Contact heat evoked potentials – impact of physiological variables

Abstract

Introduction: Contact heat evoked potentials (CHEPs) represent a new neurophysiological method of functional testing of small nerve fi bers and the spinothalamic tracts. The study aimed to confi rm the validity of published normal values for this method in the Czech population and to evaluate the infl uence of physiological and test-related variables on the CHEPs response. Patients and methods: Two groups were included in the study – a healthy control group (97 healthy volunteers; 53 women; age range 20–82 years) and a group of patients with diabetic distal sensorimotor polyneuropathy (DSPN group, 37 patients; 14 women; age range 29–77 years). In all of the participants, CHEPs were examined in the dorsum of the hand and above the ankle using basic and intensive temperature algorithm. Results: The CHEPs testing was mostly well-tolerated. The vast majority of the latencies and amplitudes of the CHEPs responses obtained in the healthy control group fell within the reference range according to the published normal values. Testrelated variables showed also a highly signifi cant impact on CHEPs values – the latencies were shorter in hands (compared to the calf) and whenever the intensive temperature algorithm was used (p < 0.001 in both cases). Women had signifi cantly higher amplitudes and shorter latencies (p < 0.05). Older volunteers had signifi cantly lower amplitudes (p < 0.05) than the younger ones. The DSPN group had longer latencies (p < 0.05) and lower amplitudes (p < 0.05) in comparison with control group. Conclusion: The study confi rmed validity of published normal values for the Czech population. For precise evaluation of the results, physiological (gender, age) and test-related parameters (tested area, temperature algorithm) should be taken into account. On a group level, CHEPs proved to be a useful tool for small-nerve fi ber dysfunction assessment in DSPN. Autoři deklarují, že v souvislosti s předmětem studie nemají žádné komerční zájmy. The authors declare they have no potential confl icts of interest concerning drugs, products, or services used in the study. Redakční rada potvrzuje, že rukopis práce splnil ICMJE kritéria pro publikace zasílané do biomedicínských časopisů. The Editorial Board declares that the manuscript met the ICMJE “uniform requirements” for