Intellectual and Academic Performance in Adults with Childhood Hemispherectomy

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Research on cognitive outcomes of adults with childhood hemispherectomies (HE) is limited. In this study, I examined intellectual and academic functioning in adults who have undergone a HE using the Wechsler Adult Intelligence Scale (WAIS-III; Wechsler, 1997) and the Wechsler Individual Achievement Test (WIAT-II; Wechsler, 2005). The WAIS-III consists of four cognitive indices (perceptual organization, processing speed, working memory, and verbal comprehension). The WIAT-II consists of four academic composite scores (reading, math, oral language, and written language). The scores of individuals with HE (N = 8) were compared to the age-based standard scores on WAIS-III and WIAT-II using a series of one-sample t tests. Means of right hemispherectomy (RHE; n = 6) and left hemispherectomy (LHE; n = 2) were compared for qualitative observations on hemispheric lateralization. Significant differences from test norms were found on perceptual organization (Cohen’s d = -1.54), processing speed (Cohen’s d = -3.78), working memory (Cohen’s d = -1.18), and mathematics (Cohen’s d = -1.28) compared to established norms of WAIS-III and WIAT-II. Individuals with HE performed significantly worse than expected on these four indices. A trend was found on Reading composite (Cohen’s d = -1.01). These differences suggested that individuals with hemispherectomy have deficits in flexibility of mental images, scanning information efficiently, manipulating sequential verbal responses, and mathematical reasoning. Further, when LHE were removed, RHE subgroup revealed larger effect size for PSI (Cohen’s d = -6.58) compared to the total sample, which implied RHE subgroup was more deficient in processing speed.

Degree Name

Doctor of Psychology in Clinical Psychology (PsyD)

First Advisor

Brown, Warren S.

Document Type





Hemispherectomy; Intellectual outcomes; Academic outcomes; Academic achievement; Academic success; Lateralization; Cerebral dominance


Cognitive Psychology | Neurosciences


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