Towards Solving the Riddle of Forgetting in Functional Amnesia: Recent Advances and Current Opinions

Abstract

Remembering the past is a core feature of human beings, enabling them to maintain a sense of wholeness and identity and preparing them for the demands of the future. Forgetting operates in a dynamic neural connection with remembering, allowing the elimination of unnecessary or irrelevant information overload and decreasing interference. Stress and traumatic experiences could affect this connection, resulting in memory disturbances, such as functional amnesia. An overview of clinical, epidemiological, neuropsychological, and neurobiological aspects of functional amnesia is presented, by preponderantly resorting to own data from patients with functional amnesia. Patients were investigated medically, neuropsychologically, and neuroradiologically. A detailed report of a new case is included to illustrate the challenges posed by making an accurate differential diagnosis of functional amnesia, a condition that may encroach on the boundaries between psychiatry and neurology. Several mechanisms may play a role in “forgetting” in functional amnesia, such as retrieval impairments, consolidating defects, motivated forgetting, deficits in binding and reassembling details of the past, deficits in establishing a first person autonoetic connection with personal events, and loss of information. In a substantial number of patients, we observed a synchronization abnormality between a frontal lobe system, important for autonoetic consciousness, and a temporo-amygdalar system, important for evaluation and emotions, which provides empirical support for an underlying mechanism of dissociation (a failure of integration between cognition and emotion). This observation suggests a mnestic blockade in functional amnesia that is triggered by psychological or environmental stress and is underpinned by a stress hormone mediated synchronization abnormality during retrieval between processing of affect-laden events and fact-processing.

Functional cognitive disorder: what is it and what to do about it?

“…Functional cognitive disorder should be distinguished from dissociative amnesia, where patients lose important autobiographical information (either for a single traumatic event or for their entire life history) 21 22. Dense retrograde amnesia before a specific time point typically occurs in dissociative amnesia, while patients with functional cognitive disorder typically have memory difficulties affecting the registration and recall of new information.…”

Social cognition in a case of amnesia with neurodevelopmental mechanisms

“…Kritchevsky et al (2004, p. 224) described a patient with functional amnesia who after the onset of amnesia became “less aware of the feelings of other individuals.” He furthermore did not comprehend jokes anymore and “interpreted them literally” (Kritchevsky et al, 2004, p. 224). Interpersonal difficulties with family members have been reported to occur after the onset of dissociative amnesia and were partly attributed to an impaired ability to properly read the familiar/close others' mental states (Rabin and Rosenbaum, 2012; Staniloiu and Markowitsch, 2012; Markowitsch and Staniloiu, 2013). …”

“…In a case series of five patients with dissociative (functional) amnesia, three out of the four patients in whom the RMET was administered, showed performance deficits on it. Dissociative amnesia is however often accompanied by other psychiatric or medical comorbidities, such as major depressive disorder (Staniloiu and Markowitsch, 2012). One could furthermore argue that, even when the co-occurring symptoms of depression do not reach the threshold for a diagnosis of an affective disorder according to the international nosologies' diagnostic criteria (so-called subclinical symptoms of depression), they can still impact on ToM functions (Cusi et al, 2011).…”

1741 – Social cognition in a case of amnesia with neurodevelopmental mechanisms

“…• Test for evaluation of prospective memory -qualitative description (Knight et al, 2010;Staniloiu and Markowitsch, 2012).…”

“…He furthermore did not comprehend jokes anymore and "interpreted them literally" (Kritchevsky et al, 2004, p. 224). Interpersonal difficulties with family members have been reported to occur after the onset of dissociative amnesia and were partly attributed to an impaired ability to properly read the familiar/close others' mental states Staniloiu and Markowitsch, 2012;Markowitsch and Staniloiu, 2013). Reinhold and Markowitsch (2007) formally assessed emotional processing and social cognition in two female adolescents (age 16 and 18, respectively) suffering from dissociative amnesia.…”