Nightmares could be early sign of Parkinson's

Horrifying dreams could be an early sign of Parkinson's disease, say experts.

Those who shout or cry in their sleep could be more likely to develop the condition within the next five years.

People who suffer from a condition known as "REM sleep disturbance" which includes nightmares and sudden kicking movements, tend to develop Parkinson's and other forms of dementia, according to the Daily Mail.

REM or rapid eye movement is the stage when people typically dream while asleep. Normal sleepers are effectively paralysed during this stage because the brain shuts off the muscles allowing the body to properly rest.

But this doesn't happen to those with REM disorders, who often act out their dreams with violent movements, reports the journal Lancet Neurology.

Scientists in Barcelona found that a fifth of those over 60 suffering from the condition went on to develop Parkinson's, and other degenerative diseases such as Lewy body dementia.

The study suggests that sleep disorders could be one of the first signs of brain diseases. This could enable doctors to diagnose conditions much earlier.

The team of researchers led by Alex Iranzo at the Neurology Department of the Hospital Clinic in Barcelona looked at 43 patients over the age of 60 who had all been diagnosed with REM sleep disorders.

They found that 30 percent had developed some form of neurological disorder two and a half years after their sleeping problem was diagnosed - in most cases Parkinson's.