Contextual novelty detection and novelty-related memory enhancement in amnestic mild cognitive impairment.

INTRODUCTION: Though novelty processing plays a critical role in memory function, little is known about how it influences learning in memory-impaired populations, such as amnestic Mild Cognitive Impairment (aMCI). METHODS: 21 aMCI patients and 22 age- and education-matched healthy older participants performed two tasks-(i) an oddball paradigm where fractals that were often repeated (60 % of the stimuli), less frequently repeated (20 %), or novel (presented once each) were shown to assess novelty preference (longer viewing time for novel than familiar stimuli), and (ii) a Von Restorff paradigm assessing novelty-related effects on memory. Participants studied 22 lists of 10 words. Among these lists, 18 contained an isolated word different from the others by its distinctive aspect, here the font size (90-point, 120-point or 150-point against 60-point for non-isolated words). The remaining four were control lists without isolated words. After studying each list, participants freely recalled the maximum words possible. RESULTS: For the oddball task, a group-by-stimulus type ANOVA on median viewing times revealed a significant effect of stimulus type, but not of group. Both groups spent more time on novel stimuli. For the Von Restorff task, both aMCI and healthy controls recalled the isolated words (presented in 120-point or 150-point, but not 90-point) better than others (excluding primacy and recency effects). Novelty-related memory benefit-gain factor-was computed as the difference between the recall scores for isolated and other words. A group-by-font size ANOVA on gain factors revealed no group effect, nor interaction, suggesting that aMCI patients benefited from novelty, alike controls. CONCLUSION: Novelty preference and the boosting effect of isolation-related novelty on subsequent recall seem preserved despite impaired episodic memory in aMCI patients. This is discussed in the light of contemporary divergent theories regarding the relationship between novelty and memory, as either being independent or parts of a continuum.

A case of severe anterograde amnesia in the era of smartphone technology.

A.V. is a young herpes simplex encephalitis (HSE) survivor who suffered extensive bilateral damage to the medial temporal lobe (MTL) leading to a severe and pervasive form of anterograde amnesia. Structural Magnetic Resonance Imaging (MRI) revealed lesions that encompass the hippocampus and amygdala in both hemispheres and that extend more laterally in the right temporal lobe. At the same time, detailed neuropsychological testing showed that the disparity between A.V.'s preserved intellectual functioning (Full Scale IQ: 115) and severe memory deficit (Delayed Memory Index: 42) is one of the largest on record. Despite this deficit, A.V. has regained a higher level of functioning and autonomy compared to previously documented amnesic cases with major bilateral MTL lesions. As a millennial, one advantage which A.V. has over prior amnesic cases is fluency with digital technology - particularly the smartphone. The analysis of his phone and specific app usage showed a pattern that is consistent with the strategy to offload cognitive tasks that would normally be supported by the MTL. A.V.'s behavior is significant in terms of rehabilitation and may have broader implications at the societal level and for public health given the ubiquity of smartphone technology and its potential to become integrated with neural mnemonic functions.

Evidence of Impaired Remote Experience-near Semantic Memory in Medial Temporal Lobe Amnesia.

Neuropsychological research suggests that "experience-near" semantic memory, meaning knowledge attached to a spatiotemporal or event context, is commonly impaired in individuals who have medial temporal lobe amnesia. It is not known if this impairment extends to remotely acquired experience-near knowledge, which is a question relevant to understanding hippocampal/medial temporal lobe functioning. In the present study, we administered a novel semantic memory task designed to target knowledge associated with remote, "dormant" concepts, in addition to knowledge associated with active concepts, to four individuals with medial temporal lobe amnesia and eight matched controls. We found that the individuals with medial temporal lobe amnesia generated significantly fewer experience-near semantic memories for both remote concepts and active concepts. In comparison, the generation of abstract or "experience-far" knowledge was largely spared in the individuals with medial temporal lobe amnesia, regardless of whether the targets for retrieval were remote or active concepts. We interpret these findings as evidence that the medial temporal lobes may have a sustained role in the retrieval of semantic memories associated with spatiotemporal and event contexts, which are cognitive features often ascribed to episodic memory. These results align with recent theoretical models proposing that the hippocampus/medial temporal lobes support cognitive processes that are involved in, but not exclusive to, episodic memory.

The relationship between semantic and episodic memory: evidence from a case of severe anterograde amnesia.

It is increasingly being recognized that new declarative, consciously accessible information can be learned in anterograde amnesia, but it is not clear whether this learning is supported by episodic or semantic memory. We report a case of a 55-year-old man who experienced severe amnesia after limited damage to the medial temporal lobe following neurosurgical complications. His general cognitive performance and knowledge of new French words and public events that occurred before and after the onset of amnesia were assessed. Performance remained satisfactory on post-morbid vocabulary and public events, with a drop in performance observed for very recent public events only, while knowledge of very recent vocabulary was comparable to that of the control subjects. The implications of these findings for our understanding of the underlying learning mechanisms are discussed. This is the first report of acquisition of consciously accessible postmorbid knowledge of public events in a patient with severe amnesia.

Impaired cognitive performance in older adults is associated with deficits in item memory and memory for object features.

Amnestic mild cognitive impairment (aMCI) is associated with damage to the perirhinal/entorhinal cortex, and consequently, deficits in item/object memory. However, cognitive assessments commonly used to identify individuals with aMCI require a clinician to administer and interpret the test. We developed a novel self-administered global cognitive assessment, called the Cognitive Assessment via Keyboard (CAKe). To assess the relationship between CAKe performance and perirhinal/entorhinal cortex-dependent memory function, participants completed the CAKe, a feature source memory task, and a context memory task. During the memory tasks, participants studied line drawings with either a green or orange internal color (feature memory runs) or external color (context memory runs) and then classified each item as old and previously presented with a "green" or "orange" color, or "new". CAKe scores were correlated with item memory accuracies and source memory accuracies on both tasks. Participants with 'impaired' CAKe performance had worse item memory and worse feature source memory accuracies than those with 'normal' CAKe performance. These results demonstrate specific deficits in item memory and feature source memory and suggest that our assessments may be a valid predictor of aMCI memory deficits.

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.

Combinatory Approaches Targeting Cognitive Impairments and Memory Enhancement: A Review.

The objective of this paper is to look at how natural medicines can improve cognition and memory when used with sildenafil, a popular erectile dysfunction medicine that also has nootropic properties. Newer treatment strategies to treat the early stages of these diseases need to be developed. Multiple factors lead to complex pathophysiological conditions, which are responsible for various long-term complications. In this review, a combination of treatments targeting these pathologies is discussed. These combinations may help manage early and later phases of cognitive impairments. The purpose of this article is to discuss a link between these pathologies and a combinational approach with the objective of considering newer therapeutic strategies in the treatment of cognitive impairments. The natural drugs and their ingredients play a major role in the management of disease progression. Additionally, their combination with sildenafil allows for more efficacy and better response. Studies showing the effectiveness of natural drugs and sildenafil are mentioned, and how these combinations could be beneficial for the treatment of cognitive impairments and amnesia are summarised. Furthermore, preclinical and clinical trials are required to explore the medicinal potential of these drug combinations.

Diencephalic versus Hippocampal Amnesia in Alzheimer's Disease: The Possible Confabulation-Misidentification Phenotype.

BACKGROUND: Alzheimer's disease (AD) is clinically heterogeneous, including the classical-amnesic (CA-) phenotype and some variants. OBJECTIVE: We aim to describe a further presentation we (re)named confabulation-misidentification (CM-) phenotype. METHODS: We performed a retrospective longitudinal case-series study of 17 AD outpatients with the possible CM-phenotype (CM-ADs). Then, in a cross-sectional study, we compared the CM-ADs to a sample of 30 AD patients with the CA-phenotype (CA-ADs). The primary outcome was the frequency of cognitive and behavioral features. Data were analyzed as differences in percentage by non-parametric Chi Square and mean differences by parametric T-test. RESULTS: Anterograde amnesia (100%) with early confabulation (88.2%), disorientation (88.2%) and non-infrequently retrograde amnesia (64.7%) associated with reduced insight (88.2%), moderate prefrontal executive impairment (94.1%) and attention deficits (82.3%) dominated the CM-phenotype. Neuropsychiatric features with striking misidentification (52.9%), other less-structured delusions (70.6%), and brief hallucinations (64.7%) were present. Marked behavioral disturbances were present early in some patients and very common at later stages. At the baseline, the CM-ADs showed more confabulation (p < 0.001), temporal disorientation (p < 0.02), misidentification (p = 0.013), other delusions (p = 0.002), and logorrhea (p = 0.004) than the CA-ADs. In addition, more social disinhibition (p = 0.018), reduction of insight (p = 0.029), and hallucination (p = 0.03) persisted at 12 months from baseline. Both the CA- and CM-ADs showed anterior and medial temporal atrophy. Compared to HCs, the CM-ADs showed more right fronto-insular atrophy, while the CA-ADs showed more dorsal parietal, precuneus, and right parietal atrophy. CONCLUSION: We described an AD phenotype resembling diencephalic rather than hippocampal amnesia and overlapping the past-century description of presbyophrenia.

Intact high-resolution working memory binding in a patient with developmental amnesia and selective hippocampal damage.

Debate continues regarding the possible role of the hippocampus across short-term and working memory tasks. The current study examined the possibility of a hippocampal contribution to precise, high-resolution cognition and conjunctive memory. We administered visual working memory tasks featuring a continuous response component to a well-established developmental amnesic patient with relatively selective bilateral hippocampal damage (Jon) and healthy controls. The patient was able to produce highly accurate response judgments regarding conjunctions of color and orientation or color and location, using simultaneous or sequential presentation of stimuli, with no evidence of any impairment in working memory binding, categorical accuracy, or continuous precision. These findings indicate that hippocampal damage does not necessarily lead to deficits in high-resolution cognitive performance, even when the damage is severe and bilateral.

Apathy and depression in amnestic and non-amnestic mild cognitive impairment.

INTRODUCTION: The information regarding neuropsychiatric symptoms associated with the main subtypes of mild cognitive impairment (MCI) is inadequate. Indeed, it is unclear whether patients with amnestic MCI (aMCI) and those with non-amnestic MCI (naMCI) are characterized by a different behavioral profile and whether the decline in the activities of daily living (ADL) is different between the two groups. Therefore, the main aim of the study is to describe the behavioral and functional profile of the two MCI subgroups and to determine whether apathy and depression are associated with functional autonomy. METHODS: Sixty-eight patients with MCI were enrolled. Out of these, 37 were classified as aMCI while 31 as naMCI according to an extensive neuropsychological evaluation assessing memory, attention, executive functions, visuospatial abilities and language. Moreover, questionnaires assessing apathy, depression and functional autonomy were administered. RESULTS: aMCI patients showed more severe depressive symptoms when compared to naMCI ones, whereas no difference was found on apathy scores. The two subgroups achieved similar results in questionnaires assessing functional autonomy. CONCLUSION: Our results supported the clinical utility of the amnestic and non-amnestic distinction since a different cognitive and behavioral profile characterized the two MCI subtypes and, as a consequence, different treatments are needed.

Reversal of Amnesia for Trauma in a Sample of Psychiatric Inpatients with Dissociative Identity Disorder and Dissociative Disorder Not Otherwise Specified.

The authors interviewed 118 highly dissociative inpatients in a Trauma Program with the Dissociative Disorders Interview Schedule, the Dissociative Experiences Scale and the Adverse Childhood Experiences questionnaire; of the 118 participants 42 met DSM-5 criteria for dissociative identity disorder and 52 for other specified dissociative disorder. The average score on the Dissociative Experiences Scale in the sample of 118 participants was 44.7. The authors also conducted semi-structured interviews inquiring about the circumstances and triggers for reversal of amnesia for childhood trauma in the participants. Only a small minority of the reversal of amnesia took place in therapy sessions, and 24 different triggers for remembering were described. Childhood sexual abuse was by far the most common type of trauma for which amnesia was reversed. The findings are inconsistent with the view that amnesia for childhood sexual abuse is reversed primarily during psychotherapy.

Time perspective and amnestic mild cognitive impairment.

OBJECTIVE: We examined time perspective in patients with amnesic mild cognitive impairment (aMCI). Prior research has shown that aMCI is associated with difficulties in experiencing time duration and succession. However, this line of inquiry has not been extended to time perspective. We examined associations between aMCI and multiple dimensions of time perspective including perceived orientations and relationships among the past, present, and future. METHOD: Thirty aMCI patients and thirty-three healthy controls participated. Measures were the Time Orientation Scale (TOS), the Time Relation Scale (TRS), and the Zimbardo Time Perspective Inventory (ZTPI), as well as a comprehensive neuropsychological evaluation. RESULTS: The TRS was associated with aMCI. Patients with aMCI were more likely to perceive that time was unrelated than the healthy older adults. Among patients with aMCI, an unrelated time perspective was associated with poorer performance in executive function measures. However, aMCI was not associated with the TOS or the ZTPI. CONCLUSIONS: Patients with aMCI have difficulty in perceiving relationships among the past, present, and future. This could be the consequence of deficits in executive functions. This research suggests that patients with aMCI may have limited understanding for how their current behaviours are related to both their past and future.

Post-traumatic amnesia.

Post-traumatic amnesia is the transient state of altered brain function that may follow a traumatic brain injury. At a practical level, an individual has emerged from post-traumatic amnesia when he or she is fully orientated and with return of continuous memory. However, the clinical manifestations are often more complex, with numerous cognitive domains commonly affected, as well as behaviour. In the acute setting, post-traumatic amnesia may easily go unrecognised; this is problematic as it has important implications for both immediate management and for longer-term prognosis. We therefore recommend its careful clinical assessment and prospective evaluation using validated tools. Patients in post-traumatic amnesia who have behavioural disturbance can be particularly challenging to manage. Behavioural and environmental measures form the mainstay of its treatment while avoiding pharmacological interventions where possible, as they may worsen agitation. Patients need assessing regularly to determine their need for further rehabilitation and to facilitate safe discharge planning.

Engagement in cognitively stimulating activities in individuals with Mild Cognitive Impairment: relationships with neuropsychological domains and hippocampal volume.

Late-life participation in cognitively stimulating activities is thought to contribute to an individual's cognitive reserve and thus protect against cognitive decline, yet its association with clinical markers of neurodegeneration is not well established. To investigate, we developed a 13-item self-report "cognitively stimulating activities" questionnaire (CSA-Q), which was completed by a community sample of 269 older adults (>50 years) at risk of dementia. Participants met criteria for Mild Cognitive Impairment (MCI) and were classified as amnestic (aMCI; n = 93) or non-amnestic (naMCI; n = 176). Weighted CSA-Q dimensions were calculated for activity intensity, mental engagement and social engagement via a panel of 23 inter-raters. The CSA-Q mean and its dimensions were examined in relation to: (a) demographics (age, sex), (b) cognitive reserve proxies (years of education, premorbid IQ), (c) neuropsychological markers across cognitive domains of executive function, processing speed, learning, and memory storage, and (d) neuroimaging markers (left and right hippocampal volume). Analyses were conducted for all MCI, as well as for aMCI and naMCI sub-types. The CSA-Q was found to have concurrent validity with cognitive reserve proxies. Among all MCI, the CSA-Q dimensions of intensity and mental engagement had moderate associations with left hippocampal volume, but not with neuropsychological performance. For naMCI, the CSA-Q had moderate associations with left hippocampal volume, and small associations with aspects of executive functioning and processing speed. No equivalent associations emerged for the aMCI subtype. Our findings show that the CSA-Q may be particularly useful for older adults with non-amnestic cognitive deficits.

Aspects of Cognitive Impairment Associated with Agitated Behaviour during Post-traumatic Amnesia.

OBJECTIVES: Post-traumatic amnesia (PTA) is a transient period of recovery following traumatic brain injury (TBI) characterised by disorientation, amnesia, and cognitive disturbance. Agitation is common during PTA and presents as a barrier to patient outcome. A relationship between cognitive impairment and agitation has been observed. This prospective study aimed to examine the different aspects of cognition associated with agitation. METHODS: The sample comprised 82 participants (75.61% male) admitted to an inpatient rehabilitation hospital in PTA. All patients had sustained moderate to extremely severe brain injury as assessed using the Westmead Post-Traumatic Amnesia Scale (WPTAS) (mean duration = 42.30 days, SD = 35.10). Participants were assessed daily using the Agitated Behaviour Scale and WPTAS as part of routine clinical practice during PTA. The Confusion Assessment Protocol was administered two to three times per week until passed criterion was achieved (mean number assessments = 3.13, SD = 3.76). Multilevel mixed modelling was used to investigate the association between aspects of cognition and agitation using performance on items of mental control, orientation, memory free recall, memory recognition, vigilance, and auditory comprehension. RESULTS: Findings showed that improvement in orientation was significantly associated with lower agitation levels. A nonsignificant trend was observed between improved recognition memory and lower agitation. CONCLUSIONS: Current findings suggest that the presence of disorientation in PTA may interfere with a patient's ability to understand and engage with the environment, which in turn results in agitated behaviours. Interventions aimed at maximizing orientation may serve to minimize agitation during PTA.

Determining affected memory domains in patients with amnestic mild cognitive impairment using computerized and interactive tests.

This study explores different episodic memory domains, namely object, temporal and spatial memory, affected in patients with a clinical diagnosis of single domain amnestic mild cognitive impairment (aMCI). 15 aMCI patients and 25 healthy controls were recruited and tested. Object, spatial, and temporal memory were tested using computerized tasks and again in interactive, real-world tasks. Controls outperformed patients on the object computerized task and showed a trend toward significance for the computerized spatial and temporal tasks, but there was no difference in spatial and temporal memory when using the interactive tasks, indicating the employment of compensatory mechanisms in patients to overcome some of the memory impairments associated with aMCI. These findings highlight that aMCI patients might delay seeking help due to compensatory mechanisms which mask their deficits in real-world situations.

Cross-cultural adaptation, translation, and validation of a Spanish version of the Westmead Post-traumatic Amnesia Scale for use following a traumatic brain injury.

Health professionals need linguistically and culturally correct tools with proven validity to effectively assess people in their native language. This study aimed to translate and validate the Westmead Post-traumatic Amnesia Scale (WPTAS) into a Spanish version to measure the progression and duration of post-traumatic amnesia (PTA) in Spanish-speaking populations. Seven native Spanish and English translators, 11 therapists and 15 people with a traumatic brain injury (TBI) and nine people with non-traumatic acquired brain injury participated in the forward-backward translation method to adapt the WPTAS. Participants with a TBI in PTA (n = 20), out of PTA (n = 21), and controls without cognitive impairment (n = 21) participated in the validation test phase by completing the WPTAS, Selective Reminding Test, Short Portable Metal Status Questionnaire, Digit Span, and Agitated Behaviour Scale. The translated version of the WPTAS produced consistent responses and appropriate errors (2%) among all pre-test participants. Results from the validation phase showed that participants in PTA scored significantly lower in all tests (p < .05) when compared with those out of PTA and controls. The Spanish version of the WPTAS created and tested in this study is culturally and linguistically appropriate as well as valid for use with Spanish speakers.

Evidence for a pervasive autobiographical memory impairment in Logopenic Progressive Aphasia.

Although characterized primarily as a language disorder, mounting evidence indicates episodic amnesia in Logopenic Progressive Aphasia (LPA). Whether such memory disturbances extend to information encoded pre-disease onset remains unclear. To address this question, we examined autobiographical memory in 10 LPA patients, contrasted with 18 typical amnestic Alzheimer's disease and 16 healthy Control participants. A validated assessment, the Autobiographical Interview, was employed to explore autobiographical memory performance across the lifespan under free and probed recall conditions. Relative to Controls, LPA patients showed global impairments across all time periods for free recall, scoring at the same level as disease-matched cases of Alzheimer's disease. Importantly, these retrieval deficits persisted in LPA, even when structured probing was provided, and could not be explained by overall level of language disruption or amount of information generated during autobiographical narration. Autobiographical memory impairments in LPA related to gray matter intensity decrease in predominantly posterior parietal brain regions implicated in memory retrieval. Together, our results suggest that episodic memory disturbances may be an under-appreciated clinical feature of LPA.

Believing in dissociative amnesia relates to claiming it: a survey of people's experiences and beliefs about dissociative amnesia.

Dissociative amnesia is one of the most controversial categories in the field of psychiatry and clinical psychology. Self-reports of dissociative amnesia in the general population, and beliefs about this topic, have so far not been subjected to empirical scrutiny. Here, we surveyed a sample from the general population (N = 1017), revealing that about a tenth (n = 102) claimed to have experienced dissociative amnesia. Some claims pertained to amnesia for traumatic autobiographical experiences (e.g., sexual assault), while other claims reflected memory loss for experiences that can be regarded as non-traumatic or non-stressful (e.g., dissociative amnesia for an anniversary). Importantly, many participants believed in the existence of dissociative amnesia, and those who claimed dissociative amnesia indicated even more belief in this phenomenon than the rest of the sample. Finally, many participants indicated to have at least once claimed to have feigned memory loss in their life, and that they experienced some form of forgetting when trying to retrieve events for which they lied upon. Overall, our findings suggest that claiming dissociative amnesia goes hand in hand with believing in dissociative amnesia.

Interindividual and intraindividual variability in amnestic mild cognitive impairment (aMCI) measured with an online cognitive assessment.

INTRODUCTION: Mean cognitive performance is worse in amnestic mild cognitive impairment (aMCI) compared to control groups. However, studies on variability of cognitive performance in aMCI have yielded inconclusive results, with many differences in variability measures and samples from one study to another. METHODS: We examined variability in aMCI using an existing older adult sample (n = 91; 51 with aMCI, 40 with normal cognition for age), measured with an online self-administered computerized cognitive assessment (Cogniciti's Brain Health Assessment). Our methodology extended past findings by using pure measures of variability (controlling for confounding effects of group performance or practice), and a clinically representative aMCI sample (reflecting the continuum of cognitive performance between normal cognition and aMCI). RESULTS: Between-group t-tests showed significantly greater between-person variability (interindividual variability or diversity) in overall cognitive performance in aMCI than controls, although the effect size was with a small to moderate effect size, d = 0.44. No significant group differences were found in within-person variability (intraindividual variability) across cognitive tasks (dispersion) or across trials of a response time task (inconsistency), which may be because we used a sample measuring the continuum of cognitive performance. Exploratory correlation analyses showed that a worse overall score was associated with greater inter- and intraindividual variability, and that variability measures were correlated with each other, indicating people with worse cognitive performance were more variable. DISCUSSION: The current study demonstrates that self-administered online tests can be used to remotely assess different types of variability in people at risk of Alzheimer`s. Our findings show small but significantly more interindividual differences in people with aMCI. This diversity is considered as "noise" in standard assessments of mean performance, but offers an interesting and cognitively informative "signal" in itself.