Association of Sleep Spindles, Sleep Apnea, and Other Polysomnography Parameters; a Single Center Preliminarily Report

Document Type : Original Articles


1 Students’ Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran

2 Health Policy Research Center, Institute of Health, Shiraz University of Medical Sciences, Shiraz, Iran


Introduction: Obstructive sleep apnea (OSA) is associated with arousals due to the
cessation of breathing during sleep. On the other hand, sleep spindles, an EEG wave mainly
seen in stage 2 of non-REM sleep (N2), are responsible for many functions including the
maintenance of sleep. We aimed to investigate the association between sleep spindles and
OSA and compare the additional polysomnography (PSG) metrics in a group of patients
with OSA.
Materials and Method: Fifty consecutive patients with moderate and severe OSA were
recruited. Association of apnea-hypopnea index (AHI) with spindles in N2 and arousals
were evaluated. Other PSG metrics were compared in the moderate versus severe group.
Results: Body mass and snore indices were significantly more in the severe group (p=0.002
and p<0.001, respectively). Arousals were more frequently seen in severe OSA cases
(p=0.064). Sleep spindle index did not have any relationship with AHI and the number
of arousals. However, arousals were weakly correlated with AHI (Spearman’s rho= 0.293,
p=0.039) and snore index (Spearman’s rho= 0.365, p=0.010).
Conclusion: Severity of OSA did not show a clear correlation with spindle density in N2.
Further studies with larger samples and a control group are needed to prove a relationship
between sleep spindles and OSA.