Affective false memories in Dementia of Alzheimer's Type

Diagnosis Framework for Probable Alzheimer's Disease and Mild Cognitive Impairment Based on Multi-Dimensional Emotion Features

BACKGROUND

Emotion and cognition are intercorrelated. Impaired emotion is common in populations with Alzheimer's disease (AD) and mild cognitive impairment (MCI), showing promises as an early detection approach.

OBJECTIVE

We aim to develop a novel automatic classification tool based on emotion features and machine learning.

METHODS

Older adults aged 60 years or over were recruited among residents in the long-term care facilities and the community. Participants included healthy control participants with normal cognition (HC, n = 26), patients with MCI (n = 23), and patients with probable AD (n = 30). Participants watched emotional film clips while multi-dimensional emotion data were collected, including mental features of Self-Assessment Manikin (SAM), physiological features of electrodermal activity (EDA), and facial expressions. Emotional features of EDA and facial expression were abstracted by using continuous decomposition analysis and EomNet, respectively. Bidirectional long short-term memory (Bi-LSTM) was used to train classification model. Hybrid fusion was used, including early feature fusion and late decision fusion. Data from 79 participants were utilized into deep machine learning analysis and hybrid fusion method.

RESULTS

By combining multiple emotion features, the model's performance of AUC value was highest in classification between HC and probable AD (AUC = 0.92), intermediate between MCI and probable AD (AUC = 0.88), and lowest between HC and MCI (AUC = 0.82).

CONCLUSIONS

Our method demonstrated an excellent predictive power to differentiate HC/MCI/AD by fusion of multiple emotion features. The proposed model provides a cost-effective and automated method that can assist in detecting probable AD and MCI from normal aging.

Memory biases in Alzheimer's disease and mild cognitive impairment. A systematic review and metanalysis

Several studies demonstrated that individuals are more likely to remember emotional than neutral information; this phenomenon is known as emotional enhancement of memory (EEM). Adults generally tend to remember negative information more efficiently than neutral or positive items. In contrast, healthy elders seem to show an opposite bias for positive information, but results are inconsistent, also because during aging, elaboration of emotional information could change as a consequence of cognitive impairment. In this systematic review and meta-analysis, we conducted literature search of studies investigating emotion memory biases in mild cognitive impairment (MCI) and Alzheimer's disease (AD) on PubMed, Scopus and PsycINFO databases following PRISMA guidelines. The findings showed that emotional memory biases are still present despite the presence of cognitive impairment, both in MCI and at least in early stages of AD. However, the direction of emotion memory biases is not consistent across studies. These results suggest that patients with cognitive impairment might still benefit from EEM and help to define targets of intervention for cognitive rehabilitation in pathological aging.

Antidepressant medications in dementia: evidence and potential mechanisms of treatment-resistance

Depression in dementia is common, disabling and causes significant distress to patients and carers. Despite widespread use of antidepressants for depression in dementia, there is no evidence of therapeutic efficacy, and their use is potentially harmful in this patient group. Depression in dementia has poor outcomes and effective treatments are urgently needed. Understanding why antidepressants are ineffective in depression in dementia could provide insight into their mechanism of action and aid identification of new therapeutic targets. In this review we discuss why depression in dementia may be a distinct entity, current theories of how antidepressants work and how these mechanisms of action may be affected by disease processes in dementia. We also consider why clinicians continue to prescribe antidepressants in dementia, and novel approaches to understand and identify effective treatments for patients living with depression and dementia.

Effect of stimuli type on affective memory of patients with different severities of cognitive impairment

OBJECTIVES

To understand the differences in affective memory performance under different degrees of cognitive impairment, this study recruited older people with different degrees of cognitive impairment, to perform emotion recognition memory tasks.

METHODS

Fifty-four elderly participants aged (65-85 years) were recruited. Of these, 18 had mild cognitive impairment, 18 had a mild form of Alzheimer's disease, and the remaining 18 were healthy. Factors such as the different emotional valences (positive, neutral, or negative) and stimulus types (pictures, words, or sounds) were manipulated to explore their influences on the emotion recognition memory of people with different degrees of cognitive impairment.

RESULTS

The results showed that people's performance to positive stimuli worsened as their degree of cognitive impairment increased. All participants had difficulty processing memory of affective sound stimuli compared to the other two stimulus types.

CONCLUSIONS

The results explain the decline in the cognitive ability process, in affective memory performance, of people with different degrees of cognitive impairment. This abnormal decline on affective memory performance could be an early diagnostic indicator of Alzheimer's disease. The results can hopefully be used as a reference for subsequent research on cognition-related diseases and age-related decline, especially regarding affective memory.

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

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that presents predominantly with impairments in learning and memory. Patients with AD are also susceptible to false memories, a clinically relevant memory distortion where a patient remembers an incorrect memory that they believe to be true. The use of cognitive strategies to improve memory performance among patients with AD by reducing false memories has taken on added importance given the lack of disease-modifying agents for AD. However, existing evidence suggests that cognitive strategies to reduce false memories in patients with AD are of limited effectiveness, although these strategies may be useful at earlier stages of the disease. The purpose of this review is to examine experimental findings of false memories and associated memory processes in patients with mild cognitive impairment due to AD and mild AD dementia. Cognitive strategies to reduce false memories in these patient populations are also reviewed. Approaches to clinically relevant future research are suggested and discussed.

Inferential false memories for emotional events in older adults

Emotional events have been shown to protect individuals against false memory when remembering scripted material. Whether the same is true also for older adults, however, is unclear, and it has been investigated in the present study. Seventy-six older adults (age range 65-89 years) were presented with a series of photographs depicting scripted events. Each event included the consequence of an action whose corresponding cause was not presented; the consequence was either neutral, negative, or positive. False recognitions of unseen causes of the consequences (i.e., 'causal errors') were calculated. A Bayesian inferential approach was adopted in order to include evidence from previous studies and to use it as a benchmark for newly collected information. Older adults showed enhanced false memories and lower accuracy than previously reported in studies on young adults. Compared to neutral ones, both negative and positive events were associated with fewer false memories in older adults. The emotional false memory 'profile' of older adults was very similar, in terms of the effect size, to the one previously found in young adults, although the overall chances of older adults incurring errors were higher. Results are discussed considering both cognitive and socioemotional hypotheses on emotional memory in late adulthood.

Experimental Effects of Acute Exercise on Prospective Memory and False Memory

Research demonstrates that acute exercise can enhance retrospective episodic memory performance. However, limited research has examined the effects of acute exercise on prospective memory, and no studies have examined the effects of exercise on false memory performance. This study examined the potential effects of acute exercise on prospective memory and false memory performance. A between-group randomized controlled trial was employed, with participants (college students; M_age = 20 years) randomized into an exercise group (15-minute acute bout of treadmill walking; N = 25) or a control group (15 minutes of sitting; N = 26). Prospective memory was assessed from two laboratory and two naturalistic assessments outside the lab. False memory was assessed using a word-list trial. There were no statistically significant differences in prospective memory based on group allocation (F_Group×Time = 1.17; P = 0.32; η²= 0.06). However, the control group recalled more false words and had a higher rate of false memory recognition (F_Group×Time = 3.15; P = 0.01; η²= 0.26). These findings indicate that acute moderate-intensity aerobic exercise is not associated with prospective memory performance but provides some suggestive evidence that acute exercise may reduce the rate of false memories.