The Roles of Retrieval Practice Versus Errorless Learning in Strengthening Lexical Access in Aphasia

The serial order system in word production and working memory: A case series approach

Serial order is important in verbal behavior, such as sequencing words in working memory (WM) or arranging phonemes during speech. In both WM and word production, distinct processes are found for item identity and their serial order. In the current study, we investigated whether a shared system supports the serial order of verbal items (phonemes or words) across cognitive functions (WM and production) and tasks (repetition and naming). We recruited 30 participants with chronic stroke-induced aphasia. We examined WM abilities to recall item and serial order information using immediate serial recall tasks of words. We also assessed the ability to accurately sequence phonemes in word repetition and naming tasks, with its impairment indexed by the proportion of misordered phonemes among all incorrect phonemes compared to chance in phonologically related word and nonword responses. We examined how variability of this index of serial order impairment in repetition and naming relates to item and serial order WM capacities. Our findings reveal that serial order WM capacity, but not item WM capacity, was associated with the severity of serial order impairment in repetition, indicating a shared serial order system for WM and repetition. We also found that item WM, but not serial order WM, was associated with serial order impairment in naming, implying an item WM buffer for phonemic sequencing in naming. These results suggest distinct sequencing processes for repetition and naming, each linked to different WM mechanisms. Implications for word production models and the relationship between WM and word production are discussed.

Behavioral and neural effects of temporoparietal high-definition transcranial direct current stimulation in logopenic variant primary progressive aphasia: a preliminary study

Background

High-definition-tDCS (HD-tDCS) is a recent technology that allows for localized cortical stimulation, but has not yet been investigated as an augmentative therapy while targeting the left temporoparietal cortex in logopenic variant PPA (lvPPA). The changes in neuronal oscillatory patterns and resting-state functional connectivity in response to HD-tDCS also remains poorly understood.

Objective

We sought to investigate the effects of HD-tDCS with phonologic-based language training on language, cognition, and resting-state functional connectivity in lvPPA.

Methods

We used a double-blind, within-subject, sham-controlled crossover design with a 4-month between-treatment period in four participants with lvPPA. Participants completed language, cognitive assessments, and imaging with magnetoencephalography (MEG) and resting-state functional MRI (fMRI) prior to treatment with either anodal HD-tDCS or sham targeting the left supramarginal gyrus over 10 sessions. Language and cognitive assessments, MEG, and fMRI were repeated after the final session and at 2 months follow-up. Preliminary data on efficacy was evaluated based on relative changes from baseline in language and cognitive scores. Language measures included metrics derived from spontaneous speech from picture description. Changes in resting-state functional connectivity within the phonological network were analyzed using fMRI. Magnitudes of source-level evoked responses and hemispheric laterality indices from language task-based MEG were used to assess changes in cortical engagement induced by HD-tDCS.

Results

All four participants were retained across the 4-month between-treatment period, with satisfactory blinding of participants and investigators throughout the study. Anodal HD-tDCS was well tolerated with a side effect profile that did not extend past the immediate treatment period. No benefit of HD-tDCS over sham on language and cognitive measures was observed in this small sample. Functional imaging results using MEG and fMRI indicated an excitatory effect of anodal HD-tDCS compared to sham and suggested that greater temporoparietal activation and connectivity was positively associated with language outcomes.

Conclusion

Anodal HD-tDCS to the inferior parietal cortex combined with language training appears feasible and well tolerated in participants with lvPPA. Language outcomes may be explained by regression to the mean, and to a lesser degree, by ceiling effects and differences in baseline disease severity. The intervention has apparent temporoparietal correlates, and its clinical efficacy should be further studied in larger trials.

Clinical trial registration

ClinicalTrials.gov, Number NCT03805659.

Of Mouses and Mans: A Test of Errorless Versus Error-Based Learning in Children

For both adults and children, learning from one's mistakes (error-based learning) has been shown to be advantageous over avoiding errors altogether (errorless learning) in pedagogical settings. However, it remains unclear whether this advantage carries over to nonpedagogical settings in children, who mostly learn language in such settings. Using irregular plurals (e.g., "mice") as a test case, we conducted a corpus analysis (N = 227) and two preregistered experiments (N = 56, N = 99), to investigate the potency of error-based learning as a mechanism for language acquisition in 3- and 4-year-old children. The results of the corpus analysis showed that incidental feedback after errors, in the form of caregivers' reformulations of children's errors, was relatively infrequent, had modest informational value, and was rarely used by children to correct their errors immediately. The following two experiments contrasted error-based learning with errorless learning, where the correct utterance was modeled for the child before a potential error was committed. The results showed that error-based learning was not always effective, and when it was, it was certainly not superior to errorless learning. Collectively, these findings question the extension of the benefits of error-based learning from pedagogical to nonpedagogical settings and define constraints under which one mechanism may be more beneficial to learning than the other.

Repetition Priming Treatment for Anomia: Effects of Single- and Multiple-Exemplar Protocols

INTRODUCTION

Repetition priming can lead to improved naming ability in people with aphasia, but concerns have arisen from prior research about using only a single picture exemplar for each target. Specifically, it is unclear whether the observed improvements were due to learning simple correspondences between particular words and pictures rather than changes at a deeper level of lexical-semantic processing. In addition, implications for generalization after training with single exemplars were unclear. This study replicated and extended previous work to address these questions.

METHOD

Five participants with chronic aphasia participated in this repeated-measures design study, which repeatedly paired words and pictures with no feedback provided. Two participants engaged in a single-exemplar condition, with a single picture exemplar of each target used for every presentation of that target. The remaining three participants engaged in a multiple-exemplar condition, with several different pictures used for each target. Half of these targets used training pictures during naming probes, whereas half did not.

RESULTS

Primed items led to greater improvements in naming than items that were practiced but not primed. The data indicate that improvements may extend beyond stimulus-specific correspondences. Maintenance and generalization effects were mixed.

CONCLUSIONS

These data provide further support for the efficacy of repetition priming treatment for anomia. Implications and future directions are discussed.

The effect of processing semantic features on spoken word retrieval in a case series of people with aphasia

Purpose: There is a growing body of evidence showing the benefit of Semantic Feature Analysis in the treatment of word finding abilities in people with aphasia. The original technique was grounded in the hypothesis that the activation of semantic features spreads to the target and thereby facilitates its subsequent retrieval. However, it remains unclear the extent to which the focus on semantic features influences the treatment effects. The aim of this study was therefore to shed light on this issue by examining the effect of priming with semantic features (parts and functions) on target retrieval across a case series of people with aphasia.Method: 10 people with aphasia and word retrieval impairments were primed with spoken forms of words that were either the target name (identity condition, e.g. car), parts of the target (e.g. wheel) or functions of the target (e.g. drive) before later being asked to name a picture of that target. An unrelated prime condition (e.g. employ) was used as a control for test-retest effects.Result: At a group level, there was speeding of reaction times in picture naming in the identity condition relative to the unrelated condition; however, no effect of priming was found for either parts or functions. There was significantly better response accuracy in post-priming naming, but this effect did not reach significance for any individual experimental condition (identity, parts, functions) as compared to the unrelated condition, although the identity condition showed numerical improvement while the other two conditions showed decline.Conclusion: Given the lack of evidence for facilitatory effects from parts and functions of a target in a priming task, this research suggests that further research is warranted on the extent to which the improvement in word retrieval subsequent to Semantic Feature Analysis is caused by the emphasis on production of semantic features rather than from the repetition of the target name.

Theory-driven treatment modifications: A discussion on meeting the linguistic, cognitive, and psychosocial needs of individual clients with aphasia

There is a growing body of literature demonstrating that language rehabilitation can improve naming impairments for individuals with aphasia. However, there are challenges applying evidence-based research to clinical practice. Well-controlled clinical studies often consist of homogenous samples and exclude individuals who may confound group-level results. Consequently, the findings may not generalize to the diverse clients serviced by speech-language therapists. Within evidence-based guidelines, clinicians can leverage their experiences and theoretical rationale to adapt interventions to meet the needs of individual clients. However, modifications to evidence-based interventions should not alter aspects of treatment that are necessary to produce change within the treatment target. The current discussion paper uses errorless learning, errorful learning, and retrieval practice for naming in aphasia to model how treatment theories can guide clinicians in making theory-informed modifications to interventions. First, we briefly describe the learning mechanisms hypothesized to underlie errorless learning, errorful learning, and retrieval practice. Next, we identify ways clinicians can provide targeted supports to optimize learning for individual clients. The paper ends with a reflection on how well-defined treatment theories can facilitate the generation of practice-based evidence and clinically relevant decision making.

Errorless, Errorful, and Retrieval Practice for Naming Treatment in Aphasia: A Scoping Review of Learning Mechanisms and Treatment Ingredients

PURPOSE

Increasingly, mechanisms of learning are being considered during aphasia rehabilitation. Well-characterized learning mechanisms can inform "how" interventions should be administered to maximize the acquisition and retention of treatment gains. This systematic scoping review mapped hypothesized mechanisms of action (MoAs) and treatment ingredients in three learning-based approaches targeting naming in aphasia: errorless learning (ELess), errorful learning (EFul), and retrieval practice (RP). The rehabilitation treatment specification system was leveraged to describe available literature and identify knowledge gaps within a unified framework.

METHOD

PubMed and CINHAL were searched for studies that compared ELess, EFul, and/or RP for naming in aphasia. Independent reviewers extracted data on proposed MoAs, treatment ingredients, and outcomes.

RESULTS

Twelve studies compared ELess and EFul, six studies compared ELess and RP, and one study compared RP and EFul. Hebbian learning, gated Hebbian learning, effortful retrieval, and models of incremental learning via lexical access were proposed as MoAs. To maximize treatment outcomes within theorized MoAs, researchers manipulated study ingredients including cues, scheduling, and feedback. Outcomes in comparative effectiveness studies were examined to identify ingredients that may influence learning. Individual-level variables, such as cognitive and linguistic abilities, may affect treatment response; however, findings were inconsistent across studies.

CONCLUSIONS

Significant knowledge gaps were identified and include (a) which MoAs operate during ELess, EFul, and RP; (b) which ingredients are active and engage specific MoAs; and (c) how individual-level variables may drive treatment administration. Theory-driven research can support or refute MoAs and active ingredients enabling clinicians to modify treatments within theoretical frameworks.

An examination of retrieval practice and production training in the treatment of lexical-semantic comprehension deficits in aphasia

OBJECTIVE

Little research has addressed the treatment of lexical-semantic comprehension deficits (i.e., difficulty retrieving the meanings of words) in people with aphasia (PWA). Research suggests that practice retrieving names for depicted objects from long-term memory (production-based retrieval practice) more strongly benefits word retrieval for production in PWA compared to errorless learning (i.e., word repetition), which eschews retrieval practice. This study assessed whether production-based and comprehension-based retrieval practice enhance performance on errorful word-comprehension items in PWA measured relative to nonretrieval forms of training and untrained control items.

METHOD

In a within-participant group study of PWA, errorful comprehension items were assigned to (a) a production-based training module (retrieval practice vs. errorless learning); (b) a comprehension-based training module (a receptive form of retrieval practice vs. restudy). Each module comprised one training session and a 1-day and 1-week comprehension posttest on the module's trained items and an untrained item set.

RESULTS

The comprehension module conditions produced similar and superior posttest performance relative to untrained items. Both production module conditions improved posttest performance relative to untrained items, with retrieval practice conferring more durable learning and generalization indicative of refinement of semantic representations compared to errorless learning.

CONCLUSIONS

Results suggest comprehension- and production-based forms of training are both beneficial for improving lexical-semantic deficits in aphasia, with production-based retrieval practice conferring additional benefits to the targeted deficit compared to errorless learning. Future studies should examine these learning factors in schedules of training more commensurate with clinical practice and in other neurological populations (e.g., semantic dementia). (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Learning from errors: Exploration of the monitoring learning effect

The present study examined spontaneous detection and repair of naming errors in people with aphasia to advance a theoretical understanding of how monitoring impacts learning in lexical access. Prior work in aphasia has found that spontaneous repair, but not mere detection without repair, of semantic naming errors leads to improved naming on those same items in the future when other factors are accounted for. The present study sought to replicate this finding in a new, larger sample of participants and to examine the critical role of self-generated repair in this monitoring learning effect. Twenty-four participants with chronic aphasia with naming impairment provided naming responses to a 660-item corpus of common, everyday objects at two timepoints. At the first timepoint, a randomly selected subset of trials ended in experimenter-provided corrective feedback. Each naming trial was coded for accuracy, error type, and for any monitoring behavior that occurred, specifically detection with repair (i.e., correction), detection without repair, and no detection. Focusing on semantic errors, the original monitoring learning effect was replicated, with enhanced accuracy at a future timepoint when the first trial with that item involved detection with repair, compared to error trials that were not detected. This enhanced accuracy resulted from learning that arose from the first trial rather than the presence of repair simply signifying easier items. A second analysis compared learning from trials of self-corrected errors to that of trials ending in feedback that were detected but not self-corrected and found enhanced learning after self-generated repair. Implications for theories of lexical access and monitoring are discussed.

Effortful Retrieval Practice Effects in Lexical Access: A Role for Semantic Competition

Word retrieval difficulty (lexical access deficit) is prevalent in aphasia. Studies have shown that practice retrieving names from long-term memory (retrieval practice) improves future name retrieval for production in people with aphasia (PWA), particularly when retrieval is effortful. To explicate such effects, this study examined a potential role for semantic competition in the learning mechanism(s) underlying effortful retrieval practice effects in lexical access in 6 PWA. Items were trained in a blocked-cyclic naming task, in which repeating sets of pictures drawn from semantically-related versus unrelated categories underwent retrieval practice with feedback. Naming accuracy was lower for the related items at training, but next-day accuracy did not differ between the conditions. However, greater semantic-relatedness of an item to its set in the related condition was associated with lower accuracy at training but higher accuracy at test. Relevance to theories of lexical access and implications for naming treatment in aphasia are discussed.

The effects of intensity on a phonological treatment for anomia in post-stroke aphasia

INTRODUCTION

The evidence regarding optimal treatment intensity is mixed, and differing definitions have further confounded existing findings. The primary objective of this study was to compare the efficacy of Phonological Components Analysis (PCA) treatment for anomia delivered at intense and non-intense schedules, using a well-controlled design. The number of teaching episodes and active ingredients of therapy are important considerations when defining intensity. We hypothesized that an active ingredient of PCA is the self-generation of phonological components during therapy sessions. Our secondary aim was to examine whether component generation predicted treatment outcome.

METHODS

Sixteen adults (M = 52.63 years old, SD = 11.40) with chronic post-stroke aphasia (M = 4.52 years post-onset, SD = 5.55) were randomly assigned to intensive (IT) or standard (ST) PCA treatment conditions. Cumulative treatment intensity in both conditions was equivalent: ST participants received PCA 1 hour/day, 3 days/week for 10 weeks, whereas IT participants received PCA 3 hours/day, 4 days/week for 2.5 weeks. The primary outcome was naming accuracy on a set of treated and (matched) untreated words, measured pre- and post-treatment, and at four- and eight-week follow-ups.

RESULTS

IT and ST conditions were similarly efficacious. However, secondary analyses suggest an advantage for the IT condition in naming of the treated words immediately post-treatment, but not at follow-ups. The self-generation of phonological components emerged as a significant positive predictor of naming accuracy for both the treated and untreated words. However, this relationship did not reach significance once baseline anomia severity was accounted for.

CONCLUSIONS

Although replication in a larger sample is warranted, results suggest that PCA treatment is similarly efficacious when delivered at different intensities. Other factors related to the quality of treatment (i.e., active ingredients such as cue-generation) may play an important role in determining treatment efficacy and must also be considered when comparing treatment intensities.

Playing With BEARS: Balancing Effort, Accuracy, and Response Speed in a Semantic Feature Verification Anomia Treatment Game

Purpose The purpose of this study was to develop and pilot a novel treatment framework called BEARS (Balancing Effort, Accuracy, and Response Speed). People with aphasia (PWA) have been shown to maladaptively balance speed and accuracy during language tasks. BEARS is designed to train PWA to balance speed-accuracy trade-offs and improve system calibration (i.e., to adaptively match system use with its current capability), which was hypothesized to improve treatment outcomes by maximizing retrieval practice and minimizing error learning. In this study, BEARS was applied in the context of a semantically oriented anomia treatment based on semantic feature verification (SFV). Method Nine PWA received 25 hr of treatment in a multiple-baseline single-case series design. BEARS + SFV combined computer-based SFV with clinician-provided BEARS metacognitive training. Naming probe accuracy, efficiency, and proportion of "pass" responses on inaccurate trials were analyzed using Bayesian generalized linear mixed-effects models. Generalization to discourse and correlations between practice efficiency and treatment outcomes were also assessed. Results Participants improved on naming probe accuracy and efficiency of treated and untreated items, although untreated item gains could not be distinguished from the effects of repeated exposure. There were no improvements on discourse performance, but participants demonstrated improved system calibration based on their performance on inaccurate treatment trials, with an increasing proportion of "pass" responses compared to paraphasia or timeout nonresponses. In addition, levels of practice efficiency during treatment were positively correlated with treatment outcomes, suggesting that improved practice efficiency promoted greater treatment generalization and improved naming efficiency. Conclusions BEARS is a promising, theoretically motivated treatment framework for addressing the interplay between effort, accuracy, and processing speed in aphasia. This study establishes the feasibility of BEARS + SFV and provides preliminary evidence for its efficacy. This study highlights the importance of considering processing efficiency in anomia treatment, in addition to performance accuracy. Supplemental Material https://doi.org/10.23641/asha.14935812.

Cue responsiveness as a measure of emerging language ability in aphasia

Background: Prior research suggests that initial aphasia severity, lesion size, and lesion location are the most salient factors in predicting recovery outcomes. While these factors provide important prognostic information, information that is individualized and readily available to clinicians is limited. Deficits in naming are common to all aphasia types and are routinely targeted in aphasia assessment and treatment, with cues provided to facilitate lexical retrieval.Objectives: In this study, we examine aphasia recovery factors that are readily available to clinicians, examining whether a person's ability to improve naming with cues, indicating "stimulability," will be predictive of future word retrieval.Methods: Ten participants with aphasia following a left-hemisphere stroke participated in initial assessment, seven of whom met criteria for longitudinal assessment. Stroke and early clinical recovery data were collected for all participants. At four timepoints over one year we evaluated longitudinal participants' naming ability and measured the proportion of successful lexical retrieval with the presentation of phonemic, feature, and sentence cues.Results: For all participants, multiple descriptive factors regarding recovery, including lesion information, information from the acute inpatient timeframe, and communication opportunities, were examined. For individuals followed longitudinally, naming stimulability did not consistently predict naming accuracy at the subsequent assessment timepoint. Individuals' attempts at naming emerged as a metric related to future naming performance warranting further evaluation.Conclusions: Multiple factors related to recovery must be considered when providing prognostic information. Naming stimulability and attempts at naming provide some information regarding future performance, but are not consistently reliable across timepoints.

The Application of Lexical Retrieval Training in Tablet-Based Speech-Language Intervention

In the setting of shortened hospitalization periods, periods of confinement and social isolation, limited resources, and accessibility, technology can be leveraged to enhance opportunities for rehabilitative care (1). In the current manuscript, we focus on the use of tablet-based rehabilitation for individuals with aphasia, a language disorder that frequently arises post-stroke. Aphasia treatment that targets naming through effortful and errorful instances of lexical retrieval, where corrective feedback is generated on every trial, may enhance retention and generalizability of gains (2, 3). This pilot evaluation explored how six individuals with aphasia interacted with a tablet-based therapy application that targeted lexical retrieval. Participants with aphasia either (1) autonomously engaged with the therapy tasks or (2) received systematic encouragement to effortfully retrieve words. Behaviors of response latency and cue use were examined to gain insights into the behavioral patterns of both groups, as well as analyses of task accuracy and outcomes on standardized cognitive-linguistic assessments. Despite some variability, initial observations suggest that participants who received systematic training refrained from using cues to complete tasks and spent longer on each trial, which ultimately co-occurred with increased independent engagement with therapy and improved standardized outcomes. Preliminary results present an alternative means of leveraging technology to implement best-practice recommendations in the context of aphasia telerehabilitation.

Retrieval Practice in Memory- and Language-Impaired Populations: A Systematic Review

OBJECTIVE

Neurological conditions, such as multiple sclerosis and stroke, may impair memory and language. A technique called retrieval practice (RP) may improve memory and language outcomes in such clinical populations. The RP effect refers to the finding that retrieving information from memory leads to better long-term retention than restudying the same information. Although the benefits of RP have been repeatedly observed in healthy populations, less is known about its potential applications in cognitive rehabilitation in clinical populations. Here we review the RP literature in populations with acquired memory and language impairments.

METHOD

Systematic searches for studies published before January 2020 were conducted on Elsevier, PsycARTICLES, PsycINFO, Pubmed, Web of Science, and Wiley Online Library, with the terms "retrieval practice"/"testing effect" and "cognitive rehabilitation". In addition, backward and forward snowballing were used to allow the identification of important publications missed by the initial search. Studies were included if they were peer-reviewed, empirical work in which memory or language outcome measures were compared between an RP condition and a re-exposure-control condition in patients with acquired memory or language impairments.

RESULTS

Sixteen articles fulfilled the inclusion criteria. Studies from memory-impaired samples were relatively homogeneous with respect to experimental protocols and materials and favored RP over control conditions. The results were mostly positive despite short retention intervals and predominantly single-session designs. Similarly, studies from language-impaired samples focused on naming impairments in patients with aphasia and also favored RP over name repetition.

CONCLUSION

The results indicate that RP is a viable technique for cognitive rehabilitation.

Primed to cue

The behavioral effects of lexical priming are well studied in the cognitive sciences. Clinical use of the term and widespread implementation of priming based behavioral interventions has remained limited. This is despite the fact that response-contingent cueing, a behavioral intervention technique used during many cognitive-linguistic interventions, is grounded in theories of priming research. The aim of this manuscript is to connect behavioral performance changes observed following priming with those noted following cueing, providing a theoretical rationale for the therapeutic use of both priming and cueing in language and cognitive interventions. In this review, we establish a conceptual basis for how both primes and cues serve to pre-engage the neural system by triggering the retrieval of linked conceptual knowledge, resulting in faster and more accurate responses. Differences between the two (primes and cues) have been linked to timing and conscious intentional engagement, though these distinctions are often task dependent. Additionally, this paper will provide evidence of the clinical utility of priming. Studies of priming in adults with acquired brain injuries are discussed and clinical interventions based on theories of priming are examined. Furthermore, the present work will briefly detail the inhibitory effects of priming to aid clinicians and researchers in deciding how to pair primes and cues with intended retrieval targets. In summation, the present work is intended to bridge two related fields providing both theoretical and clinical insight with respect to the use of primes and cues.

Effects of distributed practice and criterion level on word retrieval in aphasia

This study examined how the distribution and amount of practice affect word retrieval in aphasia as well as how such factors relate to the efficiency of learning. The central hypothesis was that factors that enhance the learning of new knowledge also enhance persistent access to existing, but inconsistently available, word representations. The study evaluated the impact of learning principles on word retrieval by manipulating the timing and amount of retrievals for items presented for naming. Nine people with chronic aphasia with naming impairment completed the experiment. Training materials involved proper noun entities assigned to six conditions formed by crossing a 2-level factor of spacing of sessions, i.e., intersession interval (1 day versus 7 days between sessions) with a 3-level factor of number of correct retrievals per item per session, i.e., criterion level (Criterion-1, Criterion-2, and Criterion-4). Each intersession interval condition comprised three training sessions and a one-month retention test. Increasing the criterion level enhanced naming performance after short (1 day, 7 days) and long (one month) retention intervals, but these advantages came at the cost of many additional training trials. In most cases, later naming success was superior when the same number of correct retrievals of an item was distributed across multiple sessions rather than administered within one session. The substantial advantages for across-session spacing were gained at little cost in terms of additional training trials. At one-month retention, naming accuracy was numerically but not significantly higher in the 7-day versus 1-day intersession interval condition. Implications for theories of lexical access and naming treatment in aphasia are discussed.

A Review of the Application of Distributed Practice Principles to Naming Treatment in Aphasia

It is uncontroversial in psychological research that different schedules of practice, which govern the distribution of practice over time, can promote radically different outcomes in terms of gains in performance and the durability of learning. In contrast, in speech-language treatment research, there is a critical need for well-controlled studies examining the impact of the distribution of treatment on efficacy (for reviews, see Cherney, 2012; Warren, Fey, & Yoder, 2007). In this paper, we enumerate key findings from psychological research on learning and memory regarding how different schedules of practice differentially confer durable learning. We review existing studies of aphasia treatment with a focus on naming impairment that have examined how the distribution of practice affects treatment efficacy. We close by discussing potential productive lines of research to elaborate the clinical applicability of distributed practice principles to language treatment.

Retrieval practice and spacing effects in multi-session treatment of naming impairment in aphasia

Retrieval practice and spacing are two factors shown to enhance learning in basic psychological research. The present study investigated the clinical applicability of these factors to naming treatment in aphasia. Prior studies have shown that naming treatment that provides retrieval practice (i.e., practice retrieving names for objects from semantic memory) improves later naming performance in people with aphasia (PWA) more so than repetition training. Repetition training is a common form of naming treatment that can support errorless production of names for objects, but it does not provide retrieval practice. Prior work has also demonstrated enhanced naming treatment benefit in PWA when an item's training trials are separated by multiple intervening trials (i.e., spacing) compared to only one intervening trial (i.e., massing). However, in those studies, items were only trained in one session. Also, the effects of the learning factors were probed after one day and one week. The goal of the present study was to examine the effects of retrieval practice and spacing in a more clinically-inspired schedule of delivery and to assess the effects of the learning factors at retention intervals of greater functional significance. Matched sets of errorful items for each of four PWA were presented for multiple trials of retrieval practice or repetition in a spaced or massed schedule in each of multiple training sessions. Mixed regression analyses revealed that retrieval practice outperformed repetition, and spacing outperformed massing, at an initial post-treatment test administered after one week. Furthermore, the advantage for retrieval practice over repetition persisted at a follow-up test administered after one month. The potential clinical relevance of retrieval practice and spacing for multi-session interventions in speech-language treatment is discussed.

Word repetition and retrieval practice effects in aphasia: Evidence for use-dependent learning in lexical access

This study tested the hypothesis that a use-dependent learning mechanism operates at each of two stages of lexical access: retrieval of a word from semantics ("Stage 1"), followed by retrieval of the word's constituent phonemes ("Stage 2"). Two participants with aphasia were selected due to their contrasting types of naming impairment (Stage 1 versus Stage 2 difficulty). For each participant, items were assigned to naming training that involved retrieval practice (retrieval of the name from semantics) or repetition practice (hear the name and orally repeat it). Naming tests were administered one day and one week after training. The results supported the predicted training effects: (a) Because successful naming via retrieval practice requires both Stage 1 and Stage 2, this technique uses and strengthens item-specific connections in both stages. (b) Because word repetition circumvents semantically driven retrieval, this technique primarily uses and strengthens item-specific connections in Stage 2.