text: Kicking, punching and moving around during sleep might be an early sign of Parkinson's disease, a new review suggests. Moving around in sleep, and seeming to 'act out' dreams is a characteristic of a condition called rapid eye movement sleep behaviour disorder (RBD). Researchers have discovered about half of people with RBD will develop Parkinson's disease or another neurological disorder within a decade of being diagnosed, LiveScience reports. People with rapid eye movement sleep behaviour disorder (RBD) move around in their sleep and 'act out' their dreams. Up to 90 per cent of people with the condition will develop a neurological condition, a study found . Ultimately, 81 to 90 per cent of patients with RBG with develop a neurodegenerative disorder, they found. 'If you get this disorder and live long enough, you will almost certainly get Parkinson's disease or a condition similar to it — it's an early warning sign,' said Professor Michael Howell, of the University of Minnesota, and co-author of the study. People with RBD describe having vivid dreams, and they act them out theatrically while asleep. They can be fighting enemies, or fleeing danger, and actually act out these dreams in their beds. This can range from making small hand movements to thrashing around, punching, kicking and jumping out of bed. Sometimes, people with the condition can injure themselves or anyone sharing a bed with them. 'It's very important to make the bedroom environment [as] safe as possible' by removing objects that can be picked up or used as a weapon, such as guns, Professor Howell said. People with RBD move around during the rapid eye movement period of sleep, when most dreaming occurs but the body's muscles are usually paralysed by the brain stem. Those with the condition are believed to have a malfunction in their brain-stem which allows them to move around during REM sleep, and therefore act out their dreams. For most people, dreaming is purely a 'mental' activity: dreams occur in the mind while the body is at rest. But people who suffer from REM behavior disorder (RBD) act out their dreams. They physically move limbs or even get up and engage in activities associated with waking. Some engage in sleep talking, shouting, screaming, hittting or punching. Some even jump out of bed while sleeping. RBD is usually noticed when it causes danger to the sleeping person, their bed partner, or others they encounter. People with RBD move around during the rapid eye movement period of sleep, when most dreaming occurs but the body's muscles are usually paralysed by the brain stem. Those with the condition are believed to have a malfunction in their brain-stem which allows them to move around during REM sleep, and therefore act out their dreams. RBD is not curable, but it can be treated with high doses of the sleep aid or low doses of the anti-anxiety drug clonazepam. Source: National Sleep Foundation . It is a different condition from sleepwalking, Professor Howell explained, as sleepwalkers are confused when they wake up. It is normally easy to awaken someone with RBD, and they will recall clear details of the vivid dream. RBD affects 0.5 per cent of the population or 35 million people worldwide. While it is incurable, it can be managed with high doses of the sleep hormone melatonin or low doses of the anti-anxiety drug clonazepam. As part of the study, Professor Howell and his colleagues reviewed 500 studies published between 1986 and 2014 that explored the link between RBD and Parkinson's. They found between 81 and 91 per cent of patients with RBD developed a degenerative brain disorder during their lifetimes. Parkinson's disease, a condition in which part of the brain becomes progressively damaged, is characterised by a tremor, slow movement and stiff and inflexible muscles. It is caused by the breakdown of certain proteins in the brain cells that produce dopamine, a chemical that produces pleasurable feelings in response to rewarding activities. It could be that RBD results from the early stages of the breakdown of the proteins in the brain cells, meaning it could be a useful warning sign of Parkinson's disease, Professor Howell said. However, not everyone who develops Parkinson's will have RBD first. Nevertheless, the findings could help doctors find a way to catch Parkinson's early and treat Parkinson's disease while it is in its early stages, Professor Howell added. The condition is not curable, but it can be managed with drugs. An experimental therapy called deep brain simulation has shown promise in some patients. The study was published  in the journal JAMA Neurology. Parkinson's disease is caused by the breakdown of proteins in brain cells, meaning that part of the brain cannot work (pictured in red). RBD could be an early warning sign of Parkinson's disease, researchers said .
target: Lashing out in sleep is a sign of 'rapid eye movement behaviour disorder'
  Half of people with this condition will go on to develop Parkinson's disease .
  Up to 90% of people will develop another neurological disorder within 10 years .
  Sleep disorder occurs due to a brain malfunction  - meaning the brain doesn't paralyse the body's muscles during the period of sleep when people dream .