Crying out and thrashing in sleep has always been annoying for bedmates. However, new research suggests that you shouldn’t just roll over and try to go back to sleep after receiving a somnambulant kick. An article this week in Neurology, by Dr. Ronald Postuma, warns that excessive muscle activity while dreaming is not just an annoyance but also a very grave risk factor for neurodegenerative diseases.

Dr. Postuma monitored 93 patients (mean age 65) during the REM stage of their sleep, when the eyes move rapidly over dreamscapes but the body is supposed to remain paralyzed despite perceived dream movement. He then compared the excessive movement group to a control group 5, 10, and 12 years after the original sleep study.

Excessive movement served as a strong indicator of future neural problems, primarily Parkinson’s disease and Lewy body dementia. The diagnosis rate of neurodegenerative disease at 5, 10, and 12 years was 17.7%, 40.6%, and 52.4%. This is a frightening but useful study because the warning symptoms come so far before the disease that there may be time for preventative care. For example, previous studies have shown that regular exercise can significantly reduce the risk of developing Parkinson’s disease. Family members who notice excessive movement at night should recommend a prevention plan and frequent check-ups well before more debilitating symptoms emerge.