Beyond Survival - Cognition after Pediatric Brain Tumor

Background: Pediatric Brain Tumor (PBT) survivors suffer from cognitive sequelae, especially within the areas of cognitive tempo, attention, executive function and memory. The cognitive difficulties are often accentuated over the years, but knowledge about the long term trajectory is still scarce. Aim: The aim of this thesis was to examine cognitive sequelae after Pediatric Brain Tumor (PBT); risk factors, common difficulties, development and neuroimaging correlates. Methods: In study I, data from medical logs were used to examine characteristics of the patients who got access to neuropsychological services, compared to those who did not. In study II, data from 70 neuropsychological assessments were used to describe common cognitive impairments and to find risk factors. In study III, patients were invited to a follow-up study 10-13 years after diagnosis. Neuropsychological and neuroimaging data were collected and the two were compared. In study IV, longitudinal cognitive data from 173 patients were analyzed in order to describe development over time and to find risk factors for a negative development. Results: Study I: There were few differences between referred and non-referred patients. Study II: Patients had generally suppressed IQ and difficulties with executive function, memory, cognitive processing speed and attention. Risk factors were Whole-Brain Radiation Therapy (WBRT), large tumors, young age at diagnosis and male sex. Study III: Radiated as well as non-radiated patients had white matter abnormalities. Correlation between neuroimaging and cognition was low when group based statistics were used, but increased when a personalized method was used. Study IV: Most cognitive abilities showed a decline in age related scores over time unconsidered treatment given. Risk factors for impaired cognitive function at diagnosis were: male sex, WBRT, supratentorial lateral tumor, young age at diagnosis, larger tumor size and treatment with chemotherapy. Conclusions: A systematic neuropsychological follow-up is important. Risk factors for cognitive impairment and IQ decline are WBRT, large tumors, young age at diagnosis, male sex, supratentorial lateral tumor, and treatment with chemotherapy. A decline in IQ after PBT is common, unconsidered treatment given. Personalized methods of research would contribute significantly to our understanding of cognitive sequelae after PBT and its relation to neuroimaging