Use of Motion Artifact for the Detection of Respiratory Effort in Polysomnography

Measuring respiratory effort is critical when diagnosing sleep disordered breathing. In this thesis work, the use of detecting respiratory effort by using the movement artifact found in the electromyographic (EMG) and electrocardiographic (ECG) recordings used in polysomnography was investigated. The resulting signals were compared to effort measured with respiratory inductance plethysmography (RIP). The EMG and ECG signals were filtered using the Savitzy-Golay method of smoothing and differentiation of data by simplified least squares to extract the movement artifact. The validity of each resultant waveform was measured using a Pearson product moment correlation coefficient and were studied to determine the most reliable signal. A total of 12 subjects were recorded in a clinical setting, all being evaluated for obstructive sleep apnea. The ability to detect respiratory effort using movement artifact was found to perform best in the masseter. This work shows that movement artifact recovered from the EMG and ECG may be a reliable alternative for the detection of respiratory effort.