The brain of Steve Montador, a former N.H.L. player who died in February at age 35, was found to have widespread chronic traumatic encephalopathy, or C.T.E., the disease associated with repeated hits to the head.
His family plans to sue the N.H.L. for wrongful death, according to lawyers representing Montador’s estate.
Montador becomes the fifth known former N.H.L. player to have had C.T.E., which can only be diagnosed posthumously. Among its symptoms are memory loss, depression and impulse control. Some show signs of progressive dementia.
Several dozen former N.F.L. players have received diagnoses of C.T.E., which was long associated with boxing.