Memory impairment following an acquired brain injury can negatively impact daily living and quality of life—but can be reduced by memory rehabilitation. Here we review the literature on four approaches for memory rehabilitation and their associated strategies: (1) the restorative approach, aimed at a return to pre-morbid functioning, (2) the knowledge acquisition approach, involving training on specific information relevant to daily life, (3) the compensatory approach, targeted at improving daily functioning, and (4) the holistic approach, in which social, emotional, and behavioral deficits are addressed alongside cognitive consequences of acquired brain injury. Each memory rehabilitation approach includes specific strategies such as drill and practice (restorative), spaced retrieval (knowledge acquisition), memory aids (compensatory), or a combination of psychotherapy and cognitive strategies (holistic). Past research has demonstrated mixed support for the use of restorative strategies to improve memory function whereas knowledge acquisition strategies show promising results on trained tasks but little generalization to untrained tasks and activities of daily living. Compensatory strategies remain widely used but require intensive training to be effectively employed. Finally, the holistic approach is becoming more widespread due to improvements in psychosocial wellbeing, yet there are considerable resource and cost requirements. Several factors can influence rehabilitation outcomes including metacognition and emotional disturbances. Considerations for future research to improve the applicability of strategies for memory rehabilitation include assessing memory impairment severity, examining memory needs in daily life, and exploring the long-term effects of memory rehabilitation.

Author(s): Gopi, Yashoda; Wilding, Edward; Madan, Christopher R | Abstract: Remembering names is generally considered a difficult task. The face-name mnemonic strategy enhances encoding of face-name associations using a name transformation, a prominent facial feature, and interactive imagery. Name recall involves mentally retracing these steps. However, the components of the face-name mnemonic strategy are relatively unexplored. The present study tested the effectiveness of variants of the face-name mnemonic strategy in comparison to an uninstructed group for learning face-name associations. Experiment 1 demonstrated a significant advantage of the name-transformation mnemonic strategy compared to the uninstructed approach. Experiment 2 further examines the name-transformation mnemonic strategy with young adults. This study demonstrates the effectiveness of a variation of the face-name mnemonic strategy with implications for memory rehabilitation interventions.

Encoding variability refers to the situation in which repeated items are processed in different ways on each presentation. Superior memory performance resulting from encoding variability is sometimes argued to underlie important phenomena in human memory such as the spacing effect. However, the memory benefits of encoding variability are often elusive. Here we investigated encoding variability in ten experiments in which participants studied words with the same or different orienting tasks across repetitions. We have found the benefits of variable encoding to depend on the number of learning cycles and the retrieval demands at test. These results are interpreted in light of a distinction between different components of memory representations established at study, suggesting that encoding variability promoted via different orienting tasks-as implemented in the present study-fosters more elaborate encoding of semantic features. This augmented semantic component benefits memory performance only when a memory test is used that taps predominantly semantic features of memory representations, minimizing the role of contextual and relational factors. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Author(s): Zhang, RuoChong; Madan, Christopher R; Wilding, Edward | Abstract: In a memory task, focusing on to-be-remembered information while concurrently engaging in a secondary task may result in impaired memory, possibly due to limited cognitive resources. However, previous research has demonstrated circumstances where interleaving a secondary task can impair immediate recall but enhance long-term retention. This suggests that the type and difficulty of the secondary task also affected memory. The present study explores the effect of processing a secondary task on recall. In Experiment 1, increasing complexity of the secondary task resulted in a detrimental effect on delayed free recall. Experiment 2 and 3 examine the effect of increasing cognitive load with faster stimuli presentation on delayed free recall and serial recall. These findings have implications for theories advocating the domain-general nature of cognitive resources.

Event-related potential (ERP) signatures of preparation to retrieve episodic memories have been identified in several studies. A common finding is relatively more positive-going ERP activity over right-frontal sites when people prepare for episodic rather than semantic retrieval. This activity has been linked to the process of retrieval mode - a retrieval set that ensures subsequent events are treated as cues for episodic retrieval. This experiment was designed to test one explanation for why this putative index of retrieval mode was not observed in two recent experiments. Towards this end, ERPs were recorded time-locked to different task-cues indicating which of two retrieval tasks participants should prepare to complete. Each task-cue was followed by a retrieval-cue that required a memory judgment. Departures from the designs of the two studies in which null ERP results were obtained were intra-trial timings and the order in which task cues were presented. Frequentist statistics revealed that ERPs elicited by the task-cues did index preparation to retrieve. The topographies of these activities, however, did not overlap markedly with that of the putative index of retrieval mode reported previously. Bayesian analyses, moreover, provided little compelling evidence for a signature of retrieval mode. These outcomes prompt consideration of how ERP sensitivities to preparatory retrieval processing should be characterized.

The sensitivity of event-related potentials (ERPs) to the processes of recollection and familiarity has been explored extensively, and ERPs have been used subsequently to infer the contributions these processes make to memory judgments under a range of different circumstances. It has also been shown that event-related fields (ERFs, the magnetic counterparts of ERPs) are sensitive to memory retrieval processes. The links between ERFs, recollection and familiarity are, however, established only weakly. In this experiment, the sensitivity of ERFs to these processes was investigated in a paradigm used previously with ERPs. An early frontally distributed modulation varied with memory confidence in a way that aligns it with the process of familiarity, while a later parietally distributed modulation tracked subjective claims of recollection in a way that aligns it with this process. These data points strengthen the argument for employing ERFs to assess the contributions these processes can make to memory judgments, as well as for investigating the nature of the processes themselves.

According to cortical reinstatement accounts, neural processes engaged at the time of encoding are re-engaged at the time of memory retrieval. The temporal precision of event-related potentials (ERPs) has been exploited to assess this possibility, and in this study ERPs were acquired while people made memory judgments to visually presented words encoded in two different ways. There were reliable differences between the scalp distributions of the signatures of successful retrieval of different contents from 300 to 1100 ms after stimulus presentation. Moreover, the scalp distributions of these content-sensitive effects changed during this period. These findings are, to our knowledge, the first demonstration in one study that ERPs reflect content-specific processing in two separable ways: first, via reinstatement, and second, via downstream processes that operate on recovered information in the service of memory judgments.

A widely held assumption is that memory retrieval is aided by cognitive control processes that are engaged flexibly in service of memory retrieval and memory decisions. While there is some empirical support for this view, a notable exception is the absence of evidence for the flexible use of retrieval control in functional neuroimaging experiments requiring frequent switches between tasks with different cognitive demands. This absence is troublesome in so far as frequent switches between tasks mimic some of the challenges that are typically placed on memory outside the laboratory. In this experiment we instructed participants to alternate frequently between three episodic memory tasks requiring item recognition or retrieval of one of two different kinds of contextual information encoded in a prior study phase (screen location or encoding task). Event-related potentials (ERPs) elicited by unstudied items in the two tasks requiring retrieval of study context were reliably different, demonstrating for the first time that ERPs index task-specific processing of retrieval cues when retrieval goals change frequently. The inclusion of the item recognition task was a novel and important addition in this study, because only the ERPs elicited by unstudied items in one of the two context conditions diverged from those in the item recognition condition. This outcome constrains functional interpretations of the differences that emerged between the two context conditions and emphasises the utility of this baseline in functional imaging studies of retrieval processing operations.

At retrieval, people can adopt a retrieval orientation by which they recreate the mental operations used at encoding. Monitoring by retrieval orientation leads to assessing all test items for qualities related to the encoding task, which enriches foils with some of the qualities already possessed by targets. We investigated the consequences of adopting a retrieval orientation under conditions of repeated monitoring of the same foils. Participants first processed foils in the context of one of two tests encouraging different retrieval orientations. The foils were then re-used on a subsequent test in which retrieval orientation either matched or mismatched that adopted on the first test. In the aggregate data, false alarms for repeated foils were higher when there was a match between the retrieval orientations on both tests. This demonstrates that when retrieval orientation enriches foils with target like characteristics, it can backfire when repeated monitoring of the same foils is required. (C) 2016 Elsevier Inc. All rights reserved.

It has been proposed that people employ a common set of sustained operations (retrieval mode) when preparing to remember different kinds of episodic information. In two experiments, however, there was no evidence for the pattern of brain activity commonly assumed to index these operations. In both experiments event-related potentials (ERPs) were recorded time-locked to alternating preparatory cues signalling that participants should prepare for different retrieval tasks. One cue signalled episodic retrieval: remember the location where the object was presented in a prior study phase. The other signalled semantic retrieval: identify the location where the object is most commonly found (Experiment 1) or identify the typical size of the object (Experiment 2). In both experiments, only two trials of the same task were completed in succession. This enabled ERP contrasts between ‘repeat’ trials (the cue on the preceding trial signalled the same retrieval task), and ‘switch’ trials (the cue differed from the preceding trial). There were differences between the ERPs elicited by the preparatory task cues in Experiment 1 only: these were evident only on switch trials and comprised more positive-going activity over right-frontal scalp for the semantic than for the episodic task. These findings diverge from previous outcomes where the activity differentiating cues signalling preparation for episodic or semantic retrieval has been restricted to right-frontal scalp sites, comprising more positive-going activity for the episodic than for the semantic task. While these findings are consistent with the view that there is not a common set of operations engaged when people prepare to remember different kinds of episodic information, an alternative account is offered here, which is that these outcomes are a consequence of structural and temporal components of the experiment designs.

One influential explanation for the costs incurred when switching between tasks is that they reflect interference arising from completing the previous task-known as task-set inertia. We report a novel approach for assessing task-set inertia in a memory experiment using event-related potentials (ERPs). After a study phase, participants completed a test block in which they switched between a memory task (retrieving information from the study phase) and a perceptual task. These tasks alternated every two trials. An ERP index of the retrieval of study information was evident in the memory task. It was also present on the first trial of the perceptual task but was markedly attenuated on the second. Moreover, this task-irrelevant ERP activity was positively correlated with a behavioral cost associated with switching between tasks. This real-time measure of neural activity thus provides direct evidence of task-set inertia, its duration, and the functional role it plays in switch costs.

It has been suggested that retrieving episodic information can involve adopting a cognitive state or set: retrieval mode. In a series of studies, an event-related potential (ERP) index of retrieval mode has been identified in designs which cue participants on a trial-by-trial basis to switch between preparing for and then completing an episodic or non-episodic retrieval task. However, a confound in these studies is that along with task type the content of what is to be retrieved has varied. Here we examined whether the ERP index of retrieval mode remains when the contents of an episodic and non-episodic task are highly similar – both requiring a location judgement. In the episodic task participants indicated the screen location where words had been shown in a prior study phase (left/right/new); whereas in the perceptual task they indicated the current screen location of the word (top/middle/bottom). Consistent with previous studies the ERPs elicited while participants prepared for episodic retrieval were more positive-going at right-frontal sites than when they prepared for the perceptual task. This index was observed, however, on the first trial after participants had switched tasks, rather than on the second trial, as has been observed previously. Potential reasons for this are discussed, including the critical manipulation of similarity in contents between tasks, as well as the use of a predictable cue sequence.

One influential explanation for the costs incurred when switching between tasks is that they reflect interference arising from completing the previous task—known as task-set inertia. We report a novel approach for assessing task-set inertia in a memory experiment using event-related potentials (ERPs). After a study phase, participants completed a test block in which they switched between a memory task (retrieving information from the study phase) and a perceptual task. These tasks alternated every two trials. An ERP index of the retrieval of study information was evident in the memory task. It was also present on the first trial of the perceptual task but was markedly attenuated on the second. Moreover, this task-irrelevant ERP activity was positively correlated with a behavioral cost associated with switching between tasks. This real-time measure of neural activity thus provides direct evidence of task-set inertia, its duration, and the functional role it plays in switch costs.

The retrieval processes supporting recognition memory for faces were investigated using event-related potentials (ERPs). The focus for analyses was ERP old/new effects, which are the differences between neural activities associated with correct judgments to old (studied) and new (unstudied) test stimuli. In two experiments it was possible to identify three old/new effects that behaved as neural indices of the process of recollection. In both experiments there was one old/new effect that behaved as an index of the process of familiarity. These outcomes are relevant to the ongoing debate about the functional significance of ERP old/new effects and the implications that scalp-recorded electrophysiological data have for theories of the processes supporting long-term memory judgments.

The links between control over recollection and working memory capacity (WMC) were investigated using event-related potentials (ERPs) and behavioural assays. Electrophysiological evidence for a relationship between greater control over recollection and higher scores on a measure of WMC was obtained. In addition, people with high WMC who first completed a task requiring cognitive control showed no electrophysiological evidence for control over recollection on a subsequent task. This outcome suggests a causal link between control over recollection and the availability of WMC, in so far as the consequence of completing the first task was a reduction in WMC that impacted on completion of the subsequent task. All participants also completed a final recall task, on which they were asked to remember the stimuli they had encountered during the task in which ERPs were acquired. Only those participants who showed electrophysiological evidence for the exertion of control over recollection showed differences between the likelihoods of recalling stimuli over which control either had or had not been exerted. In combination, the findings provide insights into the conditions under which control over recollection occurs, and make a strong argument for including individual difference measures of resource availability when assessing how and when people exert control over what they remember.

Judgments of learning (JOLs) are assessments of how well materials have been learned. Although a wide body of literature has demonstrated a reliable correlation between memory performance and JOLs; relatively little is known about the nature of this link. Here, we investigate the relationship between JOLs and the memory retrieval processes engaged on a subsequent memory test. Participants first studied cue target word pairs and assigned JOLs to each. Later, memory for the cue word in each pair was assessed using an old/new recognition memory task, and electrophysiological measures of familiarity and recollection were examined. Recognition accuracy was superior for materials given high rather than low JOLs. Analysis of event-related potentials (ERPs) revealed that for both high and low JOL items, successful recognition elicited correlates of familiarity (the mid-frontal effect) and recollection (the left-parietal effect). Importantly, however, the magnitude of the familiarity correlate was equal for high and low JOL items, whereas the magnitude of the recollection correlate was significantly larger for items given high JOLs. These findings demonstrate that JOLs made at study correlate with memory retrieval at test-but that this correlation is specific to recollection. The electrophysiological data support the broader view that participants focus on contextual cues when making JOLs, which may later aid recollection.

Electrophysiological correlates of successful episodic retrieval were measured in an experiment where participants switched frequently between two different episodic retrieval conditions. They completed three trials of each condition before switching to the other condition. The key contrasts were between neural indices of successful retrieval that were separated according to the number of successive trials of the same condition that had been completed. An electrophysiological correlate of recollection-the left-parietal event-related potential (ERP) old/new effect-was smaller on the first and second trial than on the third successive trial that participants completed for each condition. This ERP old/new effect is assumed to index the extent to which recollection has occurred, and this outcome suggests that control over recovery of task-relevant episodic content is compromised when additional cognitive demands are imposed around the time of retrieval.