Statistical Analyses
Descriptive statistics were used to characterize the sample at baseline
and follow-up. The Behavior Assessment System for Children
(BASC)42-43 Behavioral Symptoms Index and Adaptive
Skills Composite and the Behavior Rating Inventory of Executive
Functioning (BRIEF)44-45 Global Executive Composite,
Behavioral Regulation Index, and Metacognition Index were used as
primary outcome measures. One-way analysis of variance (ANOVA) was
conducted to determine the differential impact of demographic,
diagnostic, and treatment-related characteristics on these primary
outcome measures. Pearson correlation was used to investigate the
relationship between the primary outcome measures by age at baseline,
SES, and the time interval between baseline and follow-up.
One-sample t-tests were used to compare mean T-scores with published
normative means. Rates of impairment were calculated and defined as the
frequency of scores > 1.5 S.D. above the mean of 50
(T-score > 65). Chi-square test of independence was
conducted to evaluate the differences in rates of impairment by
radiation field (CSI or focal). One-way ANOVA was performed to evaluate
the rates of impairment by age at baseline.
Analyses were performed using SPSS version 24 (IBM 2016, Chicago, IL).
Two-tailed analyses were used in all comparisons; statistical
significance was defined as p < 0.05.