sleep spindle
Characteristic EEG waveforms appearing during stage 2 sleep, consisting of 11-15 Hz activity in spindle-shaped bursts.
Full Definition
Sleep spindles are distinctive electroencephalographic features that mark the onset of stage 2 non-REM sleep. They consist of rhythmic 11-15 Hz (sigma frequency) oscillations that wax and wane in amplitude, creating a spindle-like appearance on the EEG trace. Generated by the thalamic reticular nucleus, sleep spindles typically last 0.5-3 seconds and occur every 3-10 seconds during stage 2 sleep. They are most prominent in central and parietal regions and represent a key marker of sleep consolidation. Abnormalities in sleep spindle morphology or frequency can indicate various sleep disorders or neurological conditions.
Usage
Usage note: Hyphenate when used as compound modifier; distinguish from other sleep-related EEG phenomena.
In Context
- "Well-formed sleep spindles were present bilaterally during stage 2 sleep." — Polysomnography report
- "The patient showed reduced sleep spindle density compared to age-matched controls." — Sleep study interpretation