Focal retrograde amnesia: Extending the clinical syndrome of transient epileptic amnesia

doi:10.1016/j.jocn.2010.03.005

Journal of Clinical Neuroscience

Volume 17, Issue 10, October 2010, Pages 1319-1321

https://doi.org/10.1016/j.jocn.2010.03.005 Get rights and content

Abstract

A 44-year-old woman presented with focal retrograde amnesia and complaints of rapid forgetting in the absence of episodes of transient cognitive disturbance. Her MRI and 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography (FDG-PET) were normal. On standard neuropsychological tests she performed within the normal range although a test of autobiographical memory confirmed impoverished recall especially involving recent life events. The electroencephalograph (EEG) recordings were suggestive of temporal lobe epilepsy but no clear diagnosis was established. After 4 years the patient’s recurrent brief episodes of disorientation, suggestive of transient epileptic amnesia (TEA), were corroborated by her sister. This diagnosis was confirmed by an ambulatory EEG that revealed ictal activity.

Several important points emerge from this study. Focal retrograde amnesia can be a prodromal symptom of TEA which can precede the full-blown syndrome by several years. Moreover, transient attacks might not be reported if patients live alone. The ictal EEG findings further substantiate the epileptic nature of the syndrome.

Introduction

Transient epileptic amnesia (TEA)[1], 2, 3 is characterized by recurrent brief amnesic periods often on waking presenting in middle-aged or elderly subjects. Patients complain of dense gaps in autobiographical memories⁴ and accelerated loss of new memories over days or weeks,⁵ although their performance on standard neuropsychological tests is within normal limits.⁶

The question arises of whether some patients with isolated retrograde amnesia (RGA) may have a cryptic form of TEA as electroencephalograph (EEG) findings may be subtle.⁷ We report a long-term study of a patient presenting with focal RGA and accelerated forgetting but without other clinical manifestations of TEA. Definite proof of the diagnosis emerged only 4 years later when transient “attacks” were witnessed and ambulatory EEG revealed accompanying ictal activity.

Section snippets

Case report

A 44-year-old woman presented in 2004 with a 12 months history of focal RGA. She noticed that friends and family could recall events that she could not, even when prompted. She and family members denied transient amnesia or ictal phenomena and no changes in cognition, mood, appetite or sleep. The patient did not smoke, drank no alcohol and had no history of psychiatric illnesses.

Her medical history included hypertension, a thyroidectomy and mild infrequent migraine without aura. Awake and sleep

Discussion

To our knowledge this is the first report of a patient with focal retrograde amnesia as a prodromal feature of TEA.

At presentation the patient did not meet diagnostic criteria of TEA.⁷ Her dense gaps in autobiographical memory raised the suspicion of TEA but occurred without definite epileptic features. After 4 years the diagnosis of TEA was confirmed, by the onset of transient attacks corroborated by a witness and ictal epileptic EEG activity.

These findings raise the question of what diagnosis

Acknowledgement

JRH is currently supported by an Australian Research Council Federation Fellowship [FF0776229].

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Cited by (26)

Transient epileptic amnesia is significantly associated with discrete CA1-located hippocampal calcifications but not with atrophic changes on brain imaging
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The exact etiology of transient epileptic amnesia (TEA) is currently unknown. In older individuals, common neurodegenerative dementias and small-vessel diseases (SVDs) could be major contributors. We examined these hypotheses on the basis of imaging analysis.
In total, 36 TEA patients were compared with 25 healthy controls for (1) cortical atrophic changes (in the mesial temporal, frontal, anterior temporal, and parietal regions) using four established MRI-based visual rating scales, and for (2) SVD evidence using two MRI-based visual rating scales (Fazekas and MARS scores). In 24 TEAs cases, there were also brain CT scans available that were compared with 57 controls for the presence of hippocampal calcifications (HCs).
We did not find significant differences in cortical atrophy between TEAs and controls, nor did we observe a different SVD brain load on MRI. However, TEAs were significantly associated (p < 0.01) with uni- or bilateral CA1-located HCs in half of the patients compared with the controls (less than 20 %).
This study argues in favor of a hippocampal-restricted SVD (as indicated by HCs) as one of the major etiologies of TEA, while neurodegenerative dementias are probably minor causes. It furthermore highlights the pivotal role of the CA1 hippocampal subfield in the pathophysiology of this syndrome.
Touching the void – First and third person perspectives in two cases of autobiographical amnesia linked to temporal lobe epilepsy
2018, Neuropsychologia
Citation Excerpt :
The form of autobiographical amnesia described in this paper belongs to a sixth type, which has been increasingly well documented over the past decade: Temporal lobe epilepsy: remote memory loss has now been described among patients with chronic refractory epilepsy (Viskontas et al., 2000; Addis et al., 2007a; Lah et al., 2006), following temporal lobectomy (Lah et al., 2004; Noulhiane et al., 2007), in adult-onset drug sensitive TLE (Tramoni et al., 2011), as the presenting feature of TLE in combination with subtle seizures (Jansari et al., 2010) and as a prodromal phenomenon, preceding the clinical onset of epilepsy (Hornberger et al., 2010). It is particularly common in TEA, occurring in 2/3 of patients (Butler et al., 2007).
Temporal lobe epilepsy (TLE) can be associated with a marked impairment of autobiographical memory. This is occasionally its presenting feature. We describe two individuals with severe epilepsy-associated autobiographical memory loss. Both MB and PT were reassured initially that their memory was intact on the basis of standard neuropsychological tests. Both have written detailed accounts of their symptoms. The key neuropsychological features of their cases are the relative normality of performance on standard memory tests, with preservation of semantic memory for impersonal information, in contrast to a profound amnesia for salient autobiographical episodes and an impoverishment of imaginative scene construction. First person accounts from these individuals illustrate the importance of autobiographical memory in sustaining a coherent sense of self, informing interpersonal relationships and supporting future thinking and problem-solving. These cases contribute to the growing evidence for a distinctive pattern of autobiographical memory loss associated with TLE, and indicate that it can take a severe form affecting both personal semantics and episodic recollection. Defining the phase of memory processing most relevant to this form of amnesia, and the roles of physiological and structural pathology, requires further research. The paper's title refers to the introspective ‘void’ highlighted by both MB and PT in their reports – in PT's words: ‘My primary symptom is the void that is my past’.
Accelerated Long Term Forgetting in patients with focal seizures: Incidence rate and contributing factors
2017, Epilepsy and Behavior
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There seems to be an emerging consensus that consideration of ALF is an important part of the clinical profile of patients with epilepsy. Memory performance at very long delays correlates better with subjective complaints than memory performance at standard delays [9,10] and ALF may be the first presentation of a neurological problem [8]. The likelihood of finding ALF will be influenced by many factors, including the number of tasks used to detect it, definition of “impairment”, type of to-be-remembered material and characteristics of the patient sample (e.g., especially proportion with hippocampal damage and proportion with active epilepsy).
Accelerated Long Term Forgetting (ALF) is usually defined as a memory impairment that is seen only at long delays (e.g., after days or weeks) and not at shorter delays (e.g., 30 min) typically used in clinical settings. Research indicates that ALF occurs in some patients with epilepsy, but the incidence rates and underlying causes have not been established. In this study, we considered these issues.
Forty-four patients with a history of focal seizures were tested at 30 min and 7 day delays for material from the Rey Auditory Verbal Learning Test (RAVLT) and Aggie Figures Test. Recently published norms from a matched group of 60 control subjects (Miller et al., 2015 ) were used to determine whether patients demonstrated ALF, impairment at 30 min or intact memory performance.
The incidence of ALF in the epilepsy patients (18%) was > 3 times higher than normal on the RAVLT, but no different (7%) from the incidence in normal subjects on the Aggie Figures. A different, but again significantly high, proportion of patients (36%) showed shorter-term memory deficits on at least one task. ALF was found mainly in patients with temporal-lobe epilepsy, but also occurred in one patient with an extratemporal seizure focus. Presence of a hippocampal lesion was the main predicting factor of ALF.
Many patients with a focal seizure disorder show memory deficits after longer delays that are not evident on standard assessment. The present study explored the factors associated with this ALF memory profile. These new findings will enhance clinical practice, particularly the management of patients with memory complaints.
The GABA<inf>B</inf> receptor agonist, baclofen, contributes to three distinct varieties of amnesia in the human brain - A detailed case report
2016, Cortex
We describe a patient in whom long-term, therapeutic infusion of the selective gamma-amino-butyric acid type B (GABA_B) receptor agonist, baclofen, into the cerebrospinal fluid (CSF) gave rise to three distinct varieties of memory impairment: i) repeated, short periods of severe global amnesia, ii) accelerated long-term forgetting (ALF), evident over intervals of days and iii) a loss of established autobiographical memories. This pattern of impairment has been reported in patients with temporal lobe epilepsy (TLE), in particular the subtype of Transient Epileptic Amnesia (TEA). The amnesic episodes and accelerated forgetting remitted on withdrawal of baclofen, while the autobiographical amnesia (AbA) persisted. This exceptional case highlights the occurrence of ‘non-standard’ forms of human amnesia, reflecting the biological complexity of memory processes. It suggests a role for GABA_B signalling in the modulation of human memory over multiple time-scales and hints at its involvement in ‘epileptic amnesia’.
Third International Congress on Epilepsy, Brain and Mind: Part 1
2015, Epilepsy and Behavior
Epilepsy is both a disease of the brain and the mind. Here, we present the first of two papers with extended summaries of selected presentations of the Third International Congress on Epilepsy, Brain and Mind (April 3–5, 2014; Brno, Czech Republic). Epilepsy in history and the arts and its relationships with religion were discussed, as were overviews of epilepsy and relevant aspects of social cognition, handedness, accelerated forgetting and autobiographical amnesia, and large-scale brain networks.
Transient epileptic amnesia: Update on a slowly emerging epileptic syndrome
2015, Revue Neurologique
Citation Excerpt :
The severity of the complaint contrasts with the preservation of their general cognitive abilities (see below), and their normal level of professional function and family life. Memory loss may be the most apparent and disabling manifestation of the disorder, sometimes preceding the full-blown epileptic syndrome by several years [8,14,15]. In our series, in about half of the cases, patients were first referred to a memory clinic, while only 23% were directly referred for investigation of epilepsy [9].
Transient epileptic amnesia (TEA) is a recently individualized, late-onset, pharmaco-sensitive form of mesial temporal lobe epilepsy with recurrent episodes of acute memory loss, but also interictal memory disturbances characterized by autobiographical and topographical memory impairment and a long-term consolidation deficit. In this article, we review the main clinical and electrophysiological characteristics of TEA, discuss its putative neuroanatomical substrate and mechanisms, common features and how it differs from related concepts, with the overall aim to defend the idea that TEA deserves to be recognized as a distinct epilepsy syndrome. While the pathophysiological basis remains largely unknown, emotional and/or dysimmune factors may have a potential influence. Most importantly, the concept of TEA is highly relevant to tertiary epilepsy and memory clinics, but also to routine neurology practice, leading to an adequate diagnosis and management of epilepsy-related, acute and long-standing memory deficits.
L’amnésie transitoire épileptique (ATE) est une forme d’épilepsie mésio-temporale d’individualisation récente, pharmaco-sensible, de début tardif, caractérisée par la survenue d’épisodes récurrents d’amnésie aiguë ainsi que des perturbations mnésiques interictales, comprenant des troubles de la mémoire autobiographique et topographique et de la consolidation à long terme. Cet article précise les principales caractéristiques cliniques et électrophysiologiques de l’ATE, discute de ses bases neuro-anatomiques et mécanismes physiopathologiques potentiels, ainsi que des points communs et des différences avec les concepts et entités proches, dans la perspective de défendre l’idée selon laquelle l’ATE nécessite d’être identifiée comme un syndrome épileptique distinct. Bien que ses bases physiopathologiques soient méconnues, des facteurs d’ordre émotionnel ou dysimmunitaire pourraient avoir un rôle potentiel. Au-delà de la discussion syndromique, le concept d’ATE s’avère extrêmement utile en pratique clinique, aussi bien en soin neurologique courant que dans les consultations mémoires ou les centres épileptiques spécialisés, permettant le diagnostic et la prise en charge adaptée de certaines perturbations mnésiques, aiguës ou chroniques, d’origine épileptique.

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Case ReportFocal retrograde amnesia: Extending the clinical syndrome of transient epileptic amnesia

Abstract

Introduction

Section snippets

Case report

Discussion

Acknowledgement

Transient global amnesia or transient epileptic amnesia?

QJM

Transient epileptic amnesia—a clinical update and a reformulation

J Neurol Neurosurg Psychiatry

Epilepsy presenting as memory disturbances

Epilepsia

Focal autobiographical amnesia in association with transient epileptic amnesia

Brain

Case Report
Focal retrograde amnesia: Extending the clinical syndrome of transient epileptic amnesia