Trigeminal evoked potentials and sensory deficits in atypical facial pain--a comparison with results in trigeminal neuralgia.

Trigeminal evoked potentials (TEPs) and sensory deficits in eighty-three patients admitted for first surgical treatment of facial pain were retrospectively analysed. Thirty-seven patients suffered from trigeminal neuralgia (TN), 10 from symptomatic TN (sTN), and 36 from atypical facial pain (AFP). Eighteen percent of the TN patients reported sensory deficits on the pain side, but 35% had delayed ipsilateral N13 waves. Of the sTN patients, 60% had either sensory deficits or a pathological corneal reflex and 62.5% a pathological N13. Of the AFP patients, 61% complained of sensory deficits, but only 31% had a pathological N13. The percentage of pathological P19 waves was slightly lower (20%, 50%, and 11%, respectively), but showed a similar trend. Normal TEPs were found even in the presence of a sensory deficit (reported only in the AFP group). These findings may add weight to the hypothesis of underlying psychiatric disorders in AFP.