NEW TECHNOLOGIES By Jirapan Boonnoon
The Nation
Information technology is rapidly expanding its role in the lives of most people. But while most of us think of IT in terms of business and professional support, communications and entertainment, there are a growing number of disabled and elderly people for whom information technology is lifting a severely handicapped existence up to near normalcy.
Many information-technology applications, designed to improve the quality of life of disabled children and adults and elderly people, will be highlighted at the fifth International Convention on Rehabilitation Engineering & Assistive Technology (i-CREATe 2011), which opens at the Swissotel Nai Lert Park in Bangkok on Thursday.
The following are two (of the three) such applications, developed by researchers in Thailand, that will fall under the spotlight at the three-day conference.
Brain-controlled wheelchair
Team leader Jetsada Arnin said existing brain-computer interface systems had practical problems, including accuracy with various subjects, the number of sensors required and time for training the subject.
In the Brain-Controlled Wheelchair Project, the team proposed a hybrid framework for the brain-computer interface that would be more practical for machine control.
An electrooculogram (EOG), which measures the difference in the electrical potential between the front and back of the eye in response to dark and light, is used to control the machine in the left and right directions, while an electroencephalogram (EEG), which uses electrodes placed on the scalp to measure electrical activity in the brain, is used to control the machine's forward motion, no action, and complete stop.
The team found in the two years it took to develop the system that by using only two-channel biosignals, it could achieve average classification accuracy of more than 95 per cent.
As well, to enhance the system's efficiency, automatic controls were added. These consist of an automatic forward and prevention module. An infrared sensor is used to detect obstacles while the wheelchair is moving, and automatic forward is used to control line tracking.
The system, which works under the control of measured brain waves, aims to help people with limb paralysis to control an assistive device. It is backed up by a call centre which is able to both monitor the movements of the wheelchair and control them.
"We were inspired to develop this project because we believed that disabled people should be able to find an important place in their family and society. We wanted to improve their quality of life, so they can reach any goal, like normal people," Jatsada said.
Brain-based neurofeedback device
Mahidol University's Department of Biomedical Engineering has succeeded again with a device designed to treat children with attention deficit/hyperactivity disorder (ADHD).
The leader of the student team that developed the device, Supassorn Rodrak, said ADHD was a brain disorder suffered by 6.5 per cent of children in Thailand. The usual treatment involves drugs, and these often have side effects like vomiting, dizziness and headaches.
This hybrid EEG-HEG based neuro feedback device can help with disorders associated with hyperactivity. (Photo courtesy: Bangkok Post)
Supassorn said the signals normally used in neurofeedback were electroencephalograms (EEG), which measured changes in the brain's electrical activity, and hemoencephalograms (HEG), a measure of brain blood flow that changes along with blood oxygenation.
The Mahidol team set out with the knowledge that both signals had advantages and drawbacks. It proposes that its hybrid EEG-HEG neurofeedback device eliminates the disadvantages of both signals and employs them both to achieve the highest accuracy.
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