Abolished laser-evoked potentials and normal blink reflex in midlateral medullary infarction

We investigated two patients presenting with the rare finding of almost iso lated hemianalgesia with a sensory level on the contralateral side sparing the face. Clinical findings, electrophysiological studies (absent laser-evo ked pain-related somatosensory potentials, normal electrically evoked somat osensory potentials, magnetically evoked potentials, and blink reflexes), a nd magnetic resonance, imaging showed the ventrolateral medullar tegmentum containing the spinothalamic tract to be affected by lacunar infarction. Th e blink reflex R2 component was unimpaired in both patients.