A 62-year-old man with long-standing hypertension develops sudden onset dysphagia and hoarseness. On exam, his uvula deviates to the right when he says "ah," and his gag reflex is diminished on the left. He also has reduced pain and temperature sensation over the left face. Motor strength and proprioception in the limbs are normal. MRI shows a small infarct in the left dorsolateral medulla.

Which of the following additional findings is most consistent with the involved brainstem level?

(Assume the lesion is at the level suggested by the anatomic structures present at that level.)