Sleep apnea could have an effect on the ability to form new spatial memories, such as where you last left your keys.
Researchers used a video game to determine disruption of rapid eye movement (REM) sleep (which is a consequence of sleep apnea) reduces spatial memory, NYU Langone Medica Center reported. This type of memory is primarily affected in Alzheimer's disease, and is often the cause of these patients getting lost.
"We've shown for the first time that sleep apnea, an increasingly common medical condition, might negatively impact formation of certain memories, even when the apnea is limited to REM sleep," said Dr. Andrew Varga, clinical instructor of Medicine in the Division of Pulmonary, Critical Care and Sleep Medicine at NYU Langone. "Our findings suggest memory loss might be an additional symptom for clinicians to screen for in their patients with sleep apnea."
To make their findings the researchers looked at 18 subjects with severe sleep apnea who used a continuous positive airway pressure (CPAP) machine. The participants spent two nights in the NYU Sleep Disorders Center's sleep lab where they played video games both before and after sleep. The participants used a joystick to navigate through one of two computer-generated 3-D spatial mazes.
During one of the nights the subjects used their CPAP machines normally, but on the second night it was reduced during REM sleep, allowing apnea to occur. The team found when sleep was aided by CPAP all night there was a 30 percent overnight improvement in maze completion time, but when REM sleep was inhibited there was a 4 percent reduction in navigation time.
The team also found when sleep apnea occurred during REM sleep subjects did not experience delayed reaction times on a test that measured attention, called a psychomotor vigilance test. These findings suggest sleepiness and lack of attention were not the reasons for the decline in spatial memory.
The findings were published Oct. 29 in the Journal of Neuroscience.
