Doctors create out-of-body sensations

Doctors say they have triggered out-of-body experiences in a female patient by stimulating her brain.

They believe their work may help to explain mysterious incidents when people report experiences of 'leaving' their body and watching it from above.

The doctors did not set out to achieve the effect - they were actually treating the women for epilepsy.

Awareness of a biological basis of OBEs might allow some patients to talk about them more openly

Professor Olaf Blanke

Neurologist Professor Olaf Blanke and colleagues at Geneva University Hospital in Switzerland were using electrodes to stimulate the brain.

They found that stimulating one spot - the angular gyrus in the right cortex - repeatedly caused out-of-body experiences (OBEs).

Initially, the stimulations caused the woman to feel she was "sinking" into the bed, or falling from a height.

When the current amplitude was increased, she reported leaving her body.

Floating

She told the doctors: "I see myself lying in bed, from above, but I only see my legs and lower trunk."

Further stimulations led to a feeling of lightness and "floating" close to the ceiling.

The patient was then asked to watch her real legs as current was passed through the electrodes attached to her head.

This time she reported her legs "becoming shorter". If bent, her legs appeared to be moving quickly towards her face, causing her to take evasive action.

A similar effect happened when she was asked to look at her outstretched arms.

The left arm appeared shortened, but the right arm was unaffected.

If both arms were bent by 90 degrees at the elbow, the woman felt her left lower arm and hand were moving towards her face.

The doctors believe the angular gyrus plays an important role in matching up visual information and the brain's touch and balance representation of the body.

When the two become dissociated, an out-body-experience may result.

Writing in the journal Nature, the Swiss team said out-of-body experiences tended to be short-lived, and to disappear when a person attempts to inspect the illusory body or body part.

Greater awareness

Professor Blanke told BBC News Online that out of body sensations may be caused by an overactive angular gyrus. Alternatively, the electrical stimulation might actually have depressed activity in the area.

He said it was impossible to rule out possibility that other areas of the brain were also involved.

He said there was no evidence to suggest that out-of-body experiences were linked to epilepsy.

"OBEs have been reported in neurological patients with epilepsy, migraine and after cerebral strokes, but they also appear in healthy subjects.

"Awareness of a biological basis of OBEs might allow some patients who suffer frequently from OBEs to talk about them more openly.

"In addition, physicians might take the phenomenon more seriously and carry out necessary investigations such as an EEG, MRI, and neurological examinations."