Abstract
BACKGROUND: Survivors of childhood brain tumour face significant neurocognitive late effects, including impairment in processing speed and attention. Deficits to these core cognitive domains contribute to the plateauing of age-appropriate intellectual development as the child matures. While short-term studies demonstrate the utility of methylphenidate in enhancing processing speed and attention during early recovery, its longer-term role in sustaining intellectual development remains underexplored. METHODS: The current study examined the long-term effects of methylphenidate on intellectual development in 23 survivors of childhood brain tumour, matched on multiple clinical and demographic variables against 23 controls. Intellectual assessments were conducted at baseline and after 12 months of treatment. Statistical analyses evaluated the degree of change in intellectual trajectories between groups over time. RESULTS: Bayesian hierarchical modelling showed distinct intellectual trajectories between groups, with consistent declines in the control group. Treatment with methylphenidate was associated with the preservation of age-appropriate intellectual development, with the highest posterior probability of treatment-related benefit to Fluid Reasoning (0.97), and strong-to-moderate evidence of benefits to Verbal Comprehension (0.92), Working Memory (0.91), and Processing Speed (0.84). Frequentist analyses supported these findings, demonstrating significant preservation of Fluid Reasoning over time (t = 2.14, p = 0.04). The use of chemotherapy was associated with a significant decline in Fluid Reasoning across the entire dataset; this effect was only sustained in the control group (β = - 18.6, p = 0.03). CONCLUSION: These findings highlight the long-term rehabilitative potential of methylphenidate and suggest its wider adoption could support care for survivors at risk of intellectual plateau.