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Instantaneous Respiratory Estimation from Thoracic Impedance by Empirical Mode Decomposition.

Wang FT, Chan HL, Wang CL, Jian HM, Lin SH - Sensors (Basel) (2015)

Bottom Line: This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring.Moreover, large motion artifacts disable the EMD to decompose respiratory components.A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, Hwa Hsia University of Technology, 111, Gongzhuan Rd., Zhonghe, New Taipei City 23568, Taiwan. wft.intuitive@seed.net.tw.

ABSTRACT
Impedance plethysmography provides a way to measure respiratory activity by sensing the change of thoracic impedance caused by inspiration and expiration. This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring. The empirical mode decomposition (EMD) can decompose a signal into several intrinsic mode functions (IMFs) that disclose nonstationary components as well as stationary components and, similarly, capture respiratory episodes from thoracic impedance. However, upper-body movements usually produce motion artifacts that are not easily removed by digital filtering. Moreover, large motion artifacts disable the EMD to decompose respiratory components. In this paper, motion artifacts are detected and replaced by the data mirrored from the prior and the posterior before EMD processing. A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation. Based on the experiments performing a series of static and dynamic physical activates, our results showed the proposed method had higher cross correlations between respiratory frequencies estimated from thoracic impedance and those from oronasal airflow based on small window size compared to the Fourier transform-based method.

No MeSH data available.


A block diagram of the proposed respiration analysis. Motion artifacts are first detected and replaced by mirrored data from the prior and the posterior. Numbers of intrinsic mode functions (IMFs) are subsequently computed through empirical mode decomposition. Respiration-related IMFs are identified and used to reconstruct respiration and compute instantaneous frequency and amplitude.
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sensors-15-16372-f003: A block diagram of the proposed respiration analysis. Motion artifacts are first detected and replaced by mirrored data from the prior and the posterior. Numbers of intrinsic mode functions (IMFs) are subsequently computed through empirical mode decomposition. Respiration-related IMFs are identified and used to reconstruct respiration and compute instantaneous frequency and amplitude.

Mentions: Figure 3 depicts the block diagram of EMD-based respiration analysis. First, an artifact detection and replacing algorithm is applied to detect the artifacts induced by postural changes or other motion disturbances. The affected portion is replaced by the mirror data from the prior and posterior. Then, EMD is applied to decompose this signal into numbers of IMFs. Respiration-related IMFs are identified according to an intrinsic respiratory reconstruction index. The identified IMFs are used to reconstruct respiration and estimate the instantaneous respiratory frequency and amplitude.


Instantaneous Respiratory Estimation from Thoracic Impedance by Empirical Mode Decomposition.

Wang FT, Chan HL, Wang CL, Jian HM, Lin SH - Sensors (Basel) (2015)

A block diagram of the proposed respiration analysis. Motion artifacts are first detected and replaced by mirrored data from the prior and the posterior. Numbers of intrinsic mode functions (IMFs) are subsequently computed through empirical mode decomposition. Respiration-related IMFs are identified and used to reconstruct respiration and compute instantaneous frequency and amplitude.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541883&req=5

sensors-15-16372-f003: A block diagram of the proposed respiration analysis. Motion artifacts are first detected and replaced by mirrored data from the prior and the posterior. Numbers of intrinsic mode functions (IMFs) are subsequently computed through empirical mode decomposition. Respiration-related IMFs are identified and used to reconstruct respiration and compute instantaneous frequency and amplitude.
Mentions: Figure 3 depicts the block diagram of EMD-based respiration analysis. First, an artifact detection and replacing algorithm is applied to detect the artifacts induced by postural changes or other motion disturbances. The affected portion is replaced by the mirror data from the prior and posterior. Then, EMD is applied to decompose this signal into numbers of IMFs. Respiration-related IMFs are identified according to an intrinsic respiratory reconstruction index. The identified IMFs are used to reconstruct respiration and estimate the instantaneous respiratory frequency and amplitude.

Bottom Line: This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring.Moreover, large motion artifacts disable the EMD to decompose respiratory components.A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, Hwa Hsia University of Technology, 111, Gongzhuan Rd., Zhonghe, New Taipei City 23568, Taiwan. wft.intuitive@seed.net.tw.

ABSTRACT
Impedance plethysmography provides a way to measure respiratory activity by sensing the change of thoracic impedance caused by inspiration and expiration. This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring. The empirical mode decomposition (EMD) can decompose a signal into several intrinsic mode functions (IMFs) that disclose nonstationary components as well as stationary components and, similarly, capture respiratory episodes from thoracic impedance. However, upper-body movements usually produce motion artifacts that are not easily removed by digital filtering. Moreover, large motion artifacts disable the EMD to decompose respiratory components. In this paper, motion artifacts are detected and replaced by the data mirrored from the prior and the posterior before EMD processing. A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation. Based on the experiments performing a series of static and dynamic physical activates, our results showed the proposed method had higher cross correlations between respiratory frequencies estimated from thoracic impedance and those from oronasal airflow based on small window size compared to the Fourier transform-based method.

No MeSH data available.