A user-friendly integrated software environment for heart rate variability analysis of sleep disordered breathing

We present an integrated software environment that enables sleep specialists to analyze, quantity and diagnose sleep disordered breathing based upon time-domain, frequency-domain, and nonlinear dynamics measurement measures of heart rate variability (HRV) signal. The integrated graphical user interface (GUT) and the signal processing algorithms were developed and implemented in MATLAB, This environment provides the facility to import or read sleep data (ECG, EEG, blood pressure, respiratory, oxygen saturation, etc.) under user control and displays them individually or collectively in a data window for visual inspection. It then enables the user to clip the length of data to be used in carrying out the analysis. Raw ECG data is preprocessed for reliable QRS detection and the HRV signal is derived following the guidelines of the Task Force of the European Society of Cardiology and the North American Society for Pacing and Electrophysiology, which is then displayed along with respiration signal in the analysis window. After this step time-domain, frequency- domain, and nonlinear dynamics analyses of the HRV signal are performed to extract sensitive measures used in detecting and diagnosing sleep disordered breathing. The computer analysis can then generate a complete report for the specialist and further statistical and/or automatic analyses. The system was developed and validated using data from the MIT-BIH Polysomnographic Database. After validation and reliability testing it was used to analyze sleep data for detection of sleep disordered breathing (SDB) in children. Data from normal and children diagnosed with SDB showed that the system could potentially distinguish between normal children and children suffering from sleep disordered breathing.