Mental confusion, eye movement disturbances, and ataxia are the primary symptoms of Wernicke's encephalopathy - the first, acute stage of Wernicke-Korsakoff syndrome. At first glance, confusion and ataxia may resemble the effects of severe alcohol intoxication, but they persist after intoxication wears off. Some patients with Wernicke's encephalopathy will recover completely without residual memory deficits, particularly if they are treated quickly with thiamin.
Loss of memory for past events is called retrograde amnesia. Many people with Korsakoff syndrome have some retrograde amnesia in addition to anterograde amnesia, particularly for events that occurred shortly before the onset of illness, but most can recall the distant past without difficulty.
Immediate memory is not affected. For instance, an individual with Korsakoff syndrome could repeat a sentence or string of numbers immediately after hearing them, although this information would likely be forgotten within half a minute. Preservation of immediate memory allows individuals with Korsakoff syndrome to interact with others and respond to questions. Implicit memory is also preserved, so people with Korsakoff syndrome can learn new motor skills or develop conditioned reactions to stimuli. For example, individuals who play computer games can show improved performance each time they play, even if they cannot explicitly remember having played the game before.
Confabulation is another striking feature of Korsakoff syndrome, although it is not always observed. Confabulation refers to falsification of memory. The individual appears to be making up stories to cover up for inability to remember. Confabulation often seems to involve a confusion of the past and present. For example, if patients with Korsakoff syndrome are asked why they are in the hospital, they may say they just had a baby, are recovering from pneumonia, undergoing medical tests, or even applying for a job.
Patients with Wernicke-Korsakoff syndrome may also show signs of apathy and a lack of spontaneous behavior. Emotional expression may be lacking as well.
Interestingly, autopsies often reveal brain lesions characteristic of Wernicke-Koraskoff syndrome in alcoholic patients who showed general cognitive problems like those seen in dementia, but who never developed anterograde amnesia. These findings suggest that onset may be gradual in some patients.
