Why Parkinson's patients see ghosts: Scientists discover abnormality in frontal-temporal region of sufferers' brains that can cause hallucinations
Scientists have discovered a frontal-temporal disconnection which could explain why people with Parkinson's believe they can see ghosts.
Around half of people suffering with the disease experience 'presence hallucinations' which causes them to sense a shadowy presence nearby.
The spontaneous nature of the event has made the phenomena hard to study.
PARKINSON'S DISEASE EXPLAINED
Parkinson's disease affects one in 500 people, including about 145,000 individuals in the UK.
It causes muscle stiffness, slowness of movement, tremors, sleep disturbance, chronic fatigue, an impaired quality of life and can lead to severe disability.
It is a progressive neurological condition that destroys cells in the part of the brain that controls movement.
Sufferers are known to have diminished supplies of dopamine because their nerve cells that make it have died.
There is currently no cure and no way of stopping the progression of the disease, but hundreds of scientific trials are working to change that.
A new study using brain imaging and robotics has highlighted abnormalities in the brain which might explain it.
Professor Olaf Blanke of the Swiss Federal Institute of Technology told Reuters: 'The system is actually quite simple.
'One robot is in front of the subject and will measure the movement and the second robot will feedback signals to the individual that we're testing, Parkinson's patients or healthy subject, and then when we induce a mis-match, so if the front robot is doing something else from the back robot, this is the condition when the "presence hallucination" occurs.'
Minor hallucinations often occur before other Parkinson's symptoms such as tremors and muscle rigidity.
People who have more severe hallucinations are likely to have a greater cognitive decline as the disease progresses.
Information about the hallucinations is scarce because patients are often embarrassed to report them, scientists claim.
Joseph Rey, who experiences the visions, said: 'They feel like angels protecting me. They do me no harm. They follow me around. It's reassuring in a way, because I am not alone.'
The study involved 56 Parkinson's sufferers in Switzerland and Spain.
While the disease has been traditionally defined as a movement disorder, some patients also suffer from mental symptoms like psychosis, depression, cognitive decline and even dementia.
Researchers say the growing evidence suggests that hallucinations might be precursors to these more severe mental health symptoms but they often remain under diagnosed.