Why can’t doctors diagnose CTE in a living person?
In: Biology
The most notable physiological evidence CTE can only be seen in a microscope. Specifically, repeated stress injuries to brain tissues, caused by the forces of head impacts, results in the buildup of a protein called Tau. It’s now we’ll understood exactly how or why this occurs. Nor is it universal through all areas of the brain.
Therefore several biopsy samples of tissues from different parts of the brain are needed to diagnose the condition with confidence. Tau can be identified with certain kinds of stains that color the protein in a microscope slide.
Tau may be involved in the response to stress injuries in other tissues. In the brain it weakens and eventually kills neurons. Unlike other tissues, neurons cannot simply be replaced by new cells, however. This results in cognitive decline. Tau may also play an important role in Alzheimer’s Disease.
CTE doesn’t show clearly or in any reliable way on macroscopic CT or MRI scans (but there’s ongoing research to find very subtle features that could be used to identify it.)
Taking many tissue samples from a living brain in a situation that’s not immediately life threatening, isn’t considered worth the risk of causing brain damage or other complications.
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