Respiration-related sleep disorders like obstructive sleep apnea (OSA) are often dismissed as nighttime inconveniences: loud snoring, restless sleep, daytime fatigue. But sleep apnea is far more than a sleep problem. So what’s actually happening inside the brain while someone with undiagnosed sleep apnea sleeps? Sleep Apnea Isn’t Just A Sleep Disorder“Obstructive sleep apnea is the repeated blocking of breathing occurring during sleep,” says Dr. Eric Kezirian, a professor of head and neck surgery at the David Geffen School of Medicine at UCLA. The Brain Can Bounce BackIf you have sleep apnea — or suspect you might — the good news is this: the brain is remarkably resilient.