The first case of its kind in New Zealand, a former Super Rugby player has been diagnosed post-death with a degenerative brain disease, chronic traumatic encephalopathy. 

Billy Guyton played for the Blues, Hurricanes, and Crusaders, but died in a suspected suicide aged 33. 

An examination of his brain by the Neurological Foundation's Brain Bank has now identified he had stage 2 CTE.  

Auckland University neuroscientist Helen Murray told Mike Hosking that CTE is caused by the repetitive accumulation of head impacts.  

She says it's not necessarily the number of concussions but the number of impacts, and that might not have generated any symptoms. 

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