@misc{9238185,
  abstract     = {{Continuous non-invasive monitoring of respiratory rate in laboratory mice can support research across drug efficacy, sleep, and stress and pain assessment. Established respiratory rate estimation methods exist but many conflict with the 3Rs principle through invasiveness, motion restriction, or animal stress. A cross-method comparison between two non-invasive systems on the same freely-moving animal offers a verification path that does not require an invasive reference. The goal was to conduct such a comparison, analyzing agreement between methods and when methods become unreliable dependent on behavioral state.

A signal-processing pipeline was developed for a 60 GHz pulse coherent radar
(Acconeer A121) mounted above a home cage, extracting respiratory rate from
chest-wall-displacement phase information. Twelve pipeline iterations were each accepted against a non-regression gate on a synthetic-signal benchmark. 

Resulting respiration rate estimates from the final pipeline were compared against an existing force-sensor respiratory rate metric (TrackPaw) on simultaneous recordings spanning four cages and multiple 24-hour long sessions, with neither system treated as ground truth. Agreement was characterized by Bland-Altman analysis with a repeated-measures formulation. Behavioral-state robustness was characterized by per-method coverage and by agreement between the radar flagging motion and TrackPaw's flagging travel.

After 30 s pre-pairing aggregation, the joint bias between the methods was +0.03 Hz with 95 % limits of agreement of −0.14 and +0.20 Hz. Neither method reliably produced estimates during active behavior, when radar and TrackPaw both flag motion, and most coverage from both methods happened when no motion was flagged.

Continuous non-invasive respiratory rate monitoring in the home cage appears feasible at rest. Reliable estimation during active behavior remains an open problem for both methods.}},
  author       = {{Andersson, Axel}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Comparing Radar and Force-Sensor Method agreement for Non-Invasive Respiratory Monitoring of Freely-Moving Mice}},
  year         = {{2026}},
}