Effect of age on event-based and time-based prospective memory.

The magnitude of age differences on event- and time-based prospective memory tasks was investigated in 2 experiments. Participants performed a working memory task and were also required to perform either an event- or time-based prospective action. Control participants performed either the working memory task only or the prospective memory task only. Results yielded age differences on both prospective tasks. The age effect was particularly marked on the time-based task. Performance of the event-based prospective task, however, had a higher cost to performance on the concurrent working memory task than the time-based task did, suggesting that event-based responding has a substantial attentional requirement. The older adults also made a significant number of time-monitoring errors when time monitoring was their sole task. This suggests that some time-based prospective memory deficits in older adults are due to a fundamental deficit in time monitoring rather than to prospective memory. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Metamemory and prospective memory in Parkinson's disease.

Objective: Metamemory is integral for strategizing about memory intentions. This study investigated the prospective memory (PM) deficit in Parkinson's disease (PD) from a metamemory viewpoint, with the aim of examining whether metamemory deficits might contribute to PM deficits in PD. Method: Sixteen patients with PD and 16 healthy older adult controls completed a time-based PM task (initiating a key press at two specified times during an ongoing task), and an event-based PM task (initiating a key press in response to animal words during an ongoing task). To measure metamemory participants were asked to predict and postdict their memory performance before and after completing the tasks, as well as complete a self-report questionnaire regarding their everyday memory function. Results: The PD group had no impairment, relative to controls, on the event-based task, but had prospective (initiating the key press) and retrospective (recalling the instructions) impairments on the time-based task. The PD group also had metamemory impairments on the time-based task; they were inaccurate at predicting their performance before doing the task but, became accurate when making postdictions. This suggests impaired metamemory knowledge but preserved metamemory monitoring. There were no group differences regarding PD patients' self-reported PM performance on the questionnaire. Conclusions: These results reinforce previous findings that PM impairments in PD are dependent on task type. Several accounts of PM failures in time-based tasks are presented, in particular, ways in which mnemonic and metacognitive deficits may contribute to the difficulties observed on the time-based task. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Is time-based prospective remembering mediated by self-initiated rehearsals? Role of incidental cues, ongoing activity, age, and motivation.

The present research examined self-reported rehearsal processes in naturalistic time-based prospective memory tasks (Study 1 and 2) and compared them with the processes in event-based tasks (Study 3). Participants had to remember to phone the experimenter either at a prearranged time (a time-based task) or after receiving a certain text message (an event-based task) and record the details of occasions when they thought about this intention during a 7-day delay interval. The rehearsal and retrieval of time-based tasks was mediated by more automatic than deliberate self-initiated processes. Moreover, the number of reported rehearsals without any apparent triggers was reliably higher in time- than in event-based tasks. Additional findings concern the effects of age, motivation, and ongoing activities on rehearsal and prospective memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Meta-Analytic Review of Prospective Memory and Aging.

A meta-analysis of prospective memory (PM) studies revealed that in laboratory settings younger participants outperform older participants on tests of both time- and event-based PM (rs=-.39 and -.34, respectively). Event-based PM tasks that impose higher levels of controlled strategic demand are associated with significantly larger age effects than event-based PM tasks that are supported by relatively more automatic processes (rs=-.40 vs. -.14, respectively). However, contrary to the prevailing view in the literature, retrospective memory as measured by free recall is associated with significantly greater age-related decline (r=-.52) than PM, and older participants perform substantially better than their younger counterparts in naturalistic PM studies (rs=.35 and .52 for event- and time-based PM, respectively). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and prospective memory: Examining the influences of self-initiated retrieval processes.

Past research has frequently failed to find age differences in prospective memory. This article tested the possibility that age differences would be more likely to emerge on a prospective memory task that was high in self-initiated retrieval. In the 1st experiment, participants were asked to perform an action every 10 min (a time-based task presumed to be high in self-initiated retrieval); in the 2nd experiment, participants were asked to perform an action whenever a particular word was presented (an event-based task presumed to be relatively low in self-initiated retrieval). Age differences were found with the time-based task but not with the event-based task. This pattern of age differences was again found in a 3rd experiment in which a new experimental procedure was used and the nature of the prospective memory task was directly varied. Generally, the results suggest that self-initiated retrieval processes are an important component of age-related differences across both retrospective and prospective memory tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prospective memory impairment in individuals with Parkinson's disease.

This study investigated prospective memory and its relationship to executive and memory functions in persons with Parkinson's disease (PD). Twenty-three individuals with PD and 25 healthy comparison participants participated in the study. In the prospective memory tasks, participants were asked to execute 3 actions after 20 min (time-based condition) or after a timer ring (event-based condition). A score was computed for the correct recall of the intention to perform the actions (prospective component) and for the correct execution of the actions (retrospective component). Participants with PD also received an extensive neuropsychological test battery. PD participants were less accurate than comparison participants in the prospective component of the time-based but not the event-based task. Individuals with PD were also impaired on the retrospective component of both tasks. In the PD group, a general trend toward significant correlations was found between performance level on the prospective memory component of the time-based task and scores on executive and working memory measures. These results document that prospective memory is impaired in PD possibly in relation to a dysregulation of cognitive functions associated with frontal systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time-based prospective memory impairment in patients with thalamic stroke.

The role of the thalamus in memory is potentially very complex. However, most studies on the memory impairments of thalamic lesions have focused on retrospective memory, rarely on prospective memory. To explore the effect of thalamic lesions on event-based prospective memory (EBPM) and time-based prospective memory (TBPM), respectively, and to verify the hypothesis that the thalamus is involved in the prospective memory, EBPM and TBPM tasks were administered to 18 thalamic stroke patients and 18 age- and education-matched healthy controls. In the EBPM task, subjects were asked to perform an action whenever particular words were presented. In the TBPM task, subjects were asked to perform an action at certain times. Compared with the performance of healthy controls on EBPM and TBPM tasks (EBPM, 4.3 ± 1.5; TBPM, 5.4 ± 1.0), there was a significant difference in the performance of thalamic stroke patients in the TBPM tasks (2.4 ± 1.6), but no difference was found in EBPM tasks (3.7 ± 1.1). These results may indicate that the thalamus is involved in PM and particularly in TBPM. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prospective memory functioning in mild cognitive impairment.

Objective: The present study aimed to investigate prospective memory (PM) in persons with mild cognitive impairment (MCI). Method: Twenty individuals with MCI (10 with an amnestic profile and 10 with a dysexecutive profile of cognitive impairment) and 20 control subjects (CS) were recruited. In the PM tasks, subjects had to execute three actions after 20 min had elapsed (time-based condition) or after a timer rang (event-based condition). Separate scores were computed for correct recall of the intention to perform the actions (prospective component) and for correct execution of the actions (retrospective component). Results: Although individuals with MCI were less accurate than CS in both prospective (Cohen's d ranged from 1.04 to 2.23) and retrospective (Cohen's d ranged from 0.81 to 1.06) components of the experimental task, they were significantly more impaired in the former than the latter component (Cohen's d = 0.42). Moreover, the deficit in the prospective component of the time-based task was particularly evident in MCI participants presenting with a dysexecutive impairment in respect to amnestic MCI individuals (Cohen's d = 0.99). Conclusions: Results of the present study show that the ability of subjects with MCI to comply effectively with a planned delayed intention is impaired and suggest that dysexecutive disorders are likely responsible for this deficit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlation of auditory 'oddball' P300 with verbal memory deficits in schizophrenia

BACKGROUND: The study attempts to recruit well known 'cognitive' event related potential measures as an objective estimate of cognitive and specific memory impairment in schizophrenia. METHODS: We examined 19 schizophrenic patients and 28 healthy controls using an auditory discrimination task to elicit event related potentials, and a number of neuropsychological tests, including tests of general intellectual ability, putative frontal lobe function and verbal memory. RESULTS: The late positive deflection presumed to be associated with stimulus evaluation (P300) was of lower amplitude and had a longer latency in the patients compared with controls of similar age and sex. We found correlations between P300 amplitude and latency, and neuropsychological performance scores in patients. There were correlations between decreased P300 amplitude and lower IQ and poorer memory performance, in particular, abnormal semantic clustering, discriminability and intrusion errors. Increased P300 latency was correlated with lower pre-morbid IQ, poorer total memory scores and serial clustering, but paradoxically less relative retrieval deficit and fewer intrusion errors. CONCLUSIONS: These findings suggest that abnormal P300 is generally more likely to occur in patients with memory impairment.     

Developmental change in working memory strategies: From passive maintenance to active refreshing.

Change in strategies is often mentioned as a source of memory development. However, though performance in working memory tasks steadily improves during childhood, theories differ in linking this development to strategy changes. Whereas some theories, such as the time-based resource-sharing model, invoke the age-related increase in use and efficiency of a strategy of active maintenance of memory traces, other theories, such as the task-switching model, do not mention strategy change. According to these models, either the cognitive load of the task or the duration of maintenance would account for recall performance. In the present study, we varied orthogonally these 2 factors. The results revealed that a different and unique factor affected recall performance at different ages: the duration of maintenance at age 6 and the cognitive load at age 7. As described by the task-switching model, younger children would not implement any maintenance activities while performing a concurrent task, their memory traces suffering from a time-based decay. This suggests that an increasing capacity of cognitive monitoring allows children to shift from this passive maintenance of memory traces to the active refreshing thereof at around the age of 7, reunifying the 2 current accounts of working memory development as 2 developmental stages. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A differential deficit in time- versus event-based prospective memory in Parkinson's disease.

Objective: The aim of the current study was to clarify the nature and extent of impairment in time- versus event-based prospective memory in Parkinson's disease (PD). Prospective memory is thought to involve cognitive processes that are mediated by prefrontal systems and are executive in nature. Given that individuals with PD frequently show executive dysfunction, it is important to determine whether these individuals may have deficits in prospective memory that could impact daily functions, such as taking medications. Although it has been reported that individuals with PD evidence impairment in prospective memory, it is still unclear whether they show a greater deficit for time- versus event-based cues. Method: Fifty-four individuals with PD and 34 demographically similar healthy adults were administered a standardized measure of prospective memory that allows for a direct comparison of time-based and event-based cues. In addition, participants were administered a series of standardized measures of retrospective memory and executive functions. Results: Individuals with PD demonstrated impaired prospective memory performance compared to the healthy adults, with a greater impairment demonstrated for the time-based tasks. Time-based prospective memory performance was moderately correlated with measures of executive functioning, but only the Stroop Neuropsychological Screening Test emerged as a unique predictor in a linear regression. Conclusions: Findings are interpreted within the context of McDaniel and Einstein's (2000) multiprocess theory to suggest that individuals with PD experience particular difficulty executing a future intention when the cue to execute the prescribed intention requires higher levels of executive control. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Prospective memory in children: The effects of age and task interruption.

Prospective memory (PM), remembering to carry out a task in the future, is highly relevant to children's everyday functioning, yet relatively little is known about it. For these reasons the effects of age and task interruption on PM were studied in 3 experiments. Children aged 4, 5, and 7 years were asked to name pictures in stacks of cards (the ongoing task) and to remember to do something when they saw a target picture (the PM task). Significant age differences were identified, but age explained only a small amount of variance. As predicted, children in the no-interruption condition performed significantly better than those who had to interrupt the ongoing activity in order to carry out the PM task. An additional finding was that no relation was detected between performance on prospective and retrospective memory tasks. Taken together, these findings provide support for current models of PM and identify ways to assist children's PM. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Asymétrie fonctionnelle haptique et efficience manuelle motrice chez l'enfant aveugle de 6 à 14 ans.

Studied the effects of age and handedness on the ability of blind children to discriminate Braille characters unimanually and to perform unimanual motor tasks. Human subjects: 48 male and female school-age children and adolescents (aged 6–14 yrs) (blindness). Each S was submitted to 2 series of unimanual tasks designed to measure the ability to (1) discriminate and recognize Braille characters unimanually (haptic efficiency) and (2) perform motor tasks involving tapping ability and grip-strength (motor efficiency). The time spent and number of errors in performing each task were evaluated according to the Ss' age, use of right or left hand, or use of both hands. An analysis of variance (ANOVA) and other statistical tests were used. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incentive effects on event-based prospective memory performance in children and adolescents with traumatic brain injury.

Prospective memory (PM) is the formation of an intention and remembering to perform this intention at a future time or in response to specific cues. PM tasks are a ubiquitous part of daily life. Currently, there is a paucity of information regarding PM impairments in children with traumatic brain injury (TBI) and less empirical evidence regarding effective remediation strategies to mitigate these impairments. The present study employed two levels of a motivational enhancement (i.e., a monetary incentive) to determine whether event-based PM could be improved in children with severe TBI. In a crossover design, children with orthopedic injuries and mild or severe TBI were compared on two levels of incentive (dollars vs. pennies) given in response to accurate performance. All three groups performed significantly better under the high- versus low-motivation conditions. However, the severe TBI group's high-motivation condition performance remained significantly below the low-motivation condition performance of the orthopedic injury group. PM scores were positively and significantly related to age-at-test, but there were no age-at-injury or time-postinjury effects. Overall, these results suggest that event-based PM can be significantly improved in children with severe TBI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Event-Based Prospective Memory Following Severe Closed-Head Injury.

Twenty-four severe closed-head injury (CHI) participants and 24 controls completed event-based prospective memory tasks concurrently with an ongoing working memory task. The event cue was either integrated with the ongoing working memory task (focal cue) or peripheral to it. Prospective remembering was poorer for the CHI group in both the focal- and peripheral-cue conditions. The groups did not differ on the ongoing task. The peripheral cue and the integrated focal cue also did not differ in ability to trigger prospective remembering. The results suggest that, even with highly salient event cues, severe CHI participants (> 1 year postinjury) are more likely than controls to exhibit prospective memory failures. The data revealed a link between CHI participants' prospective memory failures and momentary lapses of intention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The cognitive processes underlying event-based prospective memory in school-age children and young adults: A formal model-based study.

Fifty children 7 years of age (29 girls, 21 boys), 53 children 10 years of age (29 girls, 24 boys), and 36 young adults (19 women, 17 men) performed a computerized event-based prospective memory task. All 3 groups differed significantly in prospective memory performance, with adults showing the best performance and with 7-year-olds showing the poorest performance. We used a formal multinomial process tree model of event-based prospective memory to decompose age differences in cognitive processes that jointly contribute to prospective memory performance. The formal modeling results demonstrate that adults differed significantly from the 7-year-olds and the 10-year-olds on both the prospective component and the retrospective component of the task. The 7-year-olds and the 10-year-olds differed only in the ability to recognize prospective memory target events. The prospective memory task imposed a cost to ongoing activities in all 3 age groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit and Explicit Memory in Children With Congenital and Acquired Brain Disorder.

Implicit and explicit memory were examined in 8- to 15-year-old children with myelomeningocele and shunted hydrocephalus, severe traumatic brain injuries, or orthopedic injuries. Each group included between 22 and 29 children. Children completed a fragmented picture identification task to assess perceptual priming and a semantic decision-making task to assess conceptual priming. Each task also assessed procedural learning as well as explicit recall and recognition. All 3 groups showed significant perceptual and semantic priming of similar magnitude. In contrast, both brain-disordered groups displayed poorer explicit memory than did the comparison group. No group showed significant procedural learning on either task. Age and IQ were stronger predictors of explicit recall than of implicit memory. The findings indicate that implicit memory is relatively intact in many children with congenital and acquired brain disorders, despite deficits in explicit memory, and support the existence of separate memory systems in children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of aging and prospective memory on recognition of item and associative information.

Older adults typically perform worse than younger adults on tasks of associative, relative to item, memory. One account of this deficit is that older adults have fewer attentional resources to encode associative information. Previous researchers investigating this issue have divided attention at encoding and then have examined whether associative and item recognition were differentially affected. In the current study, we used a different cognitive task shown to tax attentional resources: event-based prospective memory. Although older adults demonstrated worse associative, relative to item, memory, the presence of the prospective memory task at encoding decreased item and associative memory accuracy to the same extent in both age groups. These results do not support the resource account of age-related associative deficits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Event-based prospective memory and executive control of working memory

In 5 experiments, the character of concurrent cognitive processing was manipulated during an event-based prospective memory task. High- and low-load conditions that differed only in the difficulty of the concurrent task were tested in each experiment. In Experiments 1 and 2, attention-demanding tasks from the literature on executive control produced decrements in prospective memory. In Experiment 3, attention was divided by different loads of articulatory suppression that did not ultimately lead to decrements in prospective memory. A high-load manipulation of a visuospatial task requiring performance monitoring resulted in worse prospective memory in Experiment 4, whereas in Experiment 5 a visuospatial task with little monitoring did not. Results are discussed in terms of executive functions, such as planning and monitoring, that appear to be critical to successful event-based prospective memory.     

What can the diffusion model tell us about prospective memory?

Cognitive process models, such as Ratcliff's (1978) diffusion model, are useful tools for examining cost or interference effects in event-based prospective memory (PM). The diffusion model includes several parameters that provide insight into how and why ongoing-task performance may be affected by a PM task and is ideally suited to analyse performance because both reaction time and accuracy are taken into account. Separate analyses of these measures can easily yield misleading interpretations in cases of speed–accuracy trade-offs. The diffusion model allows us to measure possible criterion shifts and is thus an important methodological improvement over standard analyses. Performance in an ongoing lexical-decision task was analysed with the diffusion model. The results suggest that criterion shifts play an important role when a PM task is added, but do not fully explain the cost effect on reaction time. (PsycINFO Database Record (c) 2011 APA, all rights reserved)