The role of the cerebellum in executive functioning : a study of pediatric cancers and brain tumors

Research is increasingly clear that the cerebellum serves as a major processing center in the brain for many complex functional pathways. This has led to an increasing need to understand the impact of cerebellar damage on neurocognitive functioning, including through the study of patients with posterior fossa tumors. Treatments for these tumors such as chemotherapy and cranial radiation are known to produce long-term deficits in a variety of neurocognitive domains, including executive functioning. Although it is known that the cerebellum is important for cognition and that cancer and brain tumor treatments can affect cognitive functioning, no research was found that examined the effects of cerebellar brain tumors in children above and beyond the neurocognitive effects of these treatments. The purpose of this study was to examine the effects of pediatric cerebellar brain tumors on executive functioning skills compared to children with other cancer or tumor diagnoses. Information regarding medical diagnoses, treatments, and performance on measures of executive functioning was abstracted from neuropsychological evaluation reports contained in the medical records of 32 children and adolescents (ages 8 to 18) diagnosed with cerebellar brain tumors. These participants were matched with 32 patients with other cancers or tumors outside of the central nervous system on age at diagnosis and time between diagnosis and receiving a neuropsychological evaluation. Hierarchical linear regression analyses examined the relationship between group membership (cerebellar or non-cerebellar) and executive functioning skills, specifically in the domains of cognitive flexibility, goal setting, attentional control, and information processing. Diagnosis emerged as a significant predictor of performance on tasks of goal setting and information processing after controlling for treatment exposure, with the cerebellar group demonstrating lower performance in both domains. This difference was especially pronounced on measures of information processing. Exploratory analyses also examined a four-factor developmental model of executive functioning in the full sample and found that attentional control predicted performance on other executive functioning tasks. Taken together, these results provide evidence that tumors of the cerebellum in childhood are related to worse performance on some measures of executive functioning and provide support for the theory that the cerebellum plays an important role in neurocognition.