Havana Syndrome Among Canadian Diplomats: Brain Imaging Reveals Acquired Neurotoxicity
Bibliographic record
Abstract
Abstract BACKGROUND In late 2016, US diplomats stationed in Havana began presenting with a variety of neurological manifestations that proved difficult to diagnose. Though previous studies suggested a likely association with brain injury, the mechanism of injury, brain regions involved, and etiology remained unknown. METHODS We conducted a multimodal study examining 26 Canadian diplomats and their family members, the majority of whom presented with symptoms similar to their American counterparts while residing in Havana. Assessments included a medical history, self-reported symptom questionnaires, cognitive assessments, blood tests, and brain imaging assessments (magnetic resonance imaging (MRI) and magnetoencephalography (MEG)). Individuals showing signs of brain injury underwent further neurological, visual, and audio-vestibular assessments. Eight participants were tested both before and after living in Havana. RESULTS Our assessment documents multiple functional and structural impairments, including significant spatial memory impairment, abnormal brain-stem evoked potentials, degradation of fibre tracts in the fornix and posterior corpus callosum, blood-brain barrier injury to the right basal forebrain and anterior insula, and abnormal paroxysmal slowing events of cortical activity. Subsequent mass-spectrometry and blood analyses documented reduced serum cholinesterase activity and the presence of organophosphates (Temephos) and pyrethroid metabolites (3-phenoxybenzoic acid or 3-BPA). CONCLUSIONS Our findings confirm brain injury, specify the regions involved, and raise the hypothesis of overexposure to cholinesterase inhibitors as a plausible etiology. If correct, our hypothesis bears public health ramifications (see Discussion) and suggests a course of action for reducing exposure in the future. FUNDING Global Affairs Canada.
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 | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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; both teacher heads agree on what is shown here.
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".