Comparison between Chest-Worn Accelerometer and Gyroscope Performance for Heart Rate and Respiratory Rate Monitoring

Abstract

The demand for wearable devices to simultaneously monitor heart rate (HR) and respiratory rate (RR) values has grown due to the incidence increase in cardiovascular and respiratory diseases. The use of inertial measurement unit (IMU) sensors, embedding both accelerometers and gyroscopes, may ensure a non-intrusive and low-cost monitoring. While both accelerometers and gyroscopes have been assessed independently for both HR and RR monitoring, there lacks a comprehensive comparison between them when used simultaneously. In this study, we used both accelerometers and gyroscopes embedded in a single IMU sensor for the simultaneous monitoring of HR and RR. The following main findings emerged: (i) the accelerometer outperformed the gyroscope in terms of accuracy in both HR and RR estimation; (ii) the window length used to estimate HR and RR values influences the accuracy; and (iii) increasing the length over 25 s does not provide a relevant improvement, but accuracy improves when the subject is seated or lying down, and deteriorates in the standing posture. Our study provides a comprehensive comparison between two promising systems, highlighting their potentiality for real-time cardiorespiratory monitoring. Furthermore, we give new insights into the influence of window length and posture on the systems’ performance, which can be useful to spread this approach in clinical settings.

Linear and Non-Linear Heart Rate Variability Indexes from Heart-Induced Mechanical Signals Recorded with a Skin-Interfaced IMU

“…Additionally, further efforts will be devoted to investigating the effect of respiration in HRV analysis. As it has already been demonstrated that a single IMU sensor on the chest is able to capture the respiratory rate [ 21 ], in the future we will investigate how the contextual assessment of this vital parameter can help to provide a more accurate assessment of HRV indexes (especially in the frequency domain), which has only been partially demonstrated with studies on a limited number of subjects during ECG monitoring [ 60 , 61 ]. Lastly, the study was conducted only under resting conditions, so motion artifacts that could adversely affect the results were inherently eliminated.…”

“…A single IMU (Xsens DOT by Xsens, The Netherlands) was attached with a hypoallergenic medical-grade double-sided tape at the xiphoid process level. Among the numerous body landmarks used to collect cardiac-related acceleration signals, we used the xiphoid because of good inter-subject reliability and easy identification of the body [ 21 , 22 ]. The selected IMU sensor has different features that make it ideal in this scenario.…”

“…Among others, accelerometers and gyroscopes in the last decade have been explored to extract information about the mechanical phases of the cardiac cycle from precordial vibrations captured at the chest level and changes in its angular velocities, respectively. These signals are generally known as seismocardiogram (in short SCG) [ 21 , 22 , 23 ] and gyrocardiogram (in short GCG) [ 24 ], respectively. For instance, when rightly collected from both the SCG and GCG signals, it is possible to identify some key cardiac events during both the systole and diastole [ 22 , 24 , 25 ].…”

BIOWISH: Biometric Recognition Using Wearable Inertial Sensors Detecting Heart Activity

“…Such devices are typically inexpensive, unobtrusive, resistant to electromagnetic and acoustic interferences, safe and viable for prolonged use, since they commonly have an extremely low power consumption [23]. Actually, SCG and GCG techniques are rapidly spreading in medical scenarios as alternatives to ECG for monitoring the pre-and post-procedural conditions of patients [25], allowing to estimate hemodynamic parameters that can be hardly recovered using other sensing techniques [26], [27]. Several other applications, including posture analysis and context retrieval, have been also designed using chest-worn inertial sensors [28].…”

Monitoring of Cardiorespiratory Parameters during Sleep Using a Special Holder for the Accelerometer Sensor

“…Some of them used a hydraulic sensor system filled with water [17], load cells [18], piezoelectric load [19], pressure sensors installed under the mattress [20,21] and others. With the development of highly sensitive accelerometers based on micro-electromechanical systems (MEMS), their application in various measurement fields is growing rapidly [22][23][24][25]. Unfortunately, using accelerometers to measure BCG signals remains an understudied area of metrology [13,26,27].…”