Intellectual aspects of cognitive performance in children after treatment for medulloblastoma and astrocytoma

The present study investigated the relationship between posterior fossa tumors (astrocytoma and medulloblastoma) and their respective treatments and cognitive performance in Brazilian children by measuring Intelligence Quotient (IQ). Twenty children were enrolled in the study, of whom 13 were diagnosed with astrocytoma (average age at evaluation, 10.2 years; eight girls and five boys) and seven were diagnosed with medulloblastoma (average age at evaluation, 9.2 years; five girls and two boys). The first subgroup underwent exclusively tumor resection surgery, and the second subgroup underwent surgery, chemotherapy (Vincristine, Cisplatine, and Carmustine), and radiotherapy (total dose, 54 Gy). The inclusion criteria for the clinical group were normal social and emotional behavior before the diagnosis and motor and visual performance not excessively deteriorated after surgery. All participants were submitted to the Wechsler Intelligence Scale for Children third version, and their scores were related to standard norms established for Brazilian children and compared with regard to the diagnosis subgroups and treatment modalities. Statistically significant differences were identified between the two diagnosis subgroups in Performance IQ and Processing Speed scores. The medulloblastoma subgroup presented poorer performance in all domains compared with the astrocytoma subgroup. Time interval between diagnosis and neuropsychological evaluation also had a significant effect on Processing Speed and Freedom from Distractibility in the medulloblastoma subgroup. These results provide empirical evidence of a possible significant effect of radiotherapy exposure on processing speed and global intellectual capacity.