title: Normal and pathological aging of attention in presymptomatic Huntington's, Huntington's and Alzheimer's Disease, and nondemented elderly subjects.
abstract: BACKGROUND
  Attention models view attention as having at least two components: endogenous attention defined as executive and directed by voluntary acts, and exogenous attention defined as automatic and directed by external stimulation.
  
  
  METHODS
  Three studies (2 of our own) were designed to evaluate the decline of these two components of attention in normal aging and two neurodegenerative diseases. Standardized tests derived from Posner's model of visuospatial attention were administered to normal healthy elderly participants (n = 13), patients suffering from Huntington's disease (HD; n = 17) and Alzheimer's disease (n = 15), and matched control subjects (n = 57). Outcome measures were reaction time (RT) and RT difference score (defined as invalid RT minus valid RT).
  
  
  RESULTS
  In healthy elderly participants, the decline was more pronounced for endogenous attention in situations of perceptual conflict. In Alzheimer's disease, there was a significant decline in both attention components, while in HD, voluntary attention was markedly impaired and automatic attention preserved.
  
  
  CONCLUSIONS
  Normal aging and HD are characterized by decreased endogenous attention in situations of perceptual conflict. Our data support previous findings that older people display impairment of attention in complex perceptual situations. We propose a model which allows for the separation of attention pathologies, thus improving therapeutic strategies for patients and elderly.
authors.affiliation: Service de psychiatrie et de psychologie médicale, Hôpital Saint-Antoine, Université Pierre et Marie Curie, Paris, France. charles.peretti@sat.aphp.fr
authors.forename: Charles-Siegfried
authors.initials: CS
authors.lastname: Peretti
authors.forename: Florian
authors.initials: F
authors.lastname: Ferreri
authors.forename: François
authors.initials: F
authors.lastname: Blanchard
authors.forename: Serge
authors.initials: S
authors.lastname: Bakchine
authors.forename: Charles Roger
authors.initials: CR
authors.lastname: Peretti
authors.forename: Andrei
authors.initials: A
authors.lastname: Dobrescu
authors.forename: Virginie-Anne
authors.initials: VA
authors.lastname: Chouinard
authors.forename: Guy
authors.initials: G
authors.lastname: Chouinard
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology* / Q000523:psychology; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D001288:Attention / Q000502:physiology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D003937:Diagnosis, Differential; D005149:Facial Expression; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology; D009483:Neuropsychological Tests; D011930:Reaction Time; D021641:Recognition, Psychology; D012720:Severity of Illness Index; D013997:Time Factors