Sleep measurement tools W2 L2

Polysomnography (PSG)

A comprehensive sleep study used to diagnose sleep disorders, measuring brain waves, oxygen levels, heart rate, and breathing.

Actigraphy

A non-invasive method used to monitor sleep by measuring movement, typically using a wrist-worn device.

Sleep Diary

A subjective measure used to record sleep patterns, including sleep duration and latency, usually filled out upon waking.

Sleep Latency

The time it takes to fall asleep after turning off the lights.

Sleep Efficiency

The ratio of total sleep time to total time spent in bed, expressed as a percentage.

Sensitivity

The measure of a tool's ability to correctly identify sleep events.

Specificity

The measure of a tool's ability to correctly identify wake events.

Awake after Sleep Onset (WASO)

The total duration of wakefulness after initially falling asleep.

REM Sleep

Rapid Eye Movement sleep, a stage of sleep characterized by quick eye movements and known for vivid dreaming.

Wearable Sleep Monitors

Devices worn on the body, such as watches or rings, that track sleep patterns and activities.

Nearable Devices

Sleep monitoring devices placed close to the bed, such as under a mattress or pillow.

Arable Devices

Sleep trackers that are situated next to the bed, often using sound waves to monitor sleep.

Sleep Onset

The point in time when a person first falls asleep.

REM Latency

The duration from sleep onset to the first occurrence of REM sleep.

Sleep Offset

The time at which a person wakes up after sleeping.

Validation Study

Research conducted to determine the accuracy and reliability of a sleep measurement tool compared to a gold standard.

Bland-Altman Plot

A graphical method used to compare two measurement techniques by plotting the difference against the average of the two methods.

Self-assessment of Sleep

The personal evaluation of one's own sleep quality and duration, which can differ from objective measurements.

Circadian Rhythm

The physical, mental, and behavioral changes that follow a 24-hour cycle, responding primarily to light and darkness.

Total Sleep Time (TST)

The actual amount of time a person spends sleeping during a sleep period.

Light Sleep

A sleep stage characterized by light sleep, often considered stages 1 and 2 of the sleep cycle.

Deep Sleep

The restorative stage of sleep, typically associated with stages 3 and 4 of the sleep cycle.

Technology Standards in Sleep Tracking

Guidelines developed to ensure consistency and accuracy in terminology and measurement methods among sleep tracking devices.