When most of us sleep, our bodies enter a state of muscle paralysis. But people with REM sleep behavior disorder lose that paralysis and are capable of acting out physical activity in their dreams, which can often times be violent.
The disorder is most common in men who also have Parkinson's disease or Lewy body dementia.
Orvis "Rig" Rigsby started showing signs of dementia a few years ago.
"He had an incident where he got very disoriented and lost in our backyard, and that's when we started looking for help from a neurologist," said wife Karen Rigsby.
At first, Dr. Ira Goodman, an adult neurologist, thought Orvis Rigsby had Alzheimer's disease.
"I initially referred him for a clinical trial for Alzheimer's disease, but right before he entered I changed my mind," Goodman explained.
Instead, Goodman diagnosed him with Lewy body dementia and REM sleep behavior disorder. The condition causes a person to act out violent dreams.
"There have been fractures, there's been subdural hematomas, and as far as spouses or bed partners, there's been reports of up to two-thirds of bed partners being injured during an episode," Goodman said.
"Sometimes he would just start yelling, or sometimes he would start punching around. Sometimes, it was like he flew off the bed," Karen Rigsby said.
Currently there is no cure.
Orvis Rigsby wears a patch that helps ease the symptoms, but keeping a watchful eye is the best defense.
"If he's having a bad night I'll still sleep in the bed with him and hold my hand on his shoulder," Karen Rigsby said.
Goodman and Karen Rigsby say not to be afraid of getting evaluated if you notice any symptoms.
"I tell everybody, 'Don't waste time, don't waste time, don't wait, don't wait, don't wait.' That's all you can say," Karen Rigsby said.
A phase-three national clinical trial is underway for a new drug called Nelotanserin to treat the REM sleep behavior disorder. Klonopin, an anti-anxiety drug, called Clonazepan in the generic form, is most commonly prescribed, but it has side effects.
Another option mentioned by the Mayo Clinic is to take a dietary supplement called Melatonin.