giovedì 5 settembre 2013

DETECTED CONSCIOUS ACTIVITY IN VEGETATIVE STATE PATIENTS! - Owen 2013

The last 2013 Adrian M. Owen’s original investigation on patients with disorders of consciousness is the first in demonstrating “that some entirely behaviorally nonresponsive patients can use selective attention to communicate” (Abstract)....



Canadian neuroscientists have detected conscious activity in a patient who has been in the so called “vegetative state” for 12 years using functional magnetic resonance imaging (fMRI).

Lorina Naci and Adrian M. Owen of Western University, in Ontario, writing in the JAMA Neurology, (JAMA Neurol. Published online August 12, 2013. doi:10.1001/jamaneurol.2013.3686; Making Every Word Count for Nonresponsive Patients), they claim that:

Despite the apparent absence of external signs of consciousness, a significant small proportion of patients with disorders of consciousness can respond to commands by willfully modulating their brain activity, even respond to yes or no questions, by performing mental imagery tasks. However, little is known about the mental life of such responsive patients, for example, with regard to whether they can have coherent thoughts or selectively maintain attention to specific events in their environment. The ability to selectively pay attention would provide evidence of a patient’s preserved cognition and a method for brain-based communication, thus far untested with functional magnetic resonance imaging in this patient group” (Abstract).

The objective of this study was to test whether selective auditory attention can be used to detect conscious awareness and communicate with behaviorally nonresponsive patients.

The two researchers design a case study performed in 3 patients with severe brain injury, 2 diagnosed as being in a minimally conscious state and 1 as being in a vegetative state. The patients constituted a convenience sample. 

Functional magnetic resonance imaging data were acquired as the patients were asked to selectively attend to auditory stimuli, thereby conveying their ability to follow commands and communicate.

The results pointed out that all patients demonstrated command following according to instructions. Two patients (1 in a minimally conscious state and 1 in a vegetative state) were also able to guide their attention to repeatedly communicate correct answers to binary (yes or no) questions.

The conclusions of this study are the follow: 

“To our knowledge, we show for the first time with functional magnetic resonance imaging that behaviorally nonresponsive patients can use selective auditory attention to convey their ability to follow commands and communicate. One patient in a minimally conscious state was able to use attention to establish functional communication in the scanner, despite his inability to produce any communication responses in repeated bedside examinations. More important, 1 patient, who had been in a vegetative state for 12 years before the scanning and subsequent to it, was able to use attention to correctly communicate answers to several binary questions. The technique may be useful in establishing basic communication with patients who appear unresponsive to bedside examinations and cannot respond with existing neuroimaging methods”.

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