False memories in patients with mild cognitive impairment and mild Alzheimer's disease dementia: Can cognitive strategies help?

Recent advances in understanding Alzheimer's Disease: diagnosis and management strategies

As the rates of Alzheimer's Disease (AD) increase in the world due to the aging of the population, research has made tremendous advances to target the two hallmark pathologies of AD: amyloid-β (Aβ) plaque deposition and neurofibrillary tangles of hyperphosphorylated tau. Here, we discuss recent advances in the clinical evaluation and management of AD, with a focus on new hypotheses related to the etiology of AD and new evidence related to AD-mimicking neurodegenerative diseases. Though recent clinical studies suggest anti-amyloid disease modifying agents may slow the progression of AD, there is currently no medication that stops it. Moreover, slowing the progression will result in more individuals in the mild cognitive impairment (MCI) and mild dementia stages of AD. Given this reality, we evaluate the development of non-pharmacological strategies to help sustain cognitive function and quality of life.

Fetal alcohol spectrum disorder and confabulation in psycholegal settings: A beginner's guide for criminal justice, forensic mental health, and legal interviewers

Fetal alcohol spectrum disorders (FASD) are neurodevelopmental/neurobehavioral conditions caused by prenatal alcohol exposure (PAE). Impairments caused by PAE contribute to the over-representation of individuals with FASD in the United States juvenile and adult criminal justice systems. These same impairments can equally impact on individuals with FASD who are witnesses to or victims of crime who also have to navigate the complexities of the criminal justice system. Difficulties include increased susceptibility to confabulation throughout the legal process that, in turn, can contribute to increased rates of poor outcomes including false confessions and wrongful convictions. Individuals with FASD are particularity at risk of confabulation when they are subjected to tactics, such as stressful and anxiety-provoking situations, threats, and leading, suggestive, or coercive questioning. Many professionals in the forensic context are unfamiliar with FASD or related confabulation risk and may unintentionally utilize tactics that intensify impacts of pre-existing impairment. This article serves as a beginner's guide for professionals working in criminal justice settings by (a) providing research-based overviews of FASD and confabulation, (b) describing how FASD may lead to confabulation, and (c) suggesting ways that professionals can modify protocols when interacting with individuals with FASD. Suggestions in this article hold the potential to decrease the risk of confabulation in the criminal justice system and decrease problematic outcomes, such as false confessions and wrongful convictions among individuals with FASD.

How non-rapid eye movement sleep and Alzheimer pathology are linked

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder characterized by the presence of senile plaques and neurofibrillary tangles. Research attempts to identify characteristic factors that are associated with the presence of the AD pathology on the one hand and that increase the risk of developing AD on the other. Changes in non-rapid eye movement (NREM) sleep may meet both requirements for various reasons. First, NREM-sleep is important for optimal memory function. In addition, studies report that the presence of AD pathology is associated with NREM-sleep changes. Finally, more and more results appear to suggest that sleep problems are not only a symptom of AD but can also increase the risk of AD. Several of these studies suggest that it is primarily a lack of NREM-sleep that is responsible for this increased risk. However, the majority investigated sleep only through subjective reporting, as a result of which NREM-sleep could not be analyzed separately. The aim of this literature study is therefore to present the results of the studies that relate the AD pathology and NREM-sleep (registered by electroencephalography). Furthermore, we try to evaluate whether NREM-sleep analysis could be used to support the diagnosis of AD and whether NREM-sleep deficiency could be a causal factor in the development of AD.

Updating the Chieti Affective Action Videos database with older adults

Validation of the Chieti Affective Action Videos (CAAV) database was replicated with a sample of older adults (age range 65-93). When designing experimental studies of emotions, it is crucial to take into consideration the differences in emotional processing between young and older adults. Therefore, the main goal of the present study was to provide an appropriate dataset for the use of CAAV in aging research. For this reason, the CAAV administration and the data collection methodology was faithfully replicated in a sample of 302 older adults. All the 360 standardized stimuli were evaluated on the emotional dimensions of valence and arousal. The CAAV validation in an older adults' population increases the potential use of this innovative tool. The present validation supports the use of the CAAV database in future experimental studies on cognitive functions in healthy and pathological aging.

DRM Paradigm: Evidence that Alzheimer's Patients Think of the Critical Lure as Often as Healthy Older Participants

BACKGROUND

Up to now, in the Deese-Roediger-McDermott (DRM) paradigm, the lower production of false memories in Alzheimer's disease has been explained in terms of non-activation of the critical lure.

OBJECTIVES

The aim of this study was to examine the critical lure activation process from items of DRM lists in Alzheimer's patients, using a free association task.

METHOD

Twenty-six young adults, 25 older adults, and 17 Alzheimer's patients performed a free association task with DRM words.

RESULTS

Analyses indicated that Alzheimer's patients produced as many critical lures in the free association task as healthy older participants, but significantly fewer than younger participants.

CONCLUSION

Our results suggest that the low production of critical lures in DRM tasks usually reported in Alzheimer's patients might not be due to a semantic deficit that prevents the activation of the critical lure.

The Role of Language Proficiency in False Memory: A Mini Review

Memory errors and, specifically, false memories in the Deese/Roediger–McDermott paradigm have been extensively studied in the past decades. Most studies have investigated false memory in monolinguals’ native or first language (L1), but interest has also grown in examining false memories in participants’ second language (L2) with different proficiency levels. The main purpose of this manuscript is to review the current state of knowledge on the role of language proficiency on false memories when participants encode and retrieve information in the same language. To do so, a systematic literature search was conducted, and the available studies were reviewed. These studies differed in, for example, age, language proficiency, or material characteristics, including both high and low associative strength lists, and they reported different results. In this review, we attempted to make sense of the apparently contradictory results by carefully identifying participants’ language dominance and L2 proficiency. Specifically, the results indicated that, first, people are more prone to produce false memories in their dominant than in their non-dominant language. This result generalizes to lists with high and low associative strength, as well as to participants of different ages. Second, false memories do not differ between two languages when speakers are equally proficient in both languages. Finally, highly proficient L2 speakers produce more false memories in their L2 than speakers with lower L2 proficiency. The results of this review will be considered in the light of the theoretical frameworks of false memories and bilingual language processing.

The Effectiveness of Item-Specific Encoding and Conservative Responding to Reduce False Memories in Patients with Mild Cognitive Impairment and Mild Alzheimer's Disease Dementia

OBJECTIVE

Patients with mild Alzheimer's disease dementia are more susceptible to false memories than healthy older adults. Evidence that these patients can use cognitive strategies to reduce false memory is inconsistent.

METHOD

In the present study, we examined the effectiveness of conservative responding and item-specific deep encoding strategies, alone and in combination, to reduce false memory in a categorized word list paradigm among participants with mild Alzheimer's disease dementia (AD), amnestic single-domain mild cognitive impairment (MCI), and healthy age-matched older controls (OCs). A battery of clinical neuropsychological measures was also administered.

RESULTS

Although use of conservative responding alone tended to reduce performance in the MCI and OC groups, both deep encoding alone and deep encoding combined with conservative strategies led to improved discrimination for both gist memory and item-specific recollection for these two groups. In the AD group, only gist memory benefited from the use of strategies, boosted equally by deep encoding alone and deep encoding combined with conservative strategies; item-specific recollection was not improved. No correlation between the use of these strategies and performance on neuropsychological measures was found.

CONCLUSIONS

These results suggest that further evaluation of these strategies is warranted as they have the potential to reduce related and unrelated memory errors and increase both gist memory and item-specific recollection in healthy older adults and individuals with amnestic MCI. Patients with AD were less able to benefit from such strategies, yet were still able to use them to reduce unrelated memory errors and increase gist memory.

When twice is better than once: increased liking of repeated items influences memory in younger and older adults

BACKGROUND

Numerous studies have reported that the repeated presentation of a stimulus leads to an increase in positive affect towards the stimulus itself (the so-called mere exposure effect). Here, we evaluate whether changes in liking due to repetition may have a differential impact on subsequent memories in younger and older adults.

METHOD

In two experiments, younger and older adults were asked to rate a series of nonwords (Experiment 1) or unfamiliar neutral faces (Experiment 2) in terms of how much they like them and then presented with a surprise yes-no recognition memory task. At study, items were repeated either consecutively (massed presentation) or with a lag of 6 intervening items (spaced presentation).

RESULTS

In both experiments, participants rated spaced repeated items more positively than massed items, i.e. they liked them most. Moreover, older adults remembered spaced stimuli that they liked most better than younger adults.

CONCLUSIONS

The findings are discussed in accordance with the mechanisms underlying positivity effects in memory and the effect of repetition on memory encoding.

Measuring global functioning in older adults with cognitive impairments using the Rasch model

Background

Cognitive and functional measures are often measured and interpreted separately during the clinical evaluation of patients with cognitive impairment. This can sometimes lead to a challenging interpretation when measures do not show concordance, especially after a clinical intervention. In this study, the development and evaluation of a new approach, using the Rasch model, that combines cognitive and functional measures in one single and more powerful measure (compared to stand-alone tests) to assess global functioning in older adults with cognitive impairment (including dementia) was presented.

Methods

Clinical data from 265 older adults’ subjects diagnosed with mild cognitive impairment, or dementia, included: The Mini-mental state examination (MMSE), the Esame Neuropsicologico Breve (ENB) – a neuropsychological battery used in Italy–, the Activities of Daily Living (ADL), and the Instrumental Activities of Daily Living (IADL) questionnaires.

Results

Patients with severe cognitive impairment showed lower global functioning score compared to patients with moderate impairment. Receiver Operating Characteristic (ROC) curve analyses were performed to determine sensitivity and specificity of the global functioning score resulting from the combined measure. Results showed that the global functioning score discriminates better between patients with severe and moderate cognitive impairment compared to the ENB, ADL, and IADL when considered separately.

Conclusions

The Rasch model was able to combine cognitive and functional measures into a single score (global functioning score). All together, these results suggest that the diverse cognitive and functional measures can be considered part of one single dimension (global functioning) and that this dimension can be measured as a single construct and score. This study offers an alternative perspective for future development of instruments that would help clinicians in measuring global functioning in older adults’ patients at different stages of cognitive impairments and different baseline level of performance.

Sleep spindle abnormalities related to Alzheimer's disease: a systematic mini-review

Accumulating evidence supports a bidirectional relationship between sleep disruption and Alzheimer's disease (AD) pathology. Among various sleep electroencephalography activities, the sleep spindle is one specific electroencephalographic rhythm that has potential to be a biomarker for AD. This review explores the association between sleep spindles and AD-related dementia from a neuropsychological perspective by a systematic re-examining of recent findings. In general, sleep spindles, characterized by density, amplitude, duration, and frequency, are disrupted in AD. Moreover, its functional coupling with slow oscillation also suffers in AD. While preliminary, our observations and comparisons suggest that spindle density rather than frequency and fast spindles rather than slow spindles could be more sensitive to AD-related dementia, and spindle plasticity provides possibilities for targeted interference. In conclusion, quantitative and qualitative features of sleep spindles represent potential non-invasive and cost-effective biomarkers for AD and provide both therapeutic and public health implications.

False Memories: The Other Side of Forgetting

OBJECTIVE

To measure caregivers' and clinicians' perception of false memories in the lives of patients with memory loss due to Alzheimer's disease (AD) and mild cognitive impairment (MCI) using a novel false memories questionnaire. Our hypotheses were that false memories are occurring as often as forgetting according to clinicians and family members.

METHOD

This prospective, questionnaire-based study consisting of 20 false memory questions paired with 20 forgetting questions had two forms: one for clinicians and the other for family members of older subjects. In total, 226 clinicians and 150 family members of 49 patients with AD, 44 patients with MCI, and 57 healthy older controls (OCs) completed the questionnaire.

RESULTS

False memories occurred nearly as often as forgetting according to clinicians and family members of patients with MCI and AD. Family members of OCs and patients with MCI reported fewer false memories compared to those of the AD group. As Mini-Mental State Examination scores decreased, the mean score increased for both forgetting and false memories. Among clinicians, correlations were observed between the dementia severity of patients seen with both forgetting and false memories questionnaire scores as well as with the impact of forgetting and false memories on daily life.

CONCLUSION

Patients with AD experience false memories almost as frequently as they do forgetting. Given how common false memories are in AD patients, additional work is needed to understand the clinical implications of these false memories on patients' daily lives. The novel false memories questionnaire developed may be a valuable tool.

Priming older adults and people with mild to moderate Alzheimer's disease problem-solving with false memories

In two experiments we investigated whether older adult controls (OACs) and people with mild and moderate Alzheimer's disease (AD) benefit from false memory priming effects in subsequent problem-solving tasks. In addition, and unlike in previous false memory priming studies with older adults, we examined latency measures in the recognition phase. In Experiment 1 participants were asked to solve compound remote associate task (CRAT) problems, half of which had been preceded by the presentation of Deese/Roediger-McDermott (DRM) lists whose critical lures (CLs) were also the solutions to those problems. In Experiment 2, we used a similar paradigm but investigated whether CLs could prime solutions to subsequent analogical reasoning problems. In this latter experiment, we also examined whether these priming effects were stronger when the activation of the CL term occurred during the memory task (was presented as part of the list; i.e., true memories) or when these items were not presented but arose during encoding due to spreading activation (i.e., false memories). We found that all three groups' performance on these tasks was facilitated only by false memories spontaneously generated from the prior presentation of DRM lists. That is, performance on CRATs and analogical reasoning tasks was better (greater accuracy and faster speed) when those problems were preceded by DRM lists whose CLs also served as the solution to those problems. These findings are consistent with previous results from studies with children, young adults, and older adults and extends them to people with more moderate AD.

Neuroimaging correlates of false memory in 'Alzheimer's disease: A preliminary systematic review

Alzheimer's disease (AD) is characterised by episodic memory impairment, but people also experience memory distortions, including false memories, which can impact on safety and reduce functioning. Understanding the neural networks that underpin false memories could help to predict the need for intervention and guide development of cognitive strategies to reduce memory errors. However, there is a relative absence of research into how the neuropathology of AD contributes to false memory generation. This paper systematically reviews the methodology and outcomes of studies investigating the neuroimaging correlates of false memory in AD. Four studies using structural imaging and three studies using functional imaging were identified. Studies were heterogenous in methodology and received mostly 'weak' quality assessment ratings. Combined, and consistent with neuroimaging findings in non-AD populations, results from identified studies provide preliminary support for the hypothesis that medial temporal lobe and prefrontal cortex dysfunction may lead to generation of false memories in AD. However, the small number of studies and significant heterogeneity within them means further study is necessary to assess replicability of results.

Sleep spindles, K-complexes, limb movements and sleep stage proportions may be biomarkers for amnestic mild cognitive impairment and Alzheimer's disease

PURPOSE

Sleep disturbances are common in Alzheimer's disease (AD) and mild cognitive impairment (MCI) patients. Non-rapid eye movement stage 3 (N3), rapid eye movement stage (REM), spindle density, and K-complex (KC) density are decreased in MCI and AD patients. Periodic limb movements in sleep (PLMS) are increased in other neurodegenerative diseases. We aimed to distinguish amnestic mild cognitive impairment (aMCI) patients from the overall population of MCI patients by comparing the N3 and REM proportions, the morphological characteristics of spindles and KCs and the periodic limb movement index (PLMI) among control, aMCI and AD subjects.

METHODS

In 92 subjects (30 controls, 32 aMCI and 30 AD), sleep stages, spindles, KCs and PLMS were recorded during the second of two nights of polysomnography (PSG). We compared the above parameters among the three groups.

RESULTS

AD and aMCI subjects had lower proportions of N3 and REM, poorer spindle and KC activities and more frequent PLMS than controls. These alterations were associated with decreased Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scores. We determined cut-off values for distinguishing aMCI and AD using logistic regression and receiver operating characteristic (ROC) analyses.

CONCLUSIONS

AD and aMCI patients have abnormal sleep stage proportions, spindles, KCs and PLMS. The combination of the above alterations may distinguish aMCI and AD patients from controls with high specificity and sensitivity.

Influence of self-referential mode on memory for aMCI patients

One's concept of the self can act as a schema, in some cases facilitating memory performance but in other cases making memory more prone to errors. In this study, we attempted to induce long-lasting self-reference effects through an autobiographical mode in younger and older adults, as well as patients with amnestic mild cognitive impairment (aMCI), predicting that a self-referential mode of thought would benefit memory. Participants first either recalled autobiographical memories or described three neutral photographs in a narrative condition. This was followed by a conventional self-referencing task. At retrieval, participants completed a recognition task. Contrary to our prediction, the self-referencing benefit emerged consistently under autobiographical and narrative modes across all groups. Although our findings indicate that self-referencing can benefit memory, it carries the risk of increasing false alarm rates when induced through an autobiographical mode and consequently the strategy should be utilized with caution.