P.101 A-waves on electrodiagnostic studies in axonal and demyelinating cases of Guillain-Barré Syndrome (GBS)
Bibliographic record
Abstract
Background: A-waves are lesser-known late responses of debated clinical significance, seen in routine motor nerve conduction studies (NCS). They are proposed to be a sensitive marker of demyelination and an early finding in acute demyelinating polyradiculoneuropathy (AIDP). We hypothesized that the presence and distribution of A-waves are discriminative markers in differentiating AIDP from axonal variants of Guillain-Barré Syndrome (GBS). Methods: We identified patients diagnosed with demyelinating and axonal forms of GBS at the Montreal Neurological Institute between 2016 and 2021. Clinical and electrophysiological data including raw NCS responses were retrospectively reviewed for 28 AIDP and 9 axonal GBS cases. Results: 20 of 28 AIDP cases had at least one A-wave in non-tibial nerves compared to 2 of 9 axonal cases. Among patients with NCS available within 2 weeks of symptom onset, 13 of 14 AIDP cases had non-tibial A-waves, compared to 0 of 6 axonal cases. Eight of 14 AIDP cases had one or more nerves with multiple A-waves within 2 weeks, compared to 0 of 6 axonal cases. Conclusions: In patients with GBS, the presence of A-waves in non-tibial nerves and of nerves with multiple A-waves are early indicators of the demyelinating variant. Early identification of GBS subtype is valuable for prognostication.
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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 | 0.003 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.005 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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; 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".