Experts cautious about implications of mass shooter’s brain injury

Brain injury experts are cautioning against drawing conclusions from newly released and limited information about evidence of a brain injury in an Army reservist who killed 18 people last year in Maine’s deadliest mass shooting.

Boston University researchers in the United States who analysed a sample of Robert Card’s brain tissue said last week they found evidence of traumatic brain injury. The analysis, requested by the Maine medical examiner, found degeneration in the nerve fibres allowing communication between different areas of the brain, inflammation and small blood vessel injury, according to Dr Ann Mckee of the university’s Chronic Traumatic Encephalopathy Centre.

Card had been an instructor at an Army hand grenade training range, where it is believed he was exposed to repeated low-level blasts. It is unknown if that caused Card’s brain injury and what role the injury may have played in his declining mental health before he opened fire at a bowling alley and bar in Lewiston on October 25.

Mckee made no connection between the injury and Card’s violent actions. “While I cannot say with certainty that these pathological findings underlie Mr Card’s behavioural changes in the last 10 months of life, based on our previous work, brain injury likely played a role in his symptoms,” Mckee said.

Dr Alexandra Filippakis, a neurologist who has treated members of the military and others for traumatic brain injuries, said last Friday she would not conclude brain injury played a role in Card’s behaviour based on Mckee’s description of her findings.

“TBI is a very broad diagnosis, and it looks different in different people. Not everybody has the same symptoms. Not everybody has the same severity of symptoms,” Filippakis said. “There’s no way that you could, with certainty, link that to a particular action.”

Filippakis, who works at Wentworth-douglass Hospital said the connectivity damage Mckee described is common and can have many causes, including ageing, high blood pressure and smoking.

But James Stone, a University of Virginia radiologist who has studied repeated low-level blast exposure in the military, said changes to Card’s brain “seemed pretty profound”. Such injuries can affect impulse control and emotional regulation, he said, and though he doesn’t know if those parts of Card’s brain were affected, “it’s certainly hard to imagine that the level of brain changes that we’re seeing in some way did not contribute to his behaviour”.

Chris Dulla, a professor and interim chair of neuroscience at Tufts School of Medicine, said he was surprised that researchers found no evidence of chronic traumatic encephalopathy, which has plagued many professional football players. “It doesn’t seem to be as cut and dry. What that speaks to is how varied traumatic brain injuries are, and how difficult they can be to diagnose, even in the postmortem brain sample, when you can study every detail.”

The findings highlight the connection between brain injuries and underlying psychological conditions, Dulla said. “If you’re already struggling with some kind of psychiatric condition or at risk for some kind of psychiatric problem, brain injuries might be something that can kind of push you over the edge and have that change really come front and centre when it might have been sort of a minor underlying thing before.”

Experts say traumatic brain injury can lead to headaches, mood changes, memory loss and sleep issues.

An Army spokesperson called the lab findings “concerning” and said they “underscore the Army’s need to do all it can to protect Soldiers against blast-induced injury”. In addition to updating the guidance on risk mitigation, the Army plans to launch a public safety campaign and will begin requiring documentation of training environments and tracking of exposed personnel. —AP