Neurobiological and psychological indicators of post-traumatic stress symptoms in children and adolescents treated for a posterior fossa brain tumour

Background Despite the established associations between paediatric brain tumour treatment, distress, and post-traumatic stress symptoms (PTSS), neither the treatment nor tumour pathology reliably account for symptom severity at the individual level. This study examined whether treatment-related changes in fronto-limbic white matter (WM), brain tissue thought to support emotion, is associated with additional variance in PTSS beyond the effect of treatment and endorsing having experienced a distressing event. Methods Thirty-six children and adolescents treated for a posterior fossa brain tumour and 17 typically developing children (TDC) completed a questionnaire assessing whether they had experienced a distressing event and measured PTSS and underwent diffusion tensor imaging. Diffusivity metrics of fronto-limbic tracts and tracts that do not support emotional functioning (control tracts) were obtained. A continuous measure of the physical, cognitive, and emotional strain of therapy (i.e., treatment burden), was estimated using the Neurological Predictor Scale. Partial Least Squares path modelling was used in an exploratory, theory-guided framework to examine statistical associations among treatment burden, distress, WM, and PTSS. Results Patients demonstrated greater radial diffusivity than TDC across fronto-limbic and control tracts. Fronto-limbic WM was associated with PTSS severity within the subclinical range and mediated the effects of treatment burden on PTSS. The control tract WM was not associated with PTSS. PTSS severity was also associated with endorsing a distressing event. Conclusions The findings support two indicators associated with dimensional variation in PTSS severity: an expected psychological indicator, through endorsing having experienced a distressing event, and a neurobiological indicator, via treatment-related changes to fronto-limbic WM. These results reflect correlational patterns in subclinical symptoms and should be interpreted as exploratory.