Posts tagged vegetative state
Articles and news from the latest research reports.
Tests conducted on Israel’s Ariel Sharon reveal significant brain activity
A team of American and Israeli brain scientists tested former Israeli Prime Minister Ariel Sharon to assess his brain responses, using functional magnetic resonance imaging (fMRI). Surprisingly, Sharon showed significant brain activity.
The team consisted of Martin Monti, an assistant professor of psychology and neurosurgery at UCLA, professors Alon Friedman, Galia Avidan and Tzvi Ganel of the Zlotowski Center for Neuroscience at Israel’s Ben-Gurion University of the Negev, and Dr. Ilan Shelef, head of medical imaging at Israel’s Soroka University Medical Center.
The 84-year-old Sharon, presumed to be in a vegetative state since suffering a brain hemorrhage in 2006, was scanned last week to assess the extent and quality of his brain processing, using methods recently developed by Monti and his colleagues. The test lasted approximately two hours.
The scientists showed Sharon pictures of his family, had him listen to his son’s voice and used tactile stimulation to assess the extent to which his brain responded to external stimuli.
To their surprise, significant brain activity was observed in each test, in specific brain regions, indicating appropriate processing of these stimulations, Monti said.
The scientists conducted three tests to assess Sharon’s level of consciousness. They asked him to imagine he was hitting a tennis ball and to imagine he was walking through the rooms of his home. They also showed him a photograph of a face superimposed on a photo of a house, asking him to focus first on the face and then on the house. The scientists found encouraging, but subtle, signs of consciousness.
"Information from the external world is being transferred to the appropriate parts of Mr. Sharon’s brain. However, the evidence does not as clearly indicate whether Mr. Sharon is consciously perceiving this information," Monti said. "We found faint brain activity indicating that he was complying with the tasks. He may be minimally conscious, but the results were weak and should be interpreted with caution."
Tzvi Ganel, who initiated the project, stressed that Sharon’s family wished to employ these new techniques not only for the benefit of the former prime minister but also for other families in a similar situation.
Science Needs a Second Opinion: Researchers Find Flaws in Study of Patients in “Vegetative State”
A team of researchers led by Weill Cornell Medical College is calling into question the published statistics, methods and findings of a highly publicized research study that claimed bedside electroencephalography (EEG) identified evidence of awareness in three patients diagnosed to be in a vegetative state.
The new reanalysis study led by Weill Cornell neurologists Drs. Andrew Goldfine, Jonathan Victor, and Nicholas Schiff, published in the Jan. 26 issue of the journal Lancet, reports the statistical results and methodology used by a research team led by University of Western Ontario scientists and published online Nov. 9, 2011, also in the Lancet, was flawed in a number of crucial ways. Due to these errors, the reanalysis concludes it is impossible to determine whether or not these vegetative state study subjects demonstrated any degree of awareness during the testing.
(Image: RightBrainPhotography)
Neuroscience offers a glimpse into the mind - and our future
Hassan Rasouli recently accomplished a remarkable feat: He lifted his thumb in a way that suggests he was making a thumbs-up gesture.
The feat was a remarkable one since doctors at Sunnybrook Health Sciences Centre in Toronto had diagnosed him as being in a persistent vegetative state (PVS), a mysterious condition in which patients appear to be awake but show no clinical signs of conscious awareness.
The condition first came to prominence in 1998 when family members, and then courts and politicians, engaged in a protracted battle over the care of Floridian Terri Schiavo. The matter was finally settled in 2005 when Schiavo, who was in a persistent vegetative state, was removed from life support and died.
Doctors at Sunnybrook similarly wanted to transfer Rasouli to palliative care, but Rasouli’s family refused. The doctors therefore sought a court order, and the Supreme Court of Canada heard arguments in the case on Monday.
The court’s decision might not affect Rasouli since, given his ability to give a thumbs-up gesture, he is no longer considered to be in a persistent vegetative state (PVS). But the case could have a profound impact on the many other patients who have been diagnosed as being in a PVS, as it could answer pressing legal questions about when someone can be removed from life support, and who has the authority to order that such support be discontinued.
The Rasouli case also raises further troubling questions of fact: Was Rasouli’s ability to give a thumbs-up gesture an indication that his condition had improved, or was he never in a persistent vegetative state? Was he, and other people similarly diagnosed, always consciously aware, but, thanks to being trapped in a paralyzed body, unable to express his thoughts?
(Illustration by Bert Dodson)
Brain-damaged man ‘aware’ of scientists’ questions
A crash victim thought to have been in a vegetative state for more than a decade has used the power of thought to tell scientists he is not in pain.
Canadian Scott Routley, from London, Ontario, communicated with researchers via a brain scan, proving that he is conscious and aware. It is the first time such a severely brain-damaged patient has been able to provide clinically relevant information to doctors.
British neuroscientist Professor Adrian Owen, who leads the research team at the Brain and Mind Institute of Western Ontario, said: “Scott has been able to show he has a conscious, thinking mind. We have scanned him several times and his pattern of brain activity shows he is clearly choosing to answer our questions. We believe he knows who and where he is.”
Prof Owen was speaking on a BBC Panorama programme to be broadcast on Tuesday night.
Western neuroscientists breakthrough on physical cause of vegetative state
By exploring parts of the brain that trigger during periods of daydreaming and mind-wandering, neuroscientists from Western University have made a significant breakthrough in understanding what physically happens in the brain to cause vegetative state and other so-called “disorders of consciousness.”
Vegetative state and related disorders such as the minimally conscious state are amongst the least understood conditions in modern medicine because there is no particular type of brain damage that is known to cause them. This lack of knowledge leads to an alarmingly high level of misdiagnosis.
In support of the study titled, “A role for the default mode network in the bases of disorders of consciousness,” Davinia Fernandez-Espejo, a post doctoral fellow at Western’s Brain and Mind Institute, utilized a technique called diffusion tensor imaging tractography to investigate more than 50 patients suffering from varying degrees of brain injury.
This state-of-the-art magnetic resonance imaging (MRI) technique allows researchers to virtually reconstruct the pathways that connect different parts of the brain in the patients while detecting subtle differences in their brain damage.
Specifically, Fernandez-Espejo was able to show that in vegetative state patients, a group of brain regions known as the default mode network that are known to activate during periods of daydreaming and mind-wandering were significantly disconnected, relative to healthy individuals.
"These findings are a first step towards identifying biomarkers that will help us to improve diagnosis and to find possible therapies for these patients" says Fernandez-Espejo. "But they also give us new information about how the healthy brain generates consciousness."
(Source: communications.uwo.ca)