Editors' Note: In this week’s WriteClick, ethics expert Bernat furthers the discussion about what it means to be conscious and outlines the difference between the Yu et al. diagnosis of “unresponsive wakefulness syndrome” vs “minimally conscious state” and the roles that EEG fMRI and neurologic examination play in these assessments. Burke et al. comment on Benarroch's article and highlight that further HCN channel investigation may shed some light on the mechanisms behind benign familial neonatal epilepsy. Richard Tenser extends the finding by Tan et al. that acyclovir-resistant herpes simplex virus may have contributed to the pathophysiology of encephalitis in the authors' patients. Megan Alcauskas, MD, and Robert C. Griggs, MD
Yu et al.1 reported additional cases of patients diagnosed in a vegetative state (unresponsive wakefulness syndrome) by clinical criteria. However, they showed fMRI or processed EEG responses indicating awareness, and therefore these patients should be diagnosed correctly as in a minimally conscious state. These cases and similar previous cases show that the neurologic examination alone may, in some cases, be insensitive to detect the presence of awareness. The medical and ethical importance of this finding has been emphasized in numerous publications over the past 6 years.2,–,4
The impact of functional neuroimaging in showing the limitations of the neurologic examination to detect awareness is reminiscent of the earlier impact of DNA genetic studies in showing the limitation of the clinical phenotypic classification of neurogenetic syndromes.
The investigators should collect all the cases in which the neurologic examination has been found inadequate to assess awareness and contrast those with the majority of cases in which the clinical examination was accurate. Perhaps there are common features of the clinically misdiagnosed cases that could inform our understanding of awareness with and without responsiveness.
- © 2013 American Academy of Neurology
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