Warming nerves for excitability testing.

Introduction The aim of this study was to find the best method of warming the median nerve before excitability testing to a standard temperature. Methods In 5 healthy subjects, the forearm and hand were warmed for 1 h to 37 degrees C by infrared lamp, water blanket, or water bath. Recordings were performed before and during warming every 10 min. Excitability indices were fitted by exponential relations, thereby calculating the time needed to reach 95% of their asymptotic end value. Results Distal motor latency, refractory period, and superexcitability at 10 ms changed exponentially with time. Warming by water bath took the shortest time (24 min); this was followed by warming by infrared lamp (34 min) and water blanket (35 min). Conclusions Warming by water bath is the quickest way. The other methods took only moderately more time. Future studies need to specify both warming method and warming time before excitability testing. Muscle Nerve, 2019