Real-Time Excitation of Slow Oscillations during Deep Sleep Using Acoustic Stimulation

Abstract

Slow-wave synchronous acoustic stimulation is a promising research and therapeutic tool. It is essential to clearly understand the principles of the synchronization methods, to know their performances and limitations, and, most importantly, to have a clear picture of the effect of stimulation on slow-wave activity (SWA). This paper covers the mentioned and currently missing parts of knowledge that are essential for the appropriate development of the method itself and future applications. Artificially streamed real sleep EEG data were used to quantitatively compare the two currently used real-time methods: the phase-locking loop (PLL) and the fixed-step stimulus in our own implementation. The fixed-step stimulation method was concluded to be more reliable and practically applicable compared to the PLL method. The sleep experiment with chronic insomnia patients in our sleep laboratory was analyzed in order to precisely characterize the effect of sound stimulation during deep sleep. We found that there is a significant phase synchronization of delta waves, which were shown to be the most sensitive metric of the effect of acoustic stimulation compared to commonly used averaged signal and power analyses. This finding may change the understanding of the effect and function of the SWA stimulation described in the literature.

Cereset Research Standard Operating Procedures for Insomnia: A Randomized, Controlled Clinical Trial

“…Within the growing non-pharmacological landscape for insomnia, there has been recent interest in using acoustic stimulation to enhance slow wave oscillations during sleep. 48 The oscillation literature suggests the pathophysiology of insomnia could be characterized by a lack of slow wave activity, thus measurement of slow wave sleep content would be beneficial in future studies.…”

Neural field model simulation of changes in cortical slow-wave sleep events by sensory stimulation in plasticity-evolving NREM sleep

“…Even, when it is known from Arnold tongues (Herrmann et al, 2016;Vosskuhl et al, 2018) that stimulation requires less energy as more specific is the stimulation frequency. It was also noted that for electroencephalogram signals, fixed-step stimulation is more reliable than phase-locking loop methods (Piorecky et al, 2021). Further, our stimulation method has zero-delay between detection and stimulus delivery, but the required time for the stimulation device must be taken in account.…”