hypnogram
Pronunciation: HIP-no-gram
Graphical representation of sleep stages over time, showing the progression through different phases of sleep.
Full Definition
A hypnogram is a visual display of sleep architecture that plots sleep stages (wake, N1, N2, N3, and REM) against time throughout the night. This graph is generated from polysomnography data and provides a quick overview of sleep quality, continuity, and stage distribution. Normal hypnograms show characteristic patterns with deeper sleep stages early in the night and increasing REM periods toward morning. Abnormal hypnograms may reveal frequent awakenings, reduced deep sleep, or disrupted REM patterns associated with various sleep disorders.
Usage
Usage note: Not to be confused with 'polysomnogram', which refers to the entire sleep study record.
In Context
- "The hypnogram demonstrated normal sleep architecture with appropriate cycling between stages." — Sleep study report
- "Review of the hypnogram revealed frequent transitions to stage N1 throughout the night." — Sleep disorder analysis