Table 1.
Variable Definitions for Sleep Parameters
| Variable Group |
Variable |
Definition |
|---|---|---|
| Sleep Continuity | Sleep Efficiency | percent of time asleep while in bed |
| Wake after sleep onset | minutes spent awake after initially falling asleep | |
| Awakenings | frequency of wake periods | |
| Sleep Disturbance | PSQI-defined sleep disturbance | |
| Transitions | transitioning into lighter sleep stages; frequency of sleep stage transitions | |
| Sleep Duration and Initiation | Sleep Onset Latency | time taken to fall asleep |
| Sleep Duration | total time spent asleep | |
| General Sleep Quality | Global Sleep Quality | subjective average of sleep quality measures |
| Sleep Quality | general measure of sleep quality as an average of sleep | |
| Composite | parameters | |
| Tiredness Upon Awakening | subjective tiredness rating | |
| Freshness Upon Awakening | subjective rating of feeling well rested | |
| Sleep Stages | Stage 1 | sleep stage composed of low amplitude mixed frequency brain activity; percentage or duration spent in Stage 1 |
| Stage 2 | sleep stage characterized by sleep spindles and K complexes; percentage or duration spent in Stage 2 | |
| Slow Wave Sleep | sleep stage defined by high amplitude, low frequency slow waves; percentage or duration spent in Slow Wave Sleep | |
| REM Sleep | sleep stage defined by rapid eye movements, low muscle tone, and low amplitude mixed frequency waves; percentage or duration spent in REM sleep | |
| NREM Sleep | sleep measures collapsed across Stages 1, 2, and/or slow wave sleep; percentage or duration spent in NREM sleep | |
| Architecture | Spindle Density | frequency or proportion of spindles during a sleep period or during a specific sleep stage |
| Spindle Activity | measure capturing both spindle amplitude and duration (i.e., intensity) | |
| Spindle Activity Change | difference between spindle activity before and after experimental task | |
| Stage 2 Epochs With Spindles Change | difference between number of epochs within Stage 2 that contain spindles before and after experimental task | |
| Relative Slow | spectral power between 0.5 and 4.0 (to 4.6) Hz divided by | |
| Wave Activity | absolute spectral power | |
| Slow Oscillation-Spindle Coupling | temporal proximity of slow oscillations and sleep spindles | |
| Brain Connectivity During Sleep | brain connectivity modelled during specific sleep stages | |
| Slow Oscillation Power | slow oscillation power increases/decreases as compared to trials without slow oscillations | |
| Spindle Power | power in the spindle frequency range (11 to 15 Hz) | |
| Delta Power | relative/absolute delta power (.5 to 4.5 Hz) during sleep period | |
| Theta Power | relative/absolute theta power (4.5 to 8.5 Hz) during sleep period | |
| Alpha Power | relative alpha power during nap | |
| Sigma Power | relative theta power during nap |
NOTE: REM = rapid eye movement; NREM = non-rapid eye movement; Sleep stages are summarized based on the American Academy of Sleep Medicine. All sleep stage measurements correspond to sleep stage quantity.