A hushed silence fell on the crowded conference room as the image of a Caucasian man, sleeping in a hospital bed, was shown on the screen.

Fast asleep, the man groaned and made jerky movements with one hand, as if fending off an attacking animal. Then, he stopped and started singing in a slurred voice, but with great gusto – to the amusement of the audience.

"He's singing a Mexican song!" Professor Eduardo Tolosa said light-heartedly in his talk "Can We Predict Who Will Get Parkinson Disease?" at the 5th Singapore International Parkinson Disease and Movement Disorders Symposium at the National Neuroscience Institute (NNI), a member of the SingHealthgroup.

A new way to look at Parkinson disease

Prof Tolosa is a neurologist from the University of Barcelona in Catalunya, Spain, and a world expert on Parkinson Disease (PD). He said the man in the video has a sleep disorder called rapid eye movement behaviour disorder (RBD). This is the loss of muscle control during deep sleep and is one of the very early symptoms of Parkinson disease (PD), showing up long before more obvious motor symptoms like tremors and mobility issues.

RBD, due to neurological changes, makes the man more prone to PD later in life. PD patients slowly lose brain cells that create dopamine, a chemical that affects emotion, perception and movement. These changes can start years before motor symptoms appear and a diagnosis is made. He presented data which showed that death in these cells starts five to 13 years before tremors happen.

A signature symptom

A person with RBD appears to be having a nightmare, making loud noises and jerky movements while in deep sleep. The movements can be of varying intensity and the sufferer can hurt himself or the person next to him.

"The patient usually dreams of being attacked or chased by strangers or wild animals, arguing with somebody or falling down," said Prof Tolosa. "The dreams occur every one to two hours, can last for several minutes and usually happen between 12 and 30 years before PD is diagnosed."

He added that doctors have documented cases in which people had unpleasant dreams and RBD 10 years and, in extreme cases, 50 years prior to getting PD. "The risk of developing PD rises dramatically for those who have a longer history of RBD," he said.

Other early signs of Parkinson disease

Another significant early symptom is the loss of smell. Prof Tolosa said that between 70 and 90 patients interviewed remembered losing their sense of smell, on average, five years before they were diagnosed with PD.

"This early symptom is like a canary in a coal mine, which can warn us of further brain changes down the road," he said. Other symptoms include constipation, erectile dysfunction, depression and cardiac abnormalities.

Read on to find out the early signs of Parkinson disease.

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