Chronic traumatic encephalopathy pathology in multiple system atrophy

Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disorder associated with repetitive traumatic brain injury. Multiple system atrophy (MSA) is a Parkinsonian disorder that can result in repetitive falls with associated head trauma. We hypothesized that patients with neurodegenerative disorders like MSA could develop CTE pathology. Therefore, we assessed CTE pathology in 139 MSA cases in our brain bank. Sections from convexity cerebral cortices were screened by immunohistochemistry with antiphospho- tau antibody. For cases with suggestive CTE pathology, further sections of basal forebrain and hippocampus were immunostained. Consensus criteria were used to make the diagnosis of CTE and aging-related tau astrogliopathy (ARTAG) was differentiated from CTE pathology. Pertinent clinical information was derived from the available records and online searches. Of the 139 MSA cases, 8 (6%) had CTE pathology and 10 (8%) had ARTAG pathology. All 8 cases with CTE were male and 4 of them had a documented history of contact sports. The median age at death in MSA with CTE was younger than in MSA without CTE or MSA with ARTAG (60, 67, and 74 years, respectively; p=0.002). Even without a known history of contact sports or head trauma, a small subset of cases with MSA had CTE pathology.