In a sense, it's just basic microscopy, although Dr. Omalu did a solid job throughout, including finding the occasional colleague who wanted to join with him, and this last part is important.
Like antibiotics, like a lot of other things, advancements in medicine can potentially come decades earlier.
So, what if the whole discovery of CTE (Chronic Traumatic Encephalopathy) had occurred during the more health-conscious '70s and before football became so huge?