Event-related brain potentials elicited by high-speed cooling of the skin: A robust and non-painful method to assess the spinothalamic system in humans

摘要

ObjectiveTo investigate whether cool-evoked potentials (CEP) elicited by brisk innocuous cooling of the skin could serve as an alternative to laser-evoked potentials (LEP), currently considered as the best available neurophysiological tool to assess the spinothalamic tract and diagnose neuropathic pain. MethodsA novel device made of micro-Peltier elements and able to cool the skin at ?300?°C/s was used to record CEPs elicited by stimulation of the hand dorsum in 40 healthy individuals, characterize the elicited responses, and assess their signal-to-noise ratio. Various stimulation surfaces (40?mm2and 120?mm2), cooling ramps (?200?°C/s and ?133?°C/s) and temperature steps (20?°C, 15?°C, 10?°C, 5?°C) were tested to identify optimal stimulation conditions. ResultsCEPs were observed in all conditions and subjects, characterized by a biphasic negative-positive complex maximal at the vertex (Cz), peaking 190–400?ms after stimulus onset, preceded by a negative wave over central-parietal areas contralateral to the stimulated hand. Their magnitude was modulated by stimulation surface, cooling ramp and temperature step. ConclusionRapid innocuous skin cooling elicits robust CEPs at latencies compatible with the conduction velocity of Aδ-fibers. SignificanceCEPs can be a complementary tool to the recording of LEPS for assessing the function of small-diameter Aδ-fibers and the spinothalamic tract.