https://orcid.org/0000-0001-5057-633X
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Abstract
Purpose
In non-rapid eye movement (NREM) stage 3 sleep (N3), phase-locked pink noise auditory stimulation can amplify slow oscillatory activity (0.5–1 Hz). Open-loop pink noise auditory stimulation can amplify slow oscillatory and delta frequency activity (0.5–4 Hz). We assessed the ability of pink noise and other sounds to elicit delta power, slow oscillatory power, and N3 sleep.
Participants and Methods
Participants (n = 8) underwent four consecutive inpatient nights in a within-participants design, starting with a habituation night. A registered polysomnographic technologist live-scored sleep stage and administered stimuli on randomized counterbalanced Enhancing and Disruptive nights, with a preceding Habituation night (night 1) and an intervening Sham night (night 3). A variety of non-phase-locked pink noise stimuli were used on Enhancing night during NREM; on Disruptive night, environmental sounds were used throughout sleep to induce frequent auditory-evoked arousals.
Results
Total sleep time did not differ between conditions. Percentage of N3 was higher in the Enhancing condition, and lower in the Disruptive condition, versus Sham. Standard 0.8 Hz pink noise elicited low-frequency power more effectively than other pink noise, but was not the most effective stimulus. Both pink noise on the “Enhancing” night and sounds intended to Disrupt sleep administered on the “Disruptive” night increased momentary delta and slow-wave activity (ie, during stimulation versus the immediate pre-stimulation period). Disruptive auditory stimulation degraded sleep with frequent arousals and increased next-day vigilance lapses versus Sham despite preserved sleep duration and momentary increases in delta and slow-wave activity.
Conclusion
These findings emphasize sound features of interest in ecologically valid, translational auditory intervention to increase restorative sleep. Preserving sleep continuity should be a primary consideration if auditory stimulation is used to enhance slow-wave activity.
Abbreviations
AASM, American Academy of Sleep Medicine; AICC, Akaike information criterion (corrected for small sample size); EEG, Electroencephalographic; ERP, Event-related potential; FFT, Fast Fourier transform; LMM, Linear mixed model; MSLT, Multiple sleep latency test; NREM, Non-rapid eye movement sleep; N1, Non-rapid eye movement sleep, stage 1; N2, Non-rapid eye movement sleep, stage 2; N3, Non-rapid eye movement sleep, stage 3; PSD, Power spectral density; PSG, polysomnography; PSQ, Post-Sleep Questionnaire; PVT, Psychomotor vigilance task; REM, Rapid eye movement; RPSGT, Registered Polysomnographic Technologist; RT, Reaction time; SO, slow oscillation/oscillatory; TST, Total sleep time.
Data Sharing Statement
Published data are available by request pending approval of a data sharing and transfer agreement with the Pennsylvania State University.
Ethics Approval and Informed Consent
The Office for Research Protections (IRB office) at the Pennsylvania State University reviewed and approved this study (#5094).
Acknowledgments
We would like to thank the participants for providing their data. Work was funded by the National Science Foundation (NSF) under grant #1622766, awarded to Gartenberg (PI; CEO Proactive Life Inc, formerly Mobile Sleep Technologies LLC (DBA SleepSpace)).
Author Contributions
OMB and DG conceived of the study, obtained funding, and supervised the project and manuscript preparation. DG and DMR created the software and coordinated the hardware used for auditory stimulus delivery. MMS and GMM collected and managed study data. MMS, GMM, and DMR processed, analyzed, and interpreted study data. All authors made substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; took part in drafting the article or revising it critically for important intellectual content; gave final approval of the version to be published; and agree to be accountable for all aspects of the work. All authors approved the final submission.
Disclosure
Dr Margeaux M. Schade reports grants, non-financial support from Proactive Life Inc, formerly Mobile Sleep Technologies LLC (DBA SleepSpace)/NSF, during the conduct of the study; grants, non-financial support from Proactive Life Inc/NIH, outside the submitted work.
Ms Gina Marie Mathew reports grants from National Science Foundation during the conduct of the study.
Dr Daniel M. Roberts reports personal fees from Proactive Life Inc, formerly Mobile Sleep Technologies LLC (DBA SleepSpace), grants from National Institutes of Health, grants from National Science Foundation, during the conduct of the study.
Dr Daniel Gartenberg reports personal fees from Proactive Life Inc, formerly Mobile Sleep Technologies LLC (DBA SleepSpace), grants from National Institutes of Health, and grants from National Science Foundation, during the conduct of the study. In addition, Dr Daniel Gartenberg has a patent, 10524661: Sleep Monitoring and Stimulation, issued to Proactive Life Inc.
Professor Orfeu Buxton reports grants from Proactive Life Inc, formerly Mobile Sleep Technologies LLC (DBA SleepSpace), during the conduct of the study; grants from Proactive Life Inc, outside the submitted work and Dr. Buxton reports current grant support from the National Institutes of Health (NIA, NIMH, NHLBI, NIMHD, NICHD, NIDDK, NCATS, NLM). Dr. Buxton received honoraria/travel support for lectures from Boston University, Boston College, Tufts School of Dental Medicine, and Allstate, and receives an honorarium from the National Sleep Foundation (sleepfoundation.org) for his work as Editor in Chief (designate) of Sleep Health.