Childhood brain tumors and related treatments disrupt the developing brain and have a cascading impact on core cognitive skills and intellectual (intelligence quotient [IQ]) and academic achievement outcomes. Theoretical models for this cascade have been developed based on the literature, but no studies thus far have empirically evaluated the models. The current study aimed to empirically test the two extant models and generate a new data-driven model of the relationships among neurodevelopmental risk factors, core cognitive skills (i.e., processing speed, attention span, working memory), and IQ and achievement outcomes. Fifty-seven adult survivors of childhood brain tumors and fifty-seven demographically matched neurotypical individuals were included in the current study. The average age at brain tumor diagnosis was 8 years, and the average time since diagnosis was 17 years. Three a priori path models tested the hypothesized relationships among variables. Results of the path analyses revealed that the hybrid model best fit the data for both survivors and controls based on all statistical criteria. For survivors, processing speed was the core cognitive skill most widely associated with neurodevelopmental risk factors and outcomes. However, working memory and attention span also had unique contributions to IQ and academic achievement. Processing speed appears to be the central cognitive skill that disrupts the other core cognitive skills of attention span and working memory, and all three make a unique contribution to IQ and academic achievement. This is best demonstrated by a novel neurodevelopmental model that combines components of two earlier untested theoretical models.

The results of the current study suggest that young age at diagnosis and radiation is associated with CB atrophy, which interacts with lesion size to impact both written and oral PS.

Due to medical advances, a large portion of children survive brain tumor diagnosis and treatment. Therefore, it is important to identify the neuroanatomical and neurocognitive outcomes associated with survivorship. This review summarizes the specific regional structural neuroimaging findings, the broad structural findings, as well as the corresponding neurocognitive domains affected in brain tumor populations. Across studies, damage is commonly reported near the cerebellum, brain stem, and subcortical regions, as well as the frontal lobes. These results are consistent with the expected neuroanatomical damage following posterior fossa brain tumors, which was the most common tumor location of the studies in this review. Damage to these regions impacts a broad range of neurocognitive outcomes, as well as a number of specific neurocognitive domains. Damage to more ventral and subcortical brain regions correlated with lower motor speed, processing speed, attention, and memory. Relevant limitations and future directions are discussed with a focus on disentangling the complex and multifaceted factors associated with the consequences of brain tumor survivorship.

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Introduction In posterior fossa tumor survivors, lower white matter integrity (WMI) in the right cerebellar-left frontal pathway has been well documented and appears to be related to proximity to the cerebellum, radiation treatment, as well as time since treatment in both cranial radiation and surgery-only treatment groups. The current study investigated theories of transneural degeneration following cerebellar tumor resection that may underlie or relate to reductions in WMI and regional brain volumes using correlations. We hypothesized a positive relationship between the volume of the right cerebellum and known white matter output pathways, as well as with the volume of structures that receive cerebellar projections along the pathway. Methods Adult survivors of childhood brain tumors were recruited ( n = 29; age, M = 22 years, SD = 5; 45% female). Age- and gender-matched controls were also included ( n = 29). Participants completed 3 T diffusion-weighted and T1 MPRAGE MRI scans. Brain structure volume relative to intracranial vault served as regional volumetric measures. Fractional anisotropy (FA) and radial diffusivity (RD) served as WMI measures. In the survivor group, partial correlations between WMI and regional volume included controlling for disease severity. Results In posterior fossa tumor survivors, the volumes of the cerebellum, thalamus, and frontal lobe were correlated with WMI of the thalamic-frontal segment of the cerebellar-frontal pathway ( r = 0.41–0.49, p < .05). Cerebellar atrophy was correlated with reduced WMI in the cerebellar-rubral segment (FA, r = −0.32 p > .05; RD, r = 0.53, p < .01). In the no-radiation survivor group, the regional volume of each structure along the pathway was associated with WMI in the cerebellar-rubral segment. In the radiation survivor group, significant correlations were found between the regional brain volume of each structure and the thalamic-frontal segment of the pathway. Discussion The results of this multimodal neuroimaging study provide correlational evidence that the mechanism of injury subsequent to brain tumor treatment may be different depending on type of treatment(s). Without radiation, the primary mechanism of injury is cerebellar tumor growth, resection, and hydrocephalus. Therefore, the most proximal connection to that injury (cerebellar-rubral pathway) was correlated with reductions in volume along the pathway. In contrast, the survivor group treated with radiation may have had possible radiation-induced demyelination of the thalamic-frontal portion of the pathway, based on a strong correlation with volume loss in the cerebellum, red nucleus, thalamus, and frontal lobe.