title: 'Executive' functions and normal aging: selective impairment in conditional exclusion compared to abstraction and inhibition.
abstract: BACKGROUND
  Some executive functions may be selectively impaired in normal aging over and above the general cognitive decline.
  
  
  METHODS
  We examined the performance of healthy high functioning young (n = 77) and older (n = 57) individuals on three 'executive' tests: conditional exclusion, abstraction, and inhibition of prepotent responses. We compared their relationships to each other and to other cognitive functions including attention, psychomotor speed and working memory.
  
  
  RESULTS
  Conditional exclusion was significantly more impaired than abstraction or inhibition in the elderly compared to the younger group and unlike them, showed a nonlinear relationship with age. These findings were independent of other cognitive functions. Analysis of PCET performance characteristics showed that older individuals were particularly impaired in attaining the last of the three achievable categories, were slower, and had fewer error monitoring resources compared to the younger group.
  
  
  CONCLUSIONS
  Conditional exclusion shows an age-related pattern of impairment distinct from inhibition and abstraction. We propose that in healthy well-functioning individuals, it taps processes integrating task set establishment and shifting in context of accumulating information. It may thus be useful as a specific marker of complex cognitive functions in studies of normal cognitive aging and in early detection of cognitive dysfunction.
authors.affiliation: Brain Behavior Laboratory, Sha'ar Menashe Mental Health Center, Mobile Post Hefer, Israel. mdsilver@tx.technion.ac.il
authors.forename: Henry
authors.initials: H
authors.lastname: Silver
authors.forename: Craig
authors.initials: C
authors.lastname: Goodman
authors.forename: Ruben C
authors.initials: RC
authors.lastname: Gur
authors.forename: Raquel E
authors.initials: RE
authors.lastname: Gur
authors.forename: Warren B
authors.initials: WB
authors.lastname: Bilker
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D001288:Attention / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000502:physiology; D012727:Sex Characteristics; D055815:Young Adult