-By Daniel Eagan

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Capitalizing on the increased awareness of the dangers of head injuries, Head Games presents a persuasive case that concussions in sports lead to irreversible brain damage. While the film tends to overstate some points at times, this is a valuable introduction to a controversial topic.

Director Steve James was also behind Hoop Dreams, a film that influenced a generation of documentarians. Rather than forge new ground, Head Games adopts prevailing documentary styles: clips from a wide variety of sources, a preponderance of talking heads, and a handful of personalities who function as narrators.

Chief among these is Christopher Nowinski, a college football player who later performed as a W.W.E. wrestler. Now co-director of the Boston University Center for the Study of Traumatic Encephalopathy, Nowinski is appealing and articulate even while delivering devastating news.

Alan Schwarz, a New York Times reporter who wrote a front-page article on National Football League injuries, appears throughout the film, as do a number of neurosurgeons. Schwartz has a more confrontational persona than the doctors, who seem eminently reasonable and objective when discussing Chronic Traumatic Encephalopathy, or CTE, an umbrella term for brain damage caused by concussions.

"The disease destroys personality," is how Dr. Ann McKee, Professor of Neurology and Pathology Boston University School of Medicine, describes CTE. She shows the results of the condition on brain scans, pointing out carpets of dense, darkened areas that represent dead cells. Brief animated sequences go into further detail about how CTE affects the brain.

The heart of Head Games is testimony from former professional athletes who suffered up to a hundred concussions while playing. Keith Primeau, a 16-year veteran of the National Hockey League, admits, "I was relieved" when a team doctor banned him from the ice after four concussions. Cindy Parlow Cone, a three-time Olympic medal winner for soccer, describes seeing stars every time she headed a ball.

James and his crew can back up much of this testimony with footage of the actual concussions occurring, although Head Games loses some credibility by re-enacting Nowinksi's wrestling injuries.

This is a documentary with an agenda, not an attempt at objective reporting, and even if you agree with the film's positions, it's hard not to feel that you are being manipulated at times. Examples include a long sequence about Owen Thomas, a college player who committed suicide, or footage of the Near North Raiders, a team of grade-school kids, and their coach Darryl Young.

Much of the film concerns the National Football League, which has come under increasing criticism for its concussion policies. Nowinski uncovers evidence that the NFL was systematically underreporting concussions for years, even while admitting that its retired players show abnormal rates of Alzheimer's and suicide.

James extends his film to include ice hockey, soccer and lacrosse, but his most troubling footage is of children like Chayse Primeau, a teenager who loves hockey for its violence, and who still wants to play after incurring two concussions. Parents may be the best audience for Head Games, a film that asks some very tough questions.