Reproducibility and feasibility of neurophysiological assessment of the sensory trigeminal system for future application to paroxysmal headaches.

As the distribution of pain in primary headaches suggests involvement of the trigeminal sensory pathways, trigeminal somatosensory evoked potentials (TSEP) and blink reflexes (BR) may provide important information about their functional integrity. Functional differences between symptomatic and non-symptomatic sides and between measurements during and outside attacks may be particularly informative. These tests should therefore be reproducible and should require a suitable number of patients for future studies in patients with primary, paroxysmal headaches. We performed TSEP and BR twice in 22 healthy volunteers, in order to calculate sample sizes based on reproducibility data. This is, to our knowledge, the first study investigating the reproducibility of TSEP and BR measurements. Latencies of TSEP and BR are appropriate for future studies, as their reproducibility allows practical sample sizes (less than 25 subjects). Duration, amplitude and area parameters of the BR responses were less appropriate for longitudinal studies.