News
 International
 National
 Embassy News
 Arts & Living
 Business
 Travel & Hotel
 Medical Tourism New
 Taekwondo
 Media
 Letters to Editor
 Photo Gallery
 Cartoons/Comics/Humor
 News Media Link
 TV Schedule Link
 News English
 Life
 Hospitals & Clinics
 Flea Market
 Moving & Packaging
 Religious Service
 Korean Classes
 Korean Weather
 Housing
 Real Estate
 Home Stay
 Room Mate
 Job
 English Teaching
 Translation/Writing
 Job Offered/Wanted
 Business
 Hotel Lounge
 Foreign Exchanges
 Korean Stock
 Business Center
 PR & Ads
 Entertainment
 Arts & Performances
 Restaurants & Bars
 Tour & Travel
 Shopping Guide
 Community
 Foreign Missions
 Community Groups
 PenPal/Friendship
 Volunteers
 Foreign Workers
 Useful Services
 ST Banner Exchange
  Medical Tourism
Medical News
Faster Help for Stroke Victims
Elderly stroke victim

Scientists have developed a quick, easy and cheap vision test to find out which part – and how much – of the brain of a stroke victim has been damaged, potentially enabling them to save more lives.

The test requires patients to look into a device for about ten minutes, enabling it to be used in the early stages of a stroke – even if the patient cannot move their limbs or speak.

This can help doctors diagnose and treat the stroke quickly and accurately, which is vital, as early treatment can greatly improve a person’s chances of survival and recovery, say Dr Corinne Carle and Professor Ted Maddess from The Vision Centre and The Australian National University.

According to the World Health Organisation, stroke is currently the world’s sixth commonest cause of death, accounting for 4.9% of all fatalities. In Australia it kills about 9000 people a year and hospitalises 35,000.

“Our new test automatically tracks the response of the patient’s eye pupils to different colours, and can show doctors whether the injury is located in the evolutionarily ‘new brain’ or the ‘old brain’,” Dr Carle says.

“The distinction is important because the ‘old brain’, or midbrain, controls things like the heart rate and blood pressure of the body. So if you find that the midbrain has been damaged, you’ll need to treat the patient much more aggressively, because there’s a higher risk of death.”

On the other hand, an injury in the ‘new brain’ – the cortex – may cause permanent blindness in a part of the person’s visual field, or difficulty in their thoughts, speech and movement, but has a lower risk of death, she says.

Using the TrueField Analyzer, a device developed by Prof. Maddess’ Vision Centre team and the Australian company Seeing Machines, the researchers tested how the pupils respond to images on LCD screens. A mixture of red, green and yellow coloured stimuli were provided to each eye, at 24 locations in the person’s visual field.

Two video cameras using infrared lighting recorded the instant response of the pupils, which was then analysed by a computer.

The colours red, green and yellow were chosen because they are processed by different parts of the brain, Dr Carle explains. In mammals, the cortex, or ‘new brain’, is the most recently evolved area, and allows humans to differentiate between red and green.

The ‘ancient’ midbrain, on the other hand, is red-green colourblind, but can detect the colour yellow.

“If the pupils don’t react when red changes to green, we know that the damage is in the cortex. The same concept applies to the yellow stimulus,” says Dr Carle. “The test has been successful in checking the vision of people with glaucoma or type-1 diabetes, and we have now tweaked the stimuli for stroke patients as well.”

Prof. Ted Maddess says that the test will complement various types of brain scans.

“A CT scan tells you where the bleed is, but it doesn’t show you everything,” he says. “For instance, the blood could have cleared up in a particular part of the brain during the scan, or where swelling has reduced the function of a nearby part that looks fine on the scan. It may also miss injuries that are too small, or those that occur in the midbrain, where it doesn’t scan well.”

This is where the test can be useful, Prof. Maddess says. As every single vision cell is wired into a different part of the brain, by testing a particular area in the visual field, doctors can check if the corresponding part of the brain is functioning or not.

The test can be used to monitor stroke patients’ recovery, Prof. Maddess says: “Currently, apart from brain scans, there is no cheap, routine test that can quantify the amount of improvement that results from a treatment. Stroke patients have a very high risk of recurrence, so it’s important that doctors can accurately assess their recovery.”

“The TrueField Analyzer is small, affordable and the test only takes ten minutes,” he says. Working together with neurologists, the research team will start clinical tests with stroke patients in February this year.

The team’s study “The pupillary response to color and luminance variant multifocal stimuli” by Corinne F. Carle, Andrew C. James and Ted Maddess is published in the latest issue of Investigative Ophthalmology & Visual Science (IOVS). See: http://1.usa.gov/T3PdRH

The Vision Centre is funded by the Australian Research Council as the ARC Centre of Excellence in Vision Science.

More information:

Dr Corinne Carle, The Vision Centre and ANU, ph +61 (0)423 983 737
Professor Ted Maddess, The Vision Centre and ANU, ph +61 (0)4 1144 3415 or 02 615 4099
Julian Cribb, The Vision Centre media contact, 0418 639 245

http://www.vision.edu.au

Distributed by SciNews.com.au




 

back

 

 

 

The Seoul Times Shinheungro 25-gil 2-6 Yongsan-gu, Seoul, Korea 04337 (ZC)
Office: 82-10-6606-6188 Email:seoultimes@gmail.com
Copyrights 2000 The Seoul Times Company  ST Banner Exchange