Korsakoff syndrome (KS) is a disorder of the central nervous system characterized by amnesia, deficits in explicit memory, and confabulation. This neurological disorder is caused by a deficiency of thiamine (vitamin B1) in the brain, and it is typically associated with and exacerbated by the prolonged, excessive ingestion of alcohol. Korsakoff syndrome is often accompanied by Wernicke encephalopathy; this combination is called Wernicke–Korsakoff syndrome.Korsakoff syndrome is named after Sergei Korsakoff, the Russian neuropsychiatrist who described it during the late 19th century. Signs and symptoms
There are seven major symptoms of Korsakoff syndrome, an amnestic-confabulatory syndrome:
anterograde amnesia, memory loss for events after the onset of the syndrome
retrograde amnesia, memory loss extends back for some time before the onset of the syndrome
amnesia of fixation, also known as fixation amnesia (loss of immediate memory, a person being unable to remember events of the past few minutes)
confabulation, that is, invented memories which are then taken as true, due to gaps in memory, with such gaps sometimes associated with blackouts
minimal content in conversation
lack of insight
apathy – interest in things is quickly lost, and there is an indifference to changeBenon R. and LeHuché R. (1920) described the characteristic signs of Korsakoff syndrome with some additional features including: confabulation (false memories), fixation amnesia, paragnosia or false recognition of places, mental excitation, and euphoria.Thiamine is essential for the decarboxylation of pyruvate, and deficiency during this metabolic process is thought to cause damage to the medial thalamus and mammillary bodies of the posterior hypothalamus, as well as generalized cerebral atrophy.
Treatment typically requires taking thiamine orally for 3 to 12 months, though only about 20 percent of cases are reversible. If treatment is successful, improvement will become apparent within two years, although recovery is slow and often incomplete.As an immediate form of treatment, a pairing of intravenous or intramuscular thiamine with a high concentration of B-complex vitamins can be administered three times daily for 2–3 days. In most cases, an effective response will be observed. A single dose of 1 gram of thiamine can also be administered to achieve a clinical response. In those who are seriously malnourished, the sudden availability of glucose without proper bodily levels of thiamine to metabolize is thought to cause damage to cells. Thus, the administration of thiamine along with an intravenous form of glucose is often good practice.Treatment for the memory aspect of KS can also include domain-specific learning, which when used for rehabilitation is called the method of vanishing cues. Such treatments aim to use intact memory processes as the basis for rehabilitation. Those who used the method of vanishing cues in therapy were found to learn and retain information more easily.People diagnosed with KS are reported to have a normal life expectancy, presuming that they abstain from alcohol and follow a balanced diet. Empirical research has suggested that good health practices have beneficial effects in Korsakoff syndrome. Epidemiology
Rates varies between countries, but it is estimated to affect around 12.5% of heavy drinkers. References


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