Electrical Perceptual Threshold Testing - validation study

Abstract

Study Design : Prospective experimental Objectives : To investigate inter-rater and intra-rater reliability of electrical perceptual threshold (EPT) testing in assessing somatosensory function in healthy volunteers. Setting: Spinal Injuries Unit, Royal North Shore Hospital, Sydney, NSW, Australia Methods: Cutaneous electrical stimulation of 4 dermatomes at American Spinal Injuries Association (ASIA) sensory key points (C3, T1, L3, S2) was performed on 40 control subjects. The lowest ascending stimulus intensity at which sensation was perceived was recorded as the EPT. Mean EPT values for each dermatome, as determined by 2 testers at two time points, were examined and plotted against a normative template. Differences and associations between intra- and inter-rater measurements, and left-right measurements were investigated. EPT results for 2 people with spinal cord injuries were also examined. Results : EPT measurements from left and right sides, obtained from the two time points and two testers, were found to be strongly associated, with the exception of left and right side measurements at the S2 dermatome. No significant differences in the mean EPT for tester or time period were found. The intra- and inter-rater reliability was good for all dermatomes tested. Mean EPT measurements fell within the range of a normative template at each of the 4 dermatomes tested. Conclusion : EPT is an objective, reproducible and quantifiable method of assessing sensation in a control group. However, caution should be applied in certain dermatomes such as S2 where there was large variation between left and right side measurements. Sponsorship : New South Wales Office of Science and Medical Research