EEG finds consciousness in people in vegetative state

Signs of consciousness have been detected in three people previously thought to be in a vegetative state, with the help of a cheap, portable device that can be used at the bedside.

"There's a man here who technically meets all the internationally agreed criteria for being in a vegetative state, yet he can generate 200 responses [to direct commands] with his brain," says Adrian Owen of the University of Western Ontario.

"Clearly this guy is not in a true vegetative state. He's probably as conscious as you or I are."

In 2005, Owen's team, used functional MRI to show consciousness in a person who was in a persistent vegetative state (PVS), for the first time.

PVS is also known as 'wakeful unconsciousness', whereby the body still functions but the mind is unresponsive.

However, fMRI is costly and time-consuming, so his team set about searching for simple and cost-effective solutions for making bedside diagnoses of PVS.

Now, they have devised a test that uses the relatively inexpensive and widely available electroencephalogram (EEG).

An EEG uses electrodes attached to the scalp to record electrical activity in the brain.

Imagine wiggling your toes
Owen and his team used an EEG on 16 people thought to be in a PVS and compared the results with 12 healthy controls while they were asked to imagine performing a series of tasks.

Each person was asked to imagine at least four separate actions – either clenching their right fist or wiggling their toes.

In three of the people with PVS, brain regions known to be associated with those tasks lit up with activity, despite physical unresponsiveness.

This suggested to the researchers that the subjects were carrying out a complex set of cognitive functions including hearing the command, understanding language, sustaining attention and tapping into working memory.

"It isn't the case that just because somebody doesn't respond they're not conscious," Owen says. "There's a growing body of data now demonstrating that many of these patients aren't what they appear."

Criteria of Vegetative State (PVS)
"The diagnostic criteria for vegetative state have to change," he adds. The official diagnosis for PVS was formulated in the 1970s, before neuro-imaging was widely used, says Owen.

The last update was made in 1995, but the criteria for declaring someone conscious is still based on whether an outside observer believes the patient is trying to communicate.

Morten Overgaard, a cognitive neuroscientist at Aalborg and Aarhus University in Denmark, says that determining whether Owen's patients are actually responding consciously or whether they are unconsciously reacting to suggestions from the command is difficult to know without further study.

"If this is suggested as a standalone test to decide whether a person is conscious or not, then we need [signs] that are very strong and not just an indication of consciousness," he says.


Absence of Awareness
The test cannot prove the absence of awareness, but it can identify people who weren't thought to be conscious, says Damian Cruse, a collaborator on the study.

This was particularly apparent when 25 per cent of the healthy controls returned EEG readings that were below expected levels of conscious thought.

Communicating with carers
However, for those people previously considered to be unaware of their surroundings, communicating with their caretakers through EEG tests could change their life. "We're trying to work out how to use this technique to find out more about somebody's internal mental state," says Owen. "It opens up the possibilities for potentially facilitating recovery. If you have a channel of communication with a patient, you can have that patient play a role in therapeutic intervention."

China Embraces GM Strains of Rice and Corn

China has approved genetically modified strains of rice and corn in a move experts say could dramatically boost crop yields and help the world's most populous nation avoid food shortages.

The Ministry of Agriculture said it had issued initial production licences for genetically modified rice and corn, paving the way for commercial cultivation of high-yielding and pest-resistant grain and cereal crops.

In a fax to AFP this week, the ministry said the decision was "an important outcome of China's research on genetic engineering technology".

"It lays a good foundation for commercial production," the ministry said.

Further approvals are required before the genetically modified rice and corn can be grown commercially, it added.

Huang Dejun, chief analyst with Beijing Orient Agribusiness Consultant, said the government wanted the agricultural industry "to be prepared" for a potential grain shortage.

"China's grain security is guaranteed now... but it is hard to rule out the possibility (of a shortage) as living standards improve or yields slump because of a sharp decrease in the area of farming land or serious impacts of climate change," Huang said.

The technology could increase rice and corn yields by about 30 percent, Huang estimated.

Beijing said in July 2008 that it aimed to cultivate high-yielding and pest-resistant genetically modified grains as it faces the challenge of feeding its 1.3 billion people and battles shrinking arable land and climate change.

China is a major producer of genetically modified cotton and vegetables such as peppers and tomatoes.

But Greenpeace China said the commercialisation of genetically modified rice was a "dangerous genetic experiment" and called on Beijing to make public the health and environmental studies used in the certification process.

"Rice is the most important staple food for Chinese people and our babies grow up on rice," said Lorena Luo, Greenpeace China's food and agriculture campaigner.

"People have the right to know whether the rice they eat has any health risk. Who are these... scientists in the committee to make the decision for 1.3 billion people?"

No varieties of genetically modified rice are currently grown commercially in the world although several have been approved, according to the International Rice Research Institute in the Philippines.

China produces about 20 percent of the world's corn and 30 percent of its rice, according to the US Department of Agriculture website.

China's cabinet in July 2008 approved a mid- and long-term grain security plan that aims to keep annual output above 500 million tonnes by 2010 and increase production to more than 540 million tonnes a year by 2020.

Premier Wen Jiabao said at the time that China faces serious challenges in ensuring it will have enough grain to feed its population in the decades to come, citing urbanisation and climate change as two major problems.

But at a conference on world food security in Rome last month, Chinese Vice Premier Hui Liangyu said China now has a "favourable food security situation" with abundant grain reserves and sufficient supply of staple crops, according to the China Daily.