Jayne E. Freeman

Deficient acquisition and consolidation: intertrial free recall performance in Alzheimer's disease and mild cognitive impairment.

Previous research demonstrates that dementia of the Alzheimer type (DAT) is characterised by deficits of episodic memory, especially in the acquisition of new material. As well as this deficit in acquisition, some researchers have also argued for a deficit in consolidation in DAT. We examined acquisition and consolidation by measuring the intertrial gained and lost access in DAT, Mild Cognitive Impairment (MCI) and controls.We report findings from a study of clinical data based on assessment of patients using three free recall trials of a word list. We found that both DAT and MCI groups showed a deficit in acquisition and consolidation of items between trials relative to controls. Moreover, the DAT group was significantly impaired relative to the MCI group for both acquisition and consolidation. Correlations within each group showed that there were strong relationships between intertrial measures and standard measures of memory function. Importantly in no group was there a significant correlation between our measures of acquisition and consolidation: we argue that these measures reflect different underlying processes, and the failure to consolidate in DATand MCI is not related to the deficit in acquisition. Finally, we showed strong correlations between our measure and dementia severity, suggesting that acquisition and consolidation both get worse as the dementia progresses.

The representation of delayed intentions: a prospective subject-performed task?

To-be-enacted material is more accessible in tests of recognition and lexical decision than material not intended for action (T. Goschke & J. Kuhl, 1993; R. L. Marsh, J. L. Hicks, & M. L. Bink, 1998). This finding has been attributed to the superior status of intention-related information. The current article explores an alternative (action-superiority) account that draws parallels between the intended enactment effect (IEE) and the subject performed task effect. Using 2 paradigms, the authors observed faster recognition latencies for both enacted and to-be-enacted material. It is crucial to note that there was no evidence of an IEE for items that had already been executed during encoding. The IEE was also eliminated when motor processing was prevented after verbal encoding. These findings suggest an overlap between overt and intended enactment and indicate that motor information may be activated for verbal material in preparation for subsequent execution.

Chronic consumption of flavanone-rich orange juice is associated with cognitive benefits: an 8-wk, randomized, double-blind, placebo-controlled trial in healthy older adults

BACKGROUND Research indicates that the chronic consumption of flavonoids is associated with cognitive benefits in adults with mild cognitive impairment and neurodegenerative disease, although to our knowledge, there have been no such studies in healthy older adults. Furthermore, the effects of commonly consumed orange juice flavanones on cognitive function remain unexplored. OBJECTIVE We investigated whether 8 wk of daily flavanone-rich orange juice consumption was beneficial for cognitive function in healthy older adults. DESIGN High-flavanone (305 mg) 100% orange juice and an equicaloric low-flavanone (37 mg) orange-flavored cordial (500 mL) were consumed daily for 8 wk by 37 healthy older adults (mean age: 67 y) according to a crossover, double-blind, randomized design separated by a 4-wk washout. Cognitive function, mood, and blood pressure were assessed at baseline and follow-up by using standardized validated tests. RESULTS Global cognitive function was significantly better after 8-wk consumption of flavanone-rich juice than after 8-wk consumption of the low-flavanone control. No significant effects on mood or blood pressure were observed. CONCLUSIONS Chronic daily consumption of flavanone-rich 100% orange juice over 8 wk is beneficial for cognitive function in healthy older adults. The potential for flavanone-rich foods and drinks to attenuate cognitive decline in aging and the mechanisms that underlie these effects should be investigated.

The intention‐superiority effect for naturally occurring activities: The role of intention accessibility in everyday prospective remembering in young and older adults

This study examined age differences in the accessibility of a single pool of naturally occurring intentions both before and after completion. Following Maylor, Darby, and Della Sala (2000), accessibility was measured in terms of the number of activities generated in a 4‐minute activity fluency task. Each participant undertook two such tasks. A prospective task in which they generated activities intended for completion during the following week and a retrospective task, 1 week later, in which they generated activities carried out over the previous week. In a partial replication of Maylor et al.s findings, young, but not healthy older, adults generated more to‐be‐completed intentions than completed ones, demonstrating an intention‐superiority effect (ISE) for everyday activities. The absence of an ISE for older adults appeared to reflect the reduced accessibility of intentions prior to completion, rather than the impaired inhibition of fulfilled intentions. Moreover, both groups showed greater inaccessibil...

Aging and the Accessibility of Performed and To-Be-Performed Actions

In young adults information designated for future enactment is more readily accessible from memory than information not intended for enactment (e.g. Goschke & Kuhl, 1993). We examined whether this advantage for to-be-enacted material is reduced in older adults and thus whether attenuated action accessibility could underlie age-associated declines in prospective remembering. Young and older adults showed an equivalent increase in accessibility (faster recognition latencies) for to-be-enacted items over items intended for verbal report. Both age groups also showed increased accessibility for actions performed at encoding compared with verbally encoded items. Moreover, these effects were non-additive, suggesting similarities in the representation of completed and to-be-completed actions.

Neural Correlates of True and False Memory in Mild Cognitive Impairment

The goal of this research was to investigate the changes in neural processing in mild cognitive impairment. We measured phase synchrony, amplitudes, and event-related potentials in veridical and false memory to determine whether these differed in participants with mild cognitive impairment compared with typical, age-matched controls. Empirical mode decomposition phase locking analysis was used to assess synchrony, which is the first time this analysis technique has been applied in a complex cognitive task such as memory processing. The technique allowed assessment of changes in frontal and parietal cortex connectivity over time during a memory task, without a priori selection of frequency ranges, which has been shown previously to influence synchrony detection. Phase synchrony differed significantly in its timing and degree between participant groups in the theta and alpha frequency ranges. Timing differences suggested greater dependence on gist memory in the presence of mild cognitive impairment. The group with mild cognitive impairment had significantly more frontal theta phase locking than the controls in the absence of a significant behavioural difference in the task, providing new evidence for compensatory processing in the former group. Both groups showed greater frontal phase locking during false than true memory, suggesting increased searching when no actual memory trace was found. Significant inter-group differences in frontal alpha phase locking provided support for a role for lower and upper alpha oscillations in memory processing. Finally, fronto-parietal interaction was significantly reduced in the group with mild cognitive impairment, supporting the notion that mild cognitive impairment could represent an early stage in Alzheimer’s disease, which has been described as a ‘disconnection syndrome’.

Enhancing prospective memory in mild cognitive impairment: The role of enactment

Introduction: Prospective memory (PM) is a fundamental requirement for independent living which might be prematurely compromised in the neurodegenerative process, namely in mild cognitive impairment (MCI), a typical prodromal Alzheimer’s disease (AD) phase. Most encoding manipulations that typically enhance learning in healthy adults are of minimal benefit to AD patients. However, there is some indication that these can display a recall advantage when encoding is accompanied by the physical enactment of the material. The aim of this study was to explore the potential benefits of enactment at encoding and cue-action relatedness on memory for intentions in MCI patients and healthy controls using a behavioral PM experimental paradigm. Method: We report findings examining the influence of enactment at encoding for PM performance in MCI patients and age- and education-matched controls using a laboratory-based PM task with a factorial independent design. Results: PM performance was consistently superior when physical enactment was used at encoding and when target–action pairs were strongly associated. Importantly, these beneficial effects were cumulative and observable across both a healthy and a cognitively impaired lifespan as well as evident in the perceived subjective difficulty in performing the task. Conclusions: The identified beneficial effects of enacted encoding and semantic relatedness have unveiled the potential contribution of this encoding technique to optimize attentional demands through an adaptive allocation of strategic resources. We discuss our findings with respect to their potential impact on developing strategies to improve PM in AD sufferers.

The effects of age, enactment, and cue-action relatedness on memory for intentions in the Virtual Week task

ABSTRACT The current study investigated the influence of encoding modality and cue-action relatedness on prospective memory (PM) performance in young and older adults using a modified version of the Virtual Week task. Participants encoded regular and irregular intentions either verbally or by physically performing the action during encoding. For half of the intentions there was a close semantic relation between the retrieval cue and the intended action, while for the remaining intentions the cue and action were semantically unrelated. For irregular tasks, both age groups showed superior PM for related intentions compared to unrelated intentions in both encoding conditions. While older adults retrieved fewer irregular intentions than young adults after verbal encoding, there was no age difference following enactment. Possible mechanisms of enactment and relatedness effects are discussed in the context of current theories of event-based PM.

Acting is the Key: New directions for the stimulation of prospective memory in mild cognitive impairment

Background: The fulfillment of delayed intended actions (e.g. taking medication or attending an appointment) is described in the literature as prospective memory (PM), and is often pointed out as a fairly common concern for healthy adults in everyday life constituting a fundamental requirement for independent living across the lifespan. PM may be compromised in the course of healthy aging and may be particularly disrupted very early in the neurodegenerative process, namely at the stage of Mild Cognitive Impairment (MCI), which usually represents an initial phase of Alzheimer’s disease (AD), severely affecting a self-sufficient life-style and causing immense apprehension to caregivers. Methods: We have addressed this issue by investigating whether enactment at encoding could improve PM performance and whether these potential benefits were dependent of the relationship between the retrieval cue and its associated action. We report findings that explored this hypothesis in 64 young adults aged 18-39 years (M ¼ 20.41, SD ¼ 3.553) and 64 educationally matched older adults aged 58-90 years (M ¼ 71.17, SD ¼ 7.204) using a behavioral PM testing paradigm with a 2 X 2 X 2 between-subject factorial design. Results: Older adults’ PM performance (like that of their younger counterparts) benefited from enactment at encoding and from a strong semantic cue-action relation. Furthermore, there were no reliable effects of encoding modality or cue-action relatedness on performance accuracy or speed, despite a generalized slowness associated with age. Importantly, these beneficial effects were maintained across the lifespan, and even under high attentional demands. Figure 1. Mean proportion of PM cues eliciting a correct response at the appropriate moment in each Method of Encoding X Cue-Action Relatedness X Age