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Classification of intellectual disability using the W echsler I ntelligence S cale for C hildren: Full S cale IQ or G eneral A bilities I ndex?
Author(s) -
Koriakin Taylor A,
Mccurdy Mark D,
Papazoglou Aimilia,
Pritchard Alison E,
Zabel T Andrew,
Mahone E Mark,
Jacobson Lisa A
Publication year - 2013
Publication title -
developmental medicine and child neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.658
H-Index - 143
eISSN - 1469-8749
pISSN - 0012-1622
DOI - 10.1111/dmcn.12201
Subject(s) - intellectual disability , wechsler adult intelligence scale , psychology , intelligence quotient , neuropsychology , intellectual impairment , wechsler intelligence scale for children , borderline intellectual functioning , developmental psychology , working memory , clinical psychology , cognition , psychiatry
Aim We examined the implications of using the F ull S cale IQ ( FSIQ ) versus the G eneral A bilities I ndex ( GAI ) for determination of intellectual disability using the W echsler I ntelligence S cales for C hildren, fourth edition ( WISC ‐ IV ). Method Children referred for neuropsychological assessment (543 males, 290 females; mean age 10y 5mo, SD 2y 9mo, range 6–16y) were administered the WISC ‐ IV and the A daptive B ehavior A ssessment S ystem, s econd e dition ( ABAS ‐ II ). Results GAI and FSIQ were highly correlated; however, fewer children were identified as having intellectual disability using GAI ( n =159) than when using FSIQ ( n =196). Although the 44 children classified as having intellectual disability based upon FSIQ (but not GAI ) had significantly higher adaptive functioning scores than those meeting intellectual disability criteria based upon both FSIQ and GAI , mean adaptive scores still fell within the impaired range. FSIQ and GAI were comparable in predicting impairments in adaptive functioning. Interpretation Using GAI rather than FSIQ in intellectual disability diagnostic decision‐making resulted in fewer individuals being diagnosed with intellectual disability; however, the mean GAI of the disqualified individuals was at the upper end of criteria for intellectual impairment (standard score 75), and these individuals remained adaptively impaired. As GAI and FSIQ were similarly predictive of overall adaptive functioning, the use of GAI for intellectual disability diagnostic decision‐making may be of limited value.