Poor sleep has been linked to an increased dementia risk , though we don’t yet know exactly how one affects the other.

But roughly 90% of people with the sleep condition known as isolated REM sleep behaviour disorder (iRBD) go on to develop Parkinson’s or Lewy body dementia, according to a study published in Neurology .

The leader of the research team, Professor Shady Rahayel, said iRBD is “not just restless sleep – it’s a neurological warning sign”.

But what is iRBD, and what does the new study show?

What is REM sleep behaviour disorder?

This is a condition where you physically or verbally act out in your sleep.

Its symptoms include thrashing around, shouting, and “sudden, often violent arm and leg movements during REM sleep”. It is also known as “dream-enacting behaviour”

See Full Page