Self-reference effect on memory in healthy aging, mild cognitive impairment and Alzheimer's disease: Influence of identity valence

Destination Memory for Self-Related Information: When I Tell Elvis Presley about My Favorite Food

Destination memory, the ability to remember to whom information was previously delivered, has found to be influenced by social processing and social interactions. This memory has also been shown to be compromised in normal aging. Our paper investigated whether older adults would demonstrate better destination memory for self-related information than for general information.

METHODS

We asked younger adults and older adults to tell self-related information (e.g., "I like Chinese food") and semantic information (e.g., "the moon is smaller than the sun") to pictures of celebrities (e.g., Elvis Presley).

RESULTS

Analysis showed higher destination memory for self-related information than for semantic information in older adults and younger adults.

DISCUSSION

Older adults may draw on self-related information to improve memory and social interactions.

Change in the psychological self in people living with dementia: A scoping review

Alterations in one's sense of self are often considered a significant psychological symptom of dementia. However, the self is not a unified construct; it consists of a set of closely connected, yet substantive, manifestations which might not be equally impacted by dementia. Recognising the multidimensional nature of the self, the current scoping review aimed to explore the nature and scope of the evidence demonstrating change in the psychological self in people living with dementia. Adopting a cognitive psychological framework, a hundred and five (105) quantitative and qualitative studies were reviewed, and findings were organised into three main types of self-manifestations: high-order manifestations, functional aspects of the self, and foundational manifestations. Overall, the results show that although there are alterations in some of these different manifestations of the self, these do not imply a global loss of selfhood. Despite notable cognitive changes during dementia, it seems that preserved aspects of self may be enough to compensate for potential weakening of some self-processes such as autobiographical recall. Better understanding alterations in selfhood is key to addressing psychological symptoms of people living with dementia, such as feelings of disconnection and reduced agency, and may inform new pathways for dementia care interventions.

Effect of self-imagination on memory for older adults and aMCI patients

Imagining an event from a personal perspective has been found to be able to enhance memory for words and sentences for healthy younger adults and brain-injured patients. However, little is known about how people with amnestic mild cognitive impairment (aMCI) respond to self-imagination, in comparison to healthy older adults. In the current study, participants were asked to process a group of objects using either a self-imagination approach or a baseline strategy in which the self was not heavily involved. Self-imagination shows a mnemonic advantage over the control strategy, though this pattern emerged more clearly for healthy older adults. Furthermore, suggestive evidence indicates that cognitive ability supports self-reference benefits for healthy older adults, but not aMCI patients. These findings extended previous research to reveal the effectiveness of self-imagination for older adults using pictorial stimuli and supported the viewpoint that aMCI could qualitatively change the way that cognitive resources are engaged.

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.

Effect of Cognitive Control on Age-Related Positivity Effects in Attentional Processing - Evidence From an Event-Related Brain Potential Study

Studies investigating age-related positivity effects during facial emotion processing have yielded contradictory results. The present study aimed to elucidate the mechanisms of cognitive control during attentional processing of emotional faces among older adults. We used go/no-go detection tasks combined with event-related potentials and source localization to examine the effects of response inhibition on age-related positivity effects. Data were obtained from 23 older and 23 younger healthy participants. Behavioral results showed that the discriminability index (d') of older adults on fear trials was significantly greater than that of younger adults [t(44)=2.37, p=0.024, Cohen's d=0.70], whereas an opposite pattern was found in happy trials [t(44)=2.56, p=0.014, Cohen's d=0.75]. The electroencephalography results on the amplitude of the N170 at the left electrode positions showed that the fear-neutral face pairs were larger than the happy-neutral ones for the younger adults [t(22)=2.32, p=0.030, Cohen's d=0.48]; the older group's right hemisphere presented similar tendency, although the results were not statistically significant [t(22)=1.97, p=0.061, Cohen's d=0.41]. Further, the brain activity of the two hemispheres in older adults showed asymmetrical decrement. Our study demonstrated that the age-related "positivity effect" was not observed owing to the depletion of available cognitive resources at the early attentional stage. Moreover, bilateral activation of the two hemispheres may be important signals of normal aging.

The influence of emotional narrative content on the self-reference effect in memory

This study investigated how emotional language usage impacts self-referential effects in memory in healthy older adults and individuals with amnestic mild cognitive impairment (aMCI). To heighten self-focus, 37 healthy older adults and 22 aMCI participants narrated autobiographical memories and then encoded words using a self-referencing or a semantic strategy. We were interested in how narrating autobiographical memories impacted subsequent memory. We probed narrative language usage with the Linguistic Inquiry and Word Count text analysis program, testing the degree to which language from the narrated autobiographical memories contain emotional (positive and negative) words that predicted the self-reference effect across groups. Results indicated that higher levels of positive emotional language were related to larger self-reference effects in memory. In conclusion, narrating autobiographical memories using emotional language influenced the effectiveness of self-referencing as a memory strategy for both healthy older adults and aMCI participants.

Hyperconnectivity of Self-Referential Network as a Predictive Biomarker of the Progression of Alzheimer's Disease

BACKGROUND

Self-referential processing is associated with the progression of Alzheimer's disease (AD), and cerebrospinal fluid (CSF) proteins have become accepted biomarkers of AD.

OBJECTIVE

Our objective in this study was to focus on the relationships between the self-referential network (SRN) and CSF pathology in AD-spectrum patients.

METHODS

A total of 80 participants, including 20 cognitively normal, 20 early mild cognitive impairment (EMCI), 20 late MCI (LMCI), and 20 AD, were recruited for this study. Independent component analysis was used to explore the topological SRN patterns, and the abnormalities of this network were identified at different stages of AD. Finally, CSF pathological characteristics (i.e., CSF Aβ, t-tau, and p-tau) that affected the abnormalities of the SRN were further determined during the progression of AD.

RESULTS

Compared to cognitively normal subjects, AD-spectrum patients (i.e., EMCI, LMCI, and AD) showed a reversing trend toward an association between CSF pathological markers and the abnormal SRN occurring during the progression of AD. However, a certain disease state (i.e., the present LMCI) with a low concentration of CSF tau could evoke more hyperconnectivity of the SRN than other patients with progressively increasing concentrations of CSF tau (i.e., EMCI and AD), and this fluctuation of CSF tau was more sensitive to the hyperconnectivity of the SRN than the dynamic changes of CSF Aβ.

CONCLUSION

The integrity of the SRN was closely associated with CSF pathological characteristics, and these findings support the view that the hyperconnectivity of the SRN will play an important role in monitoring the progression of the pre-dementia state to AD.

Behavioural and ERP evidence of the self-advantage of online self-relevant information

The present study examined whether individuals experienced the same cognitive advantage for online self-relevant information (nickname) as that experienced for information encountered in real life (real name) through two experiments at both the behavioural and neural levels (event-related potential, ERP). The results indicated that individuals showed the same cognitive advantage for nicknames and real names. At the behavioural level, a nickname was detected as quickly as the real name, and both were detected faster than a famous name; at the neural level, the P300 potential elicited by one’s nickname was similar to that elicited by one’s real name, and both the P300 amplitudes and latencies were larger and more prolonged than those elicited by other name stimuli. These results not only confirmed the cognitive advantage for one’s own nickname and indicated that this self-advantage can be extended to online information, but also indicated that the virtual self could be integrated into the self and further expanded individuals’ self-concept.

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.

Self-Reference Effect and Self-Reference Recollection Effect for Trait Adjectives in Amnestic Mild Cognitive Impairment

OBJECTIVES

The self-reference effect (SRE), enhanced memory for self-related information, has been studied in healthy young and older adults but has had little investigation in people with age-related memory disorders, such as amnestic mild cognitive impairment (aMCI). Self-referential encoding may help to improve episodic memory in aMCI. Additionally, self-referential processing has been shown to benefit recollection, the vivid re-experiencing of past events, a phenomenon that has been termed the self-reference recollection effect (SRRE; Conway & Dewhurst, 1995). Furthermore, it remains unclear whether the valence of stimuli influences the appearance of the SRE and SRRE.

METHODS

The current study investigated the SRE and SRRE for trait adjective words in 20 individuals with aMCI and 30 healthy older adult controls. Ninety trait adjective words were allocated to self-reference, semantic, or structural encoding conditions; memory was later tested using a recognition test.

RESULTS

While healthy older adults showed a SRE, individuals with aMCI did not benefit from self-referential encoding over and above that of semantic encoding (an effect of "deep encoding"). A similar pattern was apparent for the SRRE; healthy controls showed enhanced recollection for words encoded in the self-reference condition, while the aMCI group did not show specific benefit to recollection for self-referenced over semantically encoded items. No effects of valence were found.

CONCLUSIONS

These results indicate that while memory for trait adjective words can be improved in aMCI with deep encoding strategies (whether self-reference or semantic), self-referencing does not provide an additional benefit. (JINS, 2018, 24, 821-832).

Self-reference enhances relational memory in young and older adults

The present study investigated the influence of self-reference on two kinds of relational memory, internal source memory and associative memory, in young and older adults. Participants encoded object-location word pairs using the strategies of imagination and sentence generation, either with reference to themselves or to a famous other (i.e., George Clooney or Oprah Winfrey). Both young and older adults showed memory benefits in the self-reference conditions compared to other-reference conditions on both tests, and the self-referential effects in older adults were not limited by low memory or executive functioning. These results suggest that self-reference can benefit relational memory in older adults relatively independently of basic memory and executive functions.

The self-reference effect in dementia: Differential involvement of cortical midline structures in Alzheimer's disease and behavioural-variant frontotemporal dementia

Encoding information in reference to the self enhances subsequent memory for the source of this information. In healthy adults, self-referential processing has been proposed to be mediated by the cortical midline structures (CMS), with functional differentiation between anterior-ventral, anterior-dorsal and posterior regions. While both Alzheimer's disease (AD) and behavioural-variant frontotemporal dementia (bvFTD) patients show source memory impairment, it remains unclear whether they show a typical memory advantage for self-referenced materials. We also sought to identify the neural correlates of this so-called 'self-reference effect' (SRE) in these patient groups. The SRE paradigm was tested in AD (n = 16) and bvFTD (n = 22) patients and age-matched healthy controls (n = 17). In this task, participants studied pictures of common objects paired with one of two background scenes (sources) under self-reference or other-reference encoding instructions, followed by an item and source recognition memory test. Voxel-based morphometry was used to investigate correlations between SRE measures and regions of grey matter atrophy in the CMS. The behavioural results indicated that self-referential encoding did not ameliorate the significant source memory impairments in AD and bvFTD patients. Furthermore, the reduced benefit of self-referential relative to other-referential encoding was not related to general episodic memory deficits. Our imaging findings revealed that reductions in the SRE were associated with atrophy in the anterior-dorsal CMS across both patient groups, with additional involvement of the posterior CMS in AD and anterior-ventral CMS in bvFTD. These findings suggest that although the SRE is comparably reduced in AD and bvFTD, this arises due to impairments in different subcomponents of self-referential processing.