THE UTILITY OF SPECTRAL ANALYTIC TECHNIQUES IN THE STUDY OF THE AUTONOMIC REGULATION OF BEAT-TO-BEAT HEART-RATE-VARIABILITY

Heart rate (HR) and HR variability have received considerable attentio n in psychophysiologic research for their utility as non-invasive indi ces of autonomic nervous system (ANS) regulatory function. Differences in HR patterns have been reported for subjects differing in degree of conduct disturbance or behaviofal inhibition, and those exhibiting ea rly temperamental and cognitive developmental differences. While these findings appear robust, the models of ANS regulatory activity drawn f rom the interpretation of these observations still lack support. This is due in part to the methods used to analyze the HR data and in part to preconceptions about the autonomic regulation of HR. HR variability can be studied in the frequency domain with spectral techniques, whic h complement the understanding of HR regulation obtained from time dom ain methods. Spectral techniques permit the identification of the dist ribution of the HR variability, as well as the characteristics of the cardiac parasympathetic and sympathetic regulatory influences mediatin g the HR variability. Frequency domain analysis of the relationships b etween physiologic functions provide further information about the sou rces of the HR variability and the mediation by the two branches of th e ANS. The potential of spectral techniques to extend the utility of H R and HR variability as difference measures and indices of ANS regulat ory function, and for the purposes of constructing psychophysiologic m odels, remains to be explored.