Assessing stroke patients’ prospective memory using virtual reality

Communication-related aspects of prospective memory: an exploratory factor analysis of prospective memory questionnaires

PURPOSE

Prospective memory (PM) questionnaires are frequently used to evaluate perceptions of PM skills in daily life. This study aimed to systematically investigate communication-specific attributes using pre-existing PM self-rating questionnaires to inform clinicians and researchers about the role of PM in cognitive communicative evaluations.

METHODS

PM-related items from three questionnaires (i.e., Prospective Memory Questionnaire, Comprehensive Assessment of Prospective Memory, and Prospective and Retrospective Memory Questionnaire) were compiled and embedded in Google Forms and distributed to 70 Speech-Language Pathologists (SLPs) with expertise in Cognitive Communicative Disorders across India. Participants first identified items related to communication, and were then contacted to rate the communication-related PM items using a Likert scale for their degree of appropriateness. Responses from 40 SLPs were obtained and subjected to item-content validity index (i-CVI) and exploratory factor analysis (EFA).

RESULTS

Of the 114 PM items, 28 received ratings over 50% for their relevance to communication. Of the 28 items, 21 had an i-CVI score greater than 0.8. After the removal of overlapping content, 14 items were finalized and subjected to EFA, which resulted in four factors: PM failure due to loss of communicative content, PM failure due to loss of communicative intent, PM cost due to ongoing interference, and PM failure linked to the priority of communicative intent.

CONCLUSION

This study highlights communication-related aspects of PM that can be used as a framework for SLPs to assess and research PM skills.

The immersive virtual memory task: Assessing object-location memory in neurological patients using immersive virtual reality

TRIAL REGISTRATION

German Clinical Trials Register identifier: DRKS00024005.

Development of the Virtual Kitchen Protocol for Prospective Memory: a virtual reality-based measure of everyday prospective memory abilities

INTRODUCTION

Prospective memory is the ability to remember to accomplish a task at a specified point in the future. While this cognitive ability has a large impact on daily functioning, it is rarely assessed during neuropsychological evaluations. Furthermore, existing clinical prospective memory measures are few in number and have significant limitations, including applicability to everyday functioning and appropriate norming for older adulthood. There are also many gaps in the literature on prospective memory, such as how environmental factors affect performance across the lifespan.

METHOD

In the current study, we develop and establish a new virtual reality-based measure of prospective memory, the Virtual Kitchen Protocol for Prospective Memory. Young adults (ages 18-29; n = 56), healthy older adults (ages 60-90; n = 94), and clinical older adults (ages 62-90; n = 30) were compared on their performances on both the developed virtual reality prospective memory test and a parallel paper-and-pencil prospective memory test to investigate the impact of test environment across participant group.

RESULTS

The Virtual Kitchen Protocol for Prospective Memory was found to adequately differentiate between young adult, healthy older adult, and clinical older adult populations - suggesting baseline ability for prospective memory assessment in clinical settings with older adults and potential for future improvement of neuropsychological evaluations. Additionally, the developed virtual prospective memory task appeared to mimic environmental factors in everyday life but did not replicate the benefit previously measured in healthy older adults' prospective memory ability in naturalistic settings.

CONCLUSIONS

Overall, the current study built upon extant knowledge of prospective memory in both normal and abnormal aging, suggesting future directions in replicating familiar home environments. Findings provided additional evidence toward future validation of virtual reality assessment tools in clinical neuropsychological evaluations of cognitive abilities, such as prospective memory, with both healthy and clinical older adult populations.

The impact of using implementation intentions as task instructions on prospective memory performance after stroke

Prospective Memory (PM), the ability to remember to carry out intentions in the future, is often impaired after stroke. Little is known about rehabilitation of PM post-stroke with literature limited by small sample sizes and reliance on self-reported memory performance. Implementation intentions may make prospective remembering more automatic and follow a simple if-then structure (if X occurs, then I will do Y), focusing on the cue rather than the task. We aimed to investigate the effect of implementation intentions on PM post-stroke. Twenty-eight individuals with stroke and 27 controls were randomly allocated to a standard instruction or implementation intention condition and completed an assessment battery over two sessions. Implementation intention instructions were provided for PM tasks on the Delayed Message Task, Lexical Decision Prospective Memory Task (LDPMT), and the Virtual Reality Prospective Memory Shopping Task. The implementation intention groups performed better on all PM tasks compared to the standard instruction group, but no results reached statistical significance, likely due to the small sample size. In addition, the implementation intentions group monitored the time significantly more on the LDPMT than those in the standard instruction group.

Prospective Memory and Regional Functional Connectivity in Subcortical Ischemic Vascular Disease

Objectives: Patients with subcortical ischemic vascular disease (SIVD) often have prominent frontal dysfunction. However, it remains unclear how SIVD affects prospective memory (PM), which strongly relies on the frontoparietal network. The present study aimed to investigate PM performance in patients with early stage SIVD as compared to those with Alzheimer's disease (AD) and to older adults with normal cognition, and to explore the neural correlates of PM deficits. Method: Patients with very-mild to mild dementia due to SIVD or AD and normal controls (NC) aged above 60 years were recruited. Seventy-three participants (20 SIVD, 22 AD, and 31 NC) underwent structural magnetic resonance imaging (MRI), cognitive screening tests, and a computerized PM test. Sixty-five of these participants (19 SIVD, 20 AD, and 26 NC) also received resting-state functional MRI. Results: The group with SIVD had significantly fewer PM hits than the control group on both time-based and non-focal event-based PM tasks. Among patients in the very early stage, only those with SIVD but not AD performed significantly worse than the controls. Correlational analyses showed that non-focal event-based PM in SIVD was positively correlated with regional homogeneity in bilateral superior and middle frontal gyri, while time-based PM was not significantly associated with regional homogeneity in any of the regions of interest within the dorsal frontoparietal regions. Conclusions: The findings of this study highlight the vulnerability of non-focal event-based PM to the disruption of regional functional connectivity in bilateral superior and middle frontal gyri in patients with SIVD.

Highlighting the protective or degenerative role of AMPK activators in dementia experimental models

AMP-activated protein kinase (AMPK) is a serine/threonine kinase and a driving or deterrent factor in the development of neurodegenerative diseases and dementia. AMPK affects intracellular proteins like the mammalian target of rapamycin (mTOR). Peroxisome proliferator-activated receptor-γ coactivator 1-α (among others) contributes to a wide range of intracellular activities based on its downstream molecules such as energy balancing (ATP synthesis), extracellular inflammation, cell growth, and neuronal cell death (such as apoptosis, necrosis, and necroptosis). Several studies have looked at the dual role of AMPK in neurodegenerative diseases such as Parkinson's disease (PD), Alzheimer's disease (AD), and Huntington disease (HD) but the exact effect of this enzyme on dementia, stroke, and motor neuron dysfunction disorders has not been elucidated yet. In this article, we review current research on the effects of AMPK on the brain to give an overview of the relationship. More specifically, we review the neuroprotective or neurodegenerative effects of AMPK or AMPK activators like metformin, resveratrol, and 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside on neurological diseases and dementia, which exert through the intracellular molecules involved in neuronal survival or death.

The Assessment and Prediction of Prospective Memory after Stroke

OBJECTIVE

Prospective memory (PM) is the memory used when intentions are to be carried out in the future. Little research has been conducted examining PM after stroke. This study aimed to determine if PM is impaired after stroke through comparison of individuals with stroke to healthy controls. Additionally, it aimed to explore the predictors of PM performance post-stroke.

METHOD

Twenty-eight individuals with stroke and 27 neurologically healthy controls completed the Cambridge Prospective Memory Test (CAMPROMPT), 2 self-report PM questionnaires, and multiple cognitive measures.

RESULTS

Individuals with stroke performed significantly lower on both event- and time-based PM than controls on the CAMPROMPT, indicating PM impairment. Event-based PM after stroke was significantly predicted by age, retrospective memory (RM), and global cognitive function, whereas time-based PM was only predicted by the metacognitive skill of note-taking. Age and note-taking predicted time-based PM for controls, whereas only age predicted event-based PM for control participants.

CONCLUSIONS

The findings of this study have helped to confirm that PM impairment does exist after stroke, particularly when using a standardised PM measure. Furthermore, PM impairment may be predicted by variables, such as age, strategy use, RM, and cognitive ability.

Self-reported prospective memory after stroke

Prospective Memory (PM) is the memory for completing future intentions. This study aimed to compare self-reported PM of individuals with stroke to healthy controls, to determine if PM is impaired after stroke. Additionally, self-reported PM for individuals with stroke was compared to significant-other reports, ascertaining a level of self-awareness of PM function. Twenty-eight individuals with stroke, 25 significant-others, and 27 healthy controls completed the Brief Assessment of PM (BAPM) and the Prospective and Retrospective Memory Questionnaire (PRMQ) as part of a larger study. Individuals with stroke reported significantly more Basic Activities of Daily Living (BADL) PM failures compared to controls on Part A of the BAPM. On Part B, individuals with stroke reported BADL PM failures to be less problematic/important than controls, suggesting a lack of self-awareness into the consequences of PM failure. Individuals with stroke also reported significantly more PM and RM failures compared to controls on the PRMQ. No significant differences were found between individuals with stroke and their significant-others on both the BAPM and PRMQ. Results of this study helped to clarify the previous research and highlighted that individuals with stroke reported more PM failures than controls but underestimated the importance of such memory lapses.

A review of prospective memory in individuals with acquired brain injury

OBJECTIVE

Prospective memory (PM) deficits have emerged as an important predictor of difficulty in daily life for individuals with acquired brain injury (BI). This review examines the variables that have been found to influence PM performance in this population. In addition, current methods of assessment are reviewed with a focus on clinical measures. Finally, cognitive rehabilitation therapies are reviewed, including compensatory, restorative and metacognitive approaches.

METHOD

Preferred reporting items for systematic reviews and meta-analyses guidelines were used to identify studies. Studies were added that were identified from the reference lists of these.

RESULTS

Research has begun to elucidate the contributing variables to PM deficits after BI, such as attention, executive function and retrospective memory components. Imaging studies have identified prefrontal deficits, especially in the region of BA10 as contributing to these deficits. There are now several clinical measures available with good psychometric properties. Rehabilitation techniques have mostly focused on compensatory strategies, but, in addition, some restorative and metacognitive approaches have shown preliminary promise.

CONCLUSIONS

PM deficits are a common and important deficit after BI. Clinical evaluation is recommended and further understanding of rehabilitation techniques is needed.

Location-based prospective memory

This study explores location-based prospective memory. People often have to remember to do things when in a particular location, such as buying tissues the next time they are in the supermarket. For event cognition theory, location is important for structuring events. However, because event cognition has not been used to examine prospective memory, the question remains of how multiple events will influence prospective memory performance. In our experiments, people delivered messages from store to store in a virtual shopping mall as an ongoing task. The prospective tasks were to do certain activities in certain stores. For Experiment 1, each trial involved one prospective memory task to be done in a single location at one of three delays. The virtual environment and location cues were effective for prospective memory, and performance was unaffected by delay. For Experiment 2, each trial involved two prospective memory tasks, given in either one or two instruction locations, and to be done in either one or two store locations. There was improved performance when people received instructions from two locations and did both tasks in one location relative to other combinations. This demonstrates that location-based event structure influences how well people perform on prospective memory tasks.

Is binding decline the main source of the ageing effect on prospective memory? A ride in a virtual town

Objective: This study was designed to improve our understanding of prospective memory (PM) changes in ageing, and to identify the cognitive correlates of PM decline, using a virtual environment, to provide a more realistic assessment than traditional laboratory tasks.

Design: Thirty-five young and 29 older individuals exposed to a virtual town were asked to recall three event-based intentions with a strong link between prospective and retrospective components, three event-based intentions with a weak link, and three time-based intentions. They also underwent retrospective episodic memory, executive functions, binding in working memory, processing speed, and time estimation assessments.

Results: Older individuals recalled fewer intentions than young adults. While age-related PM decline affected the recall of both prospective and retrospective components, the recall of the latter seemed more challenging for older individuals when the link was weak. This PM decline was linked to an age-related decline in the binding process in working memory, as well as in processing speed, executive functioning, and episodic memory, depending on the nature of intentions.

Conclusion: PM appears to be sensitive to ageing, even when the device is thought to be ecological. This decline is particularly pronounced when controlled processes are needed.

Correspondence between Subjective and Objective Cognitive Functioning Following Chemotherapy for Breast Cancer

This study examined subjective and objective cognitive functioning in 26 female breast cancer survivors (BCS) who received chemotherapy treatment that finished .5 to 5 years prior to testing and compared their results to 25 demographically matched women with no history of cancer. Participants were assessed on prospective memory (PM) tasks; neuropsychological tests of processing speed, attentional flexibility with greater cognitive load, executive function, and verbal memory; self-report measures of cognitive dysfunction and PM failures; and distress. The BCS group showed significantly slower speed of processing and reduced attentional flexibility, and reported significantly more cognitive complaints and PM failures than the control group on five of six self-report measures. The groups did not differ on other PM or neuropsychological measures or on a measure of distress. Subjective cognition correlated with some neuropsychological tests and with a virtual reality PM task. Objective cognitive impairments were associated with reduced quality of life in the BCS group. The results provide some evidence of both self-reported impairment and objective cognitive dysfunction following chemotherapy treatment.

Prospective Memory After Stroke: A Scoping Review

The aim of this paper was to review the limited, but growing, literature on prospective memory (PM) following stroke using a scoping study methodology. Multiple databases were systematically searched and yielded 11 studies that were classified as observational (n = 7) or intervention studies (n = 4) and reviewed for quality. PM impairment after stroke was more commonly identified using behavioural measures compared to self-report measures. There were mixed findings regarding the extent and nature of PM impairment poststroke; however, more studies reported impairment for time-based PM, compared to both event- and activity-based PM. Studies examining rehabilitative techniques for PM resulted in mixed findings and were limited as most were case studies of poor methodological quality. Overall previous research in this area was limited as most studies were often underpowered due to small sample sizes, or used single-item measures which may not be robust enough to reliably measure PM impairment. Additionally, the methods used to measure PM were varied and many studies did not control for retrospective memory impairment, which could impact the results, as PM has both a retrospective (remembering both the action and when it needs to be completed) and prospective component (remembering to perform the action when appropriate). In conclusion, PM impairment is apparent poststroke, specifically for time-based PM. However, more research is needed to determine why PM impairment occurs, and how it can be improved.

Virtual reality for cognitive rehabilitation after brain injury: a systematic review

[Purpose] The purpose of this review was to investigate various types of VR programs and their use in cognitive evaluations and interventions for patients with brain injury. [Subjects and Methods] PubMed, Cochrane, and OTseeker electronic databases were searched with the search terms. At of 350 titles and abstracts were retrieved, and 17 articles were selected for this review. Selected articles were assessed on the level of evidence using the Physiotherapy Evidence Database (PEDro) scale. [Results] Articles assessing the impact of cognitive impairments in memory were most commonly found, and VR interventions elicited positive effects in patients with brain injury. [Conclusion] VR can be considered a new tool for cognitive rehabilitation after brain injury. VR interventions also have a number of advantages, e.g. cost-effectiveness, compared to other interventions.

Validation of the Cambridge Prospective Memory Test (Hong Kong Chinese version) for people with stroke

This study aimed to develop and evaluate a Hong Kong Chinese version of the Cambridge Prospective Memory Test (CAMPROMPT-HKCV). Thirty-three subjects at least one year post-stroke participated in the study. They were simultaneously rated on version A of the CAMPROMPT-HKCV by two testers to establish its internal consistency and inter-rater reliability. Raters used the parallel versions of the test (A and B), in rating 10 patients within 2 weeks to establish the parallel form reliability. Another 10 were also assessed on the same day using both version A of the CAMPROMPT-HKCV and the Rivermead Behavioural Memory Test-Chinese version (RBMT-CV) to establish concurrent validity. A new group of 40 stroke patients and 44 healthy controls was recruited to establish its sensitivity and specificity. Results indicated that test-retest reliability on time-based, event-based and total scores, and inter-rater reliability for versions A and B of the test were high. Cronbach's alpha of the event-based score was higher than that of the time-based score. The reliability and concurrent validity of the parallel forms were established. There was a significant difference in performance on CAMPROMPT-HKCV (version A) between the stroke group and the healthy control group. ROC analysis showed that the ability of the cut-off CAMPROMPT-HKCV (total score) to differentiate PM problems was 20.5 (out of 36) with sensitivity at 95.5% and specificity at 55.9%. Further study in developing stratified norms across different age groups in Chinese-speaking stroke patients is recommended.

Novel insights into the rehabilitation of memory post acquired brain injury: a systematic review

Objective: Acquired Brain Injury (ABI) frequently results in memory impairment causing significant disabilities in daily life and is therefore a critical target for cognitive rehabilitation. Current understanding of brain plasticity has led to novel insights in remediation-oriented approaches for the rehabilitation of memory deficits. We will describe 3 of these approaches that have emerged in the last decade: Virtual Reality (VR) training, Computer-Based Cognitive Retraining (CBCR) and Non-Invasive Brain Stimulation (NBS) and evaluate its effectiveness.

Methods: A systematic literature search was completed in regard to studies evaluating interventions aiming to improve the memory function after ABI. Information concerning study content and reported effectiveness were extracted. Quality of the studies and methods were evaluated.

Results: A total of 786 studies were identified, 15 studies met the inclusion criteria. Three of those studies represent the VR technique, 7 studies represent CBCR and 5 studies NBS. All 3 studies found a significant improvement of the memory function after VR-based training, however these studies are considered preliminary. All 7 studies have shown that CBCR can be effective in improving memory function in patients suffering from ABI. Four studies of the 5 did not find significant improvement of the memory function after the use of NBS in ABI patients.

Conclusion: On the basis of this review, CBCR is considered the most promising novel approach of the last decade because of the positive results in improving memory function post ABI. The number of studies representing VR were limited and the methodological quality low, therefore the results should be considered preliminary. The studies representing NBS did not detect evidence for the use of NBS in improving memory function.

Functional correlates of prospective memory in stroke

INTRODUCTION

Prospective memory is the ability to remember actions to be performed later in time or when a certain event occurs. Multiple cognitive processes are involved in prospective memory, and the degree to which automatic or effortful processes are involved may differ for different types of prospective memory tasks. This study aimed to investigate prospective memory (dys)functioning in stroke patients, and to get more insight in which cognitive processes are involved in time- versus event-based prospective memory.

METHODS

We investigated 39 community-dwelling stroke survivors and 53 matched control participants. Assessment included naturalistic and experimental event- and time-based prospective memory tasks, as well as standard neuropsychological measures of (retrospective) memory, processing speed and attention/executive functioning.

RESULTS

41% of the stroke patients performed significantly worse than control participants on prospective memory tasks. Deficits in prospective memory occurred as frequently as impairments in retrospective memory (33%, χ(2)(1, N=39)=3.4, p=.066), and more often than impairments in attention/executive functioning (15%, χ(2)(1, N=39)=5.2, p=.022) and speed of processing (23%, χ(2)(1, N=39)=6.5, p=.011). Regression analyses showed that event-based ('focal') prospective memory is supported by retrospective memory, indicating that it is a relatively simple and automatic process. Time-based (non-'focal') prospective memory proved to be a more complex process, requiring active monitoring of the environment. Performance was predicted by speed of processing, attention/executive functioning and retrospective memory. Thirteen percent of the patients suffered from selective prospective memory impairment, which was associated with damage to the superior temporal gyrus.

CONCLUSIONS

Impairment of prospective memory occurs frequently after stroke. Different cognitive operations are involved in distinct types of prospective memory. Results fit within the multi-process framework of prospective memory and help further specify its contents.

The use of virtual reality for episodic memory assessment: effects of active navigation

Episodic memory was assessed using Virtual Reality (VR). Forty-four (44) subjects visualized a target virtual apartment containing specific objects in each room. Then they visualized a second virtual apartment comprised of specific objects and objects shared by the two apartments. Subjects navigated in the virtual apartments in one of the following two conditions: active and passive. Four main episodic memory components were scored from the VR exposures: (1) learning effect; (2) active forgetting effect; (3) strategies at encoding and at retrieval; and (4) false recognitions (FRs). The effect of navigation mode (active vs. passive) on each memory component was examined. Active subjects had better learning and retrieval (recognition hits) performances compared to passive subjects. A beneficial effect of active navigation was also observed on the source-based FR rates. Active subjects made fewer source-based FRs compared to passive subjects. These overall results for the effect of active navigation are discussed in terms of the distinction between item-specific and relational processing.

The ecological and construct validity of a newly developed measure of executive function: the Virtual Library Task

Virtual reality (VR) assessment paradigms have the potential to address the limited ecological validity of pen and paper measures of executive function (EF) and the pragmatic and reliability issues associated with functional measures. To investigate the ecological validity and construct validity of a newly developed VR measure of EF, the Virtual Library Task (VLT); a real life analogous task--the Real Library Task (RLT); and five neuropsychological measures of EF were administered to 30 patients with traumatic brain injury (TBI) and 30 healthy Controls. Significant others for each participant also completed the Dysexecutive Questionnaire (DEX), which is a behavioral rating scale of everyday EF. Performances on the VLT and the RLT were significantly positively correlated indicating that VR performance is similar to real world performance. The TBI group performed significantly worse than the Control group on the VLT and the Modified Six Elements Test (MSET) but the other four neuropsychological measures of EF failed to differentiate the groups. Both the MSET and the VLT significantly predicted everyday EF suggesting that they are both ecologically valid tools for the assessment of EF. The VLT has the advantage over the MSET of providing objective measurement of individual components of EF.

Use of Virtual Reality Tasks to Assess Prospective Memory: Applicability and Evidence

Virtual reality (VR) is a term used to describe computer-generated virtual environments that the patient can explore and interact with in real time. In this review, the use of VR to construct ecologically valid tasks for use in neuropsychological assessment and rehabilitation is discussed with particular reference to the measurement of prospective memory (PM) abilities. PM, the ability to act upon delayed intentions, is an example of an everyday ability requiring the coordination of a different cognitive processes that is ideally suited to research and rehabilitation using VR. Studies investigating PM and related abilities in patients with brain impairments are surveyed, and it is established that there is evidence for the utility of applying VR procedures to measure prospective remembering. Future research could usefully focus on the construction of a standardised testing procedure with credible psychometric characteristics. In particular, there needs to be evidence for the criterion validity of such tests. Another potential research avenue is the evaluation of VR platforms as tools to teach memory skills and awareness of impairments. It is concluded that difficulties in adapting programs to specific clinical needs, technical issues, and the reluctance of many clinicians to use computer-based technology need to be overcome before VR is likely to be widely used to measure PM.

The role of rostral prefrontal cortex in prospective memory: a voxel-based lesion study

Patients with lesions in rostral prefrontal cortex (PFC) often experience problems in everyday-life situations requiring multitasking. A key cognitive component that is critical in multitasking situations is prospective memory, defined as the ability to carry out an intended action after a delay period filled with unrelated activity. The few functional imaging studies investigating prospective memory have shown consistent activation in both medial and lateral rostral PFC but also in more posterior prefrontal regions and non-frontal regions. The aim of this study was to determine regions that are necessary for prospective memory performance, using the human lesion approach. We designed an experimental paradigm allowing us to assess time-based (remembering to do something at a particular time) and event-based (remembering to do something in a particular situation) prospective memory, using two types of material, words and pictures. Time estimation tasks and tasks controlling for basic attention, inhibition and multiple instructions processing were also administered. We examined brain-behaviour relationships with a voxelwise lesion method in 45 patients with focal brain lesions and 107 control subjects using this paradigm. The results showed that lesions in the right polar prefrontal region (in Brodmann area 10) were specifically associated with a deficit in time-based prospective memory tasks for both words and pictures. This deficit could not be explained by impairments in basic attention, detection, inhibition or multiple instruction processing, and there was also no deficit in event-based prospective memory conditions. In addition to their prospective memory difficulties, these polar prefrontal patients were significantly impaired in time estimation ability compared to other patients. The same region was found to be involved using both words and pictures, suggesting that right rostral PFC plays a material nonspecific role in prospective memory. This is the first lesion study showing that rostral PFC is crucial for time-based prospective memory. The findings suggest that time-based and event-based prospective memory might be supported at least in part by distinct brain regions. Two particularly plausible explanations for the deficit rest upon a possible role for polar prefrontal structures in supporting in time estimation, and/or in retrieving an intention to act. More broadly, the results are consistent with the view that the deficit of rostral patients in multitasking situations might at least in part be explained by a deficit in prospective memory.

Ecological prospective memory assessment in patients with traumatic brain injury

PRIMARY OBJECTIVE

Prospective memory (PM) impairments are often observed after traumatic brain injury (TBI). Although PM is crucial for daily functioning, few sensitive, valid and ecological clinical tests are available. To address these concerns, the authors developed a PM task, the TEMP, using naturalistic stimuli, in which each PM phase and component is evaluated independently in time- and event-based conditions.

MAIN OUTCOMES AND RESULTS

The results show that moderate and severe TBI patients (n = 30), evaluated after spontaneous neurological recovery, experienced problems in learning the delayed intentions content and retrieving these intentions in the right context (prospective component), especially in the time-based condition. They also recalled fewer associated actions (retrospective component), but only in the time-based condition. Correlations revealed that the retrospective component was mainly supported by episodic retrospective memory processes, while the prospective component was supported by episodic retrospective memory processes, along with attentional and executive functions. Moreover, there was a significant correlation between performance on the TEMP and results on a questionnaire assessing PM functioning in daily living completed by participants' relatives.

CONCLUSIONS

The TEMP therefore appears to be a sensitive tool for assessing PM problems that combines internal and ecological validity.

Validation of a new measure of prospective memory: the Royal Prince Alfred Prospective Memory Test

Prospective memory problems are common in patients with brain injury, but appropriate measures are limited. The reliability and validity of the newly designed Royal Prince Alfred Prospective Memory Test (RPA-ProMem), which has three alternate versions, was investigated in 20 healthy volunteers and 20 neurological patients with everyday prospective memory problems. The RPA-ProMem was found to be easy to score reliably (inter-rater reliability = .90) and its three versions were well matched (delayed alternate-form reliability = .71). Test validity and sensitivity to patient deficits were also supported. This new measure of prospective memory should be particularly useful in situations that require repeated assessments, such as evaluation of rehabilitation efforts.

The assessment and rehabilitation of prospective memory problems in people with neurological disorders: a review

People with neurological disorders often report difficulty with prospective memory (PM), that is, remembering to do things they had intended to do. This paper briefly reviews the literature regarding the neuropsychology of PM function, concluding that from the clinical perspective, PM is best considered in terms of its separable but interacting mnemonic and executive components. Next, the strengths and limitations in the current clinical assessment of PM, including the assessment of component processes, desktop analogues of PM tasks, and naturalistic PM tasks, are outlined. The evidence base for the rehabilitation of PM is then considered, focusing on retraining PM, using retrospective memory strategies, problem-solving training, and finally, electronic memory aids. It is proposed that further research should focus on establishing the predictive validity of PM assessment, and refining promising rehabilitation techniques.

An assessment of prospective memory retrieval in women with chronic fatigue syndrome using a virtual-reality environment: an initial study

People with chronic fatigue syndrome (CFS) have increased rates of depression, anxiety, and illness intrusiveness; they may also suffer from cognitive problems such as retrospective memory (RM) deficits and concentration difficulties that can stem from diminished information-processing capability. We predicted that this diminished capacity may also lead to deficits in other cognitive functions, such as prospective memory (ProM). Event-, time-, and activity-based ProM was assessed in 11 women with CFS and 12 healthy women using a computer-generated virtual environment (VE). RM was assessed using a free-recall test, and subjective assessment of both ProM and RM was assessed by questionnaire. Groups were equivalent in age and measures of IQ. People with CFS performed slightly worse than healthy controls on both the event- and time-based ProM measures, although these were not statistically significant. However, the CFS group performed significantly worse than the healthy controls on both the free recall-task and on subjective assessment of both RM and ProM. Women with CFS do have some subtle decrements in memory, particularly RM. However, it is possible that the decrements found in the present sample would be greater in real life. Further studies utilizing both healthy controls and illness controls are now needed to ascertain how sensitive the VE measure is and to inform the development of tasks in the VE that place progressively increasing demands on working memory capacity.

A computer-based procedure for assessing functional cognitive skills in patients with neurological injuries: The virtual street

PRIMARY OBJECTIVE

The aim of the present investigation was to construct and pilot test a computer-based multi-tasking procedure that could be used to assess the ability of patients with neurological damage to remember instructions in the real world.

RESEARCH DESIGN

A simulated street scene was constructed from a network of photographs and sounds that patients could move through using a touch screen. Three patients with severe, moderate or mild cognitive impairment were assessed on a range of neuropsychological tests and three multi-tasking procedures based in the street. The performance of each patient was compared with that of a matched control.

PROCEDURE

Three tests were administered, each of which involved 'walking' along the length of the street once. On the first test, participants were given up to five errands to remember while moving along the street. On the other two tests they were given three instructions to carry out repeatedly (e.g. 'Record the name of the nearest shop when you hear a dog bark'). In one condition they were given the three instructions on a sheet they could consult and in the other they had no list.

OUTCOMES AND RESULTS

In each case the patient performed more poorly on the multi-tasking test than the matched control. The patients' performance on the computer-based tests was consistent with clinical descriptions of their memory-related deficits.

CONCLUSION

The results illustrate the way in which computer presentation of naturalistic stimuli can be used to construct flexible and standardized tests of memory functioning that have enhanced ecological validity.

Virtual enriched environments in paediatric neuropsychological rehabilitation following traumatic brain injury: Feasibility, benefits and challenges

A frequent consequence of traumatic brain injury (TBI) is a significant reduction in patients' cerebral activation/arousal, which clinicians agree is not conducive to optimal rehabilitation outcomes. In the context of paediatric rehabilitation, sustained periods of inactivity are particularly undesirable, as contemporary research has increasingly called into question the Kennard principle that youth inherently promotes greater neural plasticity and functional recovery following TBI. Therefore, the onus to create rehabilitation conditions most conducive to harnessing plasticity falls squarely on the shoulders of clinicians. Having noted the efficacy of environmental enrichment in promoting neural plasticity and positive functional outcomes in the animal literature, some researchers have suggested that the emerging technology of Virtual Reality (VR) could provide the means to increase patients' cerebral activation levels via the use of enriched Virtual Environments (VEs). However, 10 years on, this intuitively appealing concept has received almost no attention from researchers and clinicians alike. This paper overviews recent research on the benefits of enriched environments in the injured brain and identifies the potential and challenges associated with implementing VR-based enrichment in paediatric neuropsychological rehabilitation.

Prefrontal cortex involvement in the event-based prospective memory: evidence from patients with lesions in the prefrontal cortex

PRIMARY OBJECTIVE

The aim of the present study was to investigate the event-based prospective memory (EBPM) and time-based prospective memory (TBPM) in patients with lesion in prefrontal cortex (PFC) and test the hypothesis that the prefrontal cortex is involved in the prospective memory (PM) network.

RESEARCH DESIGN

The performance of patients with lesion in PFC (n = 30) was compared with that of a demographically matched control group (n = 30).

METHODS AND PROCEDURES

A neuropsychological battery of tests including EBPM and TBPM tasks were administered to both groups.

MAIN OUTCOME AND RESULTS

The group with lesion in PFC were significantly impaired in EBPM, but insignificantly impaired in TBPM tasks. There was no difference in performance of EBPM and TBPM tasks between the patients with lesion in the left and the right PFC.

CONCLUSIONS

These results suggest that the patients with lesion in PFC were impaired in EBPM, but not in TBPM, implying that EBPM and TBPM may have different neural substrates. It is possible that PFC is more selectively involved in EBPM, but less in TBPM.

Impairments in prospective and retrospective memory following stroke

Prospective memory (PM) is the ability to carry out a planned intention at a future time. We studied PM deficits in a group of community-dwelling stroke survivors compared with normal controls. Twelve stroke patients and 12 matched controls performed a series of tests assessing executive function, prospective (PM) and retrospective memory (RM). Patients performed less well than controls on laboratory measures of PM and associative RM; they also showed deficits on standard tests of RM and executive control. The groups did not differ on more structured clinical measures of executive function, RM, PM or self-rated PM and RM. The results are discussed in terms of an impairment in the ability to 'self-initiate' effortful cognitive processes.

Reliability and normative data for the comprehensive assessment of prospective memory (CAPM)

The Comprehensive Assessment of Prospective Memory (CAPM) is a questionnaire designed to evaluate frequency of prospective memory (PM) failures in people with brain injury. The aims of this study were to investigate the psychometric properties of the CAPM, including test-retest reliability and internal consistency, and to establish normative data by comparing CAPM scores between groups on the basis of sex, age, and education. Data were collected on 95 people aged 15-60 years living in the community, with no history of brain injury, using the CAPM. The results showed that the test-retest reliability and internal consistency for the CAPM were within acceptable ranges, indicating that the CAPM provides a stable and homogenous measure of an individual's self-report of PM failures. Normative data are presented in two age groups based on the significant difference found between the age groups 15-30 years and 31-60 years. These established norms can be used to describe perceived or observed behaviours indicative of PM failure in patients with brain injury by comparing CAPM ratings from significant others with the norms. The CAPM questionnaire provides researchers or clinicians with a stable and reliable assessment option that specifically focuses on PM for individuals with brain injury.

Novel design of interactive multimodal biofeedback system for neurorehabilitation

A previous design of a biofeedback system for Neurorehabilitation in an interactive multimodal environment has demonstrated the potential of engaging stroke patients in task-oriented neuromotor rehabilitation. This report explores the new concept and alternative designs of multimedia based biofeedback systems. In this system, the new interactive multimodal environment was constructed with abstract presentation of movement parameters. Scenery images or pictures and their clarity and orientation are used to reflect the arm movement and relative position to the target instead of the animated arm. The multiple biofeedback parameters were classified into different hierarchical levels w.r.t. importance of each movement parameter to performance. A new quantified measurement for these parameters were developed to assess the patient's performance both real-time and offline. These parameters were represented by combined visual and auditory presentations with various distinct music instruments. Overall, the objective of newly designed system is to explore what information and how to feedback information in interactive virtual environment could enhance the sensorimotor integration that may facilitate the efficient design and application of virtual environment based therapeutic intervention.

A controlled clinical comparison of attention performance in children with ADHD in a virtual reality classroom compared to standard neuropsychological methods

In this initial pilot study, a controlled clinical comparison was made of attention perforance in children with attention deficit-hyperactivity disorder (ADHD) in a virtual reality (VR) classroom. Ten boys diagnosed with ADHD and ten normal control boys participated in the study. Groups did not significantly differ in mean age, grade level, ethnicity, or handedness. No participants reported simulator sickness following VR exposure. Children with ADHD exhibited more omission errors, commission errors, and overall body movement than normal control children in the VR classroom. Children with ADHD were more impacted by distraction in the VR classroom. VR classroom measures were correlated with traditional ADHD assessment tools and the flatscreen CPT. Of note, the small sample size incorporated in each group and higher WISC-III scores of normal controls might have some bearing on the overall interpretation of results. These data suggested that the Virtual Classroom had good potential for controlled performance assessment within an ecologically valid environment and appeared to parse out significant effects due to the presence of distraction stimuli.

Is Learning and Memory Different in a Virtual Environment?

It has been suggested that virtual reality may provide a medium for producing neuropsychological measures with greater ecological validity. The present study examined the usefulness of virtual reality (VR) to assess learning and memory in individuals with traumatic brain injury (TBI). A total of 20 TBI participants were compared with 20 healthy controls on their ability to learn and recall 16 target items presented within a VR-based generic office environment. The results indicated that VR memory testing accurately distinguished the TBI group from controls. Additionally, non-memory-impaired TBI participants acquired targets at the same rate as HC participants. Finally, there was a significant relationship between the VR Office and a standard neuropsychological measure of memory, suggesting the construct validity of the task. These findings suggest that the VR Office provides a viable medium for measuring learning and memory. The present results provide preliminary support for the ecological validity of the VR Office, which ultimately can improve assessment of real-world functioning following TBI.

Differential involvement of regions of rostral prefrontal cortex (Brodmann area 10) in time- and event-based prospective memory

Rostral prefrontal cortex (approximating Brodmann area 10) has been shown repeatedly to have a role in the maintenance and realization of delayed intentions that are triggered by event cues (i.e., event-based prospective memory). The cerebral organization of the processes associated with the use of time cues (time-based prospective memory) has however received less attention. In two positron emission tomography (PET) studies we therefore examined brain activity associated with time- and event-based prospective memory tasks. In the time-based condition of the first study, young healthy volunteers were asked to make a prospective response based on their self-estimation of the passage of time while engaged in an attention-demanding ongoing activity. In the time-based condition of the second study, participants had a clock available in the ongoing task display and did not need to estimate the time for the prospective response. In the event-based condition of both studies, participants were asked to make a prospective response when prospective cues were presented in ongoing trials. Both studies showed activation differences in rostral prefrontal cortex according to whether the task was time- or event-based. In study one, an area of left superior frontal gyrus was more active in the time-based condition. In study two, three rostral prefrontal regions were more active in the time-based condition: right superior frontal gyrus, anterior medial frontal lobe and anterior cingulate gyrus. A region in left superior frontal gyrus, different from the area found in the first study, was more active in the event-based condition. These results indicate involvement of multiple brain regions of rostral prefrontal cortex in time- and event-based prospective memory. The results are interpreted as reflecting the differing processing demands made by event- or time-based prospective memory tasks, and the differing demands of time-based tasks according to whether a clock is present as an aid.

The effects of distraction on prospective remembering following traumatic brain injury assessed in a simulated naturalistic environment

The aim of this investigation was to assess deficits in prospective remembering following chronic traumatic brain injuries (TBI), under conditions of high and low distraction. We constructed a virtual shopping precinct from photographs, sounds, and video segments linked together. The street was divided into halves, a low distraction zone and a high distraction zone (with increased visual and auditory noise). Twenty persons with TBI (7 severe, 7 very severe, 6 extremely severe) and 20 matched controls completed ongoing and prospective memory tasks while "walking" along the street. In the ongoing task, participants were given ten errands to complete with a checklist accessible at any time. The prospective component required responding to three targets that appeared repeatedly. As predicted, the TBI group performed both the ongoing and the prospective components of the street task poorly compared with the controls and was more affected by distractions. The results suggest that the real-life deficits in memory skills reported by persons with TBI may become more apparent when remembering engages executive processes and that computer simulations can be used to construct sensitive measures of practical memory abilities.

Virtual reality in brain damage rehabilitation: review

Given the high incidence of brain injury in the population, brain damage rehabilitation is still a relatively undeveloped field. Virtual reality (VR) has the potential to assist current rehabilitation techniques in addressing the impairments, disabilities, and handicaps associated with brain damage. The main focus of much of the exploratory research performed to date has been to investigate the use of VR in the assessment of cognitive abilities, but there is now a trend for more studies to encompass rehabilitation training strategies. This review describes studies that have used VR in the assessment and rehabilitation of specific disabilities resulting from brain injury, including executive dysfunction, memory impairments, spatial ability impairments, attention deficits, and unilateral visual neglect. In addition, it describes studies that have used VR to try to offset some of the handicaps that people experience after brain injury. Finally, a table is included which, although not an exhaustive list of everything that has been published, includes many more studies that are relevant to the use of VR in the assessment and rehabilitation of brain damage. The review concludes that the use of VR in brain damage rehabilitation is expanding dramatically and will become an integral part of cognitive assessment and rehabilitation in the future.