During caloric testing, what is the expected eye movement in a brainstem-intact patient when cold water is introduced?

During caloric testing, what is the expected eye movement in a brainstem-intact patient when cold water is introduced?

• A. No eye movement
• B. Eyes deviate slowly toward the cold water
• C. Eyes rapid nystagmus toward the cold stimulus
• D. Eyes move away from the cold water

Answer: (B)

The eye movement pattern tested by caloric irrigation reflects the vestibulo-ocular reflex. Cold water in the ear creates endolymph flow that makes the eyes drift slowly toward the irrigated ear, with a quick corrective movement (nystagmus) away from it. In a brainstem-intact patient, you first see a slow deviation toward the cold stimulus. That is why the best answer is the eye drifting slowly toward the cold water. The rapid corrective movement is away from the cold water, and other options describe either no movement or the rapid phase, which is not the initial response.

The eye movement pattern tested by caloric irrigation reflects the vestibulo-ocular reflex. Cold water in the ear creates endolymph flow that makes the eyes drift slowly toward the irrigated ear, with a quick corrective movement (nystagmus) away from it. In a brainstem-intact patient, you first see a slow deviation toward the cold stimulus. That is why the best answer is the eye drifting slowly toward the cold water. The rapid corrective movement is away from the cold water, and other options describe either no movement or the rapid phase, which is not the initial response.