A few belated points about the surprising and slightly troubling #NEJM study (https://www.nejm.org/doi/full/10.1056/NEJMoa2400645) on cognitive motor dissociation in #DisordersOfConsciousness, which I think have been underemphasized in the conversation so far:
The topline finding was that 25% of patients without observable responses to commands had fMRI or EEG evidence of awareness (physiologically meaningful activity modulation to specific commands). This is quite a bit higher than in earlier, smaller studies, many only using either fMRI or EEG.
A very surprising finding to me was in Figure S5. This shows even with the lowest possible bedside CRS-R score of 0, clinically doing nothing at the bedside, someone could have fMRI or EEG evidence of awareness. Some prior literature considers threshold scores in the range of 8 to 10, but the figure suggests that no bedside examination procedure can exclude preserved conscious awareness. This is super-humbling.
Also, 25% is really conservative, and almost certainly an underestimate. The fMRI and EEG tasks and statistical thresholds are demanding; maybe because they're from #cogsci research, they're designed to limit the likelihood of false positives. This comes at the cost of many false negatives, as seen in light blue (merely the known false negatives, there are still more undetected false negatives)--these patients follow commands at the bedside but their fMRI and EEG tests are negative. Also, given behavioral variability over time, serial assessments would have revealed more positives. While in science it's a priority to avoid false positives, arguably in the clinical setting false negative findings about consciousness are a bigger problem.
And: while this study used formal CRS-R scoring procedures from research, we know that informal clinical diagnoses of coma or the vegetative state are even less sensitive to signs of consciousness than the CRS-R. So overall in clinical settings we can presume there are many more patients falsely assessed as unconscious.
I don't do clinical work anymore with patients with disorders of consciousness, but I would take this study as a humbling reminder of how much we still don't know about consciousness and the brain. It reinforces the clinical teaching I received to treat every clinically comatose and vegetative person as if they might be covertly aware. Our bedside examination procedures and these new high-tech tests are highly specific for consciousness but also very insensitive and nonconcordant.
Philosophically and conceptually, there's important work to be done to design more sensitive and less stringent indicators of awareness, and to think more about the balance to strike between false positive and false negative findings in tests for these patients.
![@Dana _ Foundation Introducing the Neurotech Justice Accelerator at Mass General Brigham. Together we aim to advance g equitable access to beneficial neurotechnologies f and mitigate their societal, f < legal, and clinical risks. . ] . 0N LI\ T @ Mass General Brigham I](https://cdn.masto.host/sciencemastodoncom/media_attachments/files/113/312/443/733/914/842/original/d49f07386b979d27.jpg "@Dana _ Foundation Introducing the Neurotech Justice Accelerator at Mass General Brigham. Together we aim to advance g equitable access to beneficial neurotechnologies f and mitigate their societal, f < legal, and clinical risks. . ] . 0N LI\ T @ Mass General Brigham I")
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