What is the level of evidence for the amnestic effects of sedatives in pediatric patients? A systematic review and meta-analyses

Background

Studies have suggested that benzodiazepines are amnestic drug par excellence, but when taken together, what level of evidence do they generate? Are other sedatives as amnestic as benzodiazepines? The aim of this study was to assess the level of scientific evidence for the amnestic effect of sedatives in pediatric patients who undergo health procedures.

Methods

The literature was searched to identify randomized controlled trials that evaluated anterograde and retrograde amnesia in 1-19-year-olds who received sedative drugs during health procedures. Electronic databases, including PubMed, Scopus and Cochrane Library besides clinical trial registries and grey literature were searched. Two independent reviewers performed data extraction and risk of bias assessment using the Cochrane Collaboration's Tool. The meta-analyses were performed by calculating relative risk (RR) to 95% confidence intervals (CI). The quality of the evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation approach.

Results

Fifty-four studies were included (4,168 participants). A higher occurrence of anterograde amnesia was observed when benzodiazepines, the most well-studied sedatives (n = 47), were used than when placebo was used (n = 12) (RR = 3.10; 95% CI: 2.30–4.19, P<0.001; I² = 14%), with a moderate level of evidence. Higher doses of alpha2-adrenergic agonists (clonidine/dexmedetomidine) produced more anterograde amnesia than lower doses (n = 2) (RR = 1.83; 95% CI: 1.03–3.25; P = 0.038; I² = 0%), with a low level of evidence; benzodiazepines’ amnestic effects were not dose-dependent (n = 3) (RR = 1.54; 95% CI: 0.96–2.49; P = 0.07; I² = 12%) but the evidence was low. A qualitative analysis showed that retrograde amnesia did not occur in 8 out of 10 studies.

Conclusions

In children, moderate evidence support that benzodiazepines induce anterograde amnesia, whereas the evidence for other sedatives is weak and based on isolated and small studies. Further clinical trials focused on the amnesia associated with non-benzodiazepine sedatives are therefore needed.

Trial registration

PROSPERO CRD42015017559.

Transient global amnesia in immediate postoperative period: A diagnostic dilemma

INTRODUCTION

Transient Global Amnesia (TGA) is short-term inability to form new memories despite otherwise normal neurological function. There is associated anterograde and retrograde amnesia. The memory loss is often accompanied by repetitive questioning and temporal disorientation while higher cognitive functions are preserved. The symptoms usually resolve by 24h.

CASE REPORT

We present an interesting case of 31year old female who was planned for robotically assisted right sided pyeloplasty. 30min after emergence from anaesthesia patient was disoriented, with retrograde and anterograde amnesia, but neurological function was intact. Neurologic imaging revealed no abnormality. 36h later patient was able to recall everything.

DISCUSSION

The pathogenesis of TGA has more recently been attributed to cerebral venous hypertension resulting from retrograde jugular venous flow. Precipitating events are Valsalva manoeuvre, emotion/stress/pain, Excessive exertion, sexual intercourse and swimming in cold water.

CONCLUSION

TGA presents dramatically, it needs to be differentiated from cerebral event. It resolves on its own. But one needs to be aware of existence of such an entity.

Functional (dissociative) retrograde amnesia

Retrograde amnesia is described as condition which can occur after direct brain damage, but which occurs more frequently as a result of a psychiatric illness. In order to understand the amnesic condition, content-based divisions of memory are defined. The measurement of retrograde memory is discussed and the dichotomy between "organic" and "psychogenic" retrograde amnesia is questioned. Briefly, brain damage-related etiologies of retrograde amnesia are mentioned. The major portion of the review is devoted to dissociative amnesia (also named psychogenic or functional amnesia) and to the discussion of an overlap between psychogenic and "brain organic" forms of amnesia. The "inability of access hypothesis" is proposed to account for most of both the organic and psychogenic (dissociative) patients with primarily retrograde amnesia. Questions such as why recovery from retrograde amnesia can occur in retrograde (dissociative) amnesia, and why long-term new learning of episodic-autobiographic episodes is possible, are addressed. It is concluded that research on retrograde amnesia research is still in its infancy, as the neural correlates of memory storage are still unknown. It is argued that the recollection of episodic-autobiographic episodes most likely involves frontotemporal regions of the right hemisphere, a region which appears to be hypometabolic in patients with dissociative amnesia.

Predicting Retrograde Autobiographical Memory Changes Following Electroconvulsive Therapy: Relationships between Individual, Treatment, and Early Clinical Factors

BACKGROUND

Loss of personal memories experienced prior to receiving electroconvulsive therapy is common and distressing and in some patients can persist for many months following treatment. Improved understanding of the relationships between individual patient factors, electroconvulsive therapy treatment factors, and clinical indicators measured early in the electroconvulsive therapy course may help clinicians minimize these side effects through better management of the electroconvulsive therapy treatment approach. In this study we examined the associations between the above factors for predicting retrograde autobiographical memory changes following electroconvulsive therapy.

METHODS

Seventy-four depressed participants with major depressive disorder were administered electroconvulsive therapy 3 times per week using either a right unilateral or bitemporal electrode placement and brief or ultrabrief pulse width. Verbal fluency and retrograde autobiographical memory (assessed using the Columbia Autobiographical Memory Interview - Short Form) were tested at baseline and after the last electroconvulsive therapy treatment. Time to reorientation was measured immediately following the third and sixth electroconvulsive therapy treatments.

RESULTS

Results confirmed the utility of measuring time to reorientation early during the electroconvulsive therapy treatment course as a predictor of greater retrograde amnesia and the importance of assessing baseline cognitive status for identifying patients at greater risk for developing later side effects. With increased number of electroconvulsive therapy treatments, older age was associated with increased time to reorientation. Consistency of verbal fluency performance was moderately correlated with change in Columbia Autobiographical Memory Interview - Short Form scores following right unilateral electroconvulsive therapy.

CONCLUSIONS

Electroconvulsive therapy treatment techniques associated with lesser cognitive side effects should be particularly considered for patients with lower baseline cognitive status or older age.

[A profound retrograde amnesia of almost 30 years and the role of organic, intentional and psychogenic factors]

A 57-year-old man was referred to the Department of Psychiatry & Psychology of a university hospital because of recurrent depressive episodes. He claimed to have had a total amnesia for approximately the first 30 years of his life following an incident resembling a fugue. This case of a focal retrograde amnesia shows the limitations of a dichotomic view of organic, psychogenic and intentional factors.

Focal retrograde amnesia: voxel-based morphometry findings in a case without MRI lesions

Focal retrograde amnesia (FRA) is a rare neurocognitive disorder presenting with an isolated loss of retrograde memory. In the absence of detectable brain lesions, a differentiation of FRA from psychogenic causes is difficult. Here we report a case study of persisting FRA after an epileptic seizure. A thorough neuropsychological assessment confirmed severe retrograde memory deficits while anterograde memory abilities were completely normal. Neurological and psychiatric examination were unremarkable and high-resolution MRI showed no neuroradiologically apparent lesion. However, voxel-based morphometry (VBM)-comparing the MRI to an education-, age-and sex-matched control group (n = 20) disclosed distinct gray matter decreases in left temporopolar cortex and a region between right posterior parahippocampal and lingual cortex. Although the results of VBM-based comparisons between a single case and a healthy control group are generally susceptible to differences unrelated to the specific symptoms of the case, we believe that our data suggest a causal role of the cortical areas detected since the retrograde memory deficit is the preeminent neuropsychological difference between patient and controls. This was paralleled by grey matter differences in central nodes of the retrograde memory network. We therefore suggest that these subtle alterations represent structural correlates of the focal retrograde amnesia in our patient. Beyond the implications for the diagnosis and etiology of FRA, our results advocate the use of VBM in conditions that do not show abnormalities in clinical radiological assessment, but show distinct neuropsychological deficits.

[Neuropsychological examination among patients suffering from transient global amnesia]

Transient global amnesia (TGA) is a temporary disease with an unexplained aetiology. The clinical picture of TGA is characterised by retrograde amnesia (spanning from several days to several years), anterograde amnesia (from few to several hours, most often from 4 to 8), significant disorientation with respect to time (about 50% of the patients) and place (above 90% patients), preserved auto-orientation and preserved ability to recognise other people. The onset of transient global amnesia is sudden and unpredictable. Memory impairments in TGA are unspecific and they are not limited to one single sense or to one given type of material. In TGA there is a lack of comorbid neurological symptoms. Among 10-20% patients after one TGA episode there is a possibility of a next one. Among the risk factors of transient global amnesia we can distinguish biological and psychological variables. The aim of the study is to present symptoms and aetiology of TGA and to show several neuropsychological methods which can be used in differential diagnosis.

Immediate peri-operative memory

BACKGROUND

Information about anterograde and retrograde amnesias in the immediate peri-operative period is scarce. During this period, assessment of memory for real-life events is also rare. We hypothesized that there would be both anterograde and retrograde amnesias and memory for peri-operative events would be better than for verbal memory.

METHODS

We studied 40 patients who underwent general anesthesia and surgery and 19 control volunteers who were matched to the patients but did not have surgery. Patients completed the state anxiety part of the Spielberger State-Trait Anxiety Inventory in the pre-operative period. They were presented with three word lists in the holding area, the operating room before induction of anesthesia and the recovery room. Memory for the words was tested the next day by recall and recognition tests. Memory for events that happened on the day of surgery was tested by administering a questionnaire. The control subjects were tested similarly but did not complete the events questionnaire. Retrograde amnesia would be demonstrated by a decline in patients' memory from the holding area to the operating room which exceeded any corresponding changes in controls; anterograde amnesia would be demonstrated by memory impairment of the patients in the recovery room, relative to controls.

RESULTS

Recall and recognition of words were significantly impaired in the recovery room with a decline from 12% in the holding area to zero% in the recovery room for recall and from 43% to 7% for recognition. The decline in memory from the holding area to the operating room was not significantly greater in patients than in controls, 80% vs. 56% for recall and 27% vs. 14% for recognition. There were no significant differences for recognition of events which happened in the three rooms.

CONCLUSIONS

We were unable to detect retrograde amnesia. Patients' memory for neutral stimuli in the recovery room was severely impaired. The events questionnaire proved to be insensitive.

[A review of methods for the assessment of symptom validity: an update 2002 to 2005]

Continuing a previous review on problems and strategies for the assessment of negative response bias (Fortschr Neurol Psychiatr 2002;70:126-138), an update on research published from 2002 to 2005 is provided. More than 400 journal articles were included in the analysis, It was found that symptom validity tests or effort tests are generally accepted as the one method which is best developed for the assessment of negative response bias. Other methods, including questionnaires and rating methods, are reviewed. Three important applications of symptom validity assessment are analysed in some more detail: retrograde amnesia, post-traumatic stress disorder, and pain. --Research activities in the field of what was previously called "malingering research" have not decreased, so further important developments can be expected in the years to come.

Persistent autobiographical amnesia: a case report

We describe a 47-year-old man who referred to the Emergency Department for sudden global amnesia and left mild motor impairment in the setting of increased arterial blood pressure. The acute episode resolved within 24 hours. Despite general recovery and the apparent transitory nature of the event, a persistent selective impairment in recollecting events from some specific topics of his personal life became apparent. Complete neuropsychological tests one week after the acute onset and 2 months later demonstrated a clear retrograde memory deficit contrasting with the preservation of anterograde memory and learning abilities. One year later, the autobiographical memory deficit was unmodified, except for what had been re-learnt. Brain MRI was normal while H20 brain PET scans demonstrated hypometabolism in the right globus pallidus and putamen after 2 weeks from onset, which was no longer present one year later. The absence of a clear pathomechanism underlying focal amnesia lead us to consider this case as an example of functional retrograde amnesia.

Long-term memory following transient global amnesia: an investigation of episodic and semantic memory

BACKGROUND

Several studies noted persistence of memory impairment following an episode of transient global amnesia (TGA) with standard tests.

AIM

To specify long-term memory impairments in a group of patients selected with stringent criteria.

METHODS

Both retrograde and anterograde memory were investigated in 32 patients 13-67 months after a TGA episode with original tasks encompassing retrograde semantic memory (academic, public and personal knowledge), retrograde episodic memory (autobiographical events) and anterograde episodic memory.

RESULTS

Patients had preserved academic and public knowledge. Pathological scores were obtained in personal verbal fluency for the two most recent periods, and patients produced less autobiographical events than controls. However, when they were provided time to detail, memories were as episodic as in controls regardless of their remoteness. Anterograde episodic tasks revealed a mild but significant impairment of the capacity of re-living the condition of encoding, i.e. the moment at which words were presented.

CONCLUSIONS

Patients who have suffered from an episode of TGA manifest deficits of memory focused on the retrieval of both recent semantic information and episodic memories and especially the capacity of re-living. These deficits may not result from a deterioration of memory per se but rather from difficulties in accessing memories.

A retrospective controlled study into memory complaints reported by depressed patients after treatment with electroconvulsive therapy and pharmacotherapy or pharmacotherapy only

Few studies have been conducted comparing complaints of memory problems using objective and subjective memory scales in depressed patients who received electroconvulsive therapy (ECT) + pharmacotherapy or treatment with pharmacotherapy only. Patients who suffer from depression according to the Diagnostic and Statistical Manual of Mental Disorder (Fourth Edition) criteria and who were admitted within the past 5 years before this study in a general psychiatric hospital were screened for inclusion. Objective retrograde amnesia was assessed using the Autobiographical Memory Interview and the Amsterdam Media Questionnaire (AMQ). Subjective retrograde amnesia was assessed using the Squire Subjective Memory Questionnaire and the ECT Retrograde Amnesia and Perception Scale (ERAPS), a newly developed scale. Twenty of the 84 patients who received ECT + pharmacotherapy and 30 of the 196 patients who received pharmacotherapy only participated in the study. Patients' ERAPS memory scores were compared with proxies' ERAPS memory scores of the patients to assess the reliability of memory complaints. The ECT + pharmacotherapy group was found to suffer more from memory problems using the AMQ 1990 test. There was also a difference for the proxy's ERAPS memory score, reflecting the conviction of proxies from the ECT + pharmacotherapy patients that these patients suffer more memory problems due to the illness, treatment with pharmacotherapy, or ECT. The differences could not be explained by the influence of determinants for retrograde amnesia. ECT + pharmacotherapy patients did not attribute their memory problems mainly to ECT but put equal "blame" on the depressive illness, treatment with pharmacotherapy, and ECT. The analyses suggest that the AMQ 1990s test is (more) sensitive in registering retrograde amnesia than the other scales used in the study.

Emotion-induced retrograde amnesia and trait anxiety

Emotional arousal can both enhance and impair memory. Considering that both emotional memory and trait anxiety (TA) have been associated with adrenergic activity, the authors investigated whether there is an association between 2 opposite emotional memory biases and the TA. The authors used a procedure recently put forward by B. A. Strange, R. Hurlemann, and R. J. Dolan (2003) to elicit an emotion-induced retrograde amnesia (ERA) coupled to an emotional memory enhancement (EME). The authors contrasted the association between these emotional memory biases and the TA in several conditions involving different levels of encoding and types of recall. The results presented here indicated a significant interaction of the TA with EME and ERA and the dependency of these biases on the consciously controlled use of memory.

Acute retrograde amnesia as first presentation in terminal metastatic cancer

A case is presented of a 2-week onset of acute retrograde amnesia as initial presentation, caused by presumed cancer. While acute retrograde amnesia has been reported in the literature, a report linked to cancer has not previously been published. An 82-year-old Caucasian woman presented to the emergency department, with 3-day history of increasing confusion and mild frontal headaches. Until 2 weeks previously she had been living on her own and coping with her activities of daily life. She believed very firmly that she was living with her husband in the house in which they lived in over 30 years ago. A magnetic resonance imaging scan demonstrated a lesion extending from cortex anteriorly to the right basal ganglia posteriorly. Postgadolinium enhancement was consistent with a diagnosis of a primary or secondary neoplasm. In some patients, cognitive behaviour changes or amnesia is the sole presenting feature of a serious underlying pathology. A lesion in either the temporal or frontal lobe can lead to this presentation. A family conference was convened and there was decision to take a conservative approach and not to investigate further. She was discharged to the care of her daughter and died 3 months later without return of her memory.

Effects of Temporal Lobe Epilepsy on Retrograde Memory

PURPOSE

In a previous investigation (Lah et al., 2004), we found deficits in retrograde memory in patients who had undergone temporal lobectomy (TL). In this study, we set out to determine whether such deficits are present before surgery in patients with temporal lobe epilepsy (TLE).

METHODS

Memory for public and autobiographic facts and events was assessed in patients with focal left-sided (n=15) or right-sided (n=14) TLE and healthy control subjects (n=15). The impact of epilepsy and underlying cognitive deficits on retrograde memory also was examined.

RESULTS

Patients with left TLE demonstrated retrograde memory deficits across domains. Patients with right TLE showed defective recall only in the autobiographic domain. Young age at onset (younger than 14 years) was associated with greater difficulties in recall of famous events, and patients receiving polytherapy had significantly reduced recall of autobiographic events compared with those receiving monotherapy. In most cases, deficient memory for the past was associated with impairments in other cognitive skills, especially language abilities.

CONCLUSIONS

In unoperated-on patients with TLE, we found deficits in retrograde memory that were similar to those seen after TL, with the pattern of deficits being influenced by side of lesion, anticonvulsant medication, and word-finding deficits. Unlike patients tested after right TL, patients with right TLE did not have difficulty recalling details of famous events, which raises the possibility that right TL results in a decline in this aspect of retrograde memory.

Significant life events and the shape of memories to come: a hypothesis

Much has been said about how significant life events modulate our response to stimuli that are integral to those events. However, we know less about the more general consequences of these events, that is, how they affect subsequent learning abilities that are seemingly irrelevant to the initial event. Here, it is proposed that significant life events, most often stressful in nature, alter future learned responses by inducing nonspecific and persistent changes in neuroanatomical structures. These changes are induced in the presence of sex and stress hormones, which are released either in response to the event itself or as a consequence of stages of life. To illustrate, the effects of acute stressful experience on learning processes and their regulation by the release of hormones are reviewed. I discuss how these events and their hormonal consequences alter anatomical substrates such as those involved in neurogenesis and synaptogenesis. It is proposed that these modulatory processes allow past experiences to change the shape of memories to come. In this way, memorable life events become less about the past and more about the future.

Interictal slow-wave focus in left medial temporal lobe during bilateral electroconvulsive therapy

The interictal state between two electroconvulsive therapy (ECT) sessions is clinically characterised by possible cognitive adverse effects like mild amnestic syndrome. ECT-induced amnestic deficits can persist for several weeks after ECT. Electrophysiologically, slowing of brain electrical activity in the interictal state has often been reported. Especially, for bilateral ECT a correlation between enhanced left frontotemporal theta activity and retrograde amnesia has been demonstrated. This study focuses on the topographic distribution of cortical slow-wave oscillations during the interictal state of a bilateral ECT cycle. Twelve patients with major depression have been investigated with 32-channel resting EEG 24 h after the 6th ECT session. As controls, 8 major depressive patients were investigated prior to antidepressive treatment. The generating sources of slow-wave activity are estimated within the theta frequency band with low-resolution brain electromagnetic tomography. Source analysis revealed a distinct pattern of theta activity in the depth of the left temporal lobe (fusiform and parahippocampal gyri, Brodmann areas 37 and 36, respectively; p< 0.05) during the interictal state. This finding suggests a dysfunction of the left medial temporal lobe memory system during the interictal state of a bilateral ECT cycle. It will further be discussed whether it is possible to obtain information about activity of deep brain structures like the hippocampal formation from scalp-recorded signals.

Functional MR imaging of psychogenic amnesia: a case report

We present here a case in which functional MR imaging (fMRI) was done for a patient who developed retrograde psychogenic amnesia for a four year period of her life history after a severe stressful event. We performed the fMRI study for a face recognition task using stimulation with three kinds of face photographs: recognizable familiar faces, unrecognizable friends' faces due to the psychogenic amnesia, and unfamiliar control faces. Different activation patterns between the recognizable faces and unrecognizable faces were found in the limbic area, and especially in the amygdala and hippocampus.

Functional amnesia: clinical description and neuropsychological profile of 10 cases

We carried out the first neuropsychological study of a series of patients with functional amnesia. We evaluated 10 patients, first with a neurological examination and then with three tests of anterograde amnesia and four tests of retrograde amnesia. Excluding one patient who later admitted to malingering, all patients had a significant premorbid psychiatric history and one or more possible precipitating factors for their amnesia. Eight of the 10 patients still had persistent retrograde amnesia at our last contact with them (median = 14 mo after the onset of amnesia). On tests of anterograde amnesia, the patients performed normally as a group, though some patients scored poorly on tests of verbal memory. On tests of retrograde amnesia, all patients had difficulty re-collecting well-formed autobiographical memories of specific events from their past. In contrast, patients performed as well as controls at distinguishing the names of cities from fictitious city names. On remote memory tests for past public events and famous faces, different patients exhibited different but internally consistent patterns of impaired and spared performance. The variability in the clinical and neuropsychological findings among our patients may be understood by supposing that memory performance is poor in proportion to how directly a test appears to assess a patient's common sense concept of memory. The presentation of patients with functional amnesia is as variable as humankind's concept of what memory is and how it works.

The dynamic time course of memory recovery in transient global amnesia

AIMS

To investigate the dynamic time course of transient global amnesia (TGA)--that is, the process of recovery and the interindividual variability--by testing four patients during the day of TGA itself (on three occasions) and at follow up (on two occasions).

METHODS

A specially designed protocol focusing on semantic (both conceptual and autobiographical knowledge) and episodic (both anterograde and retrograde components) memory.

RESULTS

Every patient showed marked impairment of both anterograde and retrograde episodic memory during the acute phase, with a relative preservation of personal and conceptual semantic knowledge. During the following phase, the authors observed similarities and differences among the patients' patterns of recovery. In general, retrograde amnesia recovered before the anterograde amnesia and anterograde episodic memory was recovered gradually in every case. In contrast, shrinkage of retrograde amnesia was more heterogeneous. In two of the patients, this shrinkage followed a chronological gradient and the most remote events were recovered first. In the two other patients, it depended more on the strength of the trace, and there was no temporal gradient. For the latter, an executive deficit could account for difficulties in accessing both conceptual knowledge and autobiographical memories.

CONCLUSIONS

This profile of recovery suggests a "neocortical to medial temporal" process in every case, and the possibility of an additional frontal dysfunction in some cases. Hence, the acute phase seems to be characterised by a common episodic impairment. This variability between subjects appears in the recovery phase with two different patterns of impairment.

?What do you remember about Chernobyl?? A new test of memory for media?mediated events

We devised a new test for assessing remote memory for media-mediated events, i.e. events that are reported by and known through the media. The test consists of a verbal questionnaire covering famous events that occurred over a long period of time, from 1976 to 2000, specifically designed for use with the Italian population. A free recall procedure was adopted which makes use of progressive cues. The test can be easily updated for inclusion of future events. Normative and test-retest reliability data are presented. The test provides a new tool for assessing media-mediated memory whenever an extensive assessment of retrograde memory performance is required, both in normal people and in brain-damaged patients.

Behavioural disturbances following Japanese B encephalitis

Clinically, Japanese B encephalitis (JBE) is often overlooked as its occurrence in Western countries is rare. However, its neurological, cognitive and psychiatric sequelae constitute a major public health problem in the Far East where JBE is endemic. European and American subjects may however experience the JBE when returning from a Far East journey. In such cases, misdiagnosis is frequent because of the unawareness of psychiatrists and physicians. The present review, therefore, documents the behavioural and cognitive sequelae of JBE. This reactivates the debate concerning the vaccination against the virus all the more that the literature enlightens the importance of the vaccination for those who undertake frequent and extensive tourist excursions to the Orient but still discusses it for occasional travellers. Following is a case-report of a young western European post-graduate student who has contracted JBE by experiencing an acute febrile delirium during an unusual short stay in South East Asia. Pyramidal syndrome, Parkinsonism and amnesia were the prominent acute deficits. Whereas these faded in great part during convalescence, emotional and behavioural instability associated with affective involvement, obsessive-compulsive symptoms and cognitive impairments appeared. A partial recovery was however obtained with neuroleptics, lithium and following electro-convulsive therapy. Organic personality syndrome was persistent and thereafter constituted the main sequelae syndrome. Hypersomnia and several enuretic episodes persisted.

Retrograde amnesia in patients with rupture and surgical repair of anterior communicating artery aneurysms

The retrograde amnesia of patients with memory loss related to rupture and surgical repair of anterior communicating artery (ACoA) aneurysms is compared with the retrograde amnesia of temporal amnesic patients and nonamnesic control participants. Two tests which focus on popular culture but which differ according to extent of news exposure and the cognitive processes necessary for task performance were used to measure retrograde memory. ACoA patients demonstrated more significant retrograde memory problems than did nonamnesic controls; however, the severity and pattern of their memory loss was less severe than that seen in association with temporal amnesia. Different factors influenced the remote memory loss of respective groups: ACoA patients' problems were related to impaired lexical retrieval whereas temporal amnesic patients had problems secondary to both retrieval and storage deficits.

[Clinical symptoms, pathopsychological peculiarities and mechanisms of biographic amnesia]

Clinical and pathopsychological analysis of 16 men, aged 15-53 years, was carried out. In premorbid stage, hysterical, hystero-epileptoid, schizoid, emotional-unstable features were found in 12 patients and personality accentuation--in 4 patients. There were the absence of marked cognitive disturbances and safety operational functions of intellect, i.e. memory. In all patients, the projective pathopsychological tests allowed determining subjectively significant disturbances of interpersonal communication that, in combination with selective character of amnesia and intact character of formal intellect, suggested functional mechanisms underlying the analyzing state.

Malingering and Retrograde Amnesia: The Historic Case of the Collegno Amnesic

Assessment of feigned cognitive disorders is an important field of neuropsychology because of its applications to forensic settings. Strategies for detecting malingering in amnesia are available for anterograde amnesia. Less attention has been given to malingering in retrograde amnesia. The case of the 'Smemorato di Collegno' (The Collegno Amnesic) is probably the most famous case of malingered retrograde amnesia ever known in Italy. In 1926, a man who appeared to have lost all his autobiographical memories and identity spent nearly a year in the Collegno asylum of Turin without a name. He was later initially identified as Giulio Canella, Director of the 'Scuola Normale di Verona' who had disappeared during the war in 1916. He was suspected of later identified as being Mario Bruneri, a petty crook from Turin who played the part of an amnesic whose retrograde memory gradually returned. A lengthy investigation was required before this conclusion was reached. Several clinicians and renowned academics evaluated the case, but only Alfredo Coppola, diagnosed "malingered retrograde amnesia" using a method that was extremely innovative for the times. The aim of the present paper is to review the original cognitive evaluation and the strategies used for malingering detection in the "Collegno case". The outcome of the case is then discussed in the light of present-day forensic neuropsychology and the level of advancement of mental examination achieved in the 1920s in Europe is highlighted.

A case of psychogenic fugue: I understand, aber ich verstehe nichts

Psychogenic fugue is a disorder of memory that occurs following emotional or psychological trauma and results in a loss of one's personal past including personal identity. This paper reports a case of psychogenic fugue in which the individual lost access not only to his autobiographical memories but also to his native German language. A series of experiments compared his performance on a variety of memory and language tests to several groups of control participants including German-English bilinguals who performed the tasks normally or simulated amnesia for the German language. Neuropsychological, behavioral, electrophysiological and functional neuroimaging tests converged on the conclusion that this individual suffered an episode of psychogenic fugue, during which he lost explicit knowledge of his personal past and his native language. At the same time, he appeared to retain implicit knowledge of autobiographical facts and of the semantic or associative structure of the German language. The patient's poor performance on tests of executive control and reduced activation of frontal compared to parietal brain regions during lexical decision were suggestive of reduced frontal function, consistent with models of psychogenic fugue proposed by Kopelman and Markovitsch.

Long-term amnesia: a review and detailed illustrative case study

Long-term amnesia is a slowly developing form of anterograde amnesia accompanied by retrograde amnesia of variable severity (Kapur, 1996; 1997) often associated with damage to the anterior temporal neocortex and epileptic seizures. The precise neural and functional deficits that underlie this condition are unknown. A patient, JL, who has this condition following a closed-head injury, is described in detail. Her injury caused bilateral anterior temporal neocortex damage that was more extensive on the left and right-sided damage to the perirhinal and orbitofrontal cortices. The hippocampus appeared to be intact bilaterally. Epilepsy developed within two years of JL's injury. Apart from her memory impairments, JL's cognitive functions, including high-level visual perception, attention, semantic memory and executive functions were well preserved. Her memory also seemed well preserved for at least 30 minutes following encoding. The one exception was the patient's relatively greater impairment at difficult visual recognition tests for which verbalization may not have been an effective strategy. This problem may have been caused by JL's right-sided perirhinal and orbitofrontal cortex damage. Her recall and recognition was clearly impaired after a three-week delay. She also showed a retrograde amnesia, which appeared to be milder than her remote post-morbid memory deficit. JL's remote memory was preserved for information first encountered in either the pre- or post-morbid period provided the information had received sufficient rehearsal over long periods of time. Her long-term amnesia may have been caused by anterior temporal neocortex damage, possibly in association with her epileptic seizures. Whether the condition is heterogeneous, involves a deficit in slow consolidation, disruption of unconsolidated memories, or blockage of maintenance or disruption of insufficiently rehearsed memories whether or not these have been slowly consolidated is discussed.

[Disturbance of the knowledge representation in patients with arteriovenous malformations of the deep brain structures]

One hundred eighty patients with arteriovenous malformations (AVM) of the deep brain structures (caudate nucleus, thalamus, cingulated gyrus, hippocampus and corpus callosus) have been examined. Disturbance of the premorbid knowledge representations (selective retrograde amnesia) was found in 31 subjects. All the patients, in dependence in what structure the AVM was situated, survival severe intraventricular haemorrhage with long period of unconsciousness. The majority of the patients have haemorrhage from right hemisphere AVM. Neuropsychological syndrome was identical in all the patients: representation of major historical data was damaged worst, sequence of events representation was less damaged. Actualization of autobiography and events aspects was not practically disturbed. Neuropsychological examination revealed a combine dysfunction of frontal, temporal (preferentially right hemisphere) lobes and diencephalous region. The author concluded that in patients with AVM of the deep brain structures selective retrograde amnesia was found after severe intraventricular haemorrhage on the background of combined dysfunction of medio-basal regions (preferentially, right hemisphere) and diencephalon region. After surgical removal of any structure, any development of "novel" memory disturbances, like selective retrograde amnesia, was not observed.

Consolidation theory and retrograde amnesia in humans

Recent research on the cognitive dysfunctions experienced by human anmesic patients indicates that very long term (multidecade) changes may occur in memory. Flat retrograde amnesia (RA), consisting of a uniform memory deficit for information from all preamnesia time periods, indicates a simple, monolithic retrieval problem, whereas graded RA, with greater memory deficits for information from recent as opposed to remote time periods, suggests the presence of a gradual long-term encoding, or consolidation, process. An evaluation of 247 outcomes from 61 articles provides strong evidence of graded RA across different cerebral injuries, materials, and test procedures, as well as in measures of both absolute and relative (patient vs. control) performance. Future conceptualizations of human memory should address the possibility that memories increase in resistance to forgetting, or reduction in trace fragility, across many decades.

Pure retrograde amnesia following a mild head trauma: a neuropsychological and metabolic study

After a minor closed head injury, a 33-year-old man acquired extensive retrograde amnesia (RA) covering the previous ten years and concerning autobiographical, semantic and procedural memories. The patient's learning abilities remained excellent and he recovered considerable information from his wife, the media and personal documents. This relearned information did not, however, provide a sense of personal experience in the first weeks. CT and MRI failed to show brain damage, but EEG and SPECT examination showed a marked right temporal dysfunction. After three months the patient had almost completely recovered from RA. Interestingly, a parallel recovery was observed in the second SPECT obtained at this period. There was clearly a blockade of retrieval, while the stored engrams were probably intact. The mechanisms underlying such a functional amnesia are discussed in the light of previous reports of amnesia without brain lesions.

Two cases of functional focal retrograde amnesia with impairment of object use

We report on two patients, TH and KN, with focal retrograde amnesia (FRA). Their memory loss regarding life events extended to their whole lives, whereas they could acquire and retain new information. They also showed prominent deficits in production and comprehension of common words. In addition, at least in the testing situation, they were impaired in their recognition and use of familiar objects. Although both cases of FRA followed an episode that can cause brain pathology, MRI revealed no structural abnormality in either patient. Stressful situations preceding the onset were evident in KN, but not in TH. We discuss their impairments of object knowledge from a neuropsychological perspective, and we interpret the etiology of their condition as a functional rather than a psychogenic amnesia.

Focal retrograde amnesia documented with matching anterograde and retrograde procedures

Focal retrograde amnesia is an unusual and theoretically challenging form of memory disorder. The case of a 65-year-old woman presenting with focal retrograde amnesia is reported. Following a cardiac arrest and subsequent hypoxia she remained in a coma for 24 h with evidence of epileptiform activity during the early recovery period. MR scans, 4 and 7 months post-onset, showed mild bifrontal atrophic changes mainly affecting white matter areas. An [18F]fluorodeoxyglucose resting PET scan 1-year post-onset demonstrated right occipito-temporo-parietal hypometabolism. We were able to document the patient's performance on an extensive range of anterograde and retrograde tests and to monitor her recovery of function by assessing her performance at 4, 12 and 24 months post-onset. Spared anterograde memory was observed on a range of verbal and non-verbal tests, including matched tasks that compared pre-illness and post-illness onset recollections. In contrast, her performance on retrograde memory tests, using detailed autobiographical and public events verbal and photographic tasks, showed a temporally-graded retrograde amnesia, more particularly affecting memory for autobiographical episodes. Possible mechanisms underlying CH's focal retrograde amnesia are discussed in terms of Damasio's time-locked multiregional retroactivation model.

H.M., word knowledge, and aging: support for a new theory of long-term retrograde amnesia

This study develops a new theory of long-term retrograde amnesia that encompasses episodic and semantic memory, including word knowledge. Under the theory, retrograde amnesia in both normal individuals and hippocampal amnesics reflects transmission deficits caused by aging, nonrecent use of connections, and infrequent use of connections over the life span. However, transmission deficits cause severe and irreversible retrograde amnesia only in amnesics who (unlike normal persons) cannot readily form new connections to replace nonfunctioning ones. The results of this study are consistent with this theory: For low-frequency but not high-frequency words, a famous "hippocampal amnesic" (H.M.) at age 71 performed worse than memory-normal control participants in a lexical decision experiment and a meaning-definition task (e.g., What does squander mean?). Also as predicted, H.M.'s lexical decision performance declined dramatically between ages 57 and 71 for low-frequency words, but was age-invariant for high-frequency words.

Right medial thalamic lesion causes isolated retrograde amnesia

Pervasive retrograde amnesia without anterograde memory impairment has rarely been described as a consequence of circumscribed brain damage. We report this phenomenon in a 33 yr-old, right-handed man (JG) in association with the extension in the right thalamus of a previously small, bilateral thalamic lesion. JG presented with a dense amnesia for autobiographical material more than a few years old, with some sparing of recent memories. Furthermore, he was completely unable to recognise famous people or world events. Many other aspects of semantic knowledge were intact and there was no evidence of general intellectual impairment, executive dysfunction or loss of visual imagery. Magnetic resonance imaging revealed an acute lesion in the right thalamus and two small, symmetrical, bilateral non-acute thalamic lesions. Follow-up neuropsychological assessment indicated a stable pattern of impaired retrograde and spared anterograde memory over 18 months and psychiatric assessments yielded no evidence of confabulation, malingering or other symptoms to suggest psychogenic amnesia. JG's profile indicates that the division of declarative memory into just two categories - episodic and semantic - is inadequate. Rather, his case adds to the growing body evidence to suggest that world knowledge pertaining to people and events is stored or accessed similarly to autobiographical information and differently from other types of more general factual knowledge. We hypothesize that the right mediodorsal thalamic nucleus and immediately surrounding regions comprise the central processing mechanism referred to by McClelland (Revue Neurologique, 150 (1994) 570) and Markowitsch (Brain Research Review, 21 (1995) 117) as responsible for inducing and co-ordinating the recall of these sorts of cortically stored memory engrams.

[Dissociation of retrograde memory impairment in a case of herpetic encephalitis]

OBJECTIVE

To report an uncommon case of memory impairment after meningoencephalitis.

METHOD

Detailed description of the history, the lesions, the evolution and review of the bibliography.

RESULTS

A 33 year-old man showed a loss of verbal anterograde memory and a dissociation of retrograde memory impairment after an herpetic meningo-encephalitis with lesions predominant in the left temporal lobe. The patient had impairment of verbal anterograde memory. Visual memory, procedural one were intact. He had normal performances in frontal tests. Neuropsychological assessment revealed major loss of episodic biographical memory and public events memory, but sparing of semantic biographical memory and professional knowledge. This patient who was amnesic but who had not difficulties with visual memory, procedural memory, frontal abilities and didactic memory conserved ability to work.

CONCLUSION

This case report emphasize the multiplicity of the memory systems and the likely links between episodic biographical memory, semantic biographical memory, autobiographic episodic memory, public event memory and didactic memory.

'I know your name but not your face': explaining modality-based differences in access to biographical knowledge in a patient with retrograde amnesia

In current functional models of person recognition it is proposed that there exists a single common body of semantic information concerning people accessible from all modalities (e.g. names, faces). In this paper, we present evidence that challenges this view. Two experiments are discussed investigating residual autobiographical and public knowledge in a patient suffering from retrograde amnesia. Knowledge about people was investigated in each case by asking a series of questions, ranging from the very general to the very specific. Experiment 1 examined knowledge about famous people. The results showed that the patient accessed more information about famous people when cued with names than when cued with faces. Experiment 2 examined knowledge about people known personally to the patient. Again, the same pattern of results emerged. While the patient responded accurately to all questions posed with name cues, her ability to recall the same information when prompted with face cues was clearly inferior. This modality-based difference in accessing biographical knowledge is discussed in relation to models of person recognition.