Functional (dissociative) retrograde amnesia

Lifelong impairment in episodic re-experiencing: Neuropsychological and neuroimaging examination of a new case of Severely Deficient Autobiographical Memory

Autobiographical memory (AM) represents a complex and multimodal cognitive function, that allows an individual to collect and retrieve personal events and facts, enabling to develop and maintain the continuity of the self over time. Here we describe the case of DR (acronym of the fictional name Doriana Rossi), a 53-year-old woman, who complains of a specific and lifelong deficit in recalling autobiographical episodes. Along with an extensive neuropsychological assessment, DR underwent a structural and functional MRI examination to further define this impairment. The neuropsychological assessment revealed a deficit in episodic re-experiencing of her own personal life events. DR showed reduced cortical thickness in the Retrosplenial Complex in the left hemisphere, and in the Lateral Occipital Cortex, in the Prostriate Cortex and the Angular Gyrus in the right hemisphere. An altered pattern of activity in the calcarine cortex was detected during ordering of autobiographical events according to her own personal timeline. The present study provides further evidence about the existence of a severely deficient autobiographical memory condition in neurologically healthy people, with otherwise preserved cognitive functioning. Furthermore, the present data provide new important insights into neurocognitive mechanisms underpinning such a developmental condition.

Behavioral, neurological, and psychiatric frailty of autobiographical memory

Autobiographical-episodic memory is considered to be the most complex of the five long-term memory systems. It is autonoetic, which means, self-reflective, relies on emotional colorization, and needs the features of place and time; it allows mental time traveling. Compared to the other four long-term memory systems-procedural memory, priming, perceptual, and semantic memory-it develops the latest in phylogeny and ontogeny, and is the most vulnerable of the five systems, being easily impaired by brain damage and psychiatric disorders. Furthermore, it is characterized by its fragility and proneness to distortion due to environmental influences and subsequent information. On the brain level, a distinction has to be made between memory encoding and consolidating, memory storage, and memory retrieval. For encoding, structures of the limbic system, with the hippocampus in its center, are crucial, for storage of widespread cortical networks, and for retrieval again a distributed recollection network, in which the prefrontal cortex plays a crucial role, is engaged. Brain damage and psychiatric diseases can lead to what is called "focal retrograde amnesia." In this context, the clinical picture of dissociative or functional or psychogenic amnesia is central, as it may result in autobiographical-emotional amnesia of the total past with the consequence of an impairment of the self as well. The social environment therefore can have a major impact on the brain and on autobiographical-episodic memory processing. This article is categorized under: Psychology > Memory.

Disordered eating as a repercussion of sexual assault: a consequence to consider

PURPOSE

This study aims at clarifying the links between sexual violence and disordered eating (DE).

METHODS

In a sample of 12,638 victims of self-reported sexual violence, we analyzed the situation of 546 victims that declared having developed DE. We assessed the characteristics of the assault (age, type of aggression) and the medical consequences (PTSD, depression, suicide attempts, anxiety disorders, etc.).

RESULTS

DE prevalence was 4.3% in the victim sample. The age of the first assault in DE victims was significantly lower than that of the whole population (12 years vs 16 years for median; p < 0.001). A much higher prevalence of sexual assault consequences was present in victims developing DE with odd ratios (OR) for: self-mutilation (OR = 11.5 [8.29-15.95], p < 0.001); depression (OR = 5.7 [4.81-6.86], p < 0.001); self-medication (OR = 5.3 [3.86-7.19], p < 0.001); suicide attempts (OR = 4.5 [3.59-5.67], p < 0.001); post-traumatic stress disorder (OR = 3.8 [2.99-4.78], p < 0.001); anxiety troubles (OR = 5.2 [4.11-6.47], p < 0.001); alcoholism (OR = 4.0 [2.81-5.58], p < 0.001).

CONCLUSION

This study confirms the link between DE and sexual violence, especially in childhood, leading to severe psychological consequences. In this context, DE should be envisaged as a coping strategy accompanying emotional dysregulation due to traumatic events, and be treated as such.

LEVEL OF EVIDENCE

Level IV: Evidence obtained from multiple time series analysis such as case studies.

Acute-onset amnesia: transient global amnesia and other causes

Acute-onset amnesia is a dramatic neurological presentation that can cause considerable concern to both patient and clinician. The patient typically presents with an inability not only to retain new memories but also to access previously acquired memories, suggesting disturbance of hippocampal function. Transient global amnesia (TGA) is the most common cause of acute-onset amnesia, and is characterised by a profound anterograde and retrograde amnesia that typically lasts for up to 24 hours. Although TGA has a strikingly stereotypical presentation, it can be challenging to distinguish from other causes of acute-onset amnesia, including posterior circulation strokes, transient epileptic amnesia, psychogenic amnesia, post-traumatic amnesia, and toxic/drug-related amnesia. Here, we describe the general approach to the patient with acute amnesia; summarise the clinical and neuropsychological differences between the potential causes; and, provide practical recommendations to aid diagnosis and management of acute amnesia. Regardless of cause and the dramatic presentation, non-ischaemic acute-onset amnesia generally has a favourable prognosis.

Increased Pupil Size during Future Thinking in a Subject with Retrograde Amnesia

Recent research has assessed pupil size during past thinking in patients with retrograde amnesia. Building on this research, we assessed pupil size during future thinking in a retrograde amnesia patient. To this end, we measured pupil size during past and future thinking in L, a 19-year-old, right-handed man free of neurological/psychiatric disorders except for retrograde amnesia that occurred after an episode of fugue. During a past thinking condition, we invited L to retrieve retrograde events (i.e., events that occurred before amnesia) and anterograde events (i.e., events that occurred after amnesia). During a future thinking condition, we invited him to imagine events that might occur the following week, the following month, and in the new year. Past and future thinking occurred while L's pupil size was monitored with eye-tracking glasses. L demonstrated higher specificity during future than during past thinking. Critically, the results demonstrated a larger pupil size during future than during past thinking. The larger pupil size during future thinking observed in L can be attributed to the high cognitive load involved in future thinking. Our study not only demonstrates preserved future thinking in a patient with dissociative retrograde amnesia, but also shows that pupillometry can be used for the physiological assessment of future thinking in retrograde amnesia patients.

Amnesia in your pupils: decreased pupil size during autobiographical retrieval in a case of retrograde amnesia

We investigate whether retrograde-amnesia can be indexed with pupil activity. We present the case of L, 19-year-old, without neurological or psychiatric disorders except for retrograde-amnesia. We invited L to retrieve retrograde and anterograde memories while his pupil size was monitering with eye-tracking glasses. Results demonstrated impaired retrograde retrieval but successful anterograde retrieval in L. He also attributed lower emotional value and visual imagery to his retrograde compared to his anterograde memories. Critically, smaller pupils were observed during retrograde than during anterograde retrieval. Our study provides the first evidence on the value of pupillometry as a potential physiological marker of amnesia.

Stress- and trauma-related blockade of episodic-autobiographical memory processing

Memory disorders without a direct neural substrate still belong to the riddles in neuroscience. Although they were for a while dissociated from research and clinical arenas, risking becoming forgotten diseases, they sparked novel interests, paralleling the refinements in functional neuroimaging and neuropsychology. Although Endel Tulving has not fully embarked himself on exploring this field, he had published at least one article on functional amnesia (Schacter et al., 1982) and ignited a seminal article on amnesia with mixed etiology (Craver et al., 2014). Most importantly, the research of Endel Tulving has provided the researchers and clinicians in the field of dissociative or functional amnesia with the best framework for superiorly understanding these disorders through the lens of his evolving concept of episodic memory and five long term memory systems classification, which he developed and advanced. Herein we use the classification of long-term memory systems of Endel Tulving as well as his concepts and views on autonoetic consciousness, relationships between memory systems and relationship between episodic memory and emotion to describe six cases of dissociative amnesia that put a challenge for researchers and clinicians due to their atypicality. We then discuss their possible triggering and maintaining mechanisms, pointing to their clinical heterogeneity and multifaceted causally explanatory frameworks.

State-Dependent Memory: Neurobiological Advances and Prospects for Translation to Dissociative Amnesia

In susceptible individuals, overwhelming traumatic stress often results in severe abnormalities of memory processing, manifested either as the uncontrollable emergence of memories (flashbacks) or as an inability to remember events (dissociative amnesia, DA) that are usually, but not necessarily, related to the stressful experience. These memory abnormalities are often the source of debilitating psychopathologies such as anxiety, depression and social dysfunction. The question of why memory for some traumatic experiences is compromised while other comparably traumatic experiences are remembered perfectly well, both within and across individuals, has puzzled clinicians for decades. In this article, we present clinical, cognitive, and neurobiological perspectives on memory research relevant to DA. In particular, we examine the role of state dependent memory (wherein memories are difficult to recall unless the conditions at encoding and recall are similar), and discuss how advances in the neurobiology of state-dependent memory (SDM) gleaned from animal studies might be translated to humans.

Dissoziative Amnesie und Migration

Zusammenfassung. Dissoziative Amnesie verläuft unter Umständen chronisch und kann zu lebenslanger Arbeitsunfähigkeit führen. Die Krankheit tritt gehäuft im Zusammenhang mit Migration auf und verläuft dann schwerer als in anderen Fällen. Sie ist im Grunde reversibel, d. h., der Abruf der Gedächtnisinhalte ist nur blockiert. Betroffen sind Patienten, die nicht verarbeitete Stress- und Traumaerlebnisse als Hintergrund haben und dann ein erneutes Stresserlebnis erfahren, welches zum dissoziativen Amnesiezustand führt. Es wird postuliert, dass in erster Linie Patienten betroffen sind, die im neuen Heimatland nicht ausreichend und ihrem Anspruch entsprechend Fuß fassen konnten. Mangelnde Sprachkenntnisse und eine nicht den Erwartungen entsprechende neue Arbeitssituation sind am ehesten als Gründe anzuführen.