Feasibility Analysis of Applying Non-Invasive Core Body Temperature Measurement in Sleep Research

Core body temperature (CBT) emerges as a pivotal physiological marker in sleep research, and the commonly employed invasive CBT measurements significantly disrupt the sleep process itself. Non-invasive CBT measurement offers a viable solution to this challenge but lack validation. In this sleep study, simultaneous invasive and non-invasive measurements of CBT were conducted on 14 subjects. Ingestible capsule was chosen to represent invasive measurement, while external GreenTeg patch was selected as representative device for noninvasive measurement. Quantitative comparisons of two measurements were conducted from four perspectives: correlation, consistency, difference, and stability, and results indicated: (1) A significant correlation was observed between two real-time measurements, and correlation became stronger as ambient temperature decreased. (2) Consistency of most data group can be acceptable as most of them fell within the 95% agreement range. (3) Non-invasive instrument exhibited substantial error for unstable core temperature, yet displayed relatively small error for stable core temperature. (4) Stability of difference between two measurements was poor during 64.3% of the time intervals, and this performance deteriorated further in unstable state. In summary, existing non-invasive measurement can serve as a reference for sleep research, but caution is warranted when applying it to real-time and unstable analyses. Additionally, feasibility of algorithm optimization makes the future of non-invasive measurements promising.