Trigeminal evoked potentials following brief air puff: enhanced signal-to-noise ratio.

Trigeminal somatosensory evoked potentials (TSEPs) were studied by using fast-rising air puffs generated by a high-speed air control system. Within 100 ms, air puff stimulation of the face elicited three negative and three positive components over the contralateral, as well as the ipsilateral, sensory area. The air puff TSEPs showed a uniform change in peak latencies and amplitudes as a function of stimulus intensity. The bilateral distribution of the TSEPs stands in sharp contrast to the exclusively contralateral distribution of the SEPs to stimulation of the hand. Air puffs evoked a larger response than electrical stimulation, although the latency remained the same. Unlike electrical stimuli, air puff induces neither stimulus nor muscle artifacts. This, combined with the higher amplitude of the recorded response, enhances the signal-to-noise ratio.