Characterizing and comparing adaptive and academic functioning in children with low average and below average intellectual abilities.

The recent American Academy of Clinical Neuropsychology (AACN) consensus statement on uniform labeling of performance test scores places children who were previously characterized as having "borderline intellectual functioning" within the low average (LA; full scale intellectual quotient (FSIQ) between 80-89) or below average (BA; FSIQ between 70-79) categories. Given limited research examining functional differences across FSIQ groups using AACN's uniform labeling, this study examined adaptive and academic functioning by FSIQ group in youth referred for (neuro)psychological evaluation. Primary comparisons of interest were between LA and BA groups. Participants were 2,516 children between 6 to 13 years with standardized measures of intellectual, adaptive, and academic functioning. Participants were included if their FSIQ ranged from average to exceptionally low. Group differences in adaptive functioning and academic achievement were examined. The LA group did not differ from the BA group in overall adaptive functioning and several domains of adaptive functioning (i.e. social, practical), but demonstrated slightly stronger adaptive skills in the conceptual domain. While the LA group evidenced slightly better word reading and math computation scores than the BA group, these statistically significant differences were not clinically -meaningful. In this clinically referred sample, children with LA and BA intellectual abilities demonstrated similar adaptive skills, but slightly different academic achievement. Both groups demonstrated lower adaptive and academic functioning than children with average range FSIQs. These results suggest that adaptive functioning should be assessed during (neuro)psychological evaluations even when children do not have extremely low FSIQs.