Review article
Amnestic syndromes resulting from brain injury

The aim of the paper is to present the classic viewpoint on amnestic disorders and its verification in the light of recent publications.

Amnestic syndromes, as traditionally defined, are disorders caused by brain injuries, characterized by general, profound impairment in learning of new information and remembering information acquired before brain damage. It is assumed that memory dysfunction occurs in relative isolation, i.e. attention and general intelligence are relatively spared. It is commonly acknowledged that short-term/working memory and non declarative memory systems are intact in amnestic patients. According to localization of the lesion, three amnesic syndromes are widely described: medial temporal lobe amnesia, diencephalic amnesia and basal forebrain amnesia. The paper is concerned with the traditional way of defining and differentiation of amnestic disorders. Both aspects may be imprecise or even invalid in some cases.

The paper presents the bulk of data about memory dysfunctions and functional and anatomical changes in the brain that result in amnesic disorders. Some remarks regarding the problem of generality and isolation of memory dysfunctions are mentioned. The widely accepted opinion regarding preserved short-term and non declarative memory functions is criticized. Moreover, issues related to other cognitive functions that influence memory are discussed. Additionally, the importance of functional changes in broad neural networks, often beyond structural abnormalities, is stressed. These data point to the necessity of revision and clarification of the classic definition and differentiation of amnestic disorders.