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

Obstructive sleep apnea (OSA) is associated with arousals due to thecessation of breathing during sleep. On the other hand, sleep spindles, an EEG wave mainlyseen in stage 2 of non-REM sleep (N2), are responsible for many functions including themaintenance of sleep. We aimed to investigate the association between sleep spindles andOSA and compare the additional polysomnography (PSG) metrics in a group of patientswith OSA. Fifty consecutive patients with moderate and severe OSA wererecruited. Association of apnea-hypopnea index (AHI) with spindles in N2 and arousalswere evaluated. Other PSG metrics were compared in the moderate versus severe group. Body mass and snore indices were significantly more in the severe group (p=0.002and 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 numberof 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). 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 relationshipbetween sleep spindles and OSA.