Clinical and Neuropathological Evaluations of the New Brunswick Neurological Syndrome of Unknown Cause
Bibliographic record
Abstract
Importance: In 2019, an alleged "mystery" neurological illness emerged in New Brunswick, Canada. Despite extensive media attention, no case description has been published to date. Objective: To report on 25 patients with a diagnosis of New Brunswick neurological syndrome of unknown cause (NSUC) who subsequently received a second, independent clinical reassessment or neuropathological examination between 2020 and 2025. Design, Setting, and Participants: This cross-sectional study of cases derived from a cohort of patients (n = 222) who had received an NSUC diagnosis. Four movement disorder neurologists and 2 behavioral neurologists carried out clinical evaluations at 2 hospitals in New Brunswick and Ontario, Canada. Neuropathological diagnoses were obtained in Ontario by a neuropathologist and a second reviewer, both blinded to the case histories. Eligible patients were offered a second opinion; 4 families of deceased patients provided consent for reporting autopsies and waivers of consent were obtained for 7. Exposure: NSUC as described in the case definition circulated by Public Health New Brunswick in 2021. Main Outcomes and Measures: Findings from the independent clinical evaluations and diagnoses obtained through neuropathological examination. Results: Among 105 eligible patients, 14 patients (aged 20-55 years; 8 female, 6 male) received clinical evaluations, and 11 patients (aged 56-82 years; 5 female, 6 male) had neuropathological diagnoses. Well-known conditions were identified in all 25 cases, including common neurodegenerative diseases, functional neurological disorder, traumatic brain injury, and metastatic cancer. Based on the 11 autopsy cases, a new disease was extremely unlikely, with a probability less than .001. When applying the 95% confidence interval for the true probability of no new disease, the data revealed a high probability between 87% and 100%. Conclusions and Relevance: There was no evidence supporting a diagnosis of NSUC in this cohort. The data inclusive of independent examinations and neuropathology strongly supported the presence of several neurodegenerative and non-neurodegenerative conditions. Unfounded concerns that a potentially fatal mystery disease, possibly induced by an environmental toxin, is causing the patients' neurological symptoms has been amplified in traditional and social media. Second, independent clinical evaluations are needed for any patient given a diagnosis of NSUC.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".