Investigating the relationship between periodontitis and specific memory processes in the search for cognitive markers of Alzheimer's disease risk.

The spontaneous retrieval deficit (SRD) hypothesis argues that individuals in the preclinical stages of Alzheimer's disease (AD) are particularly impaired in spontaneous retrieval, which manifests in reduced mind-wandering. Our main purpose was to provide novel evidence to support the SRD hypothesis by investigating, for the first time, the relationship between mind-wandering and periodontitis, the latter being the risk factor for AD. The second objective was to address the lack of deeper understanding of the relationship between oral health and specific cognitive abilities by investigating whether periodontitis would be primarily associated with memory. Sixty community-dwelling dementia-free older adults completed neuropsychological tests that focused on various cognitive abilities and a computerised task, during which mind-wandering was evaluated. Periodontal health was assessed subjectively, and through an oral examination by a qualified dentist that focused on visible periodontitis-related changes in gingival tissues and the number of periodontitis bacteria. In line with our predictions, objective and subjective symptoms of poorer periodontal health were associated with less mind-wandering, providing further support for the SRD hypothesis. Again in line with predictions, poorer periodontal health was associated with worse episodic memory, with no relationship between periodontitis and the measure targeting various cognitive abilities, from which memory was excluded.

"It was not mentioned": Improving responses to unanswerable questions using retrieval instructions.

Previous research shows that posing many questions about an event may lead to asking questions about unwitnessed details and that people sometimes provide substantive and erroneous answers to them. Therefore, two experiments investigated the role of the problem-solving and judgment processes, which are unrelated to memory access, in improving responding to unanswerable questions. Experiment 1 compared the effects of a brief retrieval training with the effects of an instruction to increase the criterion of reporting. As expected, the two manipulations had different effects on participants' answers, which demonstrates that training can do more than just instigate more cautious responding. However, we found evidence against our prediction that an enhancement in metacognitive ability underlies improved responding after training. Experiment 2 investigated, for the first time, the role of constant awareness that questions can be unanswerable and that such questions should be rejected. We compared the effects of training with the effects of a small change in response format that ensured such awareness. The effects of the two manipulations were similar, which supports our prediction that the constant awareness of unanswerable questions is a key factor behind improved responding. Practical implications for the eyewitness memory domain are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Deficits in spontaneous and stimulus-dependent retrieval as an early sign of abnormal aging.

Research on early cognitive markers of Alzheimer's disease is primarily focused on episodic memory tests that involve deliberate retrieval. Our purpose was to provide clear evidence to support a novel Spontaneous Retrieval Deficit hypothesis, which predicts that people at pre-clinical stages of dementia, including those with amnestic Mild Cognitive Impairment (aMCI), are particularly impaired on tasks based on spontaneous retrieval. We compared 27 aMCI individuals and 27 healthy controls on mind-wandering while performing a task during which there were exposed to either highly meaningful or unmeaningful pictures. The substantial reduction in mind-wandering among individuals with aMCI was found with exposure to highly meaningful stimuli, but not to unmeaningful pictures, and it was most pronounced for past-oriented thoughts, i.e., involuntary autobiographical memories. Those findings provide strong support for this novel hypothesis, and show that it is the spontaneous, but bottom-up and cue-driven processes, for which meaningful environmental stimuli are crucial, that are very promising early markers of the disease.

Implementation intentions speed up young adults' responses to prospective memory targets in everyday life.

Prospective memory (PM), which is the ability to remember to do something in the future, is vitally important for successful everyday functioning. Although young adults demonstrate high PM abilities in laboratory settings, their abilities to complete intended actions in naturalistic settings are surprisingly low. The present study tested the effectiveness of various encoding techniques in improving young adults' performance in everyday life. Ninety-two participants were asked to remember to take photographs of receipts for a duration of seven days. The task instructions were either given alone or followed by: (a) the if-then statement, (b) visualising the task, or (c) the combination of the if-then statement plus visualisation. The if-then statement alone significantly speeded up responses to the prospective memory targets, i.e., less time elapsed between getting a receipt and taking a photograph of it. With no effect of the if-then statement on the proportion of correct PM responses, the results may suggest that the if-then statement strengthened the PM cue-intention association but did not influence the PM cue saliency.

Dementia-Free Older Adults with Subjective Cognitive Impairment Show Lower Mood and No Deficits of Spontaneous Memory Retrieval.

The aim of the present study was to investigate whether spontaneous retrieval deficits could be found in individuals with Subjective Cognitive Impairment (SCI). The sample consisted of 52 participants over 65 years of age (mean age = 76.00; SD = 7.48) with 11 males. We asked 26 individuals with SCI and 26 individuals without SCI to perform a prospective memory (PM) task that had previously demonstrated spontaneous retrieval deficits in individuals with Mild Cognitive Impairment. The results did not demonstrate the expected differences in a PM task based on spontaneous retrieval [t(50) = -.05; p = .964, d = .01]. However, participants' mood did predict their subjective memory complaints (ß = -.51; p < .001) and their subjective assessment of their future memory performance (r = -.38; p < .01). The findings are in line with numerous studies which have shown that SCI is more related to mood disturbance than to objective cognitive functioning.

The role of inhibitory control and ADHD symptoms in the occurrence of involuntary thoughts about the past and future: An individual differences study.

In everyday life, people often experience involuntary thoughts about their personal past and future events in response to incidental cues in the environment. Yet, despite the abundance of such cues, our consciousness is not constantly flooded by these involuntary autobiographical memories (IAMs) and involuntary future thoughts (IFTs). The main goal of the present study was to further investigate the possibility that cognitive inhibitory control keeps these involuntary cognitions at bay. To test this inhibition hypothesis, we conducted a large-scale study (n = 157) in which groups of participants with different levels of inhibitory control (low, medium, high) and individuals with ADHD spectrum symptoms were engaged in a laboratory vigilance task in which the frequency of IFTs and IAMs was assessed. Contrary to predictions, although participants across groups differed significantly in terms of their individual inhibitory control capacity, the number of IFTs and IAMs reported during the vigilance task was comparable. In addition, individuals with the ADHD spectrum symptoms did not report more spontaneous thoughts compared to other groups. Together, these findings lend little support for the idea that inhibition is a key mechanism that regulates the occurrence of IAMs and IFTs in everyday life. Other possible mechanisms and avenues for future research are discussed.

Everyday memory failures across adulthood: Implications for the age prospective memory paradox.

Despite the prevalence of everyday memory failures, little is known about which specific types have the strongest impact on everyday life, and whether their impact changes across adulthood. An investigation of memory failures at different ages is particularly informative to disentangle the age paradox in prospective memory, which seems to suggest that remembering to perform intended actions in everyday life improves with age. Therefore, 58 young adults, 40 middle-aged adults, and 54 elderly adults recorded their memory failures as and when they occurred during a 7-day period, and described how serious and consequential they were. Failures were coded into several subcategories of retrospective memory, prospective memory, and absent-minded lapses. It was prospective memory lapses that were overall the most common, serious and consequential ones. Young adults had substantially more prospective memory failures than the elderly and middle-aged adults who did not differ from each other. A young adult disadvantage still held up when lifestyle differences between young adults and the elderly were taken into account. Our findings support the age-related benefit previously found in naturalistic prospective memory tasks, and suggest that it is robust across various types of prospective memory tasks. The results also suggest that the benefit may result from both young adults having poor everyday prospective memory, compared to any adults of a greater age, and everyday prospective memory being spared from age-related decline between the middle and late adulthood.

Deficits in Spontaneous Cognition as an Early Marker of Alzheimer's Disease.

In the absence of a pharmacological cure, finding the most sensitive early cognitive markers of Alzheimer's disease (AD) is becoming increasingly important. In this article we review evidence showing that brain mechanisms of spontaneous, but stimulus-dependent, cognition overlap with key hubs of the default mode network (DMN) that become compromised by amyloid pathology years before the clinical symptoms of AD. This leads to the formulation of a novel hypothesis which predicts that spontaneous, but stimulus-dependent, conscious retrieval processes, that are generally intact in healthy aging, will be particularly compromised in people at the earliest stages of AD. Initial evidence for this hypothesis is presented across diverse experimental paradigms (e.g., prospective memory, mind-wandering), and new avenues for research in this area are outlined.

Everyday Memory Failures in Older Adults with Amnestic Mild Cognitive Impairment.

Identifying people with amnestic mild cognitive impairment (aMCI), who are at increased risk of developing Alzheimer's disease, is important for improving early disease management and care. Although self- or informant-reported memory problems constitute one of the diagnostic criteria of aMCI, there is currently little empirical knowledge about the frequency and nature of everyday memory failures in aMCI compared to age-matched healthy controls. Consequently, clinicians rely on their personal judgements when assessing the seriousness of reported memory failures. To address this gap in our knowledge, 32 aMCI participants and 38 healthy controls recorded their everyday memory failures as and when they occurred during a 7-day period, in a portable diary-booklet, by filling in a short questionnaire on a diary page. Descriptions of memory failures were coded into several subcategories of retrospective memory, prospective memory, and absent-minded failures. Results showed that a total number of recorded failures was significantly higher in participants with aMCI than controls. This group difference was mainly due to aMCI participants recording a higher number of retrospective memory failures, while groups did not differ in the number of prospective memory and absent-minded failures. Additionally, while certain types of failures (i.e., forgetting appointments and well-learned procedures) were recorded by a proportion of aMCI patients, they were never reported in a control group. Overall compliance rates were high and did not differ across the groups, suggesting that a structured diary method is feasible to use with aMCI patients, and can provide useful information about everyday memory functioning in this population.

How intention to retrieve a memory and expectation that a memory will come to mind influence the retrieval of autobiographical memories.

While involuntary memories are retrieved with no intention and are usually unexpected (when one is not waiting for a memory to arise), voluntary memories are intended and expected (when one is searching and waiting for a memory to arise). The present study aimed to investigate the effects of retrieval intentionality (i.e. wanting to retrieve a memory) and monitoring processes (i.e. waiting for a memory to appear) during autobiographical memory retrieval. In addition, we introduced two novel laboratory conditions that have not been used in previous research on voluntary memories: in the first, participants were asked to report anything they could think of in response to each cue word; in the second, they could skip a word if nothing came to mind. These novel manipulations allowed us to differentiate between voluntary memories retrieved in response to experimenter-generated cues (when participants were forced to provide a memory or a thought for each cue) and self-selected cues (when participants were free to not answer a cue if they found it too difficult). We found that highly accessible memories were mostly experienced when retrieval was involuntary and unexpected, while memories with low accessibility were accessed through intentional retrieval and monitoring processes. Response times for memories recalled in the experimenter-generated cue conditions were longer compared to the self-selected cue conditions. This novel finding shows that experimenter-generated recall favours memories with low accessibility; it further supports the idea that, in a substantial number of trials, voluntary memories are directly rather than effortfully retrieved. The idea that the driving force behind differences between involuntary and voluntary memories is not the intention per se is further discussed.

Why are we not flooded by involuntary thoughts about the past and future? Testing the cognitive inhibition dependency hypothesis.

In everyday life, involuntary thoughts about future plans and events occur as often as involuntary thoughts about the past. However, compared to involuntary autobiographical memories (IAMs), such episodic involuntary future thoughts (IFTs) have become a focus of study only recently. The aim of the present investigation was to examine why we are not constantly flooded by IFTs and IAMs given that they are often triggered by incidental cues while performing undemanding activities. One possibility is that activated thoughts are suppressed by the inhibitory control mechanism, and therefore depleting inhibitory control should enhance the frequency of both IFTs and IAMs. We report an experiment with a between-subjects design, in which participants in the depleted inhibition condition performed a 60-min high-conflict Stroop task before completing a laboratory vigilance task measuring the frequency of IFTs and IAMs. Participants in the intact inhibition condition performed a version of the Stroop task that did not deplete inhibitory control. To control for physical and mental fatigue resulting from performing the 60-min Stroop tasks in experimental conditions, participants in the control condition completed only the vigilance task. Contrary to predictions, the number of IFTs and IAMs reported during the vigilance task, using the probe-caught method, did not differ across conditions. However, manipulation checks showed that participants' inhibitory resources were reduced in the depleted inhibition condition, and participants were more tired in the experimental than in the control conditions. These initial findings suggest that neither inhibitory control nor physical and mental fatigue affect the frequency of IFTs and IAMs.

Reduced mind-wandering in mild cognitive impairment: Testing the spontaneous retrieval deficit hypothesis.

OBJECTIVE: Research on early cognitive markers of Alzheimer's disease (AD) is primarily focused on declarative episodic memory tests that involve deliberate and effortful/strategic processes at retrieval. The present study tested the spontaneous retrieval deficit hypothesis, which predicts that people with amnestic mild cognitive impairment (aMCI), who are at increased risk of developing AD, are particularly impaired on tasks that rely on spontaneous retrieval processes. METHOD: Twenty-three participants with aMCI and 25 healthy controls (HC) completed an easy vigilance task and thought probes (reporting what was going through their mind), which were categorized as spontaneous thoughts about the past (i.e., involuntary memories), current situation, and future (i.e., spontaneous prospection). RESULTS: Participants with aMCI reported significantly fewer spontaneous thoughts or mind-wandering than HC. This effect was driven by significantly fewer involuntary memories, although groups did not differ in the number of current and future thoughts. CONCLUSIONS: Findings provide strong support for the spontaneous retrieval deficit hypothesis. Implications for research on mind-wandering and the default network, early cognitive markers of the disease, and our theoretical understanding of the nature of cognitive deficits in AD are discussed. (PsycINFO Database Record

The first signs of prospective memory.

We conducted a study to examine the impact of motivation and length of delay on performance on prospective memory (PM) tasks in 2-year of children. A total of 158 children aged exactly 24 months were asked to perform a naturalistic PM task. Length of delay (10 min; 35 min) and motivation (high; very high) were between-subjects factors. Two thirds of children had to be excluded from the analysis because of poor retrospective memory for the PM task instructions which were no longer remembered at the end of the session. For the children who did remember the instructions, both motivation and delay had significant effects on PM. Also, their PM performance was reliably above zero, even after the long delay. The findings indicate that when children as young as 24 months are able to remember the PM task instructions they can reliably succeed in PM tasks that are intrinsically motivating for them.

Involuntary autobiographical memories are relatively more often reported during high cognitive load tasks.

Recent studies on involuntary autobiographical memories (IAMs) in daily life have shown that they are most frequently reported during daily routines (e.g. while ironing). Such studies have suggested that reporting IAMs may be influenced by the level of the ongoing task demands and availability of cognitive resources. In two studies, we investigated the effects of cognitive load on reporting IAMs. To examine the presumed cognitive load dependency of IAMs, we utilised an often-employed experimental paradigm (Schlagman & Kvavilashvili, 2008) to elicit IAMs under conditions that differed in cognitive load. When performing a vigilance task, participants had to interrupt the task each time they experienced any spontaneous mental contents and write them down. We manipulated the level of cognitive load by either instructing (cognitive load group) or not instructing (control group) participants to perform an additional demanding task. We compared the groups on the number of IAMs and other mental contents (non-IAM contents) recorded, as well as on the frequency of IAMs that was calculated as a proportion of IAMs in all mental contents reported by the participant. We expected that if reporting IAMs depends on the level of cognitive demands, then we should observe lower frequency of IAMs in the cognitive load group compared to the control group. Consistently across studies, we observed a lower number of IAMs and non-IAM contents in the cognitive load group. However, IAMs unexpectedly constituted a higher percentage of all mental contents when participants were cognitively loaded. Further implications of the cognitive load effects for IAMs research and experimental methodology are discussed.

Priming involuntary autobiographical memories in the lab.

Involuntary autobiographical memories (IAMs) are recollections of personal past that frequently and spontaneously occur in daily life. Initial studies by Mace (2005) showed that deliberately reminiscing about a certain lifetime period (e.g., high school) significantly increased the number of different IAMs from the same period in subsequent days, suggesting that priming may play a significant role in the retrieval of IAMs in everyday life. In the present study, we used a modified experimental paradigm, originally used by Schlagman and Kvavilashvili (2008), to study IAMs under well-controlled laboratory conditions. Participants completed a monotonous vigilance task twice and reported the occurrence of any spontaneous thoughts that were later classed as IAMs or other thoughts. Priming was manipulated by having experimental participants reminiscing about high school period between the two vigilance tasks and control participants playing simple games. Results showed that participants in the experimental group reported IAMs relating to high school period more frequently during the second vigilance task than those in the control group. In the experimental group, the number of high school memories was marginally higher in the second vigilance task compared to the first vigilance task with the medium effect size, but this within subjects effect was not significant in the control group. Finally, priming also enhanced the retrieval of more remote IAMs in the experimental group compared to the control group. These results suggest that priming may play a significant role in the activation and recall of IAMs and open up interesting avenues for future research.

Spontaneous retrieval deficits in amnestic mild cognitive impairment: A case of focal event-based prospective memory.

OBJECTIVE: Research on early cognitive markers of Alzheimer's disease is primarily focused on retrospective recall (of word lists, pairs of items, stories) and executive functions. However, research shows that people with amnestic mild cognitive impairment (aMCI), who are at a higher risk of developing the disease than healthy controls, are particularly impaired in remembering to do things in the future or prospective memory (PM). The aim of this study was to establish which type of event-based PM is particularly disrupted in aMCI, focal PM, based on spontaneous retrieval, or nonfocal PM that relies on strategic monitoring processes. METHOD: Thirty-eight aMCI individuals and 46 age- and education-matched healthy older adults identified the profession of each famous face presented (ongoing task) and, additionally, responded to certain professions (focal PM condition), or to certain physical features of a person presented (nonfocal PM). Only 4 aMCI individuals could not remember PM instructions at the end of the session, and were excluded from analyses. RESULTS: In comparison with healthy controls, participants with aMCI were significantly impaired in the focal PM task, but not on the nonfocal task. In both groups, monitoring indices were significantly higher in the nonfocal than focal PM condition. CONCLUSIONS: The results fully replicate and extend initial findings of Chi et al. (2014) and McDaniel, Shelton, Breneiser, Moynan, and Balota (2011), showing substantial spontaneous retrieval deficits in PM performance of aMCI individuals. Possible brain mechanisms involved in this deficit are discussed and a novel hypothesis of more generic spontaneous retrieval deficits in aMCI is proposed. (PsycINFO Database Record

The Effects of Instruction on the Frequency and Characteristics of Involuntary Autobiographical Memories.

The present study investigated the effects of experimental instruction on the retrieval of involuntary autobiographical memories (IAMs). In previous studies of IAMs, participants were either instructed to record only memories (henceforth, the restricted group) or any thoughts (henceforth, the unrestricted group). However, it is unknown whether these two different types of instructions influence the retrieval of IAMs. The most recent study by Vannucci and her colleagues directly addressed this question and demonstrated that the frequency and phenomenological characteristics of IAMs strongly depended on the type of instruction received. The goal of the present study was to replicate these results while addressing some limitations of the Vannucci et al. study and to test three possible mechanisms proposed to explain the effect of instructions on the retrieval of IAMs. Our results accord well with the data presented by Vannucci et al. When participants were instructed to record only IAMs (the restricted group), they reported more memories and rated them as being retrieved in a more goal-oriented fashion. Their memories also were less clear, vivid, detailed and were less frequently accompanied by physiological reactions, compared to memories reported by the participants in the unrestricted group. In addition, the events to which the memories referred were rated as more unusual and personal by the restricted group. These results are consistent with the assumption that retrieval of IAMs depends on the type of instructions used in a study. In addition, our results suggest that one of the main mechanisms underlying the higher frequency of IAMs in the restricted group may be participants' ability to monitor the stream of consciousness and to extract autobiographical content from this flow. Further implications of the effect of instructions for IAMs research are discussed.

Only social feedback reduces age-related prospective memory deficits in "Virtual Week".

BACKGROUND: Prospective memory, or remembering to do things in the future, is crucial for independent living in old age. Although there is evidence of substantial age-related deficits in memory for intentions, older adults have demonstrated the ability to compensate for their deficits in everyday life. The present study investigated feedback as a strategy for facilitating prospective memory in the elderly. METHOD: Young and older adults played a computer-based task, Virtual Week, in which they had to remember to carry out life-like intentions. After each virtual day, specific feedback on prospective memory performance was automatically provided on the computer screen that participants either proceeded through by themselves (non-social feedback) or were taken through by an experimenter (social feedback). The control group received no feedback. RESULTS: We found that, compared with no-feedback group, only social feedback substantially reduced the age-related deficit in prospective memory. Older adults significantly benefited from feedback provided by the experimenter on the tasks of intermediate difficulty. Unexpectedly, prospective memory with non-social feedback was not only worse than with social feedback, but it was not any better than without any feedback at all. CONCLUSIONS: The results extended previous findings on the effectiveness of feedback in improving the memory performance of older adults to include memory for intentions. Despite the feedback meeting the critical recommendations of being specific, objective, and well-targeted, it was ineffective when the feedback displayed on the computer was not introduced by the experimenter. This has implications for computerized training tasks where automated feedback is considered crucial.

Age-related differences in everyday prospective memory tasks: the role of planning and personal importance.

The aim of the present studies was to investigate whether age-related improvement found in naturalistic but experimenter-given prospective memory (PM) tasks can be generalized to real-life intentions. In Study 1, younger, middle-aged, and older adults generated a list of intended activities for the following week; one week later they marked the tasks that they had performed. The participants were also asked to rate the importance of each listed intention and to describe the circumstances of completion that were already known to them. We found that, compared with younger adults, older adults attributed a higher degree of importance to their intentions and had the circumstances of their completion better planned. However, the age-related benefit in the PM performance for all listed intentions was not present for the very important and well-planned tasks. In Study 2 we manipulated whether younger adults engaged or not in the detailed planning of when their intentions could be completed. It was demonstrated that younger adults who had to perform detailed planning completed their intended activities more often than those who did not plan for their intentions. The results support explanations of the age-related benefit in everyday PM that highlight the role of importance and planning.

The age prospective memory paradox within the same sample in time-based and event-based tasks.

The present research investigated the age prospective memory (PM) paradox by testing the performance of the same participants on laboratory and naturalistic PM tasks. Younger, middle-aged, and older adults performed three tasks (time-based, event-based with focal cue, and event-based with nonfocal cue); first in the laboratory, then in the context of their everyday lives. Additionally, the social importance of PM tasks was manipulated in the laboratory. As expected, age-dependent declines on the laboratory tasks were reversed in the naturalistic tasks. Middle-aged adults performed as well as younger adults in the laboratory and as well as the elderly outside of the laboratory. When the social importance of laboratory tasks was stressed, the performance of younger adults fell. In addition, older adults showed higher self-reported commitment to the naturalistic tasks than both younger and middle-aged adults. Findings are discussed in the context of possible explanations for the age PM paradox.