A wearable EEG system for closed-loop neuromodulation of sleep-related oscillations

Area of Science:

• Neuroscience
• Sleep Science
• Biomedical Engineering

Background:

• Healthy sleep is vital for well-being.
• Targeting slow-wave sleep with acoustic stimuli shows promise for improving sleep quality.
• Closed-loop stimulation during other sleep phases could offer additional health benefits, but requires precise tracking of brain activity.

Purpose of the Study:

• To assess the feasibility of using a wearable device with an endpoint-corrected Hilbert transform (ecHT) algorithm for real-time tracking and phase-locked stimulation of alpha brainwaves.
• To evaluate the system's performance in measuring electroencephalogram (EEG) signals and delivering auditory stimulation during the transition to sleep in a home setting.

Main Methods:

• Developed and validated an endpoint-corrected Hilbert transform (ecHT) algorithm for precise phase measurement of neural oscillations.
• Implemented the ecHT algorithm on a headband wearable device for at-home EEG monitoring and auditory stimulation.
• Conducted a pilot sleep study to test user feasibility, data collection fidelity, and the impact of stimulation on sleep onset.

Main Results:

• The ecHT algorithm accurately computed instantaneous signal phases, enabling low-phase-error auditory stimulation.
• The wearable system reliably measured sleep-related neural activity for sleep stage scoring in a home environment.
• Users successfully operated the system independently, and auditory stimulation did not impede sleep onset.

Conclusions:

• Demonstrates the feasibility of a closed-loop wearable EEG system for real-time tracking and neuromodulation of various sleep oscillations.
• Suggests this non-invasive approach holds potential for modulating neural activity across all sleep phases.
• Paves the way for advanced sleep quality enhancement and therapeutic interventions.