Clarifying the New Brunswick Neurological Cases

About six years ago, a Canadian neurologist noticed unusual symptoms in several patients in New Brunswick, which is adjacent to Maine.

Dr. Alier Marrero reported that these patients experienced hallucinations, spasms, quick memory loss, and a bizarre sensation like bugs crawling beneath their skin. However, their symptoms and brain scans didn’t align with any clear diagnosis, leaving them somewhat enigmatic.

Since then, other neurologists have been able to assign specific diagnoses, such as Alzheimer’s, Parkinson’s, and various cancers.

A recent study published this week in JAMA Neurology supports these findings, suggesting the likelihood of a mysterious disease is incredibly low—about 1 in a million.

The study involved 25 individuals linked to the New Brunswick cluster. Eleven had passed away, with neuropathologists using autopsies to identify their illnesses. For the remaining 14 living patients, neurologists conducted cognitive tests and similar evaluations, concluding that they all had well-documented conditions like Alzheimer’s, Parkinson’s, cancer, and traumatic brain injuries.

“We really felt we had a good explanation for every case,” noted Dr. Anthony Lang, one of the study’s authors from the University Health Network’s Krembil Brain Institute.

Still, some doctors fear this won’t eliminate speculation about an unknown cause—an idea that many patients and their families still hold onto.

The authors of the study mentioned that 52 individuals in the cluster refused additional opinions, and 42 others didn’t respond to outreach. They attributed this skepticism to declining confidence in health institutions and the prevalence of misinformation, both in traditional media and online.

“These were instances of misdiagnosis leading to misinformation. Unfortunately, the physician involved continues to convince patients and families of a mysterious illness,” Lang stated.

Marrero expressed disagreement with the study in a recent statement.

“I fundamentally disagree with the conclusions and have several questions about the methods and content,” he asserted. “I am confident that our patients, families, and communities share these serious concerns.”

Dr. Valerie Sim, an associate professor of neurology at the University of Alberta, emphasized that there hasn’t been proof linking the patients’ illnesses. She pointed out that the cases are described so broadly that anyone could potentially seem to fit the profile of a mysterious illness.

“Sadly, the only commonality among these patients is the same neurologist,” Sim remarked. “Those who see different neurologists receive clear diagnoses that are not mysterious.”

James Mastrianni, a neurology professor at the University of Chicago, commented that the study reinforces the value of second opinions from specialists.

Assessing the Ongoing Investigation

The theory of a mystery illness started gaining traction in 2021 when Canadian health authorities began looking into cases based on Marrero’s reports. Despite an investigation concluding that most patients had known conditions, some families remained unconvinced. In November, New Brunswick’s premier, Susan Holt, called on the health minister to conduct a scientific review “into the mystery brain disease.”

“New Brunswickers deserve answers,” Holt stated last year. “We need to understand what is making us unwell.”

Some advocates now suspect that environmental factors might be behind the illnesses, claiming tests have shown heavy metals, pesticides, and rare antibodies in patients that warrant further examination.

“It was never just about whether a patient had an alternative diagnosis,” remarked Kat Lanteigne, an advocate from New Brunswick. “The real question is what triggered this neurodegenerative disease.”

Dr. Yves Léger, New Brunswick’s chief medical officer of health, stated recently that the new study “doesn’t change my office’s commitment to finish its own investigation into undiagnosed neurological illnesses.” His office has received 222 reports tied to the cluster.

Marrero noted that he has assessed over 500 patients in this cluster and provided considerable evidence of critical environmental exposures and unique autoimmune markers in many of them.

However, Lang argued that just because a substance is detected in blood or urine does not mean it caused any neurological symptoms.

“You can’t take a scattershot approach, find something, and then claim it’s linked to the problem,” he explained.

Navigating the Diagnosis of Neurological Issues

Neurologists disconnected from the New Brunswick situation cite multiple reasons why the cause of the illnesses continues to be debated by advocates, medical professionals, and government officials.

For one, they point out that accurate diagnoses can take a significant amount of time. Some conditions, like Alzheimer’s, can present in complex ways.

“A cohesive story from the family and a timeline is crucial to understanding if someone is developing dementia. Early signs of neurodegeneration can often be overlooked,” stated Dr. Kimberly O’Neill, a neurologist at NYU Langone Health.

One of the main symptoms leading to identifying the New Brunswick patients was a rapid onset of dementia. Families sometimes miss early signs, which can make it seem as though the dementia appeared suddenly, according to Mastrianni.

As debilitating symptoms emerge, patients and families frequently become desperate for clarity, possibly holding onto initial diagnoses longer than they should, Sim added.

“We see patients gravitating toward certain diagnoses or groups,” she noted. “That seems to be what’s happening here.”

She expressed concern about the tragedy of misdiagnoses, as patients may miss out on proper care or treatments.