An updated normative data set from the autonomic reflex screen representative of Southwestern Ontario

Abstract

In evaluating autonomic dysfunction, the autonomic reflex screen (ARS) is an established set of standardized tests to evaluate the presence and severity of autonomic dysfunction. Our laboratory previously reported normative data on 121 healthy individuals; however, the sample size in older individuals was reduced compared with other age groups. Therefore, the objective of the current study was to provide updated normative values representative of young, middle-aged, and older individuals from Southwestern Ontario. Two hundred and fifty-two healthy individuals completed quantitative sudomotor axon reflex testing, heart rate responses to deep breathing (HRDB), and Valsalva maneuver using standard protocols of the ARS. All 4 sweat sites demonstrated a significant effect of sex (p < 0.001). In addition, the proximal leg, distal leg, and foot were all significantly affected by age (p < 0.001). Cardiovagal parameters, measured via HRDB and Valsalva ratio revealed a significant regression with age (p < 0.001). These results show similar trends with previously reported normative data sets. All normative data as a function of age and sex, where appropriate, are expressed as percentiles (2.5th, 5th, 95th, 97.5th). The current study provides updated normative data describing autonomic functioning in healthy individuals obtained from the sudomotor and cardiovagal components of the ARS.