in december 1972, robert and helen celebrated the birth of their only child together, son derek. .
at the end of the video, helen spoke in an audio clip. it was her leaving a recent voice message for one of her grandsons. .
"we had (borrelia miyamotoi) as the new disease for the physicians to be aware of", told rusk. .
chronic traumatic encephalopathy (cte), a degenerative brain disease, has been linked by medical researchers to the sort of hits football players endure. .