Visual imagery: The past and future as seen by patients with Alzheimer’s disease

Déjà vu and involuntary autobiographical memories as two distinct cases of familiarity in patients with Alzheimer's disease

The continuum between involuntary autobiographical memories and déjà vu, as proposed by Barzykowski and Moulin, can be better defined by considering research on autobiographical retrieval in patients with Alzheimer's disease. Although autobiographical retrieval in patients with Alzheimer's disease can generally be associated with a sense of familiarity, involuntary retrieval can trigger an autonoetic experience of retrieval in these patients.

Effect of APOE4 Allele and Gender on the Rate of Atrophy in the Hippocampus, Entorhinal Cortex, and Fusiform Gyrus in Alzheimer's Disease

BACKGROUND

The hippocampus, entorhinal cortex, and fusiform gyrus are brain areas that deteriorate during early-stage Alzheimer's disease (AD). The ApoE4 allele has been identified as a risk factor for AD development, is linked to an increase in the aggregation of amyloid ß (Aß) plaques in the brain, and is responsible for atrophy of the hippocampal area. However, to our knowledge, the rate of deterioration over time in individuals with AD, with or without the ApoE4 allele, has not been investigated.

METHOD

In this study, we, for the first time, analyze atrophy in these brain structures in AD patients with and without the ApoE4 using the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset.

RESULTS

It was found that the rate of decrease in the volume of these brain areas over 12 months was related to the presence of ApoE4. Further, we found that neural atrophy was not different for female and male patients, unlike prior studies, suggesting that the presence of ApoE4 is not linked to the gender difference in AD.

CONCLUSION

Our results confirm and extend previous findings, showing that the ApoE4 allele gradually impacts brain regions impacted by AD.

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.

"My sympathetic clinician": perception of sympathy by patients with Alzheimer's disease increases when asked to provide autobiographical memories

BACKGROUND AND AIMS

Autobiographical memory serves to recall past personal experiences and share them with others, promoting social bonding and communication. In this study, we investigated whether encouraging patients with Alzheimer's disease (AD) to share autobiographical memories during formal neuropsychological testing may boost the patient-clinician relationship, and more specifically, the neuropsychologist's level of sympathy as perceived by patients.

METHODS

We invited patients with mild AD to perform neuropsychological testing in two conditions. In one condition, we invited patients to retrieve and share two autobiographical memories after testing, while in a control condition, the testing session ended without asking patients to retrieve and share any autobiographical memories. After the two conditions, patients were invited to rate the neuropsychologist's level of sympathy towards them.

RESULTS

Analysis demonstrated that patients perceived a higher level of sympathy when their neuropsychologist invited them to retrieve and share past personal experiences.

DISCUSSION

By inviting patients with AD to retrieve past personal experiences, clinicians can promote a sense of sharing, create a social bond and, consequently, enhance the therapeutic relationship. In other words, by inviting patients with AD to share autobiographical memories, clinicians can promote a "social glue" with their patients, boosting mutual sympathy and patients' well-being.

Vividness of visual imagery questionnaire scores and their relationship to visual short-term memory performance

Mechanisms underlying visual imagery, the ability to create vivid mental representations of a scene in the absence of sensory input, remain to be fully understood. Some previous studies have proposed that visual imagery might be related to visual short-term memory (STM), with a common mechanism involving retention of visual information over short periods of time. Other observations have shown a strong relationship between visual imagery and functional activity in the hippocampus and primary visual cortex, both regions also associated with visual STM. Here we examined the relationship of visual imagery to STM and hippocampal and primary visual cortex volumes, first in a large sample of healthy people across a large age range (N = 229 behavioural data; N = 56 MRI data in older participants) and then in patients with Alzheimer's disease and Parkinson's disease (N = 19 in each group compared to 19 age-matched healthy controls). We used a variant of the "What was where?" visual object-location binding task to assess the quality of remembered information over short delays. In healthy people, no evidence of a relationship between the vividness of visual imagery and any visual STM performance parameter was found. However, there was a significant positive correlation between visual imagery and the volumes of the hippocampus and primary visual cortex. Although visual STM performance was significantly impaired in patients with Alzheimer's disease, their vividness of visual imagery scores were comparable to those of age-matched elderly controls and patients with Parkinson's disease. Despite hippocampal volumes also being reduced in Alzheimer's patients, there appeared to be no impact on their self-reported visual imagery. In conclusion, visual imagery was not significantly related to visual STM performance, either in healthy controls or Alzheimer's or Parkinson's disease but it was related to hippocampal and visual cortex volume in healthy people.

ODor-evoked Autobiographical Memory in Alzheimer's disease?

OBJECTIVE

Because memory decline is the hallmark of Alzheimer's disease (AD), an important endeavor for both clinicians and researchers is to improve memory performances in AD. This can be pursued by olfactory stimulation of memory in patients with AD and by studying the effects of olfactory stimulation on autobiographical memory (i.e., memory for personal information). The effects of olfactory stimulation on autobiographical memory in patients with mild AD have been reported by recent research. We thus provide the first comprehensive overview of research on odor-evoked autobiographical memory in AD. We also establish the basis for solid theoretical analysis concerning the memory improvement reported by research on odor-evoked autobiographical memory in AD.

METHOD

We examined literature on odor-evoked autobiographical memories in AD and propose the "OdAMA" (Odor-evoked Autobiographical Memory in Alzheimer's disease) model.

RESULTS AND DISCUSSION

According to OdAMA model, odor exposure activates involuntary access to specific autobiographical memories, which promotes enhanced experience subjective of retrieval in patients with AD and improves their ability to construct not only recent and remote events but also future ones. The OdAMA model could serve as a guide for researchers and clinicians interested in odor-evoked autobiographical memory in AD.

The stability of visual perspective and vividness during mental time travel

When remembering or imagining, people can experience an event from their own eyes, or as an outside observer, with differing levels of vividness. The perspective from, and vividness with, which a person remembers or imagines has been related to numerous individual difference characteristics. These findings require that phenomenology during mental time travel be trait-like-that people consistently experience similar perspectives and levels of vividness. This assumption remains untested. Across two studies (combined N = 295), we examined the stability of visual perspective and vividness across multiple trials and timepoints. Perspective and vividness showed weak within-session stability when reported across just a few trials but showed strong within-session stability when sufficient trials were collected. Importantly, both visual perspective and vividness demonstrated good-to-excellent across-session stability across different delay intervals (two days to six weeks). Overall, our results suggest that people dependably experience similar visual phenomenology across occurrences of mental time travel.

Future-Oriented Repetitive Thought: Pessimistic View of Future in Patients With Alzheimer Disease

OBJECTIVE

In this study, we, for the first time, evaluated future-oriented repetitive thought in patients with Alzheimer disease (AD), that is, how they think and worry about the future.

METHODS

We administered the Future-Oriented Repetitive Thought scale to 34 patients with AD and 37 control participants. This scale assessed 3 categories of future-oriented repetitive thought: (1) pessimistic repetitive future thinking (eg, "I think about the possibility of losing people or things that are important to me"), (2) repetitive thinking about future goals (eg, "I make specific plans for how to get things that I want in life"), and (3) positive indulging about the future (eg, "When I picture good things happening in my future, it is as if they were actually happening to me now").

RESULTS

Analysis demonstrated more pessimistic repetitive future thinking, but less repetitive thinking about future goals and positive indulging about the future, in patients with AD than in control participants.

CONCLUSION

Our findings demonstrate a pessimistic view of future in patients with AD, which is possibly attributed to hopelessness and depression.

Autobiographical memory in Korsakoff syndrome: A review

Autobiographical memory (AM) (i.e., memory for personal information) is a unique form of memory that goes beyond recalling information such as what, where and when of an event, to include what that event means and why it is important to our life story. This paper therefore reviews the available literature on AM in Korsakoff syndrome (KS). It summarizes the characteristics of AM disorders in KS patients. These disorders are mainly characterized by the difficulties that patients with KS have in retrieving and reliving specific AMs and in retrieving recent and remote memories. Another core characteristic of AM disorders in KS is confabulations. This paper hypothesizes that patients with KS may produce autobiographical confabulations to support their objectives and beliefs or even to answer a social demand or simply to share personal experiences with others. Although the current evidence demonstrates disorders of AM in KS, there is a need for more research about the characteristics of these disorders. This review thus proposes several perspectives for theoretical and clinical research.

Pupil dilation as an indicator of future thinking

BACKGROUND

The pupil typically dilates in reaction to cognitive load. In this study, we, for the first time, investigated whether future thinking (i.e., the ability to generate hypothetical scenarios in the future) would result in pupil dilation.

METHODS

We recorded pupil dilation of participants during two conditions: past and future thinking. In past thinking, we invited participants to retrieve past personal events, while in future thinking, we invited them to imagine an event that may occur in the future.

RESULTS

Analysis demonstrated a larger pupil size during future than past thinking. Results also demonstrated longer retrieval time of future events compared with past ones, suggesting that future thinking perhaps requires more cognitive load than for past thinking. Interestingly, retrieval times during past and future thinking were positively correlated with pupil size.

DISCUSSION

The finding that future thinking activates pupil dilation could be due to the fact that while both past and future thinking require retrieving information from memory, future, but not past, thinking additionally requires the ability to recombine this information into novel scenarios.

The discounted future: Relationship between temporal discounting and future thinking in Alzheimer's disease

Temporal discounting refers to the tendency to prefer smaller sooner rewards over larger later rewards. Prior research has reported temporal discounting in Alzheimer's disease (AD). We thus investigated, in this study, the relationship between temporal discounting and future thinking in AD. The study included 40 patients with AD and 42 control participants. We invited participants, on a temporal discounting task, to choose between an immediate but smaller or a delayed but larger amount of money (e.g. "would you prefer 10 dollars today or 50 dollars after one month?"). We also invited the participants to imagine events that may happen in the future, a task known as future thinking. Analysis demonstrated a bias toward immediate rewards (i.e. temporal discounting) as well as difficulties to imagine specific future events in patients with AD. Critically, temporal discounting and future thinking in AD were significantly correlated. Generally speaking, a lack of thinking about the future may lead to impulsive behavior. More specifically, decline in future thinking in AD may limit the ability of patients to project themselves in time to consider outcomes of their decisions, resulting in a tendency to devaluate future rewards in favor of more imminent ones (i.e. temporal discounting).

The subjective experience of mind wandering in Alzheimer's disease

Introduction: Little is known about mind wandering in Alzheimer's disease (AD). In this study, we evaluated the subjective experience of mind wandering in AD.Methods: We invited AD patients and control participants to rate the occurrence, intentionality, emotionality, visual imagery, specificity, self-relatedness and temporal orientation of mind wandering.Results: Analysis showed that AD patients rated their mind wandering as more frequent, negative, and more oriented toward the past, but less vivid and specific than that of control participants. No significant differences were observed between AD patients and control participants regarding the intentionality or self-relatedness of mind wandering.Conclusions: These findings demonstrate the negative content in AD. Regarding the reduction of visual imagery and specificity during mind wandering, this reduction may mirror a diminished subjective experience of mind wandering in AD. Regarding temporality, our results may reflect a tendency of AD patients to reminisce over past experiences. Finally, mind wandering in AD seems to trigger significant self-related content.

The subjective experience of recollection and familiarity in Alzheimer's disease

Although the integrative memory model proposed by Bastin et al. is interesting, particularly for Alzheimer's disease, it may benefit from incorporating the subjective experience of recollection. We therefore offer complementary lines of interpretation to explain how recollection and familiarity in Alzheimer's disease can be dissociated based not only on accounts of their neural correlates but, critically, on the subjective experience of memory in patients.