Tau deposition in the spinal cord is not specific for CTE-ALS

Previous studies have reported neuropathologic findings from autopsy cases in which patients had clinical diagnoses of both chronic traumatic encephalopathy (CTE) and amyotrophic lateral sclerosis (ALS).^1,2 Not surprisingly, these cases demonstrated coexisting pathologic findings of both CTE and ALS. A recent study by Moszczynski et al.¹ found abnormal pThr¹⁷⁵ tau staining in the spinal cords from 3/5 CTE cases, 3/5 cases with both CTE and ALS, and 0/5 control cases with no known neurologic disease. Although this study did not examine any cases of sporadic ALS without coexisting CTE, the authors concluded that “the absence of tau deposition in the spinal cords of patients with sporadic ALS suggests that the spinal motor neuron tauopathy of CTE-ALS is not an incidental finding or secondary to the primary neuronal injury of ALS.¹” When this assertion was challenged in a reader response,³ the author reply urged the respondents “to assemble their case experience and submit it for peer review as it would be an important contribution to the literature.⁴”