“This means that cold water/air induces nystagmus to the opposite side of the irrigated ear and warm water/air induces nystagmus to the same side as the irrigated ear.”
So if the R ear is irrigated with cold water, we would expect L (opposite side) nystagmus, if the R ear is irrigated with warm water, we would expect R (same side) nystagmus.
“Therefore, we would expect this patient to have decreased nystagmus to the left when the right ear is irrigated with cold water/air and decreased nystagmus to the right when the right ear is irrigated with warm water/air.”
This is saying the same thing but adding in that it is a decreased nystagmus. This is because this test normally produces nystagmus following the COWS saying. If there is a uniliateral vestibular hypofunction, then the normally produced nystagmus would be lessened due to HYPOfunction.
Therefore the correct answer would be:
“Decreased left-beating nystagmus when the right ear is irrigated with cold water” as cold water causes opposite nystagmus (R irrigation causes L nystagmus)
The answer you chose is incorrect because it is stating a contralateral nystagmus was occurring with a stumulant that should have caused an ipsilateral nystagmus. Warm water would cause same side nystagmus, so it would be RIGHT beating nystagmus, not left, as the right ear was irrigated.