Age Differences in the Variability and Distribution of Sleep Spindle and Rapid Eye Movement Densities

Abstract

The present study had two main objectives. The first objective was to compare the sleep architecture of young and older adults, with an emphasis on sleep spindle density and REM density. The second objective was to examine two aspects of age differences that have not been considered in previous studies: age differences in the variability of sleep measures as well as the magnitude of age differences in phasic events across the distribution of values (i.e., at each decile rather than a single measure of location such as the mean or median. A total of 24 young (mean age = 20.75±1.78 years) and 24 older (mean age = 71.17±6.15 years) adults underwent in-home polysomnography. Whole-night spindle density was significantly higher in young adults than older adults. The two age groups did not differ significantly in whole-night REM density, although significant increases in REM density across the night were observed in both age groups. These results suggest that spindle density is more affected by age than REM density. Although age differences were observed in the degree of absolute variability (older adults had significantly larger variances than young adults for sleep efficiency and time spent awake after sleep onset), a similar pattern was also observed within the two age groups: the four sleep measures with the lowest degrees of relative variability were the same and included time spent in REM and Stage 2 sleep, total sleep time, and sleep efficiency. The distributional analysis of age differences in sleep spindle density revealed that the largest age differences were initially observed in the middle of the distributions, but as the night progressed, they were seen at the upper end of the distributions. The results reported here have potential implications for the causes and functional implications of age-related changes in sleep architecture.

Age affects sleep microstructure more than sleep macrostructure

“…The lack of effect on REM density across age is in line with some previous findings (Ficca et al ., ; Peters et al ., ; Vegni et al ., ) and contrary to others (Lauer et al ., ). Future studies may also include additional measures of REMs that not only target the quantity but also the organizational aspects of REM bursts, which according to previous studies are changed in the elderly (Ficca et al ., ; Vegni et al ., ).…”

“…In addition, K-complexes appear to be linked to delta activity and similarly regulated by homeostatic processes (Halasz, 2005). In contrast to the age-related reduction of spindle and K-complex density, the effect of age on the density of rapid eye movements (REM) is less clear (Lauer et al, 1991;Peters et al, 2014).…”

Sleep Stage Classification Using Bidirectional LSTM in Wearable Multi-sensor Systems

“…It is worth recalling the different age ranges of the training and validation sets and the test set. As observed in [26], the light sleep of young subjects is less than it of senior subjects, while the deep sleep of young subjects is more. Furthermore, the ethnic differences (White in SHHS vs. Asian in our dataset) and gender distributions also lead to dissimilar sleep patterns [27].…”

The 5α-reductase inhibitor finasteride is not associated with alterations in sleep spindles in men referred for polysomnography

“…Given that prior research has demonstrated agerelated declines in sleep spindle characteristics (Nicolas et al 2001;Peters et al 2014), correlations with age were also explored. Consistent with the prior literature, each of the four spindle parameters across all participants was significantly negatively correlated with age (r = À0.46 to À0.66, p < 0.001).…”