Dr. Clif Cleaveland

Repetitive minor blows to the head lead to an array of destructive, lifelong changes within the brain. A report earlier this month in the journal Brain links such injury, called chronic traumatic encephalopathy (CTE), to behavioral changes in the victims.

Scientists studied the donated brains of 85 people, age 17 to 98, with histories of multiple, mild head injuries. Sixty-four had been athletes and 21 military veterans. Fifty-eight of the brains came from men who had played American football at least to the level of high school. Thirty-three had played in the National Football League.

CTE is characterized by unique changes seen in microscopic and chemical analysis of brain tissue. Its severity ranges from small deposits of a complex, abnormal protein to generalized involvement of the entire brain. Brains were ranked from stage 1 to stage 4 based upon the extent of pathology.

Researchers evaluated clinical records and interviewed close family members to compile behavioral profiles for the autopsied persons.

Five of six victims of stage 1 CTE had complained of recurring symptoms ranging from headache to problems in concentration and recall. Two had been diagnosed with post-traumatic stress disorder.

Eleven of 14 victims of state 2 CTE had symptoms that including explosive, emotional outbursts, depression, impairment of short-term memory, mood swings and headaches.

Analysis of clinical records for stage 3 victims, one of whom was asymptomatic, revealed more prominent impairment of memory and decision-making, wide swings in mood and aggressiveness.

All subjects with stage 4 CTE exhibited symptoms, eventually developing severe impairment of memory and dementia.

CTE seemed to increase the risk for other disorders such as Alzheimer's disease and amyotrophic lateral sclerosis, also known as Lou Gehrig's disease. Seven CTE victims killed themselves, while six others had expressed suicidal thoughts and six died of drug or alcohol abuse.

The recent murder-suicide perpetrated by a player for the Kansas City Chiefs raises the question of CTE in the shooter. How many aggressive acts by other football players are due to CTE?

The landmark study in Brain emphasizes that CTE is a progressive disorder whose effects continue for years after retirement. CTE occurs in players of all collision sports -- football, ice hockey, lacrosse, boxing -- as well as military personnel exposed to repeated blast waves.

Concussions are the forerunners of CTE. Most concussions are either unrecognized or unreported because participants in collision sports pride themselves on toughness.

As American football players become bigger and faster, the incidence of concussions can be expected to rise unless significant changes can be made in equipment, especially helmets.

Because of rising numbers of fatalities and severe injuries to the nervous system, American football faced a ban in the early years of the 20th century. Alarmed by this prospect, President Theodore Roosevelt in 1905 contacted Harvard President Charles Lowell to lead a reform of football's rules. Despite squabbling over the details, a group of college presidents eventually formed the Intercollegiate Athletic Association to change the game to lessen risks of catastrophic injury. Serious injuries declined after tighter rules were accepted in 1910.

Primitive helmets, which were little more than leather pads, appeared in the early 1900s but use was optional. By 1939, helmets were mandatory in college games. The National Football League required helmets for all players in 1943. Plastic helmets appeared in the Army-Navy game of 1944.

Subsequent helmet design focused upon the prevention of skull fractures. Uniform safety standards were mandated in 1973. Skull fractures among players disappeared. Concussions continue.

Rules of collision sports, especially football and ice hockey, must be updated specifically to lessen brain injuries.

CTE can be compared to a house with a severe termite infestation. Destruction continues silently for years until irreversible, progressive changes lead to the collapse of the structure. The risk of CTE among athletes must be minimized. Techniques for earlier diagnosis and treatment are crucial. This smoldering epidemic must be addressed.

Contact Clif Cleaveland at cleaveland1000@comcast.net.