Can disrupted sleep cause memory, thinking problems? Study suggests so
PTC News Desk: People who have more disrupted sleep in their 30s and 40s are more likely to experience memory and cognitive issues a decade later, says a new study.
The study was published online in Neurology, the medical journal of the American Academy of Neurology.
The researchers investigated the duration and quality of people's sleep. To calculate their averages, participants wore a wrist activity monitor for three consecutive days on two separate occasions, approximately one year apart. Participants got an average of six hours of sleep.
"Given that signs of Alzheimer's disease start to accumulate in the brain several decades before symptoms begin, understanding the connection between sleep and cognition earlier in life is critical for understanding the role of sleep problems as a risk factor for the disease," author of the study, Yue Leng, PhD, of the University of California, San Francisco stated.
"Our findings indicate that the quality rather than the quantity of sleep matters most for cognitive health in middle age."
The study included 526 participants, with an average age of 40. They were followed for eleven years.
Researchers investigated the participants' sleep duration and quality. To calculate their averages, participants wore a wrist activity monitor for three consecutive days on two separate occasions, about a year apart. The participants slept for an average of six hours.
Participants also recorded their bedtimes and wake times in a sleep diary and completed a sleep quality survey with scores ranging from zero to 21, with higher scores indicating poorer sleep quality. A total of 239 people, or 46 percent, reported poor sleep with a rating greater than five.
Participants also took a variety of memory and cognitive tests.
The researchers also investigated sleep fragmentation, which is defined as repeated short interruptions of sleep. They measured both the percentage of time spent moving and the percentage of time spent not moving for one minute or less while sleeping.
After adding these two percentages together, the researchers discovered that participants had an average sleep fragmentation of 19%.
The researchers then divided the participants into three groups according to their sleep fragmentation score.
Of the 175 people with the most disrupted sleep, 44 had decreased cognitive abilities 10 years later, compared to 10 of the 176 with less disrupted sleep.
After controlling for age, gender, race, and education, people with the most disrupted sleep were more than twice as likely to have poor cognitive performance as those with the least disrupted sleep.
There was no difference in cognitive performance at midlife between the middle group and the group with the least disrupted sleep.
"More research is needed to assess the link between sleep disturbances and cognition at different stages of life and to identify if critical life periods exist when sleep is more strongly associated with cognition," Leng said in a statement.
-
