MAPT and early-onset autosomal dominant Alzheimer disease: White matter rarefaction predicted increased odds for dementia to a similar extent as p-tau among older brain donors with CTE.54In vivo MRI studies document the contribution of white matter injury to neuropsychiatric, in addition to cognitive symptoms, in people exposed to RHI.46,48,51 In Alzheimer’s disease, pathologies of the white matter have been shown to contribute to neuropsychiatric symptoms including behavioural dysregulation.107–109 Overall, the aetiology of symptoms associated with exposure to RHI is likely to be multifactorial.