[The concept of amnesia and quantitative assessment of amnesic disorders].

This article presents first a short historical overview of the different viewpoints concerning psychiatric approaches to define the concept "amnesia" (Ribot, Korsakow, K. Schneider, Bleuler, Bonhoeffer et al.). A generally accepted result is the differentiation between retrograde and anterograde amnesia. Research work of the last two decades has focussed on the experimental investigation of anterograde amnesia, the so-called amnesic syndrome. In this context four main factors responsible for memory performance are distinguished: encoding, retrieval, forgetting and interference. One of the main results of neuropsychological research in amnesia consists in having discovered a set of symptoms or features common to most if not all forms of amnesia. These features appear regardless of etiology and locus of lesion. This set or features is described in detail in the paper. On the basis of these amnesic features a clinical test was developed, the Berliner Amnesie Test (BAT). This standardized test can be used for the assessment from mild up to severe memory disorders.