Autor:innen:
Kristoffer Fehér, Bern (Switzerland)
Ximena Omlin, Bern (Switzerland)
Carlotta Louisa Schneider, Bern (Switzerland)
Leila Tarokh, Bern (Switzerland)
Yosuke Morishima, Bern (Switzerland)
Benjamin Ellenberger, Bern (Switzerland)
Simon Ruch, Bern (Switzerland)
Marc A. Züst, Bern (Switzerland)
Christian Mikutta, Bern (Switzerland)
Christoph Nissen, Bern (Switzerland)
Introduction
Recent studies indicate that selective suppression of slow wave sleep (SWS) may be an alternative to therapeutic sleep deprivation in patients with major depression. The purpose of this project was to develop and evaluate a fully automatized selective suppression of SWS based on closed-loop auditory stimulation.
Methods
A new automatized SWS suppression approach was developed and evaluated in a healthy, young population (N = 15). Stimulation was applied upon detection of SWS. SWS detection relied on a topographical template of slow waves. Stimulation involved applying discrete bursts of pink noise with a duration of 50-500 ms. The volume was increasing from 40 dB to 106 dB in 60 s, until SWS was no longer detected by the algorithm. The linear increase of volume was combined with random walks between +-2.5 dB (Ornstein-Uhlenbeck process) to add unpredictability in volume. The inter-stimulus-interval ranged between 1-4 s.
Results
The stimulation lead to a significant reduction of SWS, with an associated increase in sleep stage N2, without other significant changes in sleep continuity or architecture. Slow wave activity averaged across the night and cumulative slow wave energy at the end of the night were both reduced by about 30 % across channels and individuals, without changes in other frequency bands.
Conclusions
We demonstrate, to our knowledge for the first time, that a fully automatized approach can suppress SWS selectively without disturbing other sleep processes. Further developments bear the potential for translation to broader and even ambulatory use of automated SWS detection and modulation, and potentially for new treatment developments for major depression.