Cardiac interference in myographic signals from different respiratory muscles and levels of activity

Abstract

Abstract-An interesting approach to study pulmonary diseases is the analysis of the respiratory muscle activity by means of electromyographic (EMG) B. Signals and instrumentationFour EMG and two VMG signals were simultaneously recorded from three respiratory muscles: genioglossus, sternomastoid and diaphragm. A surface EMG signal of genioglossus muscle was recorded with two electrodes (AgAgCl) placed on the submental zone (GEN-SEMG). In the same area, an accelerometer (Entran EGA-10) was also placed to record VMG signal (GEN-VMG). In addition, genioglossus activity was also monitored by means of intraoral surface electrodes located below the tongue (GEN-EMG) [6]. Two surface electrodes and another accelerometer were placed on the sternomastoid muscle to record EMG (SMM-SEMG) and VMG (SMM-VMG) signals, respectively. Finally, surface EMG signal was recorded from the diaphragm (DIA-SEMG).The myographic signals were amplified and bandpass filtered using a multichannel analog amplifier. The selected bandwidths at -3 dB and the sampling frequencies were, respectively: 5-200 Hz, 500 Hz (VMG) and 5-400 Hz, 1000 Hz (EMG). C. Increased respiratory effortDuring the experiment subjects were in a supine position and breathed through a nose mask connected to a low-resistance respiratory nonrebreathing valve. The inspiratory port of the nonrebreathing valve was connected to the external source of a negative pressure.The experimental protocol consisted of breathing without external pressure for 5 min before the negative pressure was applied. The pressure was decreased at 90-second intervals each time by the value of -7cm H 2 O until the subject could no longer breath. The maximum pressure in absolute value reached by the subject was defined as maximum maintained pressure (MMP). For every subject, pressure in each step of the experiment was expressed as a Hz CARDIAC INTERFERENCE IN MYOGRAPHIC SIGNALS FROM DIFFERENT RESPIRATORY MUSCLES AND LEVELS OF ACTIVITY Abstract Subject Terms Report Classification unclassified Classification of this page unclassified Classification of Abstract unclassified Limitation of Abstract UUNumber of Pages 4

Coordination of respiratory muscles assessed by means of nonlinear forecasting of demodulated myographic signals

“…EMG and MMG signals were processed to reduce cardiac activity from the recordings using adaptive and singular value decomposition valued filtering (Mañanas et al, 2001b). EMG and MMG signals were full-wave rectified and demodulated by means of a 400 ms moving average window (Alonso et al, 2007; Bruce, 1984).…”

Cancellation of Cardiac Interference in Diaphragm EMG Signals Using an Estimate of ECG Reference Signal

“…The block diagram of the EMGdi ANC is shown in Fig 2. The utilized scheme is similar to the schemes proposed in [4] and [5]. The primary input to the noise canceller is the original EMGdi signal (corrupted with the ECG interference) filtered in the frequency band of the ECG interference (between 2 and 40 Hz) with a 4th order bidirectional Butterworth filter (d[n]).…”

“…However, this method segments the signal and excludes portions of the signal that may contain important information. Adaptive filtering techniques have been applied successfully in order to isolate the cardiac component from EMG noise [4], and for heart activity cancellation in EMG signals from different respiratory muscles [5], and from the EMGdi signal [6,7]. The most important part of all these adaptive filtering techniques is the artificial construction of a reference signal that must be highly correlated with the ECG interference but uncorrelated with the EMGdi activity.…”

Prediction of isometric motor tasks and effort levels based on high-density EMG in patients with incomplete spinal cord injury

“…Additionally, the power line interference was suppressed using the adaptive filter described in [22]. Channels containing measurement artifacts were identified and removed following the procedure described in [15].…”