A multi-dermatome computer-controlled electrical perceptual threshold (multi-dermatome CCEPT) test: reliability assessment and development of a preliminary healthy dermatomal reference profile

Background Electrical perceptual threshold (EPT) testing provides a quantitative measure of sensory function and may complement clinical sensory assessment after spinal cord injury (SCI). However, existing EPT workflows can be time- and labour-intensive, may rely on examiner-controlled stimulus delivery and manual recording of participant responses, and have not been standardized for testing across all 56 sensory key points used in the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). To address these limitations, we developed a multi-dermatome computer-controlled electrical perceptual threshold (multi-dermatome CCEPT) system that integrates standardized stimulus delivery, automated channel selection, direct participant-response capture, examiner verification, and synchronized data logging across bilateral dermatomal test locations. This study evaluated the within-session and between-session reliability of the multi-dermatome CCEPT system and examined whether dermatomal threshold patterns in non-disabled participants reproduced the expected healthy rostro-caudal gradient. Methods The multi-dermatome CCEPT protocol was evaluated in 16 non-disabled participants across 28 bilateral dermatomes during two sessions (median interval of 14 days). Within-session reliability was assessed across three repeated trials, and between-session test –retest over time. The perception threshold distribution across dermatomes was also examined to characterize the preliminary healthy dermatomal reference profile. Results Multi-dermatome CCEPT testing was feasible and safe, with no adverse events or intolerable discomfort reported. Within-session reliability ranged from poor to excellent across dermatome-side combinations, although most combinations demonstrated moderate-to-good reliability. Reliability was generally stronger in several cervical and upper thoracic dermatomes and more variable at selected lumbosacral sites. Between-session reliability was more heterogeneous and varied by dermatome and side, indicating greater measurement variability over the two-week interval. Despite this variability, the threshold profile demonstrated a rostro-caudal pattern, with lower thresholds in cervical and upper thoracic dermatomes and higher thresholds in lumbosacral dermatomes. Conclusion These findings support the feasibility and preliminary repeatability of multi-dermatome CCEPT for standardized EPT testing across 56 ISNCSCI sensory key points. Larger studies in non-disabled and SCI cohorts are needed to refine the protocol, establish robust normative reference profiles, and determine its potential role as an adjunct to clinical sensory assessment.