Measuring intellectual impairment in adults. A comparison between WAIS-IV and Montreal Cognitive Assessment (MoCA)

The aim of the study was to compare the cognitive performances of adults with intellectual disability in two tests different in purposes, format, length, and ease of use: WAIS-IV battery for measuring full and factorial IQs, and Montreal Cognitive Assessment (MoCA) used for the evaluation of cognitive deterioration. The two tests were administered to a sample composed of 40 adults, 27 males and 13 females, diagnosed with Mild or Moderate Intellectual Disability (age range 16-64 years, mean age 35.70).No gender differences were detected. Results show that both the total IQ and the WAIS-IV factors are significantly correlated with MoCA score, except the Processing Speed. Verbal Comprehension is the best predictor of the impairment measured by MoCA. This result is confirmed by Multidimensional Scaling. Among the single WAIS-IV subscores only Puzzle and Cancellation show small correlations with MoCA score.The memory functions assessed by MoCA result different from those of WAIS Working memory, factor more close to the MoCA visuo-spatial subdomain. Some implications for the assessment of the cognitive impairment in adults with Intellectual disability are underlined