1381 Reading Eye Movements on Polysomnography: A Marker of Wakefulness Affecting Sleep Study Interpretation

Abstract Introduction Polysomnography (PSG) relies on electrooculography (EOG) to stage sleep, particularly REM. Voluntary eye movements during wakefulness, such as slow horizontal conjugate movements resembling reading, may mimic sleep-related activity and lead to misinterpretation. Report of case(s) A young adult female presented with insomnia and occasional hallucinations. History revealed chronic sleep restriction (2–6 hours/night) due to shift work and academic demands. PSG showed minimal snoring, no obstructive sleep apnea, reduced sleep efficiency, prolonged latency, and normal REM latency. EOG demonstrated slow, horizontal, conjugate movements during wakefulness, consistent with voluntary reading-like activity. MSLT revealed borderline latency and few SOREMPs, excluding narcolepsy. She was diagnosed with insufficient sleep syndrome and delayed sleep phase secondary to lifestyle factors. Management focused on sleep hygiene, schedule optimization, behavioral strategies, and no pharmacotherapy. Differentiating “reading eye movements” from nystagmus, SSRI-related movements, scanning saccades, and REM bursts is essential. In this case, recognition of voluntary wake-specific movements prevented misclassification. Other eye movements to consider are: nystagmus (rhythmic, involuntary); "Prozac eyes" (SSRI-related in NREM); scanning (voluntary saccades awake); slow rolling (pendular in drowsiness) vs normal REM: reduced velocity/density (PSP vs. Parkinson's); Ictal (saccades/drift in seizures); roving in coma; lucid signals (voluntary in REM); lateral spikes (artifacts); epileptic nystagmus and slowed vertical saccades (PSP). Conclusion Awareness of reading eye movements on PSG is critical for accurate sleep staging and avoiding diagnostic errors. Comprehensive interpretation, incorporating clinical history should guide management. Support (if any)