-onset depression (LOD) is common, the nature and determinants of this impairment are heterogeneous. It has been suggested that neuropsychological decrements in LOD patients might result from a deficit in processing resources. In order to address this issue, we analyzed processing resources in LOD to see if their decrease explains higher-level cognition (episodic memory and naming capacity) deficits.
  
  
  METHODS
  Measures of processing speed, working memory, inhibition, episodic memory and naming capacity were administered to 14 LOD inpatients and 14 controls.
  
  
  RESULTS
  The LOD patients performed significantly worse than the controls in all domains except for inhibition. Hierarchical regression analyses showed that naming capacity impairment was totally mediated by processing speed and working memory, whereas episodic memory dysfunction was only partially mediated by working memory.
  
  
  CONCLUSIONS
  The reduction in certain processing resources (working memory, processing speed) in late-onset depressed patients appears to mediate impairments in episodic memory and naming capacity. However, episodic memory impairment cannot only be explained by processing resource decrement in LOD patients, suggesting that a primary episodic memory dysfunction is present in this condition.
authors.affiliation: Division of Geriatric Psychiatry, University Hospitals of Geneva, Geneva, Switzerland. Christophe.Delaloye@hcuge.ch
authors.forename: C
authors.initials: C
authors.lastname: Delaloye
authors.forename: S
authors.initials: S
authors.lastname: Baudois
authors.forename: F
authors.initials: F
authors.lastname: de Bilbao
authors.forename: C
authors.initials: C
authors.lastname: Dubois Remund
authors.forename: F
authors.initials: F
authors.lastname: Hofer
authors.forename: M
authors.initials: M
authors.lastname: Lamon
authors.forename: C
authors.initials: C
authors.lastname: Ragno Paquier
authors.forename: K
authors.initials: K
authors.lastname: Weber
authors.forename: F R
authors.initials: FR
authors.lastname: Herrmann
authors.forename: U
authors.initials: U
authors.lastname: Giardini
authors.forename: P
authors.initials: P
authors.lastname: Giannakopoulos
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000503:physiopathology*; D003072:Cognition Disorders / Q000150:complications*; D003863:Depression / Q000150:complications* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests