The term ‘confabulation’ appeared in the medical literature around the year 1900, with the same meaning as the old terms ‘pseudo-reminiscences, illusions of memory, or falsifications of memory’. Wernicke (1900) defined it as ‘the emergence of memories of events and experiences which have never taken place’. Over the years, diverse definitions have been proposed, often adapted to the observations made in specific groups of patients. Berlyne's (1972) is among the most popular definitions of confabulation: ‘A falsification of memory occurring in a clear consciousness in association with an organically derived amnesia.’ The term was eventually also used to denote unintentional, objectively false statements about percepts.
Diverse classifications of confabulations have been proposed, mostly reflecting the dichotomy of confabulatory phenomena that authors perceived in their patients. The most common distinction opposing momentary (or embarrassment) confabulations and fantastic (or productive) confabulations was initially proposed by Bonhoeffer (1901) and later revived by Berlyne (1972). Another distinction relates to the evocation of confabulations and juxtaposes provoked and spontaneous confabulations (Kopelman 1987). However, none of the current classifications covers all known forms of confabulation. Although the very dissociation between different forms has been challenged, there is sufficient ground for distinguishing at least four forms of confabulation: 1. Intrusions or simple provoked confabulations in memory tests; 2. Momentary confabulations upon some form of incitement, be this questions or the circumstance of a discussion. False statements can range from a simple response to a question to elaborate confabulations. Momentary confabulations are probably not a unitary disorder; 3. Fantastic confabulations, which have no basis in reality and are intrinsically nonsensical and illogical; 4. Behaviourally spontaneous confabulations, that is, confabulations reflecting a confusion of reality, which underlies currently inappropriate behaviour and statements.
Until now, only the dissociation between forms 1 and 4 rests upon formal scientific evidence (Schnider et al. 1996b). Patients may have a combination of momentary and behaviourally spontaneous confabulations, possibly also fantastic confabulations.
It is normally easy to detect confabulations in a discussion with the patient about past events, recent activities, and plans for the near future. Diverse questionnaires and interviews have been proposed, mostly in the context of scientific inquiry, to quantitatively describe the intensity and the pattern of confabulations (Mercer et al. 1977; Moscovitch 1989; Dalla Barba 1993a). The validity of these methods for discerning specific brain diseases or for distinguishing between different forms of confabulation remains unknown. The diagnosis or exclusion of behaviourally spontaneous confabulation often requires close behavioural observation.
Chapter. 11953 words. Illustrated.
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