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Armin Schnider - One of the best experts on this subject based on the ideXlab platform.
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The history of Confabulation
Oxford Scholarship Online, 2017Co-Authors: Armin SchniderAbstract:The interest in Confabulations has a long history. Starting with Korsakoff’s early reports of pseudo-reminiscences in alcoholic and malnourished patients and Kraepelin’s description of fantastic Confabulations in psychosis and syphilis, this chapter examines a rich literature which documented in fine detail the various presentations and causes of Confabulations. Korsakoff syndrome was recognized as the combination of amnesia, disorientation, and Confabulation. Authors soon distinguished between different forms of Confabulation. From the beginning, they speculated about the mechanisms and indeed anticipated most of the currently proposed models. The chapter finishes with a table comparing old and new terminology of the proposed mechanisms.
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Aetiologies and anatomy of Confabulation
Oxford Scholarship Online, 2017Co-Authors: Armin SchniderAbstract:What diseases cause Confabulations and which are the brain areas whose damage is responsible? This chapter reviews the causes, both historic and present, of Confabulations and deduces the anatomo-clinical relationships for the four forms of Confabulation in the following disorders: alcoholic Korsakoff syndrome, traumatic brain injury, rupture of an anterior communicating artery aneurysm, posterior circulation stroke, herpes and limbic encephalitis, hypoxic brain damage, degenerative dementia, tumours, schizophrenia, and syphilis. Overall, clinically relevant Confabulation is rare. Some aetiologies have become more important over time, others have virtually disappeared. While Confabulations seem to be more frequent after anterior brain damage, only one form has a distinct anatomical basis.
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Mechanisms of Confabulation
Oxford Scholarship Online, 2017Co-Authors: Armin SchniderAbstract:From the initial observations, many hypotheses have been proposed to explain Confabulations. This chapter presents the current models of Confabulation and examines their empirical basis. Is gap-filling a confirmed mechanism? What is the role of personality and motivation? Does the combination of amnesia with executive failures suffice to induce Confabulation? What is the experimental evidence for deficient monitoring processes—and how would such processes work? Is the confusion of memories in time a feature or a cause of Confabulation? A conclusion from this chapter will be that many models lack confirming experimental evidence and fail to account for the dissociation between different forms of Confabulation.
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Types of Confabulation
Oxford Scholarship Online, 2017Co-Authors: Armin SchniderAbstract:When the term ‘Confabulation’ entered the medical literature, it referred to the emergence of memories of events and experiences that never happened. However, its Latin root—meaning ‘to gossip, to chat’—allowed for a broader use of the term. This chapter gives the classic and the present-day definitions of Confabulations and proposes a distinction between memory-related (mnestic) and non-memory-related (non-mnestic) Confabulations. Early clinical observations already suggested the distinction between different forms of mnestic Confabulations. Based on the literature and our own studies, I propose to distinguish four forms of Confabulations, which partially or completely dissociate, and suggest ways to explore them.
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Disorders associated with Confabulation
Oxford Scholarship Online, 2017Co-Authors: Armin SchniderAbstract:Most clinicians would agree that Confabulation is always accompanied by amnesia and lack of insight. But is this true? Do confabulating patients really need to have a gap in memory? This chapter explores the complex relation between Confabulation and amnesia, disorientation, and false recognition and compares it with disorders provoking false statements about the current situation, the place, people, or one’s own health status, as it happens in disorders such as déjà vu, reduplicative paramnesia, Capgras and Fregoli syndromes, intermetamorphosis, and anosognosia. Elegant recent experiments have revealed a new mechanism of anosognosia for hemiplegia, but its status among Confabulations remains disputable.
Radek Ptak - One of the best experts on this subject based on the ideXlab platform.
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what does extinction have to do with Confabulation
Cortex, 2017Co-Authors: Armin Schnider, Louis Nahum, Radek PtakAbstract:Behaviourally spontaneous Confabulation denotes a distinct syndrome consisting of Confabulations that patients act upon, disorientation, and amnesia. It corresponds to the stable form of the original Korsakoff syndrome. While the syndrome may also occur in confusional states and degenerative dementia, this article is about the syndrome as it occurs after acute and focal brain damage. The patients act according to ideas and obligations that can mostly be traced back to real experiences in their past, but which are not currently valid guides of thinking and behaviour. This inability to abandon behavioural guides (anticipations) that are currently not valid corresponds to a failure of behavioural extinction and to the inability to abandon a previously rewarded choice in reversal learning when the expected reward (outcome) fails to occur, that is, following extinction trials. This article describes evidence from human and animal experiments showing that the posterior medial orbitofrontal cortex (OFC), which is typically damaged in these patients, and connected structures of the reward system contain the neural apparatus to signal the non-occurrence of anticipated outcomes, thereby presumably synchronizing thought and behaviour with current reality. Failure of this function, which we call orbitofrontal reality filtering, is associated with behaviourally spontaneous Confabulation and disorientation after acute and focal brain damage, but not with other forms of Confabulation, and not with reality confusion in degenerative dementia. Potential links with psychosis and decision making will be discussed.
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isolated prospective Confabulation in wernicke korsakoff syndrome a case for reality filtering
Neurocase, 2013Co-Authors: Armin Schnider, Louis Nahum, Jean-michel Pignat, Béatrice Leemann, Michael Wissmeyer, Karl-olof Lövblad, Radek PtakAbstract:A 57-year-old man suffered severe amnesia and disorientation, accompanied by content-specific Confabulation, due to an alcoholic Wernicke-Korsakoff syndrome. For months, he was deeply concerned about a single obligation that he thought he had to respond to, but which he had already assumed 20 years previously. This monothematic, prospective Confabulation was associated with failures of reality filtering as previously documented in behaviorally spontaneous Confabulation and disorientation: the patient failed to suppress the interference of currently irrelevant memories and to abandon anticipations that were no longer valid (impaired extinction capacity). Magnetic resonance imaging showed damage to the mamillary bodies and the dorsomedial thalamic nucleus. Positron emission tomography (FDG-PET) showed extended orbitofrontal hypometabolism. We suggest that isolated prospective Confabulation shares the core feature (acts and thoughts based on currently irrelevant memory), mechanism (failure of reality filtering), and anatomical basis (orbitofrontal dysfunction) with behaviorally spontaneous Confabulations.
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Forms of Confabulation: dissociations and associations.
Neuropsychologia, 2012Co-Authors: Louis Nahum, Radek Ptak, Aurélie Bouzerda-wahlen, Adrian G. Guggisberg, Armin SchniderAbstract:Confabulation denotes the emergence of memories of experiences and events which never took place. Whether there are distinct forms with distinct mechanisms is still debated. In this study, we explored 4 forms of Confabulation and their mechanisms in 29 amnesic patients. Patients performed tests of explicit memory, executive functions, and two test of orbitofrontal reality filtering (memory selection and extinction capacity in a reversal learning task) previously shown to be strongly associated with Confabulations that patients act upon and disorientation. Results indicated the following associations: (1) Intrusions in a verbal memory test (simple provoked Confabulations) dissociated from all other forms of Confabulation and were not associated with any specific cognitive measure. (2) Momentary Confabulations, defined as confabulatory responses to questions and measured with a Confabulation questionnaire, were associated with impaired mental flexibility, a tendency to fill gaps in memory, and with one measure of reality filtering. Momentary Confabulations, therefore, may emanate from diverse causes. (3) Behaviourally spontaneous Confabulation, characterized by Confabulations that the patients act upon and disorientation, was strongly associated with failure in the two reality filtering tasks. Behaviourally spontaneous Confabulation may be seen as a specific instance of momentary Confabulations with a distinct mechanism. (4) A patient producing fantastic Confabulations with nonsensical, illogical content had wide-spread cognitive dysfunction and failed in the reality filtering tasks. The results support the presence of truly or partially dissociable types of Confabulation with different mechanisms.
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Isolated prospective Confabulation in Wernicke–Korsakoff syndrome: a case for reality filtering
Neurocase, 2012Co-Authors: Armin Schnider, Louis Nahum, Jean-michel Pignat, Béatrice Leemann, Michael Wissmeyer, Karl-olof Lövblad, Radek PtakAbstract:A 57-year-old man suffered severe amnesia and disorientation, accompanied by content-specific Confabulation, due to an alcoholic Wernicke-Korsakoff syndrome. For months, he was deeply concerned about a single obligation that he thought he had to respond to, but which he had already assumed 20 years previously. This monothematic, prospective Confabulation was associated with failures of reality filtering as previously documented in behaviorally spontaneous Confabulation and disorientation: the patient failed to suppress the interference of currently irrelevant memories and to abandon anticipations that were no longer valid (impaired extinction capacity). Magnetic resonance imaging showed damage to the mamillary bodies and the dorsomedial thalamic nucleus. Positron emission tomography (FDG-PET) showed extended orbitofrontal hypometabolism. We suggest that isolated prospective Confabulation shares the core feature (acts and thoughts based on currently irrelevant memory), mechanism (failure of reality filtering), and anatomical basis (orbitofrontal dysfunction) with behaviorally spontaneous Confabulations.
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behaviorally spontaneous Confabulation in limbic encephalitis the roles of reality filtering and strategic monitoring
Journal of The International Neuropsychological Society, 2010Co-Authors: Louis Nahum, Béatrice Leemann, Radek Ptak, Patrice H Lalive, Armin SchniderAbstract:Behaviorally spontaneous Confabulation is characterized by a confusion of reality evident in currently inappropriate acts that patients justify with Confabulations and in disorientation. Here, we describe a 38-year-old woman lawyer hospitalized because of non-herpetic, presumably autoimmune, limbic encephalitis. For months, she considered herself at work and desperately tried to respect her falsely believed professional obligations. In contrast to a completely erroneous concept of reality, she did not confabulate about her remote personal past. In tasks proposed to test strategic retrieval monitoring, she produced no Confabulations. As expected, she failed in tasks of reality filtering, previously shown to have high sensitivity and specificity for behaviorally spontaneous Confabulation and disorientation: she failed to suppress the interference of currently irrelevant memories and she had deficient extinction capacity. The observation underscores the special status of behaviorally spontaneous Confabulation among confabulatory phenomena and of reality filtering as a thought control mechanism. We suggest that different processes may underlie the generation of false memories and their verbal expression. We also emphasize the need to present theories of Confabulation together with experimental tasks that allow one to empirically verify the theories and to explore underlying physiological mechanisms.
Takashi Tsukiura - One of the best experts on this subject based on the ideXlab platform.
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disturbance of time orientation attention and verbal memory in amnesic patients with Confabulation
Journal of Clinical and Experimental Neuropsychology, 2016Co-Authors: Honoka Shingaki, Paeksoon Park, Keita Ueda, Toshiya Murai, Takashi TsukiuraAbstract:ABSTRACTConfabulation is often observed in amnesic patients after brain damage. However, evidence regarding the relationship between Confabulation and other neuropsychological functions is scarce. In addition, previous studies have proposed two possibilities of the relationship between Confabulation and false memory, in which patients with Confabulation are likely to retrieve false memories, or Confabulations are relatively independent of false memories. The present study investigated how Confabulation is related to various cognitive functions, including orientation, attention, frontal lobe function, memory, and mental status, and to false memories, as assessed by the Deese–Roediger–Mcdermott (DRM) paradigm. Patients with organic amnesia participated, and Confabulations were evaluated using the Confabulation Battery. Amnestic patients were classified into two groups: confabulating (CP) and nonconfabulating patients (NCP). The CP group was significantly impaired in time orientation, attention, and verbal m...
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disturbance of time orientation attention and verbal memory in amnesic patients with Confabulation
Journal of Clinical and Experimental Neuropsychology, 2016Co-Authors: Honoka Shingaki, Paeksoon Park, Keita Ueda, Toshiya Murai, Takashi TsukiuraAbstract:Confabulation is often observed in amnesic patients after brain damage. However, evidence regarding the relationship between Confabulation and other neuropsychological functions is scarce. In addition, previous studies have proposed two possibilities of the relationship between Confabulation and false memory, in which patients with Confabulation are likely to retrieve false memories, or Confabulations are relatively independent of false memories. The present study investigated how Confabulation is related to various cognitive functions, including orientation, attention, frontal lobe function, memory, and mental status, and to false memories, as assessed by the Deese-Roediger-Mcdermott (DRM) paradigm. Patients with organic amnesia participated, and Confabulations were evaluated using the Confabulation Battery. Amnestic patients were classified into two groups: confabulating (CP) and nonconfabulating patients (NCP). The CP group was significantly impaired in time orientation, attention, and verbal memory, compared to the NCP group and age-matched healthy controls (HC). Results of the DRM paradigm revealed no significant difference in false memory retrieval induced by critical lures across CP, NCP, and HC groups. Confabulating responses in organic amnesia could be in part induced by disturbance of time consciousness and attention control in severe impairment of verbal memories, and Confabulation and false memory could be modulated by different cognitive systems.
Louis Nahum - One of the best experts on this subject based on the ideXlab platform.
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what does extinction have to do with Confabulation
Cortex, 2017Co-Authors: Armin Schnider, Louis Nahum, Radek PtakAbstract:Behaviourally spontaneous Confabulation denotes a distinct syndrome consisting of Confabulations that patients act upon, disorientation, and amnesia. It corresponds to the stable form of the original Korsakoff syndrome. While the syndrome may also occur in confusional states and degenerative dementia, this article is about the syndrome as it occurs after acute and focal brain damage. The patients act according to ideas and obligations that can mostly be traced back to real experiences in their past, but which are not currently valid guides of thinking and behaviour. This inability to abandon behavioural guides (anticipations) that are currently not valid corresponds to a failure of behavioural extinction and to the inability to abandon a previously rewarded choice in reversal learning when the expected reward (outcome) fails to occur, that is, following extinction trials. This article describes evidence from human and animal experiments showing that the posterior medial orbitofrontal cortex (OFC), which is typically damaged in these patients, and connected structures of the reward system contain the neural apparatus to signal the non-occurrence of anticipated outcomes, thereby presumably synchronizing thought and behaviour with current reality. Failure of this function, which we call orbitofrontal reality filtering, is associated with behaviourally spontaneous Confabulation and disorientation after acute and focal brain damage, but not with other forms of Confabulation, and not with reality confusion in degenerative dementia. Potential links with psychosis and decision making will be discussed.
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isolated prospective Confabulation in wernicke korsakoff syndrome a case for reality filtering
Neurocase, 2013Co-Authors: Armin Schnider, Louis Nahum, Jean-michel Pignat, Béatrice Leemann, Michael Wissmeyer, Karl-olof Lövblad, Radek PtakAbstract:A 57-year-old man suffered severe amnesia and disorientation, accompanied by content-specific Confabulation, due to an alcoholic Wernicke-Korsakoff syndrome. For months, he was deeply concerned about a single obligation that he thought he had to respond to, but which he had already assumed 20 years previously. This monothematic, prospective Confabulation was associated with failures of reality filtering as previously documented in behaviorally spontaneous Confabulation and disorientation: the patient failed to suppress the interference of currently irrelevant memories and to abandon anticipations that were no longer valid (impaired extinction capacity). Magnetic resonance imaging showed damage to the mamillary bodies and the dorsomedial thalamic nucleus. Positron emission tomography (FDG-PET) showed extended orbitofrontal hypometabolism. We suggest that isolated prospective Confabulation shares the core feature (acts and thoughts based on currently irrelevant memory), mechanism (failure of reality filtering), and anatomical basis (orbitofrontal dysfunction) with behaviorally spontaneous Confabulations.
-
Forms of Confabulation: dissociations and associations.
Neuropsychologia, 2012Co-Authors: Louis Nahum, Radek Ptak, Aurélie Bouzerda-wahlen, Adrian G. Guggisberg, Armin SchniderAbstract:Confabulation denotes the emergence of memories of experiences and events which never took place. Whether there are distinct forms with distinct mechanisms is still debated. In this study, we explored 4 forms of Confabulation and their mechanisms in 29 amnesic patients. Patients performed tests of explicit memory, executive functions, and two test of orbitofrontal reality filtering (memory selection and extinction capacity in a reversal learning task) previously shown to be strongly associated with Confabulations that patients act upon and disorientation. Results indicated the following associations: (1) Intrusions in a verbal memory test (simple provoked Confabulations) dissociated from all other forms of Confabulation and were not associated with any specific cognitive measure. (2) Momentary Confabulations, defined as confabulatory responses to questions and measured with a Confabulation questionnaire, were associated with impaired mental flexibility, a tendency to fill gaps in memory, and with one measure of reality filtering. Momentary Confabulations, therefore, may emanate from diverse causes. (3) Behaviourally spontaneous Confabulation, characterized by Confabulations that the patients act upon and disorientation, was strongly associated with failure in the two reality filtering tasks. Behaviourally spontaneous Confabulation may be seen as a specific instance of momentary Confabulations with a distinct mechanism. (4) A patient producing fantastic Confabulations with nonsensical, illogical content had wide-spread cognitive dysfunction and failed in the reality filtering tasks. The results support the presence of truly or partially dissociable types of Confabulation with different mechanisms.
-
Isolated prospective Confabulation in Wernicke–Korsakoff syndrome: a case for reality filtering
Neurocase, 2012Co-Authors: Armin Schnider, Louis Nahum, Jean-michel Pignat, Béatrice Leemann, Michael Wissmeyer, Karl-olof Lövblad, Radek PtakAbstract:A 57-year-old man suffered severe amnesia and disorientation, accompanied by content-specific Confabulation, due to an alcoholic Wernicke-Korsakoff syndrome. For months, he was deeply concerned about a single obligation that he thought he had to respond to, but which he had already assumed 20 years previously. This monothematic, prospective Confabulation was associated with failures of reality filtering as previously documented in behaviorally spontaneous Confabulation and disorientation: the patient failed to suppress the interference of currently irrelevant memories and to abandon anticipations that were no longer valid (impaired extinction capacity). Magnetic resonance imaging showed damage to the mamillary bodies and the dorsomedial thalamic nucleus. Positron emission tomography (FDG-PET) showed extended orbitofrontal hypometabolism. We suggest that isolated prospective Confabulation shares the core feature (acts and thoughts based on currently irrelevant memory), mechanism (failure of reality filtering), and anatomical basis (orbitofrontal dysfunction) with behaviorally spontaneous Confabulations.
-
behaviorally spontaneous Confabulation in limbic encephalitis the roles of reality filtering and strategic monitoring
Journal of The International Neuropsychological Society, 2010Co-Authors: Louis Nahum, Béatrice Leemann, Radek Ptak, Patrice H Lalive, Armin SchniderAbstract:Behaviorally spontaneous Confabulation is characterized by a confusion of reality evident in currently inappropriate acts that patients justify with Confabulations and in disorientation. Here, we describe a 38-year-old woman lawyer hospitalized because of non-herpetic, presumably autoimmune, limbic encephalitis. For months, she considered herself at work and desperately tried to respect her falsely believed professional obligations. In contrast to a completely erroneous concept of reality, she did not confabulate about her remote personal past. In tasks proposed to test strategic retrieval monitoring, she produced no Confabulations. As expected, she failed in tasks of reality filtering, previously shown to have high sensitivity and specificity for behaviorally spontaneous Confabulation and disorientation: she failed to suppress the interference of currently irrelevant memories and she had deficient extinction capacity. The observation underscores the special status of behaviorally spontaneous Confabulation among confabulatory phenomena and of reality filtering as a thought control mechanism. We suggest that different processes may underlie the generation of false memories and their verbal expression. We also emphasize the need to present theories of Confabulation together with experimental tasks that allow one to empirically verify the theories and to explore underlying physiological mechanisms.
Honoka Shingaki - One of the best experts on this subject based on the ideXlab platform.
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disturbance of time orientation attention and verbal memory in amnesic patients with Confabulation
Journal of Clinical and Experimental Neuropsychology, 2016Co-Authors: Honoka Shingaki, Paeksoon Park, Keita Ueda, Toshiya Murai, Takashi TsukiuraAbstract:ABSTRACTConfabulation is often observed in amnesic patients after brain damage. However, evidence regarding the relationship between Confabulation and other neuropsychological functions is scarce. In addition, previous studies have proposed two possibilities of the relationship between Confabulation and false memory, in which patients with Confabulation are likely to retrieve false memories, or Confabulations are relatively independent of false memories. The present study investigated how Confabulation is related to various cognitive functions, including orientation, attention, frontal lobe function, memory, and mental status, and to false memories, as assessed by the Deese–Roediger–Mcdermott (DRM) paradigm. Patients with organic amnesia participated, and Confabulations were evaluated using the Confabulation Battery. Amnestic patients were classified into two groups: confabulating (CP) and nonconfabulating patients (NCP). The CP group was significantly impaired in time orientation, attention, and verbal m...
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disturbance of time orientation attention and verbal memory in amnesic patients with Confabulation
Journal of Clinical and Experimental Neuropsychology, 2016Co-Authors: Honoka Shingaki, Paeksoon Park, Keita Ueda, Toshiya Murai, Takashi TsukiuraAbstract:Confabulation is often observed in amnesic patients after brain damage. However, evidence regarding the relationship between Confabulation and other neuropsychological functions is scarce. In addition, previous studies have proposed two possibilities of the relationship between Confabulation and false memory, in which patients with Confabulation are likely to retrieve false memories, or Confabulations are relatively independent of false memories. The present study investigated how Confabulation is related to various cognitive functions, including orientation, attention, frontal lobe function, memory, and mental status, and to false memories, as assessed by the Deese-Roediger-Mcdermott (DRM) paradigm. Patients with organic amnesia participated, and Confabulations were evaluated using the Confabulation Battery. Amnestic patients were classified into two groups: confabulating (CP) and nonconfabulating patients (NCP). The CP group was significantly impaired in time orientation, attention, and verbal memory, compared to the NCP group and age-matched healthy controls (HC). Results of the DRM paradigm revealed no significant difference in false memory retrieval induced by critical lures across CP, NCP, and HC groups. Confabulating responses in organic amnesia could be in part induced by disturbance of time consciousness and attention control in severe impairment of verbal memories, and Confabulation and false memory could be modulated by different cognitive systems.