Time-Based Prospective Memory in Children With Autism Spectrum Disorder

Practice is the best of all instructors-Effects of enactment encoding and episodic future thinking on prospective memory performance in high-functioning adults with autism spectrum disorder

Prospective memory (PM) is the ability to remember to carry out intended actions in the future. The present study investigated the effects of episodic future thinking (EFT) and enactment encoding (EE) on PM performance in autistic adults (ASD). A total of 72 autistic individuals and 70 controls matched for age, gender, and cognitive abilities completed a computerized version of the Dresden breakfast Task, which required participants to prepare breakfast following a set of rules and time restrictions. A two (group: ASD vs. controls) by three (encoding condition: EFT vs. EE vs. standard) between-subjects design was applied. Participants were either instructed to engage in EFT or EE to prepare to the different tasks prior to performing the Dresden breakfast or received standard instructions. Analyses of variance were conducted. Autism-spectrum-disorders (ASD) participants did not differ from control participants in their PM performance, regardless of which strategy they used. Compared to the standard condition, EE but not EFT improved time-based PM performance in all participants. This is the first study to find spared time-based PM performance in autistic individuals. The results confirm earlier results of beneficial effects of EE on PM performance. Findings are discussed with regards to the methodology used, sample composition as well as autistic characteristics.

Time-Based and Event-Based Prospective Memory in Adults with Autism Spectrum Disorder: A Virtual Week Investigation

PURPOSE

Autism spectrum disorder (ASD) is a complex developmental condition including persistent challenges with social communication, restricted interests, and repetitive behavior. Though prospective memory failures are commonly observed in ASD population it has been less studied among adults with ASD. Prospective memory (PM) refers to the execution of delayed intentions. There are contradictory findings of regular and irregular prospective memory task among autistic adults. The present study is an attempt to investigate prospective memory performance among adults with autism spectrum disorder using the Virtual Week board game.

METHOD

Virtual Week (Rendell & Craik, 2000) (3-day Version) is a computerized board game in which participants after rolling a die move token clockwise around the board. Each round of the board represents one virtual "day." Adults between 16 and 25 years of age who were diagnosed with ASD (N = 23) were compared with non-ASD (N = 26) adults.

RESULTS

Analyses of variance were used to analyze the data. Results revealed that autistic adults as compared to normal adults showed poorer performance on time-based task than on event-based task. A significant difference was evident between regular and irregular prospective memory tasks across both tasks among autistic adults. Results also revealed that ASD difficulties are associated with the prospective component of the irregular task.

CONCLUSIONS

Prospective memory failures are widely observed in ASD group, and have important implications for functional independence. The findings of this study provide insight into prospective memory challenges that adults with autism spectrum disorder face in a daily basis.

Do emotionally salient cues improve prospective memory performance in children and adolescents with autism?

BACKGROUND

Prospective memory (PM) describes the ability to initiate and perform a planned action after a delay. Previous studies suggest reduced PM in autism spectrum disorder (ASD); especially when tasks put high demands on executive control resources. Increasing cue salience by presenting emotional cues improves PM performance in non-autistic populations.

AIMS

To explore whether children with ASD, whose processing of emotionally connoted information might differ from that of typically developing children, may also benefit from this type of salience in PM tasks.

METHODS AND PROCEDURES

Twenty-five children with and 25 children without ASD completed a 1-back ongoing task into which an event-based PM task was embedded. Emotional salience of PM cues was varied.

OUTCOMES AND RESULTS

Children with ASD performed as well as children without ASD on the PM task and equally benefited from emotionally salient cues. Specifically, negative cues increased PM performance compared to neutral cues in both groups CONCLUSIONS AND IMPLICATIONS: The findings are consistent with the multiprocess framework which postulates that salient PM cues increase performance by promoting automatic intention retrieval and reducing executive control demands. Children with ASD seem to show similar comprehension and accessibility to emotional cues as typically developing children.

Event-Related Brain Potential Correlates of Event-Based Prospective Memory in Children With Learning Disability

Prospective memory (PM) has been reported to be impaired in children with learning disabilities (LD), but few studies have examined the underlying neural mechanism of this impairment. To address this issue, the present study applied ERP technique to explore the difference of event-based prospective memory (EBPM) in 21 children with LD and 20 non-LD children with double task paradigm. Results from behavioral data showed that LD children exhibited lower accuracy than non-LD children. The ERP results showed that the two groups displayed significant difference in the ERP components, with longer N300 latency in LD group, but there was no obvious difference found in the prospective positivity component. The present findings seem to indicate that the poor performance of LD children on PM task might be result from deficits in PM cues detection. These results provided evidence for the existence of altered PM processing in LD children, which was characterized by a selective deficit in cues detection of PM. Therefore, these findings shed new light on the neurophysiological processes underlying PM in children with LD.

Effective external reminders impair the practice effect of time-based prospective memory

The practice effect of time-based prospective memory (TBPM) refers to the phenomenon that TBPM task performance can be significantly improved by repetitive behavioural training. However, reminders are a common strategy for people to perform TBPM tasks in daily life. A large amount of evidence shows that reminders can improve TBPM performance when individuals pay less attention to time information. However, the present study was the first to explore whether external reminders might simultaneously impede the practice effect of TBPM. In this study, 81 undergraduate students were randomly assigned to control group (N = 27, M_age  = 20.00, SD_age  = 1.04), reminder group (N = 26, M_age  = 20.35, SD_age  = 1.70) and non-reminder group (N = 28, M_age  = 20.25, SD_age  = 1.17). In the training stage, the reminder group could receive effective external reminders, while the non-reminder group could not. The results of the training stage revealed that compared with the non-reminder group, the reminder group had fewer time monitoring times and better TBPM performance. In the testing stage, when reminders were removed from the reminder group, we found that compared with the control group without TBPM training, the TBPM performance of the reminder group failed to improve, while that of the non-reminder group improved significantly. Meanwhile, the time estimation ability of the reminder group was not as improved as that of the non-reminder group.

Did you hear? Auditory prospective memory cues are more beneficial for autistic than for non-autistic children and adolescents

BACKGROUND

The transition from primary to secondary school is particularly difficult for autistic children, a transition underpinned by an increase in prospective memory (PM) demands.

AIMS

To better understand PM in autistic children of the relevant age range and its underlying processes, the current study investigated the impact of cue salience (distinctiveness) on PM in autistic and non-autistic children and adolescents. The study was unique in manipulating the visual and auditory salience of PM cues. Salient cues are assumed to put lower demands on executive control resources as compared to cues that blend in with the ongoing activity.

METHODS AND PROCEDURES

The children completed a computer-based categorisation task in which an event-based PM task was embedded. The salience of PM cues was manipulated (low, high visual and high auditory salience).

OUTCOMES AND RESULTS

Results revealed that both groups benefitted from an increase in visual and auditory salience, but only autistic participants were faster to respond to auditory cues.

CONCLUSIONS AND IMPLICATIONS

Increased cue salience improved PM performance for all children. Positive effects of auditory cues were especially evident in autistic children.

Effect of Executive Function on Event-Based Prospective Memory for Different Forms of Learning Disabilities

Students with learning disabilities (LDs) suffer from executive function deficits and impaired prospective memory (PM). Yet the specificity of deficits associated with different types of LDs is still unclear. The object of the present research was to compare subgroups of students with different forms of LDs (<25th percentile) on executive function and PM. Students with a mathematics disability (MD, n = 30), reading disability (RD, n = 27), both (RDMD, n = 27), or neither (typically developing, TD, n = 30) were evaluated on a set of executive functioning tasks (e.g., updating, inhibition, and shifting) and on PM. The results showed that students with MDs and RDMDs suffered from PM deficits. Among the subtypes of LDs, the deficit is different. The students with RDMDs showed a wide range of defects in PM, shifting, inhibition, and updating. In comparison, students with MDs experienced deficits in PM and shifting, while students with RDs experienced a deficit only in updating. For the RD group, the RDMD group and the TD group, updating, and shifting significantly predicted PM. For the MD group, only shifting significantly predicted PM performance, but PM deficits were not completely confined to shifting deficits.

Increasing Extrinsic Motivation Improves Time-Based Prospective Memory in Adults with Autism: Relations with Executive Functioning and Mentalizing

Time-based prospective memory (PM) is diminished under various task demands in individuals with autism spectrum disorder (ASD). However, it is still unclear what underpins their impairment or how it could be remediated. This study explored whether instructions to prioritise one element of a PM task over another improved performance in adults with ASD (compared to a group of matched neurotypical adults), and how that is related to cognitive abilities. Results indicated that importance instructions significantly improved the PM performance of participants with ASD. Moreover, the extent of the benefit was associated significantly with objectively-measured executive set-shifting ability and self-reported inhibitory control ability (the poorer the set-shifting/inhibitory control, the greater the benefit). Implications for future research and clinical practice are discussed.

Do importance instructions improve time-based prospective remembering in autism spectrum conditions?

This study explored the impact of motivation on the memory for delayed intentions (so-called, prospective memory, PM) in autistic individuals. Specifically, we were interested in the effects of personal (i.e., receiving a reward) as compared to social motivation (i.e., performing a favour for someone). Given the well-established theory of mind deficits in autism, we expected autistic individuals to benefit more strongly from personal than social importance manipulations, whereas the opposite pattern was predicted for controls. Sixty-one adolescents with autism and 61 typically developing adolescents participated, with each group distributed equally to one of the three motivation conditions of standard, social and personal reward. Participants worked on a 2-back picture-based ongoing task in which a time-based PM task was embedded. A mixed 2 (Group) x 3 (Motivation condition) analysis of covariance with age, verbal and non-verbal abilities as covariates and correct PM responses as dependent variable indicated solely a main effect of group, with controls outperforming the autism group. In contrast to our expectations, there was no main effect of condition, no significant interaction, and none of the covariates had any significant impact. However, further planned analyses revealed that controls only outperformed autistic individuals in the personal reward condition. Controls performed significantly best when a personal reward was promised, whereas there were no significant differences between the motivation conditions for autistic individuals. Findings are discussed in terms of underlying processes.

Reinforcing the prospective remembering of children with autism spectrum disorder

Prospective memory is remembering to carry out a behavior on a particular occasion or at a specific time in the future. This form of remembering is critical for the daily functioning of children with autism spectrum disorder (ASD) and their functional independence from caregivers. We used a single-subject design to investigate whether reinforcement increased the accuracy of prospective remembering in the context of a computerized board game, Virtual Week, of four 6- to 7-year-old children diagnosed with ASD. Reinforcement increased accuracy for all participants compared to baseline performance and effects were maintained after reinforcement was discontinued for three of four children. This is the first study of which we are aware to use a reinforcement-based behavioral intervention to improve the prospective remembering of children with ASD. Limitations and areas for future research are discussed.

Development and reliability of the Prospective Memory Assessment for Children & Youth (PROMACY): A preliminary study in a nonclinical sample

Prospective memory (PM), "remembering to remember," has been linked to important functional outcomes in adults. Studies of PM in children and adolescents would benefit from the development and validation of developmentally appropriate clinical measures with known psychometric properties. The Prospective Memory Assessment for Children & Youth (PROMACY), a performance-based measure of PM, was developed for the Pediatric HIV/AIDS Cohort Study Adolescent Master Protocol, Memory and Executive Functioning Substudy, and includes Summary, Time-, and Event-based scores derived from eight trials with an ongoing word search task. Fifty-four healthy perinatally HIV-exposed, uninfected children and youth, mean age 13 years, 54% female, 76% Black/non-Hispanic, and 61% impoverished were included in this psychometric analysis. PROMACY Summary Scores demonstrated low, but broadly acceptable internal consistency as measured by Cronbach's alpha and Spearman-Brown. Better PROMACY performance was associated with older age, but no other demographic factors. Generally medium-sized correlations were observed between the PROMACY Summary Score and standard clinical measures of retrospective memory, working memory, executive functions, and IQ. Findings from this preliminary psychometric study of nonclinical children and youth provide cautious support for the internal consistency and construct validity of PROMACY's Summary Score that awaits replication and extension in larger samples of healthy children, youth and clinical populations.

A Meta-Analysis and Critical Review of Prospective Memory in Autism Spectrum Disorder

Prospective memory (PM) is the ability to remember to carry out a planned intention at an appropriate moment in the future. Research on PM in ASD has produced mixed results. We aimed to establish the extent to which two types of PM (event-based/time-based) are impaired in ASD. In part 1, a meta-analysis of all existing studies indicates a large impairment of time-based, but only a small impairment of event-based PM in ASD. In Part 2, a critical review concludes that time-based PM appears diminished in ASD, in line with the meta-analysis, but that caution should be taken when interpreting event-based PM findings, given potential methodological limitations of several studies. Clinical implications and directions for future research are discussed.

Prospective memory in youth with perinatally-acquired HIV infection

Youth with perinatal HIV infection (PHIV) are at increased risk for neurocognitive impairment (NCI). Prospective memory (PM) is a complex neurocognitive function that has been shown to be impaired in adults with HIV disease and independently associated with poorer daily living skills, including medication nonadherence. The current study sought to determine the presence and extent of PM deficits in youth with PHIV. Participants included 173 youth with PHIV and 85 youth perinatally HIV-exposed but uninfected (PHEU), mean age 14.1 years, 75% black, 18% Hispanic. Among youth with PHIV, 26% had a past AIDS-defining condition (Centers for Disease Control and Prevention [CDC], Class C), 74% did not (non-C). Adjusted generalized estimating equation models were used to compare groups (PHIV/C, PHIV/non-C, and PHEU) on the Naturalistic Event-Based Prospective Memory Test (NEPT) and the Prospective Memory Assessment for Children & Youth (PROMACY). Secondarily, subgroups defined by HIV serostatus and global NCI were compared (PHIV/NCI, PHIV/non-NCI, PHEU). PHIV/C had significantly lower NEPT scores than PHEU, with decreases of 40% in mean scores, but did not differ from PHIV/non-C. PHIV/NCI had 11-32% lower PROMACY scores and 33% lower NEPT scores compared to PHIV/non-NCI (all p < .05); significantly, lower scores for PHIV/NCI versus PHEU also were observed for PROMACY and NEPT indices. Findings suggest a subset of youth with PHIV (those with a prior AIDS-defining diagnosis) is vulnerable to PM deficits. The extent to which PM deficits interfere with development and maintenance of independent living and health-related behaviors during transition to adulthood requires further study.

Event-based prospective memory in mildly and severely autistic children

BACKGROUND

There is a growing body of research into the development of prospective memory (PM) in typically developing children but research is limited in autistic children (Aut) and rarely includes children with more severe symptoms.

AIMS

This study is the first to specifically compare event-based PM in severely autistic children to mildly autistic and typically developing children.

METHODS AND PROCEDURES

Fourteen mildly autistic children and 14 severely autistic children, aged 5-13 years, were matched for educational attainment with 26 typically developing children aged 5-6 years. Three PM tasks and a retrospective memory task were administered.

OUTCOMES AND RESULTS

Results showed that severely autistic children performed less well than typically developing children on two PM tasks but mildly autistic children did not differ from either group. No group differences were found on the most motivating (a toy reward) task.

CONCLUSIONS AND IMPLICATIONS

The findings suggest naturalistic tasks and motivation are important factors in PM success in severely autistic children and highlights the need to consider the heterogeneity of autism and symptom severity in relation to performance on event-based PM tasks.

Prospective memory in adults with high-functioning autism spectrum disorders: exploring effects of implementation intentions and retrospective memory load

This study examined, for the first time, the impact of implementation intentions on prospective memory (PM) performance in adults with autism spectrum disorders (ASD) and further explored the role of retrospective memory for PM in ASD. PM was assessed with Virtual Week, a computerized game simulating upcoming everyday-life tasks. Twenty-seven adults with ASD and 27 age- and ability-matched controls were included. Half of the participants were instructed to form implementation intentions (i.e., encoding PM tasks in form of if-then statements), while the rest received simple PM instructions. Results provide first tentative evidence for beneficial effects of implementation intentions and PM tasks with low demands on retrospective memory for adults with ASD's PM. Overall, results point to the importance of planning and retrospective memory for successful prospective remembering in ASD.

A Virtual Week study of prospective memory function in autism spectrum disorders

Prospective memory (PM) refers to the implementation of delayed intentions, a cognitive ability that plays a critical role in daily life because of its involvement in goal-directed behavior and consequently the development and maintenance of independence. Emerging evidence indicates that PM may be disrupted in autism spectrum disorders (ASDs), potentially contributing to the functional difficulties that characterize this group. However, the degree, nature, and specificity of ASD-related impairment remains poorly understood. In the current study, children between 8 and 12 years of age who were diagnosed with ASDs (n=30) were compared with typically developing children (n=30) on a child-appropriate version of the Virtual Week board game. This measure provides an opportunity to investigate the different sorts of PM failures that occur. The ASD group showed significant PM impairment on measures of time-based (but not event-based) prospective remembering. However, only a subtle difference emerged between regular and irregular PM tasks, and group differences were consistent across these tasks. Because regular and irregular tasks differentially load retrospective memory, these data imply that the PM difficulties seen in ASDs may primarily reflect a monitoring deficit and not an encoding and memory storage deficit. PM performance was poorer under conditions of high ongoing task absorption, but the magnitude of this effect did not vary as a function of group. In both groups, time-based (but not event-based) PM difficulties were associated with functional outcomes in daily life, but only an inconsistent association with executive control emerged.

Time-based and event-based prospective memory in autism spectrum disorder: the roles of executive function and theory of mind, and time-estimation

Prospective memory (remembering to carry out an action in the future) has been studied relatively little in ASD. We explored time-based (carry out an action at a pre-specified time) and event-based (carry out an action upon the occurrence of a pre-specified event) prospective memory, as well as possible cognitive correlates, among 21 intellectually high-functioning children with ASD, and 21 age- and IQ-matched neurotypical comparison children. We found impaired time-based, but undiminished event-based, prospective memory among children with ASD. In the ASD group, time-based prospective memory performance was associated significantly with diminished theory of mind, but not with diminished cognitive flexibility. There was no evidence that time-estimation ability contributed to time-based prospective memory impairment in ASD.

Do adults with autism spectrum disorders compensate in naturalistic prospective memory tasks?

The present study is the first to directly compare event- and time-based prospective memory in Autism Spectrum Disorders (ASD) using a contextual task mirroring real life demands of prospective memory. Twenty-five individuals with ASD and 25 age- and ability-matched controls completed the Dresden Breakfast task which required participants to prepare breakfast following a set of rules and time restrictions. Overall, adults with ASD had less correct time- and event-based prospective memory responses in comparison to controls, which is consistent with previous research in children with ASD. Moreover, ASD participants completed fewer tasks, followed rules less closely, and monitored the elapsing time less closely than controls. Individuals with ASD seem not to be compensating in naturalistic prospective memory tasks.

Investigating multitasking in high-functioning adolescents with autism spectrum disorders using the Virtual Errands Task

Using a modified version of the Virtual Errands Task (VET; McGeorge et al. in Presence-Teleop Virtual Environ 10(4):375-383, 2001), we investigated the executive ability of multitasking in 18 high-functioning adolescents with ASD and 18 typically developing adolescents. The VET requires multitasking (Law et al. in Acta Psychol 122(1):27-44, 2006) because there is a limited amount of time in which to complete the errands. ANCOVA revealed that the ASD group completed fewer tasks, broke more rules and rigidly followed the task list in the order of presentation. Our findings suggest that executive problems of planning inflexibility, inhibition, as well as difficulties with prospective memory (remembering to carry out intentions) may lie behind multitasking difficulties in ASD.

Similarity between Brain Activity at Encoding and Retrieval Predicts Successful Realization of Delayed Intentions

Remembering delayed intentions can be highly demanding. Accuracy in laboratory paradigms assessing prospective memory (PM) is typically well below ceiling, and failure to remember intended behaviors after a delay is a common occurrence in everyday life. However, relatively little is known of the potential differences in brain activity that distinguish successful versus unsuccessful PM. In this fMRI study, participants repeatedly encoded, stored, and then had the opportunity to retrieve intended behaviors while engaged in a distracting ongoing task. This yielded a success rate of approximately two thirds. Overall levels of brain activity distinguished successful versus unsuccessful trials at all three stages (encoding, storage, and retrieval), suggesting multiple neural determinants of PM success. In addition, the voxelwise similarity between patterns of brain activity at encoding and retrieval was greater for successful than unsuccessful trials. This was true even in posterior cingulate, which showed opposite patterns of signal change between encoding and retrieval. Thus, successful realization of delayed intentions may be associated with reinstatement of encoding context at the time of retrieval.

Event-based prospective memory performance in autism spectrum disorder

The purpose of the present study was to investigate event-based prospective memory performance in individuals with autism spectrum disorder and to explore possible relations between laboratory-based prospective memory performance and everyday performance. Nineteen children and adolescents with autism spectrum disorder and 19 matched neurotypical controls participated. The laboratory-based prospective memory test was embedded in a visuo-spatial working memory test and required participants to remember to respond to a cue-event. Everyday planning performance was assessed with proxy ratings. Although parents of the autism group rated their children's everyday performance as significantly poorer than controls' parents, no group differences were found in event-based prospective memory. Nevertheless, individual differences in laboratory-based and everyday performances were related. Clinical implications of these findings are discussed.

Are older adults more social than younger adults? Social importance increases older adults' prospective memory performance

The purpose of this study was to explore the influence of social importance on prospective remembering in younger and older adults as a possible factor contributing to the age-prospective memory paradox. Using a between-subjects design, 40 younger and 40 older adults worked on a time-based prospective memory task in which social importance was varied. Overall, younger adults outperformed older adults in the prospective memory task. Importantly, in contrast to younger adults, older adults' prospective memory performance was significantly better in the social importance condition than in the standard condition. This interaction was not reflected in participants' time-monitoring behaviour. Findings are discussed in the context of recent prospective memory theories.