A new research study has found no evidence to support the existence of an unknown neurological illness in a cohort of patients from New Brunswick, while a separate scientific review of cases is under way in the province.
The findings, released Wednesday by the peer-reviewed journal JAMA Neurology, are based on clinical and pathological (postmortem tissue) analysis of 25 individuals who were previously labelled as having Neurological Syndrome of Unknown Cause (NSUC).
The study, conducted by researchers from the Horizon Health Network in New Brunswick and the University Health Network in Ontario, is the latest development in a years-long quest for answers about a variety of neurological symptoms exhibited among individuals in the Maritime province.
The study was led by Anthony Lang, a neurologist and senior scientist at UHN’s Krembil Brain Institute.
The researchers said evidence “strongly supported the presence of several neurodegenerative and non-neurodegenerative conditions.” They added that “unfounded concerns that a potentially fatal mystery disease, possibly induced by an environmental toxin” is behind the patients’ neurological symptoms have been amplified in traditional and social media.
“There was no evidence supporting a diagnosis of NSUC in this cohort,” the study said.
Dr. Lang said in a statement that medical conditions identified included Parkinson’s disease, dementia, traumatic brain injury, and functional neurological disorder, which causes symptoms such as tremors or memory issues without clear structural brain damage.
The concerns about symptoms experienced by patients in New Brunswick have been the subject of previous examinations and have been at the centre of a conflict between local neurologist Alier Marrero and provincial health officials in recent years.
Dr. Marrero could not be reached on Wednesday for comment on the JAMA Neurology study.
The Office of the Chief Medical Officer of Health is currently investigating cases of undiagnosed neurological illness in New Brunswick after the provincial Liberal government promised a review when it won the election last fall.
The conclusions in JAMA Neurology, which are not part of the Chief Medical Officer’s evaluation, are expected to generate pushback from patients who raised concerns about previous findings.
New Brunswick launches second probe into mystery brain symptoms
In the study published Wednesday, researchers conducted clinical evaluations on 14 patients and performed 11 autopsy evaluations. A news release said 105 patients originally identified either did not respond or declined an offer for further investigation.
A much larger cohort of patients have raised concerns about neurological symptoms. Dr. Marrero, one of four doctors who initially alerted health officials about concerns in 2020, has said he has documented hundreds of affected patients in subsequent years.
In 2021, New Brunswick health officials raised concerns about a mysterious brain disease that had afflicted 48 residents of the province.
A team of New Brunswick and federal health officials were convened, but provincial officials declined $5-million in emergency research money from the Canadian Institutes of Health Research. The province said the pause was necessary to dive deeper into existing cases.
In 2022, a provincial review concluded that there was “no evidence of a shared common illness or of a syndrome of unknown cause” and recommended any future cases be reviewed by a second specialist.
The review sparked criticism among patients who took issue with the review’s methodology and the conclusions it reached. Public health advocates and Dr. Marrero also raised concerns. Premier Susan Holt then promised a scientific investigation.
New Brunswick Health Department spokesperson Tara Chislett said Tuesday that there has been significant interest and concern and that a website was launched mid-March to provide updates on the investigation, including an estimated timeline for next steps.
“It is anticipated the results of the analysis will soon be shared with the Public Health Agency of Canada, which has been supporting the Office of the Chief Medical Officer of Health in this work,” she said in a statement.
Stacie Quigley Cormier, who has advocated for at least 48 patients and family members, said her stepdaughter Gabrielle Cormier has struggled with neurological symptoms since she was 18. She is now 23 and was unable to continue studies at Mount Allison University because of her health.
Ms. Quigley Cormier said she thought the findings released Wednesday were “highly problematic.”
“Why in a province so small as New Brunswick, why are so many people experiencing these neurological symptoms, neurological conditions,” she said.
She said her stepdaughter was previously assessed by Dr. Lang who said Ms. Cormier had functional neurological disorder and he recommended treatments such as physiotherapy.
She went on to see Dr. Marrero, who then identified issues including rare antibodies and high levels of glyphosate in her system, Ms. Quigley Cormier said.
Patients and families want an independent commission outside of the work being done by New Brunswick Chief Medical Officer of Health Yves Léger. So far, neither the province nor the federal government have committed to such an arm‘s-length probe.
On the sidelines of a provincial and territorial health ministers’ meeting in Halifax earlier this year, then-federal health minister Mark Holland said in an interview that the Public Health Agency was working directly with New Brunswick to review the evidence.
He said he did not want to be prejudicial of that process when he was asked about the calls for an independent commission.