Rehabilitation Services for Young-Onset Dementia: Examples from High- and Low-Middle-Income Countries.

The WHO Dementia Global Action Plan states that rehabilitation services for dementia are required to promote health, reduce disability, and maintain quality of life for those living with dementia. Current services, however, are scarce, particularly for people with young-onset dementia (YOD). This article, written by an international group of multidisciplinary dementia specialists, offers a three-part overview to promote the development of rehabilitation services for YOD. Firstly, we provide a synthesis of knowledge on current evidence-based rehabilitative therapies for early-onset Alzheimer's disease (EOAD), behavioural variant frontotemporal dementia (bvFTD), primary progressive aphasia (PPA), and posterior cortical atrophy (PCA). Secondly, we discuss the characteristics of rehabilitation services for YOD, providing examples across three continents for how these services can be embedded in existing settings and the different roles of the rehabilitation multidisciplinary team. Lastly, we conclude by highlighting the potential of telehealth in making rehabilitation services more accessible for people with YOD. Overall, with this paper, we aim to encourage clinical leads to begin introducing at least some rehabilitation into their services, leveraging existing resources and finding support in the collective expertise of the broader multidisciplinary dementia professional community.

Global Perspectives on the Management of Primary Progressive Aphasia.

Speech-language therapists/pathologists (SLT/Ps) are key professionals in the management and treatment of primary progressive aphasia (PPA), however, there are gaps in education and training within the discipline, with implications for skills, confidence, and clinical decision-making. This survey aimed to explore the areas of need amongst SLT/Ps working with people living with PPA (PwPPA) internationally to upskill the current and future workforce working with progressive communication disorders. One hundred eighty-five SLT/Ps from 27 countries who work with PwPPA participated in an anonymous online survey about their educational and clinical experiences, clinical decision-making, and self-reported areas of need when working with this population. Best practice principles for SLT/Ps working with PwPPA were used to frame the latter two sections of this survey. Only 40.7% of respondents indicated that their university education prepared them for their current work with PwPPA. Competency areas of "Knowing people deeply," "Practical issues," "Connectedness," and "Preventing disasters" were identified as the basic areas of priority and need. Respondents identified instructional online courses (92.5%), sample tools and activities for interventions (64.8%), and concrete training on providing care for advanced stages and end of life (58.3%) as central areas of need in their current work. This is the first international survey to comprehensively explore the perspectives of SLT/Ps working with PwPPA. Based on survey outcomes, there is a pressing need to enhance current educational and ongoing training opportunities to better promote the well-being of PwPPA and their families, and to ensure appropriate preparation of the current and future SLT/P workforce.

Asynchronous, online spaced-repetition training alleviates word-finding difficulties in aphasia.

Word-finding difficulties for naming everyday objects are often prevalent in aphasia. Traditionally, treating these difficulties has involved repeated drilling of troublesome items with a therapist. Spaced repetition schedules can improve the efficiency of such training. However, spaced repetition in a therapy environment can be both difficult to implement and time-consuming. The current study evaluated the potential utility of automated, asynchronous, online spaced repetition training for the treatment of word-finding difficulties in individuals with aphasia. Twenty-one participants completed a two-week training study, completing approximately 60 minutes per day of asynchronous online drilling. The training items were identified using a pretest, and word-finding difficulties were evaluated both at the end of training (i.e., a post-test) and four weeks later (i.e., a retention test). The trained items were separated into three different spaced-repetition schedules: (1) Short-spacing; (2) Long-spacing; and (3) Adaptive-spacing. At the retention-test, all trained items outperformed non-trained items in terms of accuracy and reaction time. Further, preliminary evidence suggested a potential reaction time advantage for the adaptive-spacing condition. Overall, online, asynchronous spaced repetition training appears to be effective in treating word-finding difficulties in aphasia. Further research will be required to determine if different spaced repetition schedules can be leveraged to enhance this effect.

Focus Group Findings to Support the Preliminary Development of the Augmented Reality Education Experience (AREduX).

Dementia is considered a global health priority with projections of the disease set to increase dramatically across the world. Current support for persons living with dementia (PLWD) relies on long-term care and local service centers to provide education and support. Augmented reality-based programs continue to gain momentum across health sectors, becoming an innovative approach that provides an opportunity to have a visceral experience, which can deepen understanding and provide an embodied perspective of other groups within a relatively short time frame. There is increasing interest in developing approaches to aid patient care outcomes for PLWD and their caregivers. Hence, healthcare providers (HCPs) who are appropriately trained and equipped to provide quality care to PLWD are essential and of international concern. The purpose of this research program is to develop an augmented reality (AR) education experience (AREduX), a proof of concept prototype in the form of a digital resource that uses AR to simulate the physical and cognitive symptoms that PLWD experience. The findings from a stakeholder focus group will allow for the preliminary development of the AREduX.

Electrophysiological connectivity markers of preserved language functions in post-stroke aphasia.

Post-stroke aphasia is a consequence of localized stroke-related damage as well as global disturbances in a highly interactive and bilaterally-distributed language network. Aphasia is increasingly accepted as a network disorder and it should be treated as such when examining the reorganization and recovery mechanisms after stroke. In the current study, we sought to investigate reorganized patterns of electrophysiological connectivity, derived from resting-state magnetoencephalography (rsMEG), in post-stroke chronic (>6 months after onset) aphasia. We implemented amplitude envelope correlations (AEC), a metric of connectivity commonly used to describe slower aspects of interregional communication in resting-state electrophysiological data. The main focus was on identifying the oscillatory frequency bands and frequency-specific spatial topology of connections associated with preserved language abilities after stroke. RsMEG was recorded for 5 min in 21 chronic stroke survivors with aphasia and in 20 matched healthy controls. Source-level MEG activity was reconstructed and summarized within 72 atlas-defined brain regions (or nodes). A 72 × 72 leakage-corrected connectivity (of AEC) matrix was obtained for frequencies from theta to low-gamma (4-50 Hz). Connectivity was compared between groups, and, the correlations between connectivity and subscale scores from the Western Aphasia Battery (WAB) were evaluated in the stroke group, using partial least squares analyses. Posthoc multiple regression analyses were also conducted on a graph theory measure of node strengths, derived from significant connectivity results, to control for node-wise properties (local spectral power and lesion sizes) and demographic and stroke-related variables. Connectivity among the left hemisphere regions, i.e. those ipsilateral to the stroke lesion, was greatly reduced in stroke survivors with aphasia compared to matched healthy controls in the alpha (8-13 Hz; p = 0.011) and beta (15-30 Hz; p = 0.001) bands. The spatial topology of hypoconnectivity in the alpha vs. beta bands was distinct, revealing a greater involvement of ventral frontal, temporal and parietal areas in alpha, and dorsal frontal and parietal areas in beta. The node strengths from alpha and beta group differences remained significant after controlling for nodal spectral power. AEC correlations with WAB subscales of object naming and fluency were significant. Greater alpha connectivity was associated with better naming performance (p = 0.045), and greater connectivity in both the alpha (p = 0.033) and beta (p = 0.007) bands was associated with better speech fluency performance. The spatial topology was distinct between these frequency bands. The node strengths remained significant after controlling for age, time post stroke onset, nodal spectral power and nodal lesion sizes. Our findings provide important insights into the electrophysiological connectivity profiles (frequency and spatial topology) potentially underpinning preserved language abilities in stroke survivors with aphasia.

Maintenance and Generalization of Lexical Items in Primary Progressive Aphasia: Reflections From the Roundtable Discussion at the 2021 Clinical Aphasiology Conference.

PURPOSE: Our capacity to engage in society and maintain meaningful relationships is dependent on intact communication skills. They are compromised in a neurodegenerative language disorder termed primary progressive aphasia (PPA). Behavioral interventions for PPA are sparse and often limited to impairment-based approaches or communication skills training, although various functional interventions have been also described. The slow but relentless language decline does not naturally support maintenance and/or generalization of treatment gains, which should be the ultimate goal of any therapy. However, in some cases and under certain conditions, maintenance and generalization may be accomplished. While each type of intervention has much to offer to the PPA population, the clinical and research realms can benefit from a collective professional discussion on aspects of intervention conducive to maintenance and/or generalization of treatment gains in PPA. Such a discussion took place at the 2021 Clinical Aphasiology Conference during two roundtable sessions. The aims of the sessions were to review the premises of successful treatment approaches in PPA and to discuss factors fostering or inhibiting maintenance and generalization in PPA. CONCLUSIONS: Current literature delivers, albeit in small doses, encouraging evidence for clinicians providing language intervention to patients with PPA. Although PPA is a progressive disorder, both the immediate treatment effects and, in many cases, evidence of maintenance and generalization demonstrate that improvements may be long lasting and transferrable. Several factors may enhance maintenance and generalization effects, including repeated practice, working with multiple exemplars of treatment items, booster sessions, group programs with built-in individual sessions, spared semantics, and personal relevance, to name a few. With this evidence in hand, we need to become more diligent about measuring and reporting clinical outcomes and delivering interventions that support maintenance and generalization of therapeutic gains beyond the clinician's office. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.19836370.

Electrophysiological abnormalities as indicators of early-stage pathology in Primary Progressive Aphasia (PPA): A case study in semantic variant PPA.

Language induced and spontaneous oscillatory activity was measured using MEG in a patient with the semantic variant of Primary Progressive Aphasia (svPPA) and 15 healthy controls.The patient showed oscillatory slowing in the left anterior temporal lobe (ATL) that extended into non-atrophied brain tissue in left and right frontal areas. The white matter connections were reduced to the left and right ATL and left frontal regions, exhibiting electrophysiological abnormalities. Altered diffusion metrics in all four language tracts, indicted compromised white matter integrity. Task-related and spontaneous oscillatory abnormalities can indicate early neurodegeneration in svPPA, providing promising targets for intervention.

Primary Progressive Aphasia Presenting With Neuropsychiatric Symptoms.

We describe a case of primary progressive aphasia (PPA) with an underlying neurodegenerative motor disorder (possible ALS or PSP), presenting with symptoms of irritability and frustration, that were misdiagnosed and treated as a primary psychiatric disorder, i.e. depression. PPA is a rare neurodegenerative disorder characterized by insidious onset and gradual progression of speech and language impairment. We emphasize that PPA can initially masquerade as or be accompanied by neuropsychiatric symptoms potentially leading to misdiagnosis. Most prevalent neuropsychiatric symptoms reported in the PPA literature are agitation, depression, anxiety, apathy, irritability, abnormal appetite and disinhibition. To ensure early diagnosis of PPA, if a patient presents with new psychiatric symptoms accompanied by new onset speech and/or language impairment, referral to a specialist (i.e., neurologist and/or speech-language pathologist) is recommended.

Semantic Variant Primary Progressive Aphasia: Practical Recommendations for Treatment from 20 Years of Behavioural Research.

People with semantic variant primary progressive aphasia (svPPA) present with a characteristic progressive breakdown of semantic knowledge. There are currently no pharmacological interventions to cure or slow svPPA, but promising behavioural approaches are increasingly reported. This article offers an overview of the last two decades of research into interventions to support language in people with svPPA including recommendations for clinical practice and future research based on the best available evidence. We offer a lay summary in English, Spanish and French for education and dissemination purposes. This paper discusses the implications of right- versus left-predominant atrophy in svPPA, which naming therapies offer the best outcomes and how to capitalise on preserved long-term memory systems. Current knowledge regarding the maintenance and generalisation of language therapy gains is described in detail along with the development of compensatory approaches and educational and support group programmes. It is concluded that there is evidence to support an integrative framework of treatment and care as best practice for svPPA. Such an approach should combine rehabilitation interventions addressing the language impairment, compensatory approaches to support activities of daily living and provision of education and support within the context of dementia.

High definition transcranial direct current stimulation modulates abnormal neurophysiological activity in post-stroke aphasia.

Recent findings indicate that measures derived from resting-state magnetoencephalography (rsMEG) are sensitive to cortical dysfunction in post-stroke aphasia. Spectral power and multiscale entropy (MSE) measures show that left-hemispheric areas surrounding the stroke lesion (perilesional) exhibit pathological oscillatory slowing and alterations in signal complexity. In the current study, we tested whether individually-targeted high-definition transcranial direct current stimulation (HD-tDCS) can reduce MEG abnormalities and transiently improve language performance. In eleven chronic aphasia survivors, we devised a method to localize perilesional areas exhibiting peak MSE abnormalities, and subsequently targeted these areas with excitatory/anodal-tDCS, or targeted the contralateral homolog areas with inhibitory/cathodal-tDCS, based on prominent theories of stroke recovery. Pathological MEG slowing in these patients was correlated with aphasia severity. Sentence/phrase repetition accuracy was assessed before and after tDCS. A delayed word reading task was administered inside MEG to assess tDCS-induced neurophysiological changes in relative power and MSE computed on the pre-stimulus and delay task time windows. Results indicated increases in repetition accuracy, decreases in contralateral theta (4-7 Hz) and coarse-scale MSE (slow activity), and increases in perilesional low-gamma (25-50 Hz) and fine-scale MSE (fast activity) after anodal-tDCS, indicating reversal of pathological abnormalities. RsMEG may be a sensitive measure for guiding therapeutic tDCS.

Acquired epileptiform aphasia: 44 years after diagnosis.

We report a case of a 48-year-old woman who was diagnosed with Landau-Kleffner syndrome (LKS) at the age of 4 and reassessed by the same neurologist four decades later. While her seizures abated by the time she was 12 years old, she was left with chronic aphasia, despite receiving optimal care. Although she graduated from high school, started her own family, and was gainfully employed, she was vulnerable in situations that required clear communication. This case reflects successful management of an otherwise debilitating condition and reminds us of the vulnerability of adults with LKS and their need for a life-long support.

SafeHome: A Serious Game to Promote Safe Environments for Persons Living with Dementia.

The dementia epidemic continues to affect families across Canada. The number of persons living with dementia (PLWD) is projected to reach 1.1 million over the next 20 years, placing further financial and resource constraints on the Canadian healthcare system. Caregiver education is vital in ensuring the quality of life and safety for PLWD and can increase the time they are able to live at home, which is correlated with positive outcomes for both PLWD and their caregivers, and a reduction in system costs. However, current educational support often requires individuals to travel to local, urban service care centers and educational content is often provided in English, which can exacerbate the difficulties faced by marginalized caregivers (e.g., immigrants and those living in rural settings) who are caring for PLWD.  To address this issue, a team of researchers developed a serious game called "SafeHome" that teaches safety strategies by having players identify and rectify potential hazards in the home setting that may negatively impact on PLWD outcomes, such as falls. A usability study was conducted using an adapted, validated questionnaire and semi-structured focus groups to better understand users' experience and obtain suggestions for the SafeHome serious game improvement. Results indicated that 80% of the participants were satisfied with the activities provided through SafeHome. All participants (n = 13) made recommendations for improving the usability, functionality, and comprehensiveness of the educational content. This feedback will inform future iterations of SafeHome and add valuable contributions to the growing literature on innovative e-learning resources that support PLWD and their caregivers.

Slowing is slowing: Delayed neural responses to words are linked to abnormally slow resting state activity in primary progressive aphasia.

Neurodegenerative disorders are often characterized by neuronal "slowing," which may be assessed in different ways. In the present study, we examined the latency of neural responses to linguistic stimuli in participants diagnosed with primary progressive aphasia (PPA), as well as changes in the power spectra of resting state activity, both measured with MEG. Compared to both age-matched and younger controls, patients with PPA showed a delayed latency of 8-30 Hz event-related desynchronization (ERD) in response to semantic anomalies. In addition, resting-state MEG revealed increased power in the lower frequency delta and theta bands, but decreased activity in the higher alpha and beta bands. The task-induced and spontaneous measures of neural dynamics were related, such that increased peak latencies in response to words were correlated with a shift of spontaneous oscillatory dynamics towards lower frequencies. In contrast, older controls showed similar task related ERD latencies as younger controls, but also "speeding" of spontaneous activity, i.e. a shift towards faster frequencies. In PPA patients both increased peak latencies on task and increased slow oscillations at rest were associated with less accurate performance on the language task and poorer performance on offline cognitive measures, beyond variance accounted for by structural atrophy. A mediation analysis indicated that increased theta power accounted for the relationship between delayed electrophysiological responses and reduced accuracy in PPA patients. These results indicate that the neuropathological changes in PPA result in slowing of both task-related and spontaneous neuronal activity, linked to functional decline, whereas the speeding of spontaneous activity in healthy aging seems to have a protective or compensatory effect.

Bilingualism in Primary Progressive Aphasia: A Retrospective Study on Clinical and Language Characteristics.

BACKGROUND: Primary progressive aphasia (PPA) is a neurodegenerative disorder characterized by progressive deterioration of language. Being rare, reports of PPA in multilingual individuals are scarce, despite more than half of the world population being multilingual. METHODS: We describe clinical characteristics of 33 bilingual patients with PPA, including symptom presentation and language deficits pattern in their first (L1) and second language (L2), through a systematic literature review and new cases retrospectively identified in 5 countries. RESULTS: In total, 14 patients presented with nonfluent/agrammatic variant, 6 with semantic variant, and 13 with logopenic variant, with a median symptom onset of 2 years. Word-finding difficulties was the first symptom in 65% of all cases, initially noticed in L2, and not always the dominant language. Our group had 22 different languages as L1, and 9 as L2. At the whole-group level there was a tendency for parallel impairment in both languages, in line with the shared bilingual neural substrate hypothesis, but each PPA variant showed some heterogeneity. DISCUSSION: Each PPA variant showed heterogeneity, showing the need for comprehensive language and cognitive assessment across languages, as well as further clarification on the role of language mediators.

Spontaneous oscillatory markers of cognitive status in two forms of dementia.

Abnormal oscillatory brain activity in dementia may indicate incipient neuronal/synaptic dysfunction, rather than frank structural atrophy. Leveraging a potential link between the degree of abnormal oscillatory activity and cognitive symptom severity, one could localize brain regions in a diseased but pre-atrophic state, which may be more amenable to interventions. In the current study, we evaluated the relationships among cognitive deficits, regional volumetric changes, and resting-state magnetoencephalography abnormalities in patients with mild cognitive impairment (MCI; N = 10; age: 75.9 ± 7.3) or primary progressive aphasia (PPA; N = 12; 69.7 ± 8.0), and compared them to normal aging [young (N = 18; 24.6 ± 3.5), older controls (N = 24; 67.2 ± 9.7]. Whole-brain source-level resting-state estimates of relative oscillatory power in the delta (1-4 Hz), theta (4-7 Hz), alpha (8-12 Hz), and beta (15-30 Hz) bands were combined with gray matter volumes and cognitive scores to examine between-group differences and brain-behavior correlations. Language and executive function (EF) abilities were impaired in patients with PPA, while episodic memory was impaired in MCI. Widespread oscillatory speeding and volumetric shrinkage was associated with normal aging, whereas the trajectory in PPA indicated widespread oscillatory slowing with additional volumetric reductions. Increases in delta and decreases in alpha power uniquely predicted group membership to PPA. Beyond volumetric reductions, more delta predicted poorer memory. In patients with MCI, no consistent group difference among oscillatory measures was found. The contributions of delta/alpha power on memory abilities were larger than volumetric differences. Spontaneous oscillatory abnormalities in association with cognitive symptom severity can serve as a marker of neuronal dysfunction in dementia, providing targets for promising treatments.

Group intervention for individuals with primary progressive aphasia and their spouses: Who comes first?

Primary progressive aphasia (PPA) is a neurodegenerative dementia in which language impairment is the first and most dominant symptom. There is a considerable dearth of interventions for PPA although language rehabilitation has made headway in managing the disorder. Thus far, no comprehensive services have been proposed for PPA clients and/or their spouses. This paper describes the first structured group intervention program designated exclusively for people with PPA and their caregivers. This pilot project originates from a clinical service and presents supporting evidence for initiation of a larger study to establish an evidence-based intervention for PPA. A 10-week intervention program comprised working on language activities, learning communication strategies, counselling and education. Outcome measures administered to participants and their spouses before and after the intervention were compared showed improvements in quality of communication and coping skills in the PPA group compared to controls. Qualitative comments from all 10 participants in the active treatment group highlighted the necessity of intervention that is tailored specifically to the PPA population and addresses the needs of both individuals with PPA and their caregivers. All participants in the intervention group contributed to the study and are also co-authors of this paper.

Behavioural and neuroimaging changes after naming therapy for semantic variant primary progressive aphasia.

The objectives of this study were to examine the effects of a successful naming intervention on naming performance and brain activity in individuals with the semantic variant of primary progressive aphasia (svPPA). Four participants with svPPA were scanned while performing phonologically- and semantically-based tasks before and after an intense, 20-h naming therapy that followed the principles of errorless learning whereby errors were eliminated from the learning process. Five healthy control participants were scanned at the outset of the study and did not receive treatment. The results showed that in svPPA participants, successful re-learning of forgotten vocabulary was accompanied by activation of a larger network in bilateral brain regions and that the level of activation in the left anterior lobe may be inversely correlated with severity of semantic impairment. Our findings have implications for treatment in svPPA patients and suggest that semantic cues can improve naming, in spite of significant semantic impairment. The results indicate that intensive language therapy can lead to behavioural gains and neuroplastic changes even in individuals with more advanced anterior temporal lobe atrophy.

Functional reorganization of language networks for semantics and syntax in chronic stroke: Evidence from MEG.

Using magnetoencephalography, we investigated the potential of perilesional and contralesional activity to support language recovery in patients with poststroke aphasia. In healthy young controls, left-lateralized ventral frontotemporal regions responded to semantic anomalies during sentence comprehension and bilateral dorsal frontoparietal regions responded to syntactic anomalies. Older adults showed more extensive bilateral responses to the syntactic anomalies and less lateralized responses to the semantic anomalies, with decreased activation in the left occipital and parietal regions for both semantic and syntactic anomalies. In aphasic participants, we observed compensatory recruitment in the right hemisphere (RH), which varied depending on the type of linguistic information that was processed. For semantic anomalies, aphasic patients activated some preserved left hemisphere regions adjacent to the lesion, as well as homologous parietal and temporal RH areas. Patients also recruited right inferior and dorsolateral frontal cortex that was not activated in the healthy participants. Responses for syntactic anomalies did not reach significance in patients. Correlation analyses indicated that recruitment of homologous temporoparietal RH areas is associated with better semantic performance, whereas higher accuracy on the syntactic task was related to bilateral superior temporoparietal and right frontal activity. The results suggest that better recovery of semantic processing is associated with a shift to ventral brain regions in the RH. In contrast, preservation of syntactic processing is mediated by dorsal areas, bilaterally, although recovery of syntactic processing tends to be poorer than semantic. Hum Brain Mapp 37:2869-2893, 2016. © 2016 Wiley Periodicals, Inc.

Identifying Dysfunctional Cortex: Dissociable Effects of Stroke and Aging on Resting State Dynamics in MEG and fMRI.

Spontaneous signals in neuroimaging data may provide information on cortical health in disease and aging, but the relative sensitivity of different approaches is unknown. In the present study, we compared different but complementary indicators of neural dynamics in resting-state MEG and BOLD fMRI, and their relationship with blood flow. Participants included patients with post-stroke aphasia, age-matched controls, and young adults. The complexity of brain activity at rest was quantified in MEG using spectral analysis and multiscale entropy (MSE) measures, whereas BOLD variability was quantified as the standard deviation (SDBOLD), mean squared successive difference (MSSD), and sample entropy of the BOLD time series. We sought to assess the utility of signal variability and complexity measures as markers of age-related changes in healthy adults and perilesional dysfunction in chronic stroke. The results indicate that reduced BOLD variability is a robust finding in aging, whereas MEG measures are more sensitive to the cortical abnormalities associated with stroke. Furthermore, reduced complexity of MEG signals in perilesional tissue were correlated with hypoperfusion as assessed with arterial spin labeling (ASL), while no such relationship was apparent with BOLD variability. These findings suggest that MEG signal complexity offers a sensitive index of neural dysfunction in perilesional tissue in chronic stroke, and that these effects are clearly distinguishable from those associated with healthy aging.

Quest for the best: effects of errorless and active encoding on word re-learning in semantic dementia.

Semantic dementia is a neurocognitive disorder characterised by a steady and progressive loss of semantic knowledge in the presence of relatively preserved other cognitive skills. Recent treatment studies have proven that language rehabilitation aimed at anomia in semantic dementia can be successful. The objective of this study was to examine the separate and interactive effects of errorless vs. errorful and active vs. passive learning approaches to anomia and their effects on naming and comprehension of treated items, as well as maintenance and generalisation of treatment gains. Seven participants with semantic dementia re-learned two sets of words (one for which participants retained auditory comprehension, and one for which they did not) in each of four different treatment methods based on those approaches. Errorless learning proved more successful than errorful learning in restoring lexical representations in all but one participant while there was no interaction between effects of errorless and active approaches on treatment success. Maintenance of treatment gains showed an advantage for errorless learning at one but not three months post-treatment, although all overall gains were maintained to a significant degree at both time points. Effects of both treatment and maintenance were stronger for items for which participants showed preserved auditory comprehension. The results are discussed in a framework of progressive language disorders and applicability of errorless methods to language rehabilitation in semantic dementia.