Background & Aims
Accurate somatosensory evaluation is essential for understanding various neurological conditions, involving tactile, thermic, and pain domains.[1-2] Quantitative sensory testing (QST) plays a crucial role in noninvasive assessment,[3-4] with Semmes-Weinstein monofilaments (SWM) being a commonly used method.[5] However, challenges arise due to variations in monofilament properties. The Cutaneous Mechanical Stimulator (CMS) is a novel device designed to address these limitations. The CMS measured Mechanical Detection Thresholds (MDTs) with a portable device featuring an aluminum probe and a removable tip.[6] The primary objective of this study is to evaluate the validity and reliability of the CMS for tactile threshold measurement, comparing it with SWM in healthy subjects. Using a test-retest design with two raters over two sessions, the study aimed to assess the CMS’s potential as a reliable tool for tactile sensitivity evaluation.
Methods
Twenty-seven healthy, right-handed volunteers (14 women and 13 men, mean age 24.07 ±3.76 years) were recruited to participate in two experimental sessions. Exclusion criteria included neurological impairments, pathologic conditions affecting somatosensory perception, and chronic pain conditions. Using a test-retest design, two raters evaluated MDTs using SWM and the CMS on the dorsum of the left hand and foot in two experimental sessions approximately 2 weeks apart. Experimental sessions, lasting about 2 hours, employed SWM and CMS in randomized orders. Applying the method of limits for both instruments, MDTs were calculated as the geometric mean of infra-threshold and supra-threshold values. Statistical analyses included the Wilcoxon test for comparing MDTs measured with SWM and the CMS. Intraclass correlation coefficients (ICCs), completed with Bland-Altman plot were employed to assess the reliability and validity of the CMS in comparison to SWM.
Results
Results showed excellent reliability between SWM and CMS at both cutaneous test sites (ICC = 0.84 for the hand, 0.90 for the foot), with no significant differences between the thresholds measured by SWM and the CMS at both the hand and foot stimulation sites. Inter-session reliability was good for the hand (ICC = 0.63 for SWM, 0.73 for CMS) and fair for the foot (ICC = 0.50 for SWM, 0.42 for CMS). The MDTs on the foot differed significantly across sessions using SWM (p < 0.01), but not the CMS (p = 0.14). Inter-rater reliability was good for the hand (ICC = 0.66 for SWM, 0.82 for CMS) and fair for the foot (ICC = 0.53 for SWM, 0.60 for CMS). Significant differences were found in foot measurements of MDTs between raters using SWM (p < 0.01), but not the CMS (p = 0.74). Bland-Altman plots illustrated minimal variations, with some differences observed on the foot compared to the hand.
Conclusions
Our findings suggest that the CMS demonstrates comparable reliability to traditional monofilaments, providing a practical alternative for MDT assessments. Emphasizing the reliability of the CMS in measuring thresholds over two sessions 2 weeks apart, the results demonstrate the effectiveness of using this electronic device for MDT measurement. Notably, the hand displayed heightened sensitivity compared to the foot, aligning with established anatomical sensitivity patterns.[7] Furthermore, our study revealed that the CMS demonstrated significantly higher inter-rater reliability than the SWM for measurements on the hand, indicating its efficacy in facilitating consistent comparisons between raters and laboratories. The findings imply the potential interchangeability of the CMS with traditional monofilaments, particularly in clinical or experimental situations that require accurate and consistent data.
References
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Presenting Author
Olivier Després
Poster Authors
Topics
- Other