Spectral envelope analysis of snoring signals

In recent years, several studies have shown the relationship between snoring and obstructive sleep apnea syndrome (OSAS). Besides time domain analysis of snoring signal, the spectral features and shapes of snores can be used to discriminate simple snorers and OSAS patients. In this study, we propose a method to classify simple snorers and OSAS patients based on spectral envelope estimation of snoring signals. The formant frequencies and corresponding bandwidths are computed for both group, and the variation and consistency of the formant distributions are computed. A total of 1400 snoring episodes from 7 simple snorer and 7 OSAS patients were analyzed. Significant differences are found in the formant frequencies of both groups. The results are discussed from the view point of patho-physiological aspect

The inverse problem of bioelectricity: an evaluation

Item does not contain fulltextThis invited paper presents a personal view on the current status of the solution to the inverse problem of bioelectricity. Its focus lies on applications in the field of electrocardiography. The topic discussed is also relevant in other medical domains, such as electroencephalography, electroneurography and electromyography. In such domains the methodology involved rests on the same basic principles of physics and electrophysiology as well as on the applied techniques of signal analysis and numerical analysis