0469 Respiratory Cycle-Related EEG Changes (RCREC) Predict All-Cause Mortality in the Sleep Heart Health Study (SHHS)

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Department of Electrical and Computer Engineering



Sleep-disordered breathing (SDB) is among the most prevalent sleep disturbances in adults and is associated with an increased risk of death. This analysis focused on data from a large cohort of adults to assess whether an SDB biomarker based on quantitative analysis of sleep EEG, namely Respiratory Cycle-Related EEG Changes (RCREC), may in comparison to the standard apnea-hypopnea index (AHI) improve prediction of all-cause mortality. The RCREC are thought to represent breath-to-breath, inspiratory microarousals associated with increased work of breathing. Methods

Data were obtained from the Sleep Heart Health Study (SHHS), a multicenter longitudinal study focused on SDB and cardiovascular health of middle-aged to older adults. The RCREC values were computed in delta (0.5-4.5 Hz), theta (4.5-8.5 Hz), alpha (8.5-12.5 Hz), sigma (12.5-15.5 Hz), beta (15.5-30.5 Hz), and gamma (30.5-49.0 Hz) frequency bands. Sequential Cox Proportional Hazard models, adjusted for body-mass index, age, race, smoking status, and sex, were used to assess association with all-cause mortality. Results

Among adults with sufficient data quality (n=4427, mean age at baseline 62.8 ±10.9 (SD) years, 53% female), AHI and gamma RCREC separately showed associations with risk of mortality (adjusted OR 1.01 deaths per year per unit increase in AHI (p<0.04); 1.02 per year per 0.1 increase in gamma RCREC (p<0.0001). In a model that included AHI, gamma RCREC, and the above covariates, gamma RCREC retained significance (p<0.0001), AHI did not (p=0.14), and addition of AHI had not improved the overall model significance (Wilks’ Theorem, p=0.15). The RCREC in other frequency bands were not similarly effective. Conclusion

Gamma RCREC as a biomarker of SDB may, in comparison to the AHI, better predict all-cause mortality in the SHHS. The reason for clinical utility of gamma as opposed to other-frequency RCREC is not clear, though the reported prominence among insomniacs of gamma EEG power, thought to represent cortical hyperactivation, allows speculation that chronic repetitive nightly exposure could shorten life.

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© Sleep Research Society 2019. Publisher’s version of record: https://doi.org/10.1093/sleep/zsz067.468

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