A recent investigation by Canadian health officials has found no evidence of a new or mysterious neurological disease affecting hundreds of patients in New Brunswick and other provinces. The results of the probe by the province’s Chief Medical Officer of Health add to a growing body of research suggesting that the patients may have been misdiagnosed and are instead suffering from known neurological illnesses.
More than 500 patients have been identified by neurologist Dr. Alier Marrero as having unexplained neurological symptoms. However, the official investigation found no evidence to support Marrero’s claims that the patients’ symptoms were caused by elevated levels of herbicides and heavy metals.
The provincial study examined the cases of 222 of Marrero’s patients and reviewed the results of extensive testing he had ordered, which he said showed elevated levels of these substances. But the province’s findings showed that the herbicide levels among the cluster patients were normal when compared to the broader population in the Atlantic Canada region.
While a small number of patients did show higher than expected levels of heavy metals, officials said it was difficult to confirm the results due to issues with the way they had been tested, and there was no clear evidence to suggest the elevated levels could have led to adverse neurological health effects.
The report also found that close to 60% of patients in the group had also been seen by a second neurologist, and none of the other neurologists had raised concerns to health authorities regarding the patients’ condition.
In response to the report’s findings, health officials said any patient referred to the province with an unexplained neurological condition would now have to be examined by two separate specialists. Dr. Yves Léger, the province’s chief medical officer of health, stated that there was “mounting evidence that these patients have diagnosable conditions” and that the province was “certainly concerned about that and about patient care.”
The data from the investigation will be shared with the Public Health Agency of Canada, which will conduct a further review. Sarah Nesbitt, a patient in the cluster and an environmental advocate, expressed concerns about the limitations of the study and said some patients did prove to have elevated levels of metals in their systems. However, she remains hopeful that this is a step towards helping patients, especially those with elevated levels, get more answers and additional support for their illnesses.
The provincial report is the second conducted by the province into the purported mystery illness. The results of the previous study, which examined the first 48 patients in the cluster, were published in 2022 and similarly found no common exposures and concluded the patients were likely suffering from a range of different illnesses.
A separate research paper published in the JAMA Neurology journal last year also echoed the conclusions of the 2022 provincial report, finding that the patients had all suffered from known and diagnosable illnesses, including cancer and dementia.
Despite the findings, some patients have rejected accusations that Marrero has misdiagnosed them, and they believe he rightfully raised concerns about their test results of elevated metals. The ongoing battle over the mystery brain disease in New Brunswick continues, with patients and health officials still searching for answers.
