Neurodevelopmental impact on children treated for medulloblastoma: A review and proposed conceptual model

Abstract

The population of survivors following diagnosis and treatment for medulloblastoma is thankfully on the rise. An increased focus on the quality of that survivorship has expanded the concept of cure to include efforts aimed at improving long-term cognitive outcome. It is well established in the literature that decline in overall intellect and academic performance is experienced by a majority of those undergoing treatment for pediatric medulloblastoma. This decline is believed to be secondary to decline in core cognitive abilities, which in turn are related to underlying damage to neuroanatomical substrates. A review of research on neurodevelopmental impacts following diagnosis and treatment for pediatric medulloblastoma is presented. Particular consideration is given to studies recently published that also reflect critical collaboration among those within the fields of neuropsychology and neuro-imaging. Results from the review are combined within a conceptual model upon which to guide future research and clinical efforts. Keywords medulloblastoma; cognitive deficits; brain tumor; model; processing speed; attention; working memory Callouts 1. Based on the knowledge derived from studies of long term outcomes, it is important to consider medulloblastoma, as well as other pediatric cancers, as a condition resulting in life long morbidities related to the treatment for, but separate from, the primary presenting disease. 2.Intellectual and academic outcomes are considered distal markers and secondary to changes in underlying core cognitive skills.3. While much of the research to date has focused on risk for deficits in cognitive function, attention should also be paid to resilience. 4.Consideration of the current literature on children diagnosed and treated for medulloblastoma reveals there is at least the start of a conceptual model illustrating the likely relationships between treatment, underlying

Reading skill in adult survivors of childhood brain tumor: A theory-based neurocognitive model.

“…The significant moderated mediation, indicating a conditional indirect effect of group, supports and builds upon the neurodevelopmental model of outcomes in childhood brain tumors (Palmer, 2008). The current study's model of the relationships between white matter, reading and processing speed is in line with our hypotheses and consistent with previous work studying the relationship among these constructs.…”

Neuropsychological Outcome of Children Treated for Standard Risk Medulloblastoma in the PNET4 European Randomized Controlled Trial of Hyperfractionated Versus Standard Radiation Therapy and Maintenance Chemotherapy

“…The deficits observed in PSI for the full sample support this contention and suggest that these core cognitive skills might represent developmental precursors to overall delays in general cognitive ability. However, the considerable variability of FSIQ (range 40 to 140, 25% of survivors with IQ ≥ 100) implies that some patients do not follow the expected pathway of neurocognitive impairment in accordance with Palmer's conclusion 37 .…”

“…Collectively, the mean scores of all the survivors' IQ measures allocated either to STRT or HFRT arms fell 1 SD below the mean and approximately 10% of the participants evidenced performances 2 SD below the mean regardless of treatment. MB survivorship carries lingering effects on the patient's intellectual functioning with significant implication for other domains of QoS, namely academic achievement 36,37 .…”

“…An evidence-based conceptual model in which IQ deficits of MB survivors arise secondary to underlying impairments in core cognitive skills such as attention, processing speed and working memory 36,37 has been proposed. .…”

Access to Neuropsychologic Services After Pediatric Brain Tumor

“…However many pediatric brain tumor patients suffer from long-term physical and cognitive impairments [2][3][4][5] including deficits of attention, memory, tempo and executive function [6][7][8][9][10] . Two primary risk factors for cognitive impairments in patients with pediatric brain tumors are age at diagnosis (below 5 years) and treatment with cranial radiation therapy (CRT) [11][12][13][14] .…”