II. Indications
III. Definitions
- Actigraphy
- Accelerometer monitors patients overnight movement
- Calculates actual patient sleep time
- Calculates limb movements over time
IV. Technique
- Patient wears a sensor on their wrist or ankle overnight for days to weeks
- Device measures frequency and degree of limb movements over time
V. Interpretation
- Sleep Phases
- Sleep Duration
- Sleep Patterns
- Sleep Latency (Sleep Onset Latency)
- Time for a person to fall asleep after intending to sleep (e.g. lying down, lights off)
- Normally 10-20 minutes
- Sleep Efficiency
- Key metric in Cognitive Behavioral Therapy for Insomnia
- Normally >80%
- Sleep Efficiency = (100 * TST / TIB)
- Where TST is total sleep time
- Where TIB is time in bed