Sleep EEG diagnosis through novel method sensitive to phasic events

2020 Fiscal Year Research-status Report

• Project/Area Number: 19K12199
• Research Institution: University of Tsukuba
• Principal Investigator: Diaz Javier 筑波大学, 国際統合睡眠医科学研究機構, 研究員 (10835911)
• Co-Investigator(Kenkyū-buntansha): 佐藤 誠 筑波大学, 国際統合睡眠医科学研究機構, 教授 (50242409)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: Sleep physiology / Sleep mutants / Envelope analysis / EEG / Human Polysomnograpjy / random walk / time-domain-analysis / Computer simulations

Outline of Annual Research Achievements

Using envelope analysis in a human sleep study, it was possible to prove that people doing exercise sleep better in the next night (assessing the stability of EEG delta waves), compared with the sedentary condition (paired data). This study was recently published (doi: 10.1038/s41598-021-83817-6). The study shows the advantages of envelope analysis, enabling the extraction of EEG features which are inaccessible for classic spectral analysis.
The second branch of the project has also interesting results. From computational models assuming that EEG is originated by a superposition of pulses, we discovered a new technique to infer the theoretical pulses from the randomness of EEG. The technique is based on novel mathematical relationships (conjectures), stablished by us, and we are doing efforts to obtain their proofs in collaboration with a mathematician expert in stochastic processes. From a theoretical perspective, these findings are very valuable providing important evidence in favor of the arrhythmic nature of EEG. From a practical perspective, the technique can be used to classify bahavioral states (wakefulness and sleep states) without requiring electromiohraphy. Another pertinent example is the ability of the technique to confidently distinguish EEG from normal mice and SIK3 mutant mice (a mutant with an altered sleep phenotype). Remarkably, the technique is also significantly less sensitive to movement artifacts than classic spectral analysis.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

The main objectives of the project have reached an advanced state of development and concrete scientific results. One branch of the project (human EEG applications) has already a published results (doi: 10.1038/s41598-021-83817-6). The other branches of the project (ontology of EEG and application of envelope analysis to sleep studies in animal models) have produced already a volume of results suitable to generate at least two publications.

Strategy for Future Research Activity

The plans for the present year include: 1) to write the manuscripts mantioned above. 2) Test the applicability of our novel EEG analysys (transients analysis) in human EEG. 3) To apply envelope analysis to other human datasets (sleep studies). 4) To further explore stochastic EEG models with both theoretical and practical goals.

Causes of Carryover

In the present fiscal year, the grant will be used mainly in animal experimentation costs, animal facilities fees, and publication costs.

Research Products

• [Journal Article] Exercise improves the quality of slow-wave sleep by increasing slow-wave stability (2021)
  • Author(s): Insung Park*, Javier Diaz*, Sumire Matsumoto, Kaito Iwayama, Yoshiharu Nabekura, Hitomi Ogata, Momoko Kayaba, Atsushi Aoyagi, Katsuhiko Yajima, Makoto Satoh, Kumpei Tokuyama, Kaspar E Vogt
  • Journal Title: Scientific Reports Volume: 11 Pages: 4410
  • DOI: 10.1038/s41598-021-83817-6
  • Peer Reviewed / Open Access / Int'l Joint Research