Subtle object location perception deficits in Korsakoff's syndrome.

(Wernicke-)Korsakoff's syndrome (KS) is a neuropsychiatric syndrome, caused by vitamin B1 (thiamine) deficiency often resulting from chronic alcohol consumption. KS is characterized by severe cognitive problems, such as impaired explicit memory and executive functions. Visuospatial perception (VSP) refers to the identification of objects (object perception), and the localization of objects (space perception). Object perception can be described as the cooperation between visual representation and semantic information on the objects' functional properties. Space perception is the mental representation of visual space and objects within it from a more or less fixed view point. Although VSP is fundamental to everyday functioning and higher order cognitive functions, little knowledge is available on VSP in KS. The aim of the present study was therefore to investigate VSP in KS. Fifteen KS patients and 15 healthy controls performed the Visual Object and Space Perception battery (VOSP) for visuospatial functioning. Results show a selectively reduced performance of KS patients on object perception, but not on space perception tasks. Specifically, subclinical problems in the identification of degraded and atypical positioned objects were present in KS, and not related to general cognitive functioning. These results suggest that the thalamic nucleus, a brain circuit most typically damaged in KS, is critically involved in object integration. Moreover, this relative new perspective on VSP related to KS warrants further research on the neuropsychological evaluation of KS to index possible mild deficits in this domain, possibly negatively affecting everyday functioning in KS.