The findings, published in the Journal of the International Neuropsychological Society, report that adult survivors of pediatric posterior fossa brain tumors performed significantly lower than controls on standardized clinical tests of working memory performance administered in the study.
The researchers studied the working memory of adult survivors of childhood posterior fossa brain tumors versus a healthy control sample using functional magnetic resonance imaging (fMRI) and neuropsychological measures. Each group consisted of 17 participants.
During fMRI, the participants completed a measure called the n-back task. They were asked to monitor a series of letters and respond "yes" or "no" with their index or middle finger on a button box if an item was presented "n" items before, ranging from one to three letters back. Accurately recalling a letter two or three letters back represented higher working memory capabilities. Participants also completed other standardized clinical measures.
Whole-brain fMRI analyses also found survivors had significantly greater blood-oxygen level dependent (BOLD) activation in the left superior/middle frontal gyri and left parietal lobe of their brain during a verbal working memory task, demonstrating higher activation in these structures. Analyses revealed higher levels of activations in prefrontal regions were associated with lower behavioral performance on higher-load working memory tasks.