Having disturbed sleep -- common among people with sleep apnea -- could be doing your memory a disservice, a new study suggests.
Past research suggests that sleep helps to solidify a certain kind of memory called motor memory, which is involved when you tie your shoe or learn to play a song on the piano.
The researchers explained in the PLoS ONE study:
"Motor memories improve during off-line periods with sleep being of particular importance. Studies looking at different aspects of motor skill learning, including motor sequence, and motor adaptation tasks, have shown improvements in performance after a night of sleep, but not after an equivalent time spent awake."
Researchers from Brigham and Women's Hospital, Harvard Medical School and the Beth Israel Deaconess Medical Center in Boston wanted to see if these memory benefits were also gained when people had fragmented sleep, versus continuous sleep.
The researchers examined 16 young people who all had mild obstructive sleep apnea and 15 people without the condition. People with obstructive sleep apnea may stop breathing while sleeping because of a blocked or narrowed airway; it's associated with fragmented sleep.
The study participants all did a motor sequence learning task, and then slept overnight in a sleep lab. The researchers found that the people without mild obstructive sleep apnea had more overnight improvement at the motor task, compared with the people with the condition.
However, the researchers noted that both those with the condition and without the condition had similar learning performances before sleeping, showing that the sleep (or disturbances in sleep) was the factor at play.
Recently, a study presented at the American Stroke Association's International Stroke Conference showed that sleep apnea may be linked with small brain lesions and a symptomless form of stroke, known as silent stroke.
"We found a surprisingly high frequency of sleep apnea in patients with stroke that underlines its clinical relevance as a stroke risk factor," study researcher Dr. Jessica Kepplinger said in a statement.
Silent strokes don't have any symptoms, meaning a person typically doesn't know he or she has suffered one, ABC News reported. Having multiple silent strokes is linked with memory loss, difficulties with walking and mood problems.