Table 4.
Objective and Subjective Measures of Sleep
| Measure | Description |
|---|---|
| Overnight polysomnography | Considered the measurement standard of sleep. Includes assessment of electrical activity via electroencephalography (EEG), muscle tone via electromyogram (EMG), and eye movements via electrooculogram (EOG), along with cardiac and respiratory measures. |
| Daytime polysomnography | Multiple sleep latency test (MSLT) and Maintenance of wakefulness test (MWT) can provide valuable insight into objective sleepiness and ability to maintain wakefulness, respectively. MSLT is required for diagnosis of narcolepsy. |
| Actigraphy | Small, wristwatch-size device that is typically worn on the non-dominant hand. Models range from relatively inexpensive, non-validated commercial activity monitors to those with research-grade processors. Actigraphy has been employed in TBI.36 |
| Sleep diary | Standardized approach to measuring self-reported sleep patterns over time, and sleep diaries have been utilized as an outcome measure in patients with mTBI.14,40,41 |
| Advanced sleep measurement methods | High-density EEG (hd-EEG) and sleep neuroimaging have advanced understanding of localized and neural underpinnings of healthy and disrupted sleep, including circadian variation in brain function.47–49 |
| Questionnaire | |
| Pittsburgh Sleep Quality Index (PSQI) | Nineteen-item self-report questionnaire that assesses sleep quality and disturbances over a 1-month time interval. The PSQI has adequate psychometric properties and has been validated for insomnia in TBI.45,201 |
| Insomnia Severity Index (ISI) | Seven-item self-report questionnaire that assesses perceived sleep disturbance and daytime consequences. The ISI possesses excellent psychometric properties and is the most commonly used insomnia measure.202 |
| Epworth Sleepiness Scale | Eight items assess likelihood of falling asleep in common daytime situations, for example watching television or as a passenger in a car. Scores are summed to determine subjective sleepiness.203 |
TBI, traumatic brain injury; mTBI, mild traumatic brain injury.