Weill Cornell Neuroscientist Elucidates Differences Between Minimally Conscious and Persistent Vegetative States

Multimodal Imaging Techniques May Lead to Changes in Clinical Practice for Severely Brain-Injured Persons

Mar 31, 2003

New York, NY

At the American Academy of Neurology meeting in Honolulu today, Dr. Nicholas Schiff of Weill Cornell Medical College will present findings that continue to elucidate the differences between minimally conscious and persistent vegetative states in severely brain-injured persons. Use of multimodal neuroimaging technologies to characterize cerebral function following severe brain injuries may lead to improved diagnostic evaluation of these patients, and eventually influence clinical practice.

In a presentation entitled Pathophysiology of Minimally Conscious State (MCS)and Other Disorders of Consciousness: New Evidence and Insights from Functional Imaging, Dr. Schiff shows how modern technology can be employed to detect signs of consciousness or, at least, activity in the brains of some MCS patients.

Dr. Schiff Assistant Professor of Neurology and Neuroscience, Assistant Attending Neurologist, and Director of the Laboratory of Cognitive Neuromodulation at NewYork-Presbyterian Weill Cornell Medical Center in New York City focuses on the recent definition of diagnostic criteria for MCS and persistent vegetative state (PVS) patients. Recent efforts, he observes, by several groups, including Weill Cornell investigators, have employed a variety of neuroimaging techniques to characterize cerebral function and activity, and hereby improve diagnostic precision.

Dr. Schiff presents functional brain imaging studies of MCS and PVS patients, including recent neuroimaging correlations of preserved residual behavioral fragments and restricted cerebral activity in select PVS patients.

The results of a collaborative study with Dr. Joy Hirsch and the functional MRI Laboratory at Columbia University Medical Center indicate that some MCS patients retain connected cortical networks that underlie language comprehension and expression, despite their inability to execute motor commands or communicate reliably. In comparison, functional activation paradigms in PVS patients have not shown such activation patterns.

These data both support the conceptual separation of PVS and MCS on the basis of distinct physiological underpinnings, but also indicate some limitations for the clinical diagnosis of these conditions.

Finally, the pathophysiologic mechanisms underlying MCS are considered in the context of potential residual cognitive function or awareness.

Dr. Schiff cautions that, for now, tools like functional MRIs are not for routine clinical use. They are only for research, trying to answer the basic questions that will have to be answered before physicians can address the larger issues of trying to bring severely brain-injured persons back to health.