For example, CTE is typified by tau deposition and atrophy in the depths of the cortical sulci and has been described in former rugby players at post-mortem.11,26-29 Furthermore, computational modelling has demonstrated head impact–induced brain tissue deformation is often greatest in cortical sulci.14,19 Our observation that changes in cortical thickness are mainly seen in sulcal regions is in keeping with early changes of neurodegeneration being seen in areas exposed to high strain rates and subsequent injury as a result of repetitive head impacts. The gene discussed is MAPT; the disease is Atrophy.