Korsakoff's syndrome - a subdivision of Wernicke-Korsakoff syndrome

n. Korsakoff's syndrome is characterized by a significant retrograde memory deficit in individuals who are not otherwise cognitively impaired. Wernicke's syndrome is marked by confusion, abnormal eye movements, and inability to control muscle movement. When significant memory loss accompanies this symptom triad, the term syndrome is often applied.

There is some debate among experts regarding the precise relationship between these two disorders. The pair can be conceptualized as either separate syndromes or as one disorder with varying levels. In the latter case, Wernicke's syndrome (also known as Wernicke's encephalopathy) is recognized as the more acute phenomenon, while Korsakoff's syndrome is more chronic. In fact, some researchers have described a temporal relationship between the two disorders, with an experience of untreated symptoms of Wernicke's syndrome leading to a subsequent diagnosis of the more severe memory loss indicative of Korsakoff's syndrome.

Korsakoff's syndrome reflects a nutritional depletion, usually a thiamine (vitamin essential for neural function and the proper metabolization of carbohydrates) deficiency. This lack of essential nutrients is most often caused by the poor diet adopted by persons with severe alcoholism. In the later stages of alcoholism, persons may become ill, reducing their ability to eat and creating a situation in which the majority of caloric intake results from alcohol consumption. However, because nutrition depletion can be caused by other factors, Korsakoff's syndrome can develop in the absence of alcohol. One should also be aware that Korsakoff's syndrome is not the only disorder that can result in memory loss. Many other disorders such as herpes encephalitis, severe hypoxia, and traumatic brain injury may also result in memory impairment, but these disorders are not typically associated with the nutritional depletion evident in cases of Korsakoff's syndrome.

The memory loss apparent in cases of Korsakoff's syndrome has also been linked to specific neuropathological changes, such as neuronal loss and microhemorrhages in particular areas of the brain. These distinct patterns of atrophy may serve to explain why some persons who experience symptoms of Wernicke's syndrome may later experience the amnesiac symptoms of Korsakoff's syndrome.

Some researchers disagree about the amount of recovery that is possible after diagnosis with Korsakoff's syndrome. In fact, it is extremely unlikely for a person who has reached the level of memory loss indicative of Korsakoff's syndrome ever to recover fully. However, some researchers advocate that with proper thiamine treatment and abstinence from future alcoholic intake, some degree of recovery is possible, as long as the individual's extent of brain atrophy is minimal.

- TJM

▶ See also KORSAKOFF、PSYCHOSIS and NONALCOHOLIC KORSAKOFF'S PSYCHOSIS