Analysis of Einstein Aging Study data showed that older adults who spend more time awake at night tend to have slower processing speed, worse working memory, and poorer visual memory binding. At an individual level, participants’ processing speed was slower after a night of higher than normal night awakenings. This study Sleep Health: National Sleep Foundation Journal.
Sleep is essential for physical health, cognitive function, and emotional regulation. During sleep, your body repairs tissues, strengthens your immune system, and regulates hormones involved in appetite, stress, and growth. Adequate sleep supports memory consolidation and learning by helping the brain process and organize information. Sleep deprivation or sleep deprivation is associated with increased risk of cardiovascular disease, obesity, diabetes, depression, and immune dysfunction.
Sleep quality is determined by looking at how well and for how long a person sleeps in a row. Key indicators of good sleep quality include short sleep onset latency (falling asleep quickly), short awakenings after falling asleep (minimal amount of time awake during the night), and high sleep efficiency (most time spent in bed sleeping). Feeling rested and awake during the day is another important subjective indicator of good sleep. On the other hand, waking up frequently, staying awake for long periods during the night, or feeling excessively sleepy during the day suggests that your sleep is fragmented or of poor quality.
Study author Orfeu M. Buxton and his colleagues wanted to examine the short-term association between sleep and everyday cognitive performance in older adults without dementia. They hypothesized that people with longer nighttime awakenings, later mid-sleep periods, more naps, and shorter sleep duration would be more likely to have poorer overall cognitive performance. The authors hypothesized that at an individual level, people would have worse-than-average cognitive performance the day after a night in which their sleep was more fragmented (i.e., they woke up more often during the night).
The study authors analyzed data from the Einstein Aging Study. The study recruited participants from Bronx County, New York, who were community-dwelling, English-speaking, 70 years of age or older, free of dementia, severe hearing or vision loss, or severe psychiatric symptoms that might interfere with cognitive testing. They also did not have current alcohol or drug abuse problems or received cancer treatment within the past 12 months.
Data from 261 participants were used for this analysis. The mean age was 77.2 years, and 67% were female. Over 16 days, these people wore actigraphs on their wrists and completed cognitive assessments six times a day using smartphones provided in the study. Actigraphs are small wearable devices, usually worn on the wrist, that measure movement over time to estimate sleep-wake patterns and overall rest-activity cycles.
The cognitive assessment consisted of four different tasks. These are designed to assess visuospatial working memory, processing speed, visual working memory (item-location binding), and visual working memory (within-item feature binding). On average, the task took a total of 4 to 5 minutes to complete. Participants also completed overnight home pulse oximetry (measurement of blood oxygen saturation and pulse rate taken at night).
The results showed that participants who had longer periods of nocturnal wakefulness (awake after falling asleep) generally had slower processing speed, worse working memory, and a tendency to have worse visual memory binding (a worse ability to integrate visual features into memories of objects and scenes). At the individual level, participants who had nights with more than normal night awakenings tended to have below-average processing speed the next day.
Sleep duration, timing, and napping were not associated with performance on cognitive tests.
“These results demonstrate the short-term effects of sleep fragmentation (WASO) on next-day processing speed in older adults without dementia. A better understanding of short-term effects may identify individuals who may benefit from early intervention to prevent long-term cognitive decline,” the study authors concluded.
This study contributes to the scientific understanding of the impact of poor sleep quality on cognitive performance. However, all participants in this study were elderly. Results may vary in other age groups.
The paper, “Intra- and inter-individual associations between sleep characteristics and daily cognitive performance in a community-based sample of older adults,” was authored by Orfeu M. Buxton, Qi Gao, Jonathan G. hakun, Linying Ji, Alyssa A. Gamaldo, Suzanne M. Bertisch, Martin J. Sliwinski, Cuiling Wang, and Carol A. Derby.
