Intermediate
Technical
IVT
epoch
Pronunciation: EE-pok
A standardized 30-second segment used for sleep stage scoring in polysomnography.
Full Definition
An epoch represents the fundamental time unit for sleep analysis, consisting of exactly 30 seconds of recorded data. Sleep technologists and physicians score each epoch according to standardized criteria, assigning it to specific sleep stages (N1, N2, N3, or REM) or wake. The epoch-by-epoch analysis allows for detailed mapping of sleep architecture and identification of sleep stage transitions. Modern sleep scoring follows AASM guidelines that define specific EEG, EMG, and EOG criteria for each epoch classification.
Usage
Usage note: Always refers to the 30-second standard; other time segments should be specified explicitly.
In Context
- "The technologist scored 720 epochs during the 6-hour sleep recording." — Sleep lab report
- "Each epoch must meet specific criteria for stage N2 classification including sleep spindles or K-complexes." — Scoring manual
Also known as
30-second epoch
scoring epoch
Don't confuse with
event
segment