Sensitivity to change of the cutaneous electrical perceptual threshold test in longitudinal monitoring of spinal cord injury

Study design: Prospective longitudinal experimental study. Objectives: The aim of this study was to assess the sensitivity to change of the electrical perceptual threshold (EPT) test during the longitudinal monitoring of neurological changes in patients with incomplete spinal cord injury (SCI). Setting: National Spinal Injuries Centre, Stoke Mandeville Hospital, Buckinghamshire Hospitals NHS Trust, Buckinghamshire, UK. Methods: Perceptual threshold to 3Hz cutaneous electrical stimulation was measured in 11 patients with incomplete SCI at selected American Spinal Injuries Association (ASIA) sensory key points on four occasions. The first three measurements were performed within a 5-day period (baseline) and the fourth measurement (follow-up) at least 9 months later. The results were tested for statistical significance and the effect sizes were calculated. Results: There were no significant differences between the EPT results of the three baseline assessments. When the mean baseline and follow-up EPT results were compared, there were no significant differences in EPT values above the sensory level of lesion, but a significant difference (reduction in threshold values) was found at and below the level of SCI, with medium and large effect sizes, respectively. Conclusion: The EPT test showed good sensitivity to change in dermatomes at and directly below the sensory level of the SCI. This makes it a potentially useful quantitative sensory instrument for detecting changes in sensory function during longitudinal monitoring of patients with SCI. Spinal Cord (2011) 49, 439-444; doi:10.1038/sc.2010.123; published online 28 September 2010