That mystery brain disease plaguing people in New Brunswick? A new study finds it's not real

National Post

07-05-2025

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'Complex neurological disorders benefit from a second, independent and/or subspecialist evaluation and require multidisciplinary support throughout the diagnostic journey,' said the study that collected data between November 2023 and this past March.
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'Clinical and neuropathological evaluations demonstrated that all 25 cases were attributable to well characterized neurological disorders,' it said. 'The final primary diagnoses, and in some cases secondary diagnoses, included Alzheimer disease, Parkinson disease, progressive supranuclear palsy, other neurodegenerative conditions, functional neurological disorder, traumatic brain injury or persisting post concussion symptoms, and others.'
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The independent assessment of 25 patients 'provides no support for an undiagnosed mystery disease in New Brunswick,' said the study.
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'The gold standard, neuropathological assessments with second, blinded independent evaluations, revealed well-defined diagnoses for 11 deceased patients.'
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When all 25 cases were included in the mix, '100 per cent of patients in this sample did not have a new disease and with 95 per cent confidence, the probability of no new disease is between 87 per cent and 100 per cent,' said the study.
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'The lower bound of 87 per cent reflects a conservative estimate based on the data and statistical methods accounting for uncertainty in the sample, including the possibility of diagnostic error or unmeasured variability. However, practical knowledge and clinical reasoning suggest that the actual probability of no new disease is much closer to the upper bound of 100 per cent.'
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The new study said 'it is crucial to highlight the factors that fuel persistent public concern of a mystery disease despite the provincial investigation rejecting this possibility. Public trust in health institutions has decreased since the COVID-19 pandemic, while trust in individual healthcare professionals remains high, which can make vulnerable people susceptible to claims that the institutional oversight processes are flawed, especially if originating from trusted physicians.'
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The new research comes with a caution.
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Misinformation regarding the New Brunswick 'cluster has proliferated in both traditional and social media, from not only the predictable and easily identifiable groups coopting the crisis to suit their agenda, such as antivaccine advocates, but also those who are unknowingly amplifying an incorrect diagnosis from their physician,' said the study.
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'In this way, misdiagnosis and misinformation become inextricably entwined and amplify patient harm exponentially: to the best of our knowledge, only 14 patients sought independent reevaluation by another neurologist when offered, and 52 refused a second opinion, choosing instead to remain with the one neurologist who originally made and continues to promote the diagnosis of a mystery disease. Not only do our data indicate that affected patients likely have other diagnosable neurological conditions that could benefit from multidisciplinary treatment and other resources, but the low uptake also impedes the rigorous scientific evaluations necessary to counter the claims raised in the first place.'
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