Estimating heart rate and RSA from the mattress‐recorded kinetocardiogram

Abstract

This article describes a method for extracting heart rate (HR) and respiratory sinus arrhythmia (RSA) from the kinetocardiogram (KCG) recorded from accelerometers embedded in a mattress topper. Validation has been performed via comparison with simultaneously recorded ECG. All-night estimates of HR and RSA magnitude derived from both methods were highly correlated. KCG-derived estimates of HR were slightly lower, and those of RSA magnitude higher, than those derived from ECG. These biases are consistent with the need to constrain KCG estimation to periods free of body movement. Mattress actigraphy represents a zero-burden method of obtaining intensive longitudinal indices of cardiac status.

Autonomic Activation During Sleep in Posttraumatic Stress Disorder and Panic: A Mattress Actigraphic Study

“…Actigraphy infers sleep from immobility; however, immobility can be measured with varying precision, and may mean different things in different diagnostic groups (21,36). Analyses are now underway in our laboratory to evaluate the relative capacities of the different immobility indices obtainable from mattress actigraphy to predict PSG-defined sleep.…”

“…As with all actigraphy, epochs of low movement were used to estimate sleep vs wake, but could not provide direct information regarding sleep stage. Additional details of the estimation of HR and RSA from the KCG have been published elsewhere (21). …”

“…In employed a novel sleep assessment method, mattress actigraphy, which transduces large and small sleeper movements using accelerometers embedded in a mattress topper. These small movements include the kinetocardiogram (KCG), which, for movement-free periods, closely tracks the ECG (21). Because mattress actigraphy employs no body surface sensors, in-home recordings can be continued indefinitely.…”

Unobtrusive sleep state measurements in preterm infants – A review

“…These methods have been successfully used in adult patients (57)(58)(59)(60) Table 4). Another problem in the NICU is the signal amplitude.…”

“…The generated pulse wave can be monitored electrically with piezo elements (e.g. bed film sensors, Figure 6) (57), mechanically with load cells (58,59), or with accelerometers, known in this form of application as a kinetocardiogram (60). The difference between the methods is that the use of accelerometers needs time-varying pressure, while piezo and load sensors can also measure a constant pressure.…”