Design of portable holter recorder with MMC memory for prephase sleep apnea diagnosis

Long time digital data recordings in portable devices have become possible today with widespread usage of high capacity memories. The aim of this study is to obtain a better performance in the sleep apnea analysis by recording portable EKG recording systems as well as different clinically significant signals on flash cards for a long time. Thus in the first stage a Holter Recorder Device is designed to record ECG and respiratory signals for the diagnostic of apnea. The device is designed to handle more than two channels simultaneously. In the second phase of the study, an apnea detection algorithm using Hilbert Transform was chosen and implemented as an example among other algorithms using only ECG signals. Based on the comparison of three selected algorithms (digital filter based, differentiation based and higher order statistics based) to be used for the QRS detection for any apnea detection algorithm, differentiation based algorithm is preferred due to its better performance.