Pupillometric-Based Analysis of Central Autonomic Levels Using HHT

Abstract

This paper proposes a new application of the Hilbert-Huang transform (HHT). Pupillogram recording were analyzed through the non-traditional HHT to investigate patterns in the time-frequency parameters of Spontaneous Pupillary Oscillation (SPO) signals. The traditional Fourier transform is only useful for linear stationary signals analysis, but the HHT was designed for the analysis of non-linear and non-stationary waves. The intrinsic properties of the signals were highlighted by the HHT scheme and the results showed that SPO waves presented local and intermittent variations through the time span. The numerical parameters demonstrated that there is a wide inter-subject variation in the intrinsic time-frequency parameters contribution from each yielding mode to the total signal content.