ESPE Abstracts

Background: Reports suggest that youths with short stature (SS) exhibit academic under-achievement relative to cognitive aptitude and GH treatment diminishes the difference. However, interpretation of this achievement-aptitude discrepancy is confounded by the use of achievement and intelligence tests normed in different samples.

Objective and hypotheses: To assess whether reports of academic underachievement in SS samples are partially attributable to choice of tests and whether benefits of GH could be demonstrated using a co-normed psychometric battery. We hypothesized that the achievement-aptitude discrepancy and putative benefit of GH would be diminished through assessment using a co-normed battery (Woodcock–Johnson Battery-Revised; WJ-R).

Method: Sixty-nine youths (x¯=10.2years, 64.2% male) with SS prior to initiating GH and 54 untreated average height (AH) youths (x¯=9.87years, 48.3% male) participated. WJ-R testing occurred at baseline and at 1 year. Participants completed the WJ-R Cognitive Ability tests, yielding a Broad Cognitive Ability (BCA) score and domain-specific academic skills tests.

Results: Baseline – Compared with population norms, SS youth scored lower on BCA and 2 academic domains. SS youth also ‘overachieved’ relative to their BCA in three domains. 1-Year Follow-Up – Mean BCA in the SS group was no longer below population norms; two academic skill scores remained below norms. Paired t-tests showed ‘underachievement’ in one domain. Comparison with AH – AH youth scored significantly higher than norms on BCA and the majority of academic domains. Paired t-tests showed evidence of both over- and under-achievement at baseline and follow-up.

Conclusion: Significant effects for the SS sample challenge prior research (i.e., overachievement vs underachievement), and it remains open whether these differences are clinically meaningful as all scores were ±1 S.D. of norms. The fact that the AH comparison group did not follow the pattern observed in the GH-treated SS group suggests that observed changes are not due to maturation or practice effects.