@article{ref1,
title="Altered K-complex morphology during sustained inspiratory airflow limitation is associated with next-day lapses in vigilance in obstructive sleep apnea",
journal="Sleep",
year="2021",
author="Rapoport, David M. and Eckert, Danny J. and Varga, Andrew W. and Mazumdar, Madhu and Berkalieva, Asem and Mullins, Anna E. and Kam, Korey and Castillo, Bresne and Parekh, Ankit and Ayappa, Indu",
volume="ePub",
number="ePub",
pages="ePub-ePub",
abstract="STUDY OBJECTIVES: Determine if changes in K-complexes associated with sustained inspiratory airflow limitation (SIFL) during N2 sleep are associated with next-day  vigilance and objective sleepiness. <br><br>METHODS: Data from thirty subjects with  moderate-to-severe OSA who completed three in-lab polysomnograms: diagnostic, on  therapeutic continuous positive airway pressure (CPAP), and on suboptimal CPAP  (4cmH20 below optimal titrated CPAP level) were analyzed. Four 20-min psychomotor  vigilance tests (PVT) were performed after each PSG, every two hours. Changes in  proportion of spontaneous K-complexes and spectral characteristics surrounding  K-complexes were evaluated for K-complexes associated with both delta (∆SWAK), alpha  (∆αK) frequencies. <br><br>RESULTS: Suboptimal CPAP induced SIFL (14.7(20.9) vs. 2.9(9.2);  %total sleep time, p<0.001) with a small increase in apnea hypopnea index (AHI3A:  6.5(7.7) vs. 1.9(2.3); p<0.01) versus optimal CPAP. K-complex density (num./min of  stage N2) was higher on suboptimal CPAP (0.97±0.7 vs. 0.65±0.5, #/min, mean±SD,  p<0.01) above and beyond the effect of age, sex, AHI3A, and duration of SIFL. A  decrease in ∆SWAK with suboptimal CPAP was associated with increased PVT lapses and  explained 17% of additional variance in PVT lapses. Within-night during suboptimal  CPAP K-complexes appeared to alternate between promoting sleep and as arousal  surrogates. EEG changes were not associated with objective sleepiness. <br><br>CONCLUSIONS:  Sustained inspiratory airflow limitation is associated with altered K-complex  morphology including increased occurrence of K-complexes with bursts of alpha as  arousal surrogates. These findings suggest that sustained inspiratory flow  limitation may be associated with non-visible sleep fragmentation and contribute to  increased lapses in vigilance.<p /> <p>Language: en</p>",
language="en",
issn="0161-8105",
doi="10.1093/sleep/zsab010",
url="http://dx.doi.org/10.1093/sleep/zsab010"
}