CHICAGO (NewsNation Now) — Scientists have visual evidence supporting a long-suspected link between obstructive sleep apnea and the disease that robs patients of memory: Alzheimer’s.

Researchers in Australia and Iceland noticed spots on the brain that are a sign of Alzheimer’s in someone who suffered from sleep apnea— a serious condition that occurs when a person’s breathing is repeatedly interrupted during sleep.

“In prior research studies, we weren’t able to directly make that link or association,” Dr. Smita Patel, a neurologist at NorthShore University Health System, told NewsNation affiliate WGN. “Of course we suspect when you don’t breathe and you don’t have oxygen and that is going to do something to your brain cells, especially when you wake up and you can’t remember or you feel tired during the day.”

Scientists said patients in the study showed no signs of dementia before they died so early detection is key.

“We want to try to catch you early when you get diagnosed. We don’t want you to wait until you have symptoms like ‘I can’t remember who my children are’ or where things are in the house. So we don’t want it to progress to that extent before you start treating your sleep apnea for example,” Patel said.

The study’s authors noted the common treatment for sleep apnea, continuous positive air pressure or CPAP machine, did not appear to reduce damage. Doctors say it’s a critical factor for prevention.

“I do think the treatment for sleep apnea using the CPAP machine, especially if you have a moderate or severe degree of sleep apnea, is still going to be important,” Patel said.

 NewsNation affiliate WGN contributed to this report.