Special glasses to spot people at risk for PTSD

Nov 18 2010

People with PTSD may be in a state similar to hypnosis, and new research may help spot those prone to it

The Flashback
Around 30 percent of people surviving a traumatic event, such as a serious car crash, will go on to develop Post Traumatic Stress Disorder (PTSD). Doctors don't know who is susceptible and treating people who don't have PTSD can make things worse. However, new research by psychologist Dr Peter Naish, of the Open University, and his colleague Dr Ksenja da Silva, may help. 'PTSD is a condition that sometimes arises after a severe trauma,' explains Dr Naish, 'generally when the person fears their own death, or experiences the death of others close to them.' One of the worst symptoms is the 'flashback'. It's like 'a hallucination,' says Dr Naish, 'it gives people vivid images of the scene, as if they are there, it's very frightening.' There are many theories but the most physiological one suggests that while in normal circumstances our memory is organised by the hippocampus, at moments of heightened arousal, such as extreme fear, the amygdala takes over.

Reactivating parts of brain
The experience of a traffic accident where someone is trapped in a car, with petrol leaking and the danger of it igniting, could be revived as a flashback by the smell of petrol for example. Dr Naish explains that it is believed the amygdala may be reactivating the same parts of the brain that were active at the time, and this seems to happen with PTSD. Dr Naish's research was partly prompted by seeing some studies suggesting that people with PTSD are more than averagely hypnotisable.

Switching hemispheres
He designed glasses which used LEDs on each side which flashed a light (with a one millisecond gap), and the wearers have to say which side came on first. Normal subjects used both hemispheres of the brain to process the information, and if there was a dominant side it tended to be the left. However, in the tests the more hypnotisable people, 'switched around completely, now they were faster on the right side, implying in some sense they were switching to right hemisphere processing.' His study revealed that people with PTSD had a pattern of responses similar to people in a hypnotic state. The glasses could be used to spot who may be at risk. Dr Naish stresses this is early research, but the data looks promising.