Doctor: Chan suffers from neurocognitive disorder

The first expert to take the stand in Thomas Chan’s defence testified Wednesday that repeated concussions as a teen caused the former rugby star to suffer mentally from a neurocognitive disorder.

Chan, 21, is accused of second-degree murder in the stabbing death of his father, gastroenterologist Dr. Andrew Chan, and attempted murder in the stabbing of Dr. Chan’s partner, Lynn Witteveen, at Dr. Chan’s Haggis Drive home on Dec. 28, 2015. He has pleaded not guilty.

Since his arrest, Chan has maintained that his concussions and ingestion of magic mushrooms led to the brutal stabbing of his father and Witteveen.

Psychologist Dr. Bruno Losier was sought by Chan’s defence team in 2018 to conduct a neuropsychological assessment to determine if Chan still had residual cognitive and behavioural deficits detected in a neuropsychological evaluation done by Dr. P. Gavkovski in 2013.

Losier testified in Superior Court of Justice on Wednesday that overall the issues identified in 2013 were still present.

“What he saw in 2013 still exists in 2018 despite five years going by,” he explained.

Losier’s assessment took place over four days in the summer of 2018.

His diagnosis relied on psychological and neuropsychological testing and collateral information from Chan’s mother, and reports from Lakefield College School,

Gavkovski’s 2013 neuropsychological report and notes from Ontario Shores Centre for Mental Health Sciences psychiatrist Dr. Graham Trull.

“The current examination of Mr. Chan, five years after the initial neuropsychological assessment, supported similar profile of cognitive deficits, namely auditory attention, working memory, information processing deficits and, to a lesser degree abstractions,” Losier explained in his 18-page report.

“It was evident Mr. Chan’s cognitive abilities were challenged by the complexity of the task.”

From the information gathered, Losier determined Chan suffered multiple concussion ranging in severity of, moderate and sever, according to the American Academy of Neurology classification.

He stated that the repeated blows to the head led to mild traumatic brain injury. He noted that Chan’s age at the time of concussions, between 14 and 17, could have been factor.

“This is considered a significant period in terms of brain maturation,” Losier explained in his report, adding it might have taken longer for Chan to recover because his brain was still maturing.

He added that the multiple concussions also contributed to Chan’s cognitive and behavioural deficits.

“Mr. Chan’s condition would have been deteriorating,” Losier testified.

During cross-examination, Losier agreed with assistant Crown attorney Andrew Midwood that a mild traumatic brain injury doesn’t cause spontaneous hallucinations.

“Never in my experience,” Losier said. During the prosecution, Justice Cary Boswell heard evidence that Chan was hallucinating on the magic mushrooms when he stabbed his father and Witteveen.

Midwood carried on to suggest the diagnosis was “primary” finding because Losier himself suggested in his report that Chan consult with a physician with expertise in traumatic brain injuries.

“This may present an opportunity to investigate further the origin of the reported intracranial hypertension,” Losier said in the report, adding that a thorough examination of Mr. Chan’s brain might prove beneficial.

“It would be worthwhile to add a magnetic resonance imaging-diffuse tensor imaging sequence to any static brain imaging as means to review major white matter tract integrity and determine if any clinical correlation can be established.”

Midwood also questioned the diagnoses of the concussions, noting that the Ontario Psychological Associations guidelines for concussions state there’s still controversy, misunderstanding and debate over diagnosing concussions.

“It is a very complex and complicated landscape,” Losier said.

The trial continues Monday.