title: Inhibition deficits in individuals with intellectual disability: a meta-regression analysis.
abstract: BACKGROUND
  Individuals with intellectual disabilities (ID) are characterised by inhibition deficits; however, the magnitude of these deficits is still subject to debate. This meta-analytic study therefore has two aims: first to assess the magnitude of inhibition deficits in ID, and second to investigate inhibition type, age, IQ and the presence/absence of comorbid problems as potential moderators of effect sizes.
  
  
  METHODS
  Twenty-eight effect sizes comparing ID and age matched normal controls on inhibition tasks were included in a random effects meta-regression. Moderators were age, IQ, inhibition type and presence/absence of comorbid disorder.
  
  
  RESULTS
  The analysis showed a medium to large inhibition deficit in ID. Inhibition type significantly moderated effect size, whereas age and comorbid disorder did not. IQ significantly moderated effect size indicating increasing effect size with decreasing IQ, but only in studies that included a sample of ID participants with mean IQ > 70. The analysis indicated comparable deficits in behavioural inhibition and interference control, but no significant deficits in cognitive inhibition and motivational inhibition.
  
  
  CONCLUSIONS
  These results indicate that ID is characterised by a medium to large inhibition deficit in individuals with ID. ID seems not to be characterised by deficits in cognitive and motivational inhibition, which might indicate that distinct processes underlie distinct inhibition capacities.
authors.affiliation: University of Amsterdam, Department of Psychology, Amsterdam, The Netherlands; Cognitive Science Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands; 's Heeren Loo Groot-Emaus, Ermelo, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Bexkens
authors.forename: L
authors.initials: L
authors.lastname: Ruzzano
authors.forename: A M L
authors.initials: AM
authors.lastname: Collot D' Escury-Koenigs
authors.forename: M W
authors.initials: MW
authors.lastname: Van der Molen
authors.forename: H M
authors.initials: HM
authors.lastname: Huizenga
mesh_terms: D006801:Humans; D007266:Inhibition, Psychological; D008607:Intellectual Disability / Q000453:epidemiology* / Q000523:psychology*; D009483:Neuropsychological Tests; D012044:Regression Analysis
keywords: comorbidity; executive function; inhibition; intellectual disabilities; interference control; meta-regression