A new study has linked the loss of rapid eye movement (REM) sleep to an increased risk of Parkinson's disease.
In a series of studies on people aged between 70 and 89, researchers at the Mayo Clinic found a statistically significant correlation between the incidence of REM sleep behaviour disorder (RBD) and neuropsychological measures of attention, functioning, apathy and anxiety.
The presence of RBD among the 765 people studied was eight per cent. Of those with the condition, 21 per cent had anxiety and 11.5 per cent had apathy, compared to just eight and four per cent, respectively, among the rest of the test population.
"REM sleep behaviour disorders appear to start at the south end of the brain stem and appear to ascend," said Dr Bradley Boeve, who led the research team.
"The next site higher in the brain stem is the emotions, and this component of the syndrome appears to come later, after there has been a history of violent nightmares. Next is the motor movement centre, and the highest is the cerebral cortex and cognitive defects."
Although some treatments suppress the symptoms of RBD, Dr Boeve noted that there are currently no methods for delaying the onset of dementia and Parkinsonism in patients who suffer from the condition.
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