The principal investigator has developed a mathematical statistic, ApEn, to analyze time-series data. The primary objective of this proposal is to examine the potential use of ApEn as a biomarker of aging, to predict adverse consequences of autonomic dysfunction, such as hypotension and syncope, and to evaluate such interventions as exercise and medication. Another main objective, suggested by significant gender differences in Phase I findings, is to determine ApEn values for """"""""healthy"""""""" subjects, based on gender and race. It is anticipated that ApEn, applied to heart rate data, will provide diagnostic and predictive insights otherwise unavailable. ApEn is both mathematically and medically innovative, encapsulating the amount of regularity in data into a single number. Several studies have previously demonstrated the clinical utility of ApEn. In Phase I, we established that ApEn declines significantly with increasing age for heart rate data, and established preliminary ranges of ApEn values marking healthy cardiovascular function inn three age cohorts. In Phase II, we will establish definitive ranges of ApEn values, for each age group, as normative or as indicative of autonomic dysfunction. Potential commercial applications include a software package to compute ApEn for use in existing systems or in a solo device.
