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Journal of Neurology, Neurosurgery, and... Feb 2000Despite the growing number of instruments for the prospective measurement of post-traumatic amnesia (PTA) after traumatic brain injury, fundamental issues about the...
OBJECTIVES
Despite the growing number of instruments for the prospective measurement of post-traumatic amnesia (PTA) after traumatic brain injury, fundamental issues about the natural history of its resolution and methods of examination remain unresolved. The aims of the present study were to: (1) examine the sequence of resolution of disorientation and amnesia, and (2) determine if the method of measuring the memory component affected the duration of PTA.
METHODS
The sample comprised 31 severely injured patients admitted to a brain injury rehabilitation unit who were examined daily until they emerged from PTA. They were administered a composite PTA scale, covering orientation and memory items from standard PTA scales. Patients were consecutively allocated to one of two groups according to the method of measuring the memory component. Each group was administered identical materials with a different procedure.
RESULTS
The most common sequence for resolution of disorientation in both groups was person, followed by place, then time. Overall, amnesia resolved before disorientation in 94% of cases. Correlation coefficients between return of components of orientation and memory were all highly significant, ranging from r=0. 81 to 0.93. Significant variability occurred in the number of days to emerge from PTA according to the scale used. There was evidence that the method of measuring memory influenced the patient's capacity to consistently sustain criterion scores on the scale.
CONCLUSIONS
These results are contrary to findings in mildly injured patients, in whom orientation usually returns before memory. They also demonstrate that the duration of PTA will be dictated by the method used. These findings raise validity issues with respect to the prospective measurement of PTA, and in particular determining when an individual patient has emerged from PTA, which require further investigation.
Topics: Adolescent; Adult; Aged; Amnesia; Brain Injuries; Confusion; Female; Humans; Male; Middle Aged; Prospective Studies; Psychological Tests; Recovery of Function; Reproducibility of Results; Severity of Illness Index
PubMed: 10644784
DOI: 10.1136/jnnp.68.2.178 -
Hippocampus Nov 2014We often engage in counterfactual (CF) thinking, which involves reflecting on "what might have been." Creating alternative versions of reality seems to have parallels...
We often engage in counterfactual (CF) thinking, which involves reflecting on "what might have been." Creating alternative versions of reality seems to have parallels with recollecting the past and imagining the future in requiring the simulation of internally generated models of complex events. Given that episodic memory and imagining the future are impaired in patients with hippocampal damage and amnesia, we wondered whether successful CF thinking also depends upon the integrity of the hippocampus. Here using two nonepisodic CF thinking tasks, we found that patients with bilateral hippocampal damage and amnesia performed comparably with matched controls. They could deconstruct reality, add in and recombine elements, change relations between temporal sequences of events, enabling them to determine plausible alternatives of complex episodes. A difference between the patients and control participants was evident, however, in the patients' subtle avoidance of CF simulations that required the construction of an internal spatial representation. Overall, our findings suggest that mental simulation in the form of nonepisodic CF thinking does not seem to depend upon the hippocampus unless there is the added requirement for construction of a coherent spatial scene within which to play out scenarios.
Topics: Adult; Amnesia; Female; Hippocampus; Humans; Imagination; Male; Mental Recall; Middle Aged; Narration; Neuropsychological Tests; Thinking
PubMed: 24978690
DOI: 10.1002/hipo.22323 -
Psychological Medicine Feb 2023Little is known about the neural correlates of dissociative amnesia, a transdiagnostic symptom mostly present in the dissociative disorders and core characteristic of...
BACKGROUND
Little is known about the neural correlates of dissociative amnesia, a transdiagnostic symptom mostly present in the dissociative disorders and core characteristic of dissociative identity disorder (DID). Given the vital role of the hippocampus in memory, a prime candidate for investigation is whether total and/or subfield hippocampal volume can serve as biological markers of dissociative amnesia.
METHODS
A total of 75 women, 32 with DID and 43 matched healthy controls (HC), underwent structural magnetic resonance imaging (MRI). Using Freesurfer (version 6.0), volumes were extracted for bilateral global hippocampus, cornu ammonis (CA) 1-4, the granule cell molecular layer of the dentate gyrus (GC-ML-DG), fimbria, hippocampal-amygdaloid transition area (HATA), parasubiculum, presubiculum and subiculum. Analyses of covariance showed volumetric differences between DID and HC. Partial correlations exhibited relationships between the three factors of the dissociative experience scale scores (dissociative amnesia, absorption, depersonalisation/derealisation) and traumatisation measures with hippocampal global and subfield volumes.
RESULTS
Hippocampal volumes were found to be smaller in DID as compared with HC in bilateral global hippocampus and bilateral CA1, right CA4, right GC-ML-DG, and left presubiculum. Dissociative amnesia was the only dissociative symptom that correlated uniquely and significantly with reduced bilateral hippocampal CA1 subfield volumes. Regarding traumatisation, only emotional neglect correlated negatively with bilateral global hippocampus, bilateral CA1, CA4 and GC-ML-DG, and right CA3.
CONCLUSION
We propose decreased CA1 volume as a biomarker for dissociative amnesia. We also propose that traumatisation, specifically emotional neglect, is interlinked with dissociative amnesia in having a detrimental effect on hippocampal volume.
Topics: Humans; Female; Dissociative Identity Disorder; Hippocampus; Magnetic Resonance Imaging; Amnesia; Biomarkers
PubMed: 34165068
DOI: 10.1017/S0033291721002154 -
CNS Neuroscience & Therapeutics Oct 2015Alzheimer's disease (AD) is a progressive age-related neurodegenerative disease. Amnestic mild cognitive impairment (aMCI) is considered to represent early AD. Various... (Review)
Review
Alzheimer's disease (AD) is a progressive age-related neurodegenerative disease. Amnestic mild cognitive impairment (aMCI) is considered to represent early AD. Various aMCI clinical subtypes have been identified as either single domain (SD) or multidomain (MD). The various subtypes represent heterogeneous syndrome, indicating the different probability of progression to AD. Understanding the heterogeneous concept of aMCI can help to construct potential biomarkers to monitor the progression of aMCI to AD. This review provides an overview of various neuroimaging measures for subtypes of aMCI. Focusing on neuropsychological, structural, and functional neuroimaging findings, we found that aMCI showed differences in clinical progression and the abnormalities in MD-aMCI were distributed across temporal, frontal, and parietal cortices, which is similar to AD. This is also compatible with the notion that MD-aMCI is a transition stage between SD-aMCI and AD. Our review provided a framework for the diagnosis of clinical subtypes of aMCI and early detection and intervention of the progression from aMCI to AD.
Topics: Amnesia; Brain; Cognitive Dysfunction; Humans; Neuroimaging; Neuropsychological Tests
PubMed: 25809732
DOI: 10.1111/cns.12391 -
Revista de Neurologia Feb 2002The literature on clinical and physiophatologic characteristics of the spectrum of memory disorders in childhood is reviewed in this article.
OBJECTIVE
The literature on clinical and physiophatologic characteristics of the spectrum of memory disorders in childhood is reviewed in this article.
DEVELOPMENT
There are only a few detailed reports of permanent specific memory disorders in children. Early anoxo ischaemic bihippocampal injuries can cause a selective permanent impairment of episodic daily life memory with preservation of semantic learning and general intelligence; this dissociation has been related to partial hippocampal damage whilst the entorhinal, parahippocampal and prefrontal cortices, which are critical to systematized memorizing and work memory, keep normal. Biological psychiatry research has shown that early childhood amnesias after psychological maltreatment or abuse could be related to damage in neuronal systems which support memory, caused by glutamatergic cascade. Both severe bilateral hippocampal sclerosis (also mediated by toxic neurotransmitters) in early malignant epilepsies, and massive bilateral damage of mesial temporal lobes due to herpex virus encephalitis or Reye's syndrome, cause severe amnesic deficits, frequently accompanied by absence of any language development and autism with features of Klüver-Bucy syndrome. There are also on record some examples of Korsakoff's syndrome in children with midfossa tumors.
CONCLUSIONS
All types of classical amnesias described in adults have been observed in children. Developmental amnesias are probably more frequent than currently presumed. It must be paid special attention to selective autobiographical memory impairments in individuals who underwent a partial bihippocampal damage in perinatal or early postnatal periods; they are to be distinguished from, although it may coexist with, other clinical situations such as attention deficit disorder or semantic pragmatic disorder.
Topics: Adult; Amnesia; Brain; Child; Humans
PubMed: 12447800
DOI: No ID Found -
Cortex; a Journal Devoted To the Study... Feb 2017Some children with high-functioning autistic spectrum conditions (ASC) have been noted clinically to produce accounts and responses akin to confabulations in...
Some children with high-functioning autistic spectrum conditions (ASC) have been noted clinically to produce accounts and responses akin to confabulations in neurological patients. Neurological confabulation is typically associated with abnormalities of the frontal lobes and related structures, and some forms have been linked to poor performance on source monitoring and executive function tasks. ASC has also been linked to atypical development of the frontal lobes, and impaired performance on source monitoring and executive tasks. But confabulation in autism has not to our knowledge previously been examined experimentally. So we investigated whether patterns of confabulation in autism might share similarities with neurologically-based confabulation. Tests of confabulation elicitation, source monitoring (reality monitoring, plus temporal and task context memory) and executive function were administered to four adolescents with ASC who had previously been noted to confabulate spontaneously in everyday life. Scores were compared to a typically developing (TD) and an ASC control group. One confabulating participant was significantly impaired at reality monitoring, and one was significantly worse at a task context test, relative to both the ASC and TD controls. Three of the confabulators showed impairment on measures of executive function (Brixton test; Cognitive Estimates test; Hayling Test B errors) relative to both control groups. Three were significantly poorer than the TD controls on two others (Hayling A and B times), but the ASC control group was also significantly slower at this test than the TD controls. Compared to TD controls, two of the four confabulating participants produced an abnormal number of confabulations during a confabulation elicitation questionnaire, where the ASC controls and TD controls did not differ from each other. These results raise the possibility that in at least some cases, confabulation in autism may be less related to social factors than it is to impaired source memory or poor executive function.
Topics: Adolescent; Amnesia; Autistic Disorder; Child; Executive Function; Female; Humans; Male; Memory; Memory Disorders; Neuropsychological Tests; Surveys and Questionnaires
PubMed: 27837906
DOI: 10.1016/j.cortex.2016.10.004 -
Current Biology : CB Aug 1999
Topics: Amnesia; Brain Mapping; Humans; Memory; Memory, Short-Term; Models, Biological
PubMed: 10469602
DOI: 10.1016/s0960-9822(99)80378-9 -
Anesthesiology Apr 2005
Topics: Amnesia; Amygdala; Anesthesia; Anesthetics; Anti-Anxiety Agents; Awareness; Fear; Humans; Intraoperative Period
PubMed: 15791096
DOI: 10.1097/00000542-200504000-00002 -
Neuropsychologia Aug 2018During conversation, people integrate information from co-speech hand gestures with information in spoken language. For example, after hearing the sentence, "A piece of...
During conversation, people integrate information from co-speech hand gestures with information in spoken language. For example, after hearing the sentence, "A piece of the log flew up and hit Carl in the face" while viewing a gesture directed at the nose, people tend to later report that the log hit Carl in the nose (information only in gesture) rather than in the face (information in speech). The cognitive and neural mechanisms that support the integration of gesture with speech are unclear. One possibility is that the hippocampus - known for its role in relational memory and information integration - is necessary for integrating gesture and speech. To test this possibility, we examined how patients with hippocampal amnesia and healthy and brain-damaged comparison participants express information from gesture in a narrative retelling task. Participants watched videos of an experimenter telling narratives that included hand gestures that contained supplementary information. Participants were asked to retell the narratives and their spoken retellings were assessed for the presence of information from gesture. For features that had been accompanied by supplementary gesture, patients with amnesia retold fewer of these features overall and fewer retellings that matched the speech from the narrative. Yet their retellings included features that contained information that had been present uniquely in gesture in amounts that were not reliably different from comparison groups. Thus, a functioning hippocampus is not necessary for gesture-speech integration over short timescales. Providing unique information in gesture may enhance communication for individuals with declarative memory impairment, possibly via non-declarative memory mechanisms.
Topics: Acoustic Stimulation; Aged; Amnesia; Female; Gestures; Hippocampus; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Middle Aged; Psychomotor Performance; Speech
PubMed: 29932960
DOI: 10.1016/j.neuropsychologia.2018.06.012 -
The Primary Care Companion For CNS... May 2023
Topics: Humans; Suicide, Attempted; Charcoal; Amnesia
PubMed: 37146431
DOI: 10.4088/PCC.22cr03386