In 1947, 52 cases of WKS were documented in a prisoner of war hospital in Singapore where the prisoners diets included less than 1 mg of thiamine per day. Such cases provide an opportunity to gain an understanding of what effects this syndrome has on cognition. In this particular case, cognitive symptoms included insomnia, anxiety, difficulties in concentration, loss of memory for the immediate past, and gradual degeneration of mental state; consisting of confusion, confabulation, and hallucinations. In other cases of WKS, cognitive effects such as severely disrupted speech, giddiness, and heavy-headedness have been documented. In addition to this, it has been noted that some patients displayed an inability to focus, and the inability of others to catch patients attention.In a study conducted in 2003 by Brand et al. on the cognitive effects of WKS, the researchers used a neuropsychological test battery which included tests of intelligence, speed of information processing, memory, executive function and cognitive estimation. They found that subjects with WKS showed impairments in all aspects of this test battery but most noticeably, on the cognitive estimation tasks. This task required subjects to estimate a physical quality such as size, weight, quantity or time (e.g. What is the average length of a shower? ), of a particular item. Patients with WKS performed worse than normal control participants on all of the tasks in this category. The patients found estimations involving time to be the most difficult, whereas quantity was the easiest estimation to make.
The deficit in stimulus-reward functions was demonstrated by Oscar-Berman and Pulaski who presented patients with reinforcements for certain stimuli but not others, and then required the patients to distinguish the rewarded stimuli from the non-rewarded stimuli. WKS patients displayed significant deficits in this task. The researchers were also successful in displaying a deficit in recognition memory by having patients make a yes/no decision as to whether a stimulus was familiar (previously seen) or novel (not previously seen). The patients in this study also showed a significant deficit in their ability to perform this task. Confabulation
People with WKS often show confabulation, spontaneous confabulation being seen more frequently than provoked confabulation. Spontaneous confabulations refer to incorrect memories that the patient holds to be true, and may act on, arising spontaneously without any provocation. Provoked confabulations can occur when a patient is cued to give a response, this may occur in test settings. The spontaneous confabulations viewed in WKS are thought to be produced by an impairment in source memory, where they are unable to remember the spatial and contextual information for an event, and thus may use irrelevant or old memory traces to fill in for the information that they cannot access. It has also been suggested that this behaviour may be due to executive dysfunction where they are unable to inhibit incorrect memories or because they are unable to shift their attention away from an incorrect response. Causes
WKS is usually found in people who have used alcohol chronically. Wernicke–Korsakoff syndrome results from thiamine deficiency.