Statistical Analyses
Demographic and clinical factors were compared by radiation type (XRT vs
PRT) using Chi Square, Fisher exact test, or independent t -tests,
as appropriate. Group differences in social functioning and cognitive
functioning were assessed using analysis of covariance (ANCOVA),
covarying for the effects of time since radiation. Because peer
relations and social skills did not differ by radiation type, remaining
analyses examined the sample as a whole. To evaluate social outcomes
among pediatric brain tumor survivors, one-sample t-tests compared peer
relations and social skills with the normative mean of 50. Frequency
data on the number of participants rated as having impaired social
outcomes were examined, with impairment defined as scores falling 1.5 SD
above the mean for peer relations (i.e. < standard
score of 65) and 1.5 SD below the mean for social skills (i.e.> standard score of 35). Further,
χ2 analyses determined whether the percentage of
participants with impairment exceeded expectation assuming normal
distribution of scores (6.68%). Bivariate correlations were run to
examine relationships between social outcomes and demographic, clinical,
and cognitive variables. Predictors were included in multiple linear
regression analyses based on significant correlations with peer
relations and social skills. Demographic and clinical variables that
were significantly correlated (p < 0.05) with the
specific outcome were included in the models. Cognitive skills that
significantly correlated with either peer relations or social skills
were also included (processing speed, executive functioning, verbal
memory, and sustained attention).