Assessment of Covert Consciousness in the Intensive Care Unit: Clinical and Ethical Considerations.
Brian L Edlow, Joseph J Fins
PMID 30395042WHAT IT FOUND
In ICU cases of severe TBI, fMRI detected covert consciousness in a patient whose family withdrew care before results were known, while a patient with no fMRI or EEG response later recovered independence.
Use fMRI and EEG alongside bedside assessment, not alone.
Key findings
01A patient with a vegetative bedside diagnosis had fMRI activation during language, music, and motor imagery, indicating covert consciousness.
02A patient with no detectable fMRI or EEG responses while comatose later recovered consciousness, communication, and functional independence.
03The bedside CRS-R is more sensitive than fMRI or EEG, so fMRI and EEG should supplement rather than replace it.
STILL TO COME
How it was doneWhat they foundWhat it means for OTsWhat it means for SLPs
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What it does not show
The paper reports selected cases, not a controlled study, so it cannot establish how often fMRI or EEG changes consciousness detection or patient outcomes. The source cohort was small, with 16 patients, and the paper does not provide enough statistical power for prognostic conclusions. Both fMRI and EEG can be affected by sedation, motion, sleep, intracranial pressure, and severe brain injury disrupting the blood-flow signal used by fMRI, so results can be false positive or false negative. Even the CRS-R may fail to detect consciousness in approximately 20% of patients with vegetative state or MCS-, and fMRI and EEG failed to detect command-following in 43% and 33% of ICU patients who followed commands behaviorally. The family decisions in the reported cases happened before or without complete investigational data, so the ethical lessons do not show that sharing such data improves decision-making.
Declared interests
The authors declared no conflicts of interest. The article metadata lists NIH extramural and non-U.S. government research support.
The easy way to misread this
Do not read a negative fMRI or EEG result as proof that a patient cannot recover consciousness. The tests can miss command-following, and a patient with no detected response later recovered independence.