Individualized analysis of skin thermosensory thresholds and sensitivity in heat-sensitive people with multiple sclerosis

ABSTRACT

We investigated whether and how multiple sclerosis (MS) alters thresholds for perceiving increases and decreases in local skin temperature, as well as the sensitivity to progressively greater temperature stimuli, amongst heat-sensitive people with MS. Eleven MS patients (5 M/6 F; 51.1 ± 8.6 y, EDSS 5.7 ± 1.9) and 11 healthy controls (CTR; 7 M/4 F; 50.3 ± 9.0 y) performed warm and cold threshold tests on a hairy skin site, on both sides of the body. They also underwent a thermosensitivity test where they rated (visual analogue scale) perceived magnitude of 4 local skin stimuli (i.e. 22, 26, 34, 38°C). Individual thresholds and slopes of linear regression for thermosensitivity were z-transformed for each MS patient, and used to determine individual thermosensory abnormalities. When considering both threshold and thermosensitivity, six out of our 11 heat-sensitive patients (54.5%) exhibited skin thermosensory abnormalities. Those abnormalities varied amongst patients in terms of type (threshold vs. thermosensitivity), quality (warm vs. cold), location (left vs. right side of the body) and extent. Each of those six patients presented unique thermosensory profiles. While some patients experienced thermosensory loss in both thresholds and sensitivity and on both sides of the body, others experienced cold thermosensory loss on one side of the body only. The observed individual variability in thermosensory function among heat-sensitive MS patients highlight the need for a patient-centered approach to assessing thermosensory dysfunction and its potential implications for heat stress vulnerability in this patient group.

KEYWORDS:

• Multiple Sclerosis
• body Temperature Regulation
• thermoreceptors
• skin

Acknowledgments

The authors thank Prof George Havenith (Loughborough University) for loaning the thermo-sensory analyser for the Australian portion of the data collection.

Disclosure statement

The authors report no competing interests.

Author contributions

Experimental testing was performed at the Thermal Ergonomics Laboratory, Faculty of Health Sciences, University of Sydney, Australia and at the THERMOSENSELAB, Loughborough University, UK. All authors contributed to the conception and design of the study. DF, GC, KC, and KF performed data acquisition. DF performed data analysis and drafted the manuscript. All authors contributed to editing significant portions of the manuscript and figures. All authors approved the final version of the manuscript; and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All persons designated as authors qualify for authorship, and all those who qualify for authorship are listed.

Additional information

Funding

This work was supported by: Australian Government [Endeavor Post-Doctoral Research Fellowship; holder: Filingeri]; Multiple Sclerosis Research Australia [Postgraduate Fellowship; holder: Chaseling; Incubator Grant 14-009; holders: Jay and Davis]; Multiple Sclerosis Research Australia [Incubator Grant 14-009]; Australian Government [Endevour Research Fellowship].