Am. J. Respir. Crit. Care Med., Vol 154, No. 1, Jul 1996, 167-169.
Rapid-eye-movement-specific sleep-disordered breathing: a possible cause of excessive daytime sleepiness
JE Kass, SM Akers, TC Bartter and MR Pratter
Department of Medicine, Cooper Hospital/University Medical Center, Camden, NJ 08103, USA.
Some patients referred for polysomnography with complaints of excessive
daytime sleepiness (EDS) and clinically suspected obstructive sleep apnea
(OSA) have a respiratory disturbance index (RDI) < 10. Many would
consider these patients not to have OSA. We reviewed 34 such patients to
determine whether respiratory disturbances confined primarily to rapid eye
movement (REM) sleep correlated with an objective criterion for EDS: a mean
sleep latency (MSL) < 10 min. REM-specific events were quantified with
indices calculated for REM sleep alone. Univariate linear regression showed
that a REM-specific respiratory disturbance index (REM-RDI) and the
transient arousal index (TAI) computed for REM sleep (REM-TAI) were
associated with a low MSL (R2 = -0.35, p = 0.001; and R2 = -0.27, p = 0.01,
respectively). In our subjectively sleepy patients with an overall RDI <
10, a REM-RDI > or = 15 had the highest predictive accuracy (82%) for an
MSL < 10 min. Seventeen of the 34 study patients had a REM-RDI > or =
15. Their mean MSL was 8.3 +/- 0.8 min. We conclude that within a group of
patients with daytime sleepiness, suspected OSA, and a normal RDI, there
may be a subset who have clinically significant REM-specific
sleep-disordered breathing.
