Normative Values for Contact Heat and Cold Evoked Potentials

To establish normative values for contact heat evoked potentials (CHEP) and cold evoked potentials (CEP), providing a reference for evaluating small fibre neuropathy (SFN) and spinothalamic tract (STT) function.

Thermal quantitative sensory testing and sensory nerve conduction studies were conducted for screening subjects. CHEP and CEP were recorded from the distal volar forearm and foot dorsum of 80 healthy participants (26-75 years) using a 1.2 cm² contact thermal stimulator (ramp: 300°C/s, heat: 60°C, cold: 10°C, duration: 200 ms). Age-grouped descriptive statistics were computed. Results between age groups, stimulation sites and sex were compared.

Upper limb CEP showed > 90% detection rates across all ages. N2P2 amplitudes were larger in upper compared to lower limbs (CHEP: p = 0.032; CEP: p < 0.001). N2P2 amplitudes decreased with age for CHEP (p < 0.001) and CEP (p = 0.002). Latencies did not vary between age groups or between limbs (CHEP: p = 0.600; CEP: p = 0.351).

This normative dataset will support the clinical integration of CHEP and CEP as an objective and non-invasive technique for evaluating small fibre and STT function.

Normative data for contact heat evoked potentials (CHEP) and cold evoked potentials (CEP) were established across age groups in healthy adults, marking a key step toward their use in routine clinical neurophysiology. CHEP and CEP N2P2 amplitudes were consistently larger in upper than lower limbs, with the greatest age-related decline in the feet. Notably, CEP from the upper limbs showed the highest visualisation rates (> 90%) across all ages.