Detection of sleep apnoea using time-frequency analysis of heart rate variability

Spectral analysis of heart rate variability data requires non-standard treatment as the data are nonequispaced in time. Two methods of analysis are compared using specially generated test signals and extended for use with the Discrete Harmonic Wavelet Transform for time-frequency analysis. Two sets of patient data are then analysed, one normal subject and one with sleep apnoea. The results show the potential of time-frequency analysis in the assessment of disorders such as sleep apnoea which involve alterations in autonomic activity.