Word retrieval therapies in primary progressive aphasia

Background: Primary progressive aphasia (PPA) with its three variants is a progressive neurodegenerative dementia in which language impairment is the first and most dominant symptom. Traditionally, speech-language pathologists who deliver therapy to adults with acquired neurogenic language disorders shy away from treatment of progressive aphasia as there is no promise of lasting effects and only limited data regarding treatment efficacy.

Aims: This paper comprises the most current review of the literature focused on treatment of naming impairments in PPA, and aims to encourage and assist clinicians in selecting intervention approaches for individuals with PPA. It highlights current trends and challenges in delivering successful therapy for naming deficits in PPA.

Main Contribution: We reviewed papers that reported different forms of naming therapy for patients with PPA, which included interventions that, although not always aimed directly at anomic deficits, brought about improvement in naming. Immediate gains, maintenance, and generalisation effects are summarised, along with a variety of approaches and methodologies that can be applied to the PPA population. We also provide a list of factors that were found to contribute to the success of therapy and to the maintenance and/or generalisation of treatment gains.

Conclusions: Current literature delivers encouraging evidence for clinicians wanting to provide naming therapy to patients with PPA. Although PPA is a progressive disorder, both the immediate treatment effects and, in many cases, maintenance results show that improvements are possible. The issues of generalisation of naming gains beyond the clinician’s office still require more studies to determine the best conditions, designs, and patient suitability.     

Prophylactic treatments for anomia in the logopenic variant of primary progressive aphasia: cross-language transfer

Background: Treatment studies for anomia in primary progressive aphasia (PPA) have rarely compared multiple treatments in the same individual, and few anomia treatment studies have included participants with the logopenic variant of PPA (lvPPA).

Aims: The goals of this study were to evaluate two types of treatment for anomia in a bilingual participant (ND) with lvPPA, and to examine possible cross-language transfer of treatment effects.

Methods & Procedures: ND is a Norwegian-English bilingual woman with lvPPA who began this study at the age of 69. In the phonological treatment, ND listened to a word while viewing a corresponding picture, and she repeated the word. In the orthographic treatment, ND read a word out loud while viewing the corresponding picture, and she then copied the word. Both treatments were conducted in English, and accuracy for three tasks (oral naming, written naming, and naming to definition) was assessed in English and Norwegian. The treatment occurred over a one-year period, with eight sessions at the laboratory during the first month, followed by monthly laboratory sessions and thrice-weekly home practice sessions during the subsequent 11 months. Post-treatment assessments were conducted at 1 week, 8 months, 1 year, 20 months, and 3 years.

Outcomes & Results: Compared to untrained items, the orthographic treatment resulted in greater English written naming accuracy. This treatment also resulted in cross-language transfer: greater Norwegian oral naming and naming to definition accuracy. The phonological treatment resulted in marginally greater English oral naming accuracy, but it did not have a significant effect on naming accuracy in Norwegian.

Conclusions: These findings suggest that the orthographic treatment was effective in strengthening the orthographic representations of the treated items, which facilitated ND’s written naming performance. The pattern of cross-language transfer suggests that the orthographic treatment also strengthened the language-independent semantic representations of the treated items, thereby facilitating access to their Norwegian phonological representations.     

Relearning lost vocabulary in nonfluent progressive aphasia with MossTalk Words®

Background: The literature on aphasia has been growing rapidly, with reports of different therapeutic approaches for a post‐stroke anomia. While individuals with post‐stroke anomia frequently recover to some extent, the other end of the aphasia recovery continuum is occupied by those who experience relentless language dissolution as a result of progressive disorders such as primary progressive aphasia. One of the most recent additions to the field of aphasia rehabilitation is therapy whereby either part of or the entire therapy is administered via computer‐based programmes. There have been few treatment studies investigating the rehabilitation of language abilities in people with primary progressive aphasia (PPA).

Aims: The objectives of this investigation were to examine the ability of PPA individuals to relearn lost words and to determine the extent of benefits derived from MossTalk Words®, a computer‐based treatment for anomia.

Methods and Procedures: Using a multiple baseline across behaviours design, we explored treatment‐specific effects, maintenance, and generalisation of improvements derived from this therapy programme. Two participants with nonfluent PPA were treated, each on three lists of words for which low and stable baselines were first established. Sessions occurred two to three times a week. Treatment involved the presentation of a picture on the computer screen, with the participants being required to name it. Success in treatment was measured by probing list naming every second session. Once a participant attained 80% accuracy over two consecutive probes, or participated in 12 sessions (whichever occurred first), treatment of a list was terminated and the next list was started. Each participant was tested on all items immediately after therapy, and again 1 month later.

Outcomes and Results: Both participants improved their naming skills with the MossTalk Words®. P1 required only four sessions to reach the proposed criterion of 80% (up to 100%) correct on each list. The effects of treatment were maintained immediately and, to a lesser degree, 4 weeks later. P2 required all 12 sessions for each of the three lists. Results were variable immediately after testing, but seemingly maintained 4 weeks later.

Conclusions: The results demonstrate that both participants with primary progressive aphasia benefited (although to a different extent) from a computer‐based treatment for anomia. These results are encouraging and suggest that such a treatment may be a viable therapy approach for patients who suffer from PPA in the absence of a generalised cognitive impairment.     

“Do you have mowing the lawn?” – improvements in word retrieval and grammar following constraint-induced language therapy in primary progressive aphasia

Background: Much recent progress has been made in developing speech–language therapy in primary progressive aphasia (PPA). Several treatment approaches that have shown significant effects with people with aphasia have been adapted and re-evaluated for PPA. Constraint-induced aphasia therapy (CIAT) is a well-evaluated method that has yielded significant language improvements in people with post-stroke aphasia but has not yet been evaluated with people with PPA. Nevertheless, the combination of CIAT features like massed practice and a motivating communicative setting seem likely to make it a suitable tool for improving the speech and language performance of individuals with PPA as well.

Aims: This study investigates the effectiveness of a modified CIAT protocol on word retrieval, grammatical structure and connected speech in two individuals with non-fluent variant PPA (nfvPPA).

Methods and procedures: Two participants with nfvPPA took part in a 9-day intensive CIAT-based group therapy with additional computer-based home training. Stimuli were 120 photos of people performing daily life activities, which could be described using a simple (e.g., “The man is mowing the lawn”) or reduced (e.g., “mowing the lawn”) sentence structure. During the treatment phase, the participants were required to request picture cards from other group members using spoken language only. The task difficulty was increased hierarchically (shaped) in accordance to each participant’s performance level.

Outcomes and results: Directly after therapy, both participants achieved significant improvements in their noun and verb naming accuracy and their grammatical structure for trained items. Training effects were maintained 2 months after therapy. Moreover, generalisation to different pictures of the same item was found for both participants and one participant also showed improved grammatical structure when describing untrained pictures. No significant generalisation to untrained connected speech samples was observed for either participant.

Conclusion: This study illustrates that CIAT can be effective in people with PPA. However, further modifications of CIAT should be considered to facilitate generalisation and in order to determine which aspects of the treatment are most important.     

Long-Term maintenance of anomia treatment effects in primary progressive aphasia

ABSTRACT

This study examined the maintenance of anomia treatment effects in primary progressive aphasia (PPA). Following baseline testing, a phonological treatment and an orthographic treatment were administered over the course of six months. The treatment stimuli consisted of nouns that were consistently named correctly at baseline (Prophylaxis items) and/or nouns that were consistently named incorrectly at baseline (Remediation items). Naming accuracy was measured at baseline, and it was measured at 1 month, 8 months, and 15 months post-treatment. The change in naming accuracy from baseline to each post-treatment evaluation was calculated within each treatment condition, and within a matched untrained condition. The change in naming accuracy was then compared between the three conditions. The results of these analyses indicate that phonological and orthographic treatments are both effective in the Prophylaxis and Remediation of anomia in all three variants of PPA. For Prophylaxis items, some of the effects of each treatment can persist for as long as 15 months post-treatment. These long-term treatment effects were more robust in the orthographic treatment condition and for participants with the semantic variant of PPA.     

Semantic feature analysis targeting verbs in a quadrilingual speaker with aphasia

Background: Semantic feature analysis (SFA) is a treatment approach aimed at enhancing lexical retrieval by improving access to the semantic network in speakers with aphasia. Although there are promising results on trained items, previous studies exploring the impact of SFA on verb production in monolingual speakers have shown mixed results for generalisation to untrained items and discourse. There are few published studies investigating SFA and action naming in multilingual speakers.

Aims: The study explores the impact of SFA on trained and untrained verbs, semantics and syntax, and narrative production in the trained and untrained languages of a multilingual speaker (Japanese–English–German–Norwegian) with moderate non-fluent aphasia. Treatment was conducted in a late-acquired language (Norwegian).

Methods & Procedures: SFA was provided during an intensive schedule of about 22 hr of therapy, with approximately 10 hr per week over two and a half weeks. The treatment focused on the production of verbs in sentence contexts.

Outcomes & Results: Outcome measures include the Bilingual Aphasia Test, an action-naming test, and production of semi-spontaneous narratives.

Outcomes in the treated language: Overall, the participant responded positively to the SFA treatment. The trained verbs improved significantly, but no transfer was observed to untrained verbs. There were no changes in the formal testing of semantics or syntax, but improvements were noted in narrative production.

Cross-linguistic outcomes: Transfer to verbs in untreated German was evident. There were significant increases in the semantics and syntax in both English and German. The participant showed an improvement in discourse in English and German, although not in Japanese.

Conclusions: SFA treatment in a late-acquired language can lead to gains in the treated language and transfer to both stronger and weaker languages, with different patterns for the various languages. This indicates that SFA may be a promising method for treating multilingual speakers with aphasia. The authors further advocate the use of narratives as an assessment tool. In addition to enhancing the ecological validity of the findings, the narratives provided information not obtainable from the other assessment tools for within- and cross-linguistic therapy gains for the participant.     

Behavioural and neural changes after a “choice” therapy for naming deficits in aphasia: preliminary findings

Background: Anomia, difficulty producing words, is a pervasive symptom of many individuals with aphasia. We have developed a treatment for naming deficits—the Phonological Components Analysis (PCA) protocol—that has proven efficacious in improving word-finding abilities for individuals with post-stroke aphasia.

Aims: The aim of this investigation is to present preliminary findings exploring the potential influence of choice—that is the active engagement of a participant in therapy—on our PCA treatment.

Methods & Procedures: Five individuals with aphasia were treated in one of two conditions—Choice or No Choice. Potential changes in neural activation as a function of the treatment were also investigated. Two individuals (one from each condition) underwent functional MRI (fMRI) pre- and post-therapy.

Outcomes & Results: All the individuals demonstrated a significant treatment effect immediately post-treatment and at a 4-week follow-up and four of the five participants at an 8-week follow-up. Three also demonstrated generalisation to untrained items. Unfortunately, no clear-cut patterns emerged to allow us to make claims about the influence of choice, per se, on the behavioural manifestations of improved naming. Interestingly, the participant from the Choice condition showed neural activation changes post-treatment in frontal and parietal regions that were not evident for the participant in the No Choice condition. Moreover, these changes were accompanied by a larger treatment effect for that individual and generalisation to a novel naming task.

Conclusion: The efficacy of PCA treatment for naming deficits is further supported. In addition, the neuroimaging data suggest the possibility that active engagement of an individual in his/her therapy (in this case choosing phonological attributes of a target word) may exercise executive functions important for success in treating anomia. Also, continued exploration of task factors that may promote even better treatment effects using this protocol is warranted, as is continued investigation of the neural underpinnings associated with treatment effects.     

Masked repetition priming effects on naming in aphasia: A Phase I treatment study

Background: It has been suggested that lexical access deficits in aphasia may be the result of impaired automatic activation of the networks that support language processing, a system that operates implicitly, outside conscious awareness. This raises the question of whether there might be a way to address rebuilding these implicit networks directly, rather than through the explicit treatment protocols that are typical of aphasia therapy. Masked priming is one method by which the language system can be automatically activated, while limiting or preventing the influence of conscious, explicit processing.

Aims: This Phase I study was undertaken to investigate the potential effectiveness of masked repetition priming as a treatment for anomia.

Methods & Procedures: This study used a single-participant, ABA, multiple-baseline repeated-probe design. A total of 22 training sessions were completed across 4 weeks. Training involved repeated presentation of masked repetition primes paired with target pictures prior to attempts at naming those pictures. Untrained items were presented an equal number of times, but without prime words. Repeated naming probes administered before, during, and after treatment were used to measure effects of training (naming trained stimuli) and generalisation (naming within and across semantic categories). Pre- and post-training assessment with broader tests of language function and conversation were also completed.

Outcomes & Results: Results revealed a small effect of training on naming of trained items in one category, as well as a pattern of improvement in the other category that did not quite meet the criterion for a small effect. There was also a medium cross- category generalisation effect, although no generalisation effect was seen to untrained items within semantic categories. Improvements were seen on some measures of general language function.

Conclusions: Masked priming can elicit changes in naming ability over time, and may have potential as a tool for improving word retrieval in individuals with anomia. Results warrant further investigation.     

Generalisation of personalised cueing to enhance word finding in natural settings

Background: Personalised cueing is a treatment method for naming deficits in patients with aphasia. As part of the treatment patients choose their own cues to help recall a target word. These cues usually include personally relevant semantic information, which is hypothesised to enhance long-term naming abilities. Previous research has shown that personalised cueing can improve long-term naming accuracy in persons with aphasia. However, no research has shown that personalised cueing carries over to improved naming in natural settings.

Aims: The study aimed to examine the long-term generalisation of improved word finding using the personalised cueing method.

Methods & Procedures: Three individuals participated in 12 training trials using the personalised cueing method; 40 unnamed stimulus items were chosen for each participant. Pre-training measures of the Sentence Production Task (SPT) and Message Exchange Task (MET) were administered for each participant. Of the 40 stimulus items, 20 were then trained using the personalised cueing method across 12 training sessions. Post-training measures of the SPT and MET were then collected, along with measures on a Caregiver Partner Rating scale to assess naming accuracy in natural settings. The 20 untrained stimulus items were also probed to assess generalisation to untrained stimuli.

Outcomes & Results: Two of the three participants showed improvement in naming trained items in natural settings, but little improvement was noted on the untrained stimulus items. Results for these patients were consistent with other studies on the personalised cueing method. The third participant demonstrated a slight increase in naming accuracy over time. Shortly after this study that participant was diagnosed with Alzheimer's disease.

Conclusions: Results suggest that personalised cueing is an effective method of improving naming in certain individuals with aphasia. It also suggests that the effects of personalised cueing are maintained over time and are evident in natural settings.     

Longitudinal study of single‐word comprehension in semantic dementia: A comparison with primary progressive aphasia and Alzheimer's disease

Background: Although semantic dementia (SD) is characterised by a multimodal loss of semantic knowledge, it has been demonstrated that lexical‐semantic representations are not equally disrupted in SD and that some categories may be recognised better than others. Little is known, however, about the pattern of the category‐specific comprehension deficits in SD and whether it differs from that of other forms of progressive aphasias.

Aims: This exploratory study aimed to investigate the evolution of category‐specific deficits of single‐word comprehension in progressive aphasias.

Methods & Procedures: A total of 19 patients with a clinical diagnosis of SD, 25 patients with primary progressive aphasia with agrammatic and relatively nonfluent speech (PPA), and 25 patients with Alzheimer's disease (AD) with aphasia were studied longitudinally with the Western Aphasia Battery (WAB). The Auditory Word Recognition subtest of the WAB was utilised to assess comprehension of words derived from different semantic categories.

Outcomes & Results: The analysis revealed that, over time, category‐specific deficits of single‐word comprehension were seen in all three groups of patients. Participants with SD as well as those with PPA and AD were impaired on both pointing to fingers and the right–left orientation task. However, patients with SD were the only group that showed defective recognition of their own body parts. Interestingly, individuals with SD had no difficulties identifying colours, letters, and numbers, even during the follow‐up testing. In addition, in all three groups the extent of category‐specific deficits was associated with the severity of aphasia.

Conclusions: These results indicate that category‐specific deficits of single‐word comprehension are frequently seen not only in patients with SD but also in individuals with PPA or AD, and that the extent of these deficits is associated with the severity of aphasia. However, the pattern of these deficits is often different in these three forms of neurodegenerative conditions and more dissociations between semantic categories are observed as each of these diseases progresses.     

The relationship between baseline volume in temporal areas and post-treatment naming accuracy in primary progressive aphasia

Background: Structural imaging has not been used previously to predict the effect of treatment in primary progressive aphasia (PPA).

Aims: This study examined relationships between baseline brain volume and the effects of phonological and orthographic treatments for anomia in PPA. It was predicted that lower baseline volume would be associated with lower post-treatment naming accuracy for treated items and smaller generalisation effects.

Methods & Procedures: Twenty-one individuals with PPA participated. The treatment stimuli consisted of nouns that were consistently named correctly at baseline (Prophylaxis items) and/or nouns that were consistently named incorrectly at baseline (Remediation items). All 21 participants had Prophylaxis items, while 10 participants had Remediation items. Naming accuracy for Untrained and Trained items (Exemplar set 1) was measured. In addition, stimulus generalisation was examined by having participants name an alternative exemplar of each Untrained and Trained item (Exemplar set 2). Correlational analyses focused on the relationships between naming accuracy and volume of regions previously identified as having a role in naming and semantic processing.

Outcomes & Results: Unexpectedly, there were no significant correlations between baseline volume and post-treatment accuracy for treated items. However, baseline volume within the left temporal pole was positively correlated with post-treatment accuracy for Untrained Exemplar set 2 Prophylaxis items, while baseline volume in the left inferior temporal gyrus (ITG) was positively correlated with post-treatment accuracy for Untrained Exemplar set 1 Remediation items.

Conclusions: These findings suggest that lower volume in the left temporal pole is associated with decline for Untrained items, while lower volume in the left ITG is associated with a lack of improvement for Untrained items. Possible explanations for the different patterns observed across exemplar sets are discussed.     

Biomarkers in the primary progressive aphasias

Background: Primary progressive aphasia (PPA) is a progressive disorder of language that is increasingly recognised as an important presentation of a specific spectrum of neurodegenerative conditions.

Aims: In an era of etiologically specific treatments for neurodegenerative conditions, it is crucial to establish the histopathologic basis for PPA. In this review, I discuss biomarkers for identifying the pathology underlying PPA.

Main Contribution: Clinical syndromes suggest a probabilistic association between a specific PPA variant and an underlying pathology, but there are also many exceptions. A considerable body of work with biomarkers is now emerging as an important addition to clinical diagnosis. I review genetic, neuroimaging and biofluid studies that can help determine the pathologic basis for PPA.

Conclusions: Together with careful clinical examination, there is great promise that supplemental biomarker assessments will lead to accurate diagnosis of the pathology associated with PPA during life and serve as the basis for clinical trials in this spectrum of disease.     

Motor speech disorders associated with primary progressive aphasia

Background: Primary progressive aphasia (PPA) and conditions that overlap with it can be accompanied by motor speech disorders. Recognition and understanding of motor speech disorders can contribute to a fuller clinical understanding of PPA and its management as well as its localisation and underlying pathology.

Aims: To review the types of motor speech disorders that may occur with PPA, its primary variants, and its overlap syndromes (progressive supranuclear palsy syndrome, corticobasal syndrome, motor neuron disease), as well as with primary progressive apraxia of speech.

Main Contribution: The review should assist clinicians’ and researchers’ understanding of the relationship between motor speech disorders and PPA and its major variants. It also highlights the importance of recognising neurodegenerative apraxia of speech as a condition that can occur with little or no evidence of aphasia.

Conclusion: Motor speech disorders can occur with PPA. Their recognition can contribute to clinical diagnosis and management of PPA and to understanding and predicting the localisation and pathology associated with PPA variants and conditions that can overlap with them.     

Telerehabilitation of anomia in primary progressive aphasia

Background: The efficacy of telerehabilitation-based treatment for anomia has been demonstrated in post-stroke aphasia, but the efficacy of this method of anomia treatment delivery has not been established within the context of degenerative illness.

Aims: The current study evaluated the feasibility and efficacy of a telerehabilitation-based approach to anomia treatment within the three subtypes of primary progressive aphasia (PPA).

Methods & Procedures: Each of the three telerehabilitation participants represented a distinct subtype of PPA. Following a baseline evaluation of language and cognition, a phonological treatment and an orthographic treatment were administered to all participants over the course of 6 months. One month after the end of treatment, a post-treatment evaluation began. All treatment sessions and the majority of the evaluation sessions were administered via telerehabilitation. Treatment effects were examined within each subject, and treatment effects were also compared between each telerehabilitation participant and a group of in-person participants who had the same subtype of PPA.

Outcomes & Results: All three telerehabilitation participants exhibited positive treatment effects. CGR (nonfluent/agrammatic variant PPA) and WCH (logopenic variant PPA) showed maintenance of naming for prophylaxis items under both treatment conditions, while ACR (semantic variant PPA) demonstrated increased naming of remediation items under the phonological treatment condition. Compared to in-person participants with the same subtype of PPA, each of the telerehabilitation participants typically showed effects that were either within the expected range or larger than expected.

Conclusions: Telerehabilitation-based anomia treatment is feasible and effective in all three subtypes of PPA.     

Known,lost, and recovered: Efficacy of formal‐semantic therapy and spaced retrieval method in a case of semantic dementia

Background: Few studies have addressed rehabilitation in semantic dementia. A potentially promising method is formal‐semantic therapy, which consists of tasks in which the names of concepts and their semantic characteristics are presented. It could also be enhanced by spaced retrieval, a learning method improving retention through recalling information after increasing recall intervals.

Aims: This study explores the efficacy of both a formal‐semantic therapy and the spaced retrieval method to restore lost concepts in TBo, a woman with semantic dementia.

Methods & Procedures: The formal‐semantic therapy consisted of giving TBo semantic feedback followed by a cueing technique to facilitate naming. Formal‐semantic therapy with simple repetition was compared to formal‐semantic therapy with spaced retrieval. TBo's performance was measured throughout the study with picture naming and generation of verbal attributes. Two untrained lists were also measured for generalisation effects.

Outcomes & Results: Results indicate that, after therapy, TBo could name 3/8 of the trained items, compared to no items on the untrained lists. She also showed an increase in performance for the evocation of specific semantic attributes of concepts, reaching 6/8 of correct responses. Moreover, she maintained her performance up to 5 weeks after the end of the study. Finally, when compared to simple repeated practice, spaced retrieval did not enhance learning and no generalisation was observed between trained and non‐trained categories.

Conclusions: Along with recent results reported in the literature, TBo's results confirm that people with semantic dementia can improve their naming performance with training but that this is limited. However, formal‐semantic therapy seems very promising for retraining specific semantic attributes. Instead of focusing on naming, we suggest that therapies used in semantic dementia should aim at restoring specific and functionally relevant concepts to enable the individuals to be more autonomous in daily living.     

Cognition and anatomy in three variants of primary progressive aphasia

We performed a comprehensive cognitive, neuroimaging, and genetic study of 31 patients with primary progressive aphasia (PPA), a decline in language functions that remains isolated for at least 2 years. Detailed speech and language evaluation was used to identify three different clinical variants: nonfluent progressive aphasia (NFPA; n = 11), semantic dementia (SD; n = 10), and a third variant termed logopenic progressive aphasia (LPA; n = 10). Voxel-based morphometry (VBM) on MRIs showed that, when all 31 PPA patients were analyzed together, the left perisylvian region and the anterior temporal lobes were atrophied. However, when each clinical variant was considered separately, distinctive patterns emerged: (1) NFPA, characterized by apraxia of speech and deficits in processing complex syntax, was associated with left inferior frontal and insular atrophy; (2) SD, characterized by fluent speech and semantic memory deficits, was associated with anterior temporal damage; and (3) LPA, characterized by slow speech and impaired syntactic comprehension and naming, showed atrophy in the left posterior temporal cortex and inferior parietal lobule. Apolipoprotein E epsilon4 haplotype frequency was 20% in NFPA, 0% in SD, and 67% in LPA. Cognitive, genetic, and anatomical features indicate that different PPA clinical variants may correspond to different underlying pathological processes.     

Phonological facilitation effects on naming latencies and viewing times during noun and verb naming in agrammatic and anomic aphasia

Background: Phonological priming has been shown to facilitate naming in individuals with aphasia, as well as healthy speakers, resulting in faster naming latencies. However, the mechanisms of phonological facilitation (PF) in aphasia remain unclear.

Aims: Within discrete vs. interactive models of lexical access, this study examined whether PF occurs via the sub-lexical or lexical route during noun and verb naming in agrammatic and anomic aphasia.

Methods & Procedures: Thirteen participants with agrammatic aphasia and 10 participants with anomic aphasia and their young and age-matched controls (n = 20/each) were tested. Experiment 1 examined noun and verb naming deficit patterns in an off-line confrontation naming task. Experiment 2 examined PF effects on naming both word categories using eyetracking priming paradigm.

Outcomes & Results: Results of Experiment 1 showed greater naming difficulty for verbs than for nouns in the agrammatic group, with no difference between the two word categories in the anomic group. For both participant groups, errors were dominated by semantic paraphasias, indicating impaired lexical selection. In the phonological priming task (Experiment 2), young and age-matched control groups showed PF in both noun and verb naming. Interestingly, the agrammatic group showed PF when naming verbs, but not nouns, whereas the anomic group showed PF for nouns only.

Conclusions: Consistent with lexically mediated PF in interactive models of lexical access, selective PF for different word categories in our agrammatic and anomic groups suggest that phonological primes facilitate lexical selection via feedback activation, resulting in greater PF for more difficult (i.e., verbs in agrammatic and possibly nouns in anomic group) lexical items.     

Augmentation of spelling therapy with transcranial direct current stimulation in primary progressive aphasia: Preliminary results and challenges

Background: Primary progressive aphasia (PPA) is a neurodegenerative disease that primarily affects language functions and often begins in the fifth or sixth decade of life. The devastating effects on work and family life call for the investigation of treatment alternatives. In this article, we present new data indicating that neuromodulatory treatment, using transcranial direct current stimulation (tDCS) combined with a spelling intervention, shows some promise for maintaining or even improving language, at least temporarily, in PPA.

Aims: The main aim of the present article is to determine whether tDCS plus spelling intervention is more effective than spelling intervention alone in treating written language in PPA. We also asked whether the effects of tDCS are sustained longer than the effects of spelling intervention alone.

Methods & Procedures: We present data from six PPA participants who underwent anodal tDCS or sham plus spelling intervention in a within-subject crossover design. Each stimulation condition lasted 3 weeks or a total of 15 sessions with a 2-month interval in between. Participants were evaluated on treatment tasks as well as on other language and cognitive tasks at 2-week and 2-month follow-up intervals after each stimulation condition.

Outcomes & Results: All participants showed improvement in spelling (with sham or tDCS). There was no difference in the treated items between the two conditions. There was, however, consistent and significant improvement for untrained items only in the tDCS plus spelling intervention condition. Furthermore, the improvement lasted longer in the tDCS plus spelling intervention condition compared to sham plus spelling intervention condition.

Conclusions: Neuromodulation with tDCS offers promise as a means of augmenting language therapy to improve written language function at least temporarily in PPA. The consistent finding of generalisation of treatment benefits to untreated items and the superior sustainability of treatment effects with tDCS justifies further investigations. However, the small sample size still requires caution in interpretation. Present interventions need to be optimised, and particular challenges, such as ways to account for the variable effect of degeneration in each individual, are discussed.     

The impact of dose on naming accuracy with persons with aphasia

Background: Although aphasia rehabilitation has been shown to be efficacious, many questions remain regarding how best to deliver treatment to maximise functional gains for persons with aphasia. Treatment-delivery variables, such as intensity and dosage, are likely to influence both behavioural and structural changes during anomia treatment. While numerous protocols have concluded that treatment intensity positively impacts functional outcomes, few studies to date have examined the role that dose plays in patient outcomes for anomia treatment.

Aims: This study sought to investigate how manipulating dose of repeated confrontation naming within sessions influences naming in persons with aphasia. Repeated practice of confrontation naming, without feedback, was hypothesised to improve trained but not untrained words, to be persistent after withdrawal, and to be sensitive to the number of trials (i.e., dose) within sessions.

Methods and Procedures: A single-subject ABA design, with replication across seven participants with aphasia, was used to investigate the influence of repeated confrontation naming attempts on the acquisition and maintenance of trained pictures relative to untrained pictures. Training involved repeated attempts to name pictures, along with repeated exposure to pictures of objects (nouns) and their names, without feedback. The primary independent variable was within session dose; the dependent variable was naming accuracy.

Outcomes and Results: Naming accuracy improved for all participants for trained pictures across both acquisition and maintenance phases per visual inspection; such positive effects were not observed for untrained pictures. Effect-size calculations indicate that three of seven participants demonstrated considerable change for trained items, while one of seven participants demonstrated meaningful change for untrained items. The high-dose condition elicited small effect sizes for one participant, and large effect sizes for two of seven participants, while the low-dose condition elicited small and medium effect sizes for two of seven participants.

Conclusions: Participants across a variety of aphasia severity levels responded positively to two doses of repeated confrontation naming practice, without feedback, across phases of this naming protocol. Results are in line with principles of neuroplasticity and demonstrate that repeated practice, without feedback, can produce significant and persistent changes in naming ability for some persons with aphasia.