They found a strong correlation
between the white matter changes and the number of head hits with a peak rotational acceleration exceeding 4500 rad / sec2 and the number of head hits with a peak rotational acceleration exceeding 6,000 rad / sec2, and an especially strong correlation where the number of the former exceeded 30 - 40 for the season, and the number of the latter exceeded 10 - 15 for the season.
Using neuropsychological testing to assess cognitive performance, the researchers found a relationship
between the amount of
white matter injury and
changes in reaction time and the ability to switch
between mental tasks.