Which symptom is reversible in Wernicke-Korsakoff syndrome?

In Wernicke-Korsakoff syndrome, confusion is considered a reversible symptom primarily due to the underlying cause of this condition, which is thiamine (vitamin B1) deficiency. When patients are diagnosed and treated with adequate thiamine supplementation, the acute confusion that occurs in the Wernicke's phase can improve significantly.

Other symptoms associated with Wernicke-Korsakoff syndrome, such as ophthalmoplegia, ataxia, and specifically the long-term memory deficits seen in Korsakoff's psychosis (amnesia), do not respond as effectively to treatment, particularly once they become chronic. While some aspects of ataxia may show improvement, they are often less responsive than confusion. Ophthalmoplegia may improve with thiamine treatment, but it does not consistently reverse in the same way that confusion does. Thus, the nature of confusion being reversible with timely intervention makes it the best choice among the options provided.