From theory to therapy in aphasia: Where are we now and where to next?

Early within therapy naming probes as a clinically-feasible predictor of anomia treatment response

This study investigated the relationship between early within-therapy probe naming performance and anomia therapy outcomes in individuals with aphasia. Thirty-four adults with chronic, post-stroke aphasia participated in the Aphasia Language Impairment and Functioning Therapy (Aphasia LIFT) programme, comprised of 48 h of comprehensive aphasia therapy. Sets of 30 treated and 30 untreated items identified at baseline were probed during impairment therapy which targeted word retrieval using a combined semantic feature analysis and phonological component analysis approach. Multiple regression models were computed to determine the relationship between baseline language and demographic variables, early within-therapy probe naming performance (measured after 3 h of impairment therapy) and anomia treatment outcomes. Early within-therapy probe naming performance emerged as the strongest predictor of anomia therapy gains at post-therapy and at 1-month follow-up. These findings have important clinical implications, as they suggest that an individual's performance after a brief period of anomia therapy may predict response to intervention. As such, early within-therapy probe naming may provide a quick and accessible tool for clinicians to identify potential response to anomia treatment.

Language learning in aphasia: A narrative review and critical analysis of the literature with implications for language therapy

People with aphasia (PWA) present with language deficits including word retrieval difficulties after brain damage. Language learning is an essential life-long human capacity that may support treatment-induced language recovery after brain insult. This prospect has motivated a growing interest in the study of language learning in PWA during the last few decades. Here, we critically review the current literature on language learning ability in aphasia. The existing studies in this area indicate that (i) language learning can remain functional in some PWA, (ii) inter-individual variability in learning performance is large in PWA, (iii) language processing, short-term memory and lesion site are associated with learning ability, (iv) preliminary evidence suggests a relationship between learning ability and treatment outcomes in this population. Based on the reviewed evidence, we propose a potential account for the interplay between language and memory/learning systems to explain spared/impaired language learning and its relationship to language therapy in PWA. Finally, we indicate potential avenues for future research that may promote more cross-talk between cognitive neuroscience and aphasia rehabilitation.

Cognitive Training to Enhance Aphasia Therapy (Co-TrEAT): A Feasibility Study

Persons with aphasia (PWA) often have deficits in cognitive domains such as working memory (WM), which are negatively correlated with recovery, and studies have targeted WM deficits in aphasia therapy. To our knowledge, however, no study has examined the efficacy of multi-modal training which includes both WM training and targeted language therapy. This pilot project examined the feasibility and preliminary efficacy of combining WM training and naming therapy to treat post-stroke PWA. Chronic PWA were randomly assigned to either the a) Phonological Components Analysis (PCA) and WM intervention (WMI) condition (i.e., a computerized adaptive dual n-back task), or b) PCA and active control condition (WMC). Participants received face-to-face PCA therapy 3 times/week for 5 weeks, and simultaneously engaged in WM training or the active control condition five times/week, independently at home. Six PWA were enrolled, 3 in each condition. Feasibility metrics were excellent for protocol compliance, retention rate and lack of adverse events. Recruitment was less successful, with insufficient participants for group analyses. Participants in the WMI (but not the WMC) condition demonstrated a clinically significant (i.e., > 5 points) improvement on the Western Aphasia Battery- Aphasia Quotient (WAB-R AQ) and Boston Naming Test after therapy. Given the small sample size, the performance of two individuals, matched on age, education, naming accuracy pre-treatment, WAB-R AQ and WM abilities was compared. Participant WMI-3 demonstrated a notable increase in WM training performance over the course of therapy; WMC-2 was the matched control. After therapy, WMI-3's naming accuracy for the treated words improved from 30 to 90% (compared to 30–50% for WMC-2) with a 7-point WAB-R AQ increase (compared to 3 for WMC-2). Improvements were also found for WMI-3 but not for WMC-2 on ratings of communicative effectiveness, confidence and some conversation parameters in discourse. This feasibility study demonstrated excellent results for most aspects of Co-TrEAT. Recruitment rate, hampered by limited resources, must be addressed in future trials; remotely delivered aphasia therapy may be a possible solution. Although no firm conclusions can be drawn, the case studies suggest that WM training has the potential to improve language and communication outcomes when combined with aphasia therapy.

Semantic Versus Orthographic Preferences in Aphasia: Behavioral Evidence

In this study, we compared the orthographic and semantic preferences of healthy adults and age and gender matched adults with aphasia, an acquired language disorder. Previous research in word retrieval and word associations has addressed semantic and phonological connections, but it has not as often included analyses of orthographic skills. We matched (on age and gender) 10 neurotypical adults and 11 older adults with aphasia and administered to both groups a lexical discrimination task requiring them to select, from 18 choices, those words that were most different from three words (daughter, laughter, son). Among the choices were foil words (e.g., daughter), orthographic similarities (laughter) and semantic similarities (son). Results revealed that individuals with aphasia focused on orthographic differences, while healthy adults chose semantic differences. Further studies should further explore this orthographic focus to develop treatment strategies, using behavioral and objective measures, for word-finding deficits in aphasia.

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.

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.

Mechanisms underlying anomia treatment outcomes

Treatments for anomia have demonstrated short- and long-term efficacy. However, individual outcomes can be variable, and evidence for treatment generalization is limited. We investigated whether treatment-related measures of access to- and learning of language, namely, a) responsiveness to cues, and b) during-treatment improvements in naming, are good predictors of treatment outcomes. In addition, we investigated mechanisms underlying treatment generalization. Ten adults with chronic, post-stroke aphasia received a phonological treatment for anomia three times a week for five weeks. Naming accuracy of treated and untreated words was assessed pre- and post-treatment and at four- and eight-week follow-ups. Generalization to an untrained naming task, which involved analyses of naming accuracy and speech errors, was also assessed; speech errors were analyzed according to the Interactive Activation (IA) model of word retrieval. Group analyses indicate significant improvements in naming treated compared to untreated words, at all timepoints after therapy. Additional analyses showed significant long-term improvements in naming untreated words. Initial responsiveness to cueing and early improvement emerged as significant predictors of overall pre- to post-treatment improvements in naming treated words; naming improvements made early-on in treatment were also predictive of improvements in naming of the untreated words at follow-up. Furthermore, our study is the first to demonstrate that generalization after a phonological treatment for anomia may be driven by a strengthening of lexical-phonological connections. This study provides novel insights regarding mechanisms driving anomia treatment outcomes. Understanding such mechanisms is critical to improving existing assessment practices, optimizing treatment selection and building treatment protocols that are more likely to generalize.

"The effect of tDCS on functional connectivity in primary progressive aphasia" NeuroImage: Clinical, volume 19 (2018), pages 703-715

Transcranial direct current stimulation (tDCS) is an innovative technique recently shown to improve language outcomes even in neurodegenerative conditions such as primary progressive aphasia (PPA), but the underlying brain mechanisms are not known. The present study tested whether the additional language gains with repetitive tDCS (over sham) in PPA are caused by changes in functional connectivity between the stimulated area (the left inferior frontal gyrus (IFG)) and the rest of the language network. We scanned 24 PPA participants (11 female) before and after language intervention (written naming/spelling) with a resting-state fMRI sequence and compared changes before and after three weeks of tDCS or sham coupled with language therapy. We correlated changes in the language network as well as in the default mode network (DMN) with language therapy outcome measures (letter accuracy in written naming). Significant tDCS effects in functional connectivity were observed between the stimulated area and other language network areas and between the language network and the DMN. TDCS over the left IFG lowered the connectivity between the above pairs. Changes in functional connectivity correlated with improvement in language scores (letter accuracy as a proxy for written naming) evaluated before and after therapy. These results suggest that one mechanism for anodal tDCS over the left IFG in PPA is a decrease in functional connectivity (compared to sham) between the stimulated site and other posterior areas of the language network. These results are in line with similar decreases in connectivity observed after tDCS over the left IFG in aging and other neurodegenerative conditions.

The effect of tDCS on functional connectivity in primary progressive aphasia

Transcranial direct current stimulation (tDCS) is an innovative technique recently shown to improve language outcomes even in neurodegenerative conditions such as primary progressive aphasia (PPA), but the underlying brain mechanisms are not known. The present study tested whether the additional language gains with repetitive tDCS (over sham) in PPA are caused by changes in functional connectivity between the stimulated area (the left inferior frontal gyrus (IFG)) and the rest of the language network. We scanned 24 PPA participants (11 female) before and after language intervention (written naming/spelling) with a resting-state fMRI sequence and compared changes before and after three weeks of tDCS or sham coupled with language therapy. We correlated changes in the language network as well as in the default mode network (DMN) with language therapy outcome measures (letter accuracy in written naming). Significant tDCS effects in functional connectivity were observed between the stimulated area and other language network areas and between the language network and the DMN. TDCS over the left IFG lowered the connectivity between the above pairs. Changes in functional connectivity correlated with improvement in language scores (letter accuracy as a proxy for written naming) evaluated before and after therapy. These results suggest that one mechanism for anodal tDCS over the left IFG in PPA is a decrease in functional connectivity (compared to sham) between the stimulated site and other posterior areas of the language network. These results are in line with similar decreases in connectivity observed after tDCS over the left IFG in aging and other neurodegenerative conditions.

The effect of tDCS on functional connectivity in primary progressive aphasia

Transcranial direct current stimulation (tDCS) is an innovative technique recently shown to improve language outcomes even in neurodegenerative conditions such as primary progressive aphasia (PPA), but the underlying brain mechanisms are not known. The present study tested whether the additional language gains with repetitive tDCS (over sham) in PPA are caused by changes in functional connectivity between the stimulated area (the left inferior frontal gyrus (IFG)) and the rest of the language network. We scanned 24 PPA participants (11 female) before and after language intervention (written naming/spelling) with a resting-state fMRI sequence and compared changes before and after three weeks of tDCS or sham coupled with language therapy. We correlated changes in the language network as well as in the default mode network (DMN) with language therapy outcome measures (letter accuracy in written naming). Significant tDCS effects in functional connectivity were observed between the stimulated area and other language network areas and between the language network and the DMN. TDCS over the left IFG lowered the connectivity between the above pairs. Changes in functional connectivity correlated with improvement in language scores (letter accuracy as a proxy for written naming) evaluated before and after therapy. These results suggest that one mechanism for anodal tDCS over the left IFG in PPA is a decrease in functional connectivity (compared to sham) between the stimulated site and other posterior areas of the language network. These results are in line with similar decreases in connectivity observed after tDCS over the left IFG in aging and other neurodegenerative conditions.

A Systematic Review of Semantic Feature Analysis Therapy Studies for Aphasia

PURPOSE

The purpose of this study was to review treatment studies of semantic feature analysis (SFA) for persons with aphasia. The review documents how SFA is used, appraises the quality of the included studies, and evaluates the efficacy of SFA.

METHOD

The following electronic databases were systematically searched (last search February 2017): Academic Search Complete, CINAHL Plus, E-journals, Health Policy Reference Centre, MEDLINE, PsycARTICLES, PsycINFO, and SocINDEX. The quality of the included studies was rated. Clinical efficacy was determined by calculating effect sizes (Cohen's d) or percent of nonoverlapping data when d could not be calculated.

RESULTS

Twenty-one studies were reviewed reporting on 55 persons with aphasia. SFA was used in 6 different types of studies: confrontation naming of nouns, confrontation naming of verbs, connected speech/discourse, group, multilingual, and studies where SFA was compared with other approaches. The quality of included studies was high (Single Case Experimental Design Scale average [range] = 9.55 [8.0-11]). Naming of trained items improved for 45 participants (81.82%). Effect sizes indicated that there was a small treatment effect.

CONCLUSIONS

SFA leads to positive outcomes despite the variability of treatment procedures, dosage, duration, and variations to the traditional SFA protocol. Further research is warranted to examine the efficacy of SFA and generalization effects in larger controlled studies.

Relationship between Self-Administered Cues and Rehabilitation Outcomes in Individuals with Aphasia: Understanding Individual Responsiveness to a Technology-Based Rehabilitation Program

An advantage of rehabilitation administered on computers or tablets is that the tasks can be self-administered and the cueing required to complete the tasks can be monitored. Though there are many types of cueing, few studies have examined how participants' response to rehabilitation is influenced by self-administered cueing, which is cueing that is always available but the individual decides when and which cue to administer. In this study, participants received a tablet-based rehabilitation where the tasks were selfpaced and remotely monitored by a clinician. The results of the effectiveness of this study were published previously (Des Roches et al., 2015). The current study looks at the effect of cues on accuracy and rehabilitation outcomes. Fifty-one individuals with aphasia completed a 10-week program using Constant Therapy on an iPad targeted at improving language and cognitive deficits. Three questions were examined. The first examined the effect of cues on accuracy collapsed across time. Results showed a trend where the greater the cue use, the lower the accuracy, although some participants showed the opposite effect. This analysis divided participants into profiles based on cue use and accuracy. The second question examined how each profile differed in percent cue use and on standardized measures at baseline. Results showed that the four profiles were significantly different in frequency of cues and scores on WAB-R, CLQT, BNT, and ASHA-FACS, indicating that participants with lower scores on the standardized tests used a higher percentage of cues, which were not beneficial, while participants with higher scores on the standardized tests used a lower frequency of cues, which were beneficial. The third question examined how the relationship between cues and accuracy was affected by the course of treatment. Results showed that both more and less severe participants showed a decrease in cue use and an increase in accuracy over time, though more severe participants continued to used a greater number of cues. It is possible that self-administered cues help some individuals to access information that is otherwise inaccessible, even if there is not an immediate effect. Ultimately, the results demonstrate the need for individually modifying the levels of assistance during rehabilitation. time, though more severe participants continued to used a greater number of cues. It is possible that self-administered cues help some individuals to access information that is otherwise inaccessible, even if there is not an immediate effect. Ultimately, the results demonstrate the need for individually modifying the levels of assistance during rehabilitation.

Improved word comprehension in Global aphasia using a modified semantic feature analysis treatment

Limited research has investigated treatment of single word comprehension in people with aphasia, despite numerous studies examining treatment of naming deficits. This study employed a single case experimental design to examine efficacy of a modified semantic feature analysis (SFA) therapy in improving word comprehension in an individual with Global aphasia, who presented with a semantically based comprehension impairment. Ten treatment sessions were conducted over a period of two weeks. Following therapy, the participant demonstrated improved comprehension of treatment items and generalisation to control items, measured by performance on a spoken word picture matching task. Improvements were also observed on other language assessments (e.g. subtests of WAB-R; PALPA subtest 47) and were largely maintained over a period of 12 weeks without further therapy. This study provides support for the efficacy of a modified SFA therapy in remediating single word comprehension in individuals with aphasia with a semantically based comprehension deficit.

Treatment of Primary Progressive Aphasia

OPINION STATEMENT

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 home life call for the investigation of treatment alternatives. In this paper, we present a review of the literature on treatment approaches for this neurodegenerative disease. We also present new data from two intervention studies we have conducted, a behavioral one and a neuromodulatory one using transcranial direct current stimulation (tDCS) combined with written production intervention. We show that speech-language intervention improves language outcomes in individuals with PPA, and especially in the short term, tDCS augments generalization and maintenance of positive language outcomes. We also outline current issues and challenges in intervention approaches in PPA.

Non-linguistic learning and aphasia: evidence from a paired associate and feedback-based task

Though aphasia is primarily characterized by impairments in the comprehension and/or expression of language, research has shown that patients with aphasia also show deficits in cognitive-linguistic domains such as attention, executive function, concept knowledge and memory. Research in aphasia suggests that cognitive impairments can impact the online construction of language, new verbal learning, and transactional success. In our research, we extend this hypothesis to suggest that general cognitive deficits influence progress with therapy. The aim of our study is to explore learning, a cognitive process that is integral to relearning language, yet underexplored in the field of aphasia rehabilitation. We examine non-linguistic category learning in patients with aphasia (n=19) and in healthy controls (n=12), comparing feedback and non-feedback based instruction. Participants complete two computer-based learning tasks that require them to categorize novel animals based on the percentage of features shared with one of two prototypes. As hypothesized, healthy controls showed successful category learning following both methods of instruction. In contrast, only 60% of our patient population demonstrated successful non-linguistic category learning. Patient performance was not predictable by standardized measures of cognitive ability. Results suggest that general learning is affected in aphasia and is a unique, important factor to consider in the field of aphasia rehabilitation.

Generalization of the effects of phonological training for anomia using structural equation modelling: a multiple single-case study

Structural Equation Modelling analysis of three longitudinal er-fMRI sessions was used to test the impact of phonological training and of the generalization process on the pattern of brain connectivity during overt picture naming in two chronic anomic patients. Phonological training yielded a positive effect on the trained material. Six months after the training, a generalization of the positive impact on the untrained items was also observed. Connectivity analysis showed that training and generalization effects shared paralleled cortical patterns of functional integration. These findings may represent the neurophysiological correlate of the training-induced cognitive strategies for the compensation of anomia.

Computerised treatment of anomia in acute aphasia: Treatment intensity and training size

In this study we analysed the outcome of computer-assisted therapy (CAT) for anomia on eight acute aphasic patients. Since therapy for anomia generally leads to an item-specific effect, the aim of the present study was to investigate whether it is possible to enhance recovery from anomia by increasing the number of treated items. Two periods of five daily written-naming CAT sessions were compared: In one period the CAT included one set of 48 words (single list) and in the other period a double list of 96 items was treated. Seven out of eight patients improved in naming performance for treated items. Overall gains were superior after practising the double list, despite fewer item repetitions. These results suggest that the size of the effect of therapy for anomia depends more on the number of treated items than on the number of repetitions per item. The integration of these results within the framework of studies on intensity is discussed.

Combining treatment for written and spoken naming

Individuals with left-hemisphere damage often have concomitant impairment of spoken and written language. Whereas some treatment studies have shown that reading paired with spoken naming can benefit both language modalities, little systematic research has been directed toward the treatment of spelling combined with spoken naming. The purpose of this study was to examine the therapeutic effect of pairing a lexical spelling treatment referred to as Copy and Recall Treatment (CART) with verbal repetition of target words. This approach (CART + Repetition) was compared with treatment using verbal repetition without the inclusion of orthographic training (Repetition Only). Two individuals with moderate aphasia and severe impairment of spelling participated in the study using a multiple baseline design across stimulus sets and treatment conditions. Both participants improved spelling of targeted words as well as spoken naming of those items, but improvement in spoken naming was marked for one individual in the CART + Repetition condition, while the other participant made smaller gains in spoken than written naming irrespective of treatment condition. Consideration of the participant profiles suggested that CART + Repetition provides greater benefit when there is some residual phonological ability and the treatment serves to stimulate links between orthography and phonology.

Treatment of irregular word spelling in acquired dysgraphia: selective benefit from visual mnemonics

In contrast to the numerous treatment studies of spoken language deficits, there have been relatively few studies concerned with the treatment of spelling disorders. Among these, there have been only a small number that have targeted specific components of the spelling process. We describe a successful single case treatment study for FME, a woman with acquired dysgraphia, which was conducted within a cognitive neuropsychological framework. Pre-treatment assessment revealed a semantic deficit, impaired access to output orthography and probable additional degradation of the actual representations within the orthographic output lexicon. The treatment study was therefore directed towards relearning spellings by strengthening, and facilitating access to, specific orthographic representations for writing. In order to maximise the functional outcome for FME, treatment was focused on high frequency, irregular words. The treatment programme was carried out in two phases, one without and one with the use of mnemonics, and the results showed a selective training effect with the mnemonics alone. Treatment benefits were item specific but long lasting, and a significant improvement in FME's spelling performance was still evident at 2 months post-treatment. The current study confirms how cognitive neuropsychological theories and methods can be successfully applied to the assessment of acquired spelling impairments, and exemplifies how treatment with carefully designed mnemonics is of benefit if the inability to retrieve orthographic representations for writing is aggravated by a semantic deficit.

What does recovery from anomia tell us about the underlying impairment: The case of similar anomic patterns and different recovery

Although word-finding difficulties have been largely studied from a theoretical and a rehabilitation point of view, recovery mechanisms and especially the fact that patients with similar anomic patterns may exhibit different recovery, are still not fully understood. In the first part of the present study we investigated the word retrieval curve during therapy and the psycholinguistic variables affecting word-finding recovery patterns in three anomic subjects (PG, AH and TM). Despite the fact that all patients had similar anomia at baseline, they presented different recovery patterns during an identical therapy program. The progress during therapy and the number of sessions necessary to reach satisfactory improvement was similar in two patients (AH and TM), but differed in the third patient (PG), who needed more treatment sessions. Moreover, these two different patterns were affected by different psycholinguistic variables: words age of acquisition predicted improvement in AH and TM, whereas phonological neighbourhood predicted improvement in PG. Following the observation that phonological neighbourhood density affected the slower progress during therapy, in the second study we analysed whether this variable also predicts pseudo-word learning in healthy controls and in anomic subjects. Indeed, phonological neighbourhood predicted pseudo-word learning speed in controls and in some anomic patients. We suggest that the analysis of progress during therapy for anomia and the comparison of the variables affecting learning and recovery may provide information about the underlying nature of the anomic deficit that is not available through the simple assessment of performance.

Poststroke Aphasia

Aphasia, the loss or impairment of language caused by brain damage, is one of the most devastating cognitive impairments of stroke. Aphasia is present in 21-38% of acute stroke patients and is associated with high short- and long-term morbidity, mortality and expenditure. Recovery from aphasia is possible even in severe cases. While speech-language therapy remains the mainstay treatment of aphasia, the effectiveness of conventional therapies has not been conclusively proved. This has motivated attempts to integrate knowledge from several domains in an effort to plan more rational therapies and to introduce other therapeutic strategies, including the use of intensive language therapy and pharmacological agents. Several placebo-controlled trials suggest that piracetam is effective in recovery from aphasia when started soon after the stroke, but its efficacy vanishes in patients with chronic aphasia. Drugs acting on catecholamine systems (bromocriptine, dexamfetamine) have shown varying degrees of efficacy in case series, open-label studies and placebo-controlled trials. Bromocriptine is useful in acute and chronic aphasias, but its beneficial action appears restricted to nonfluent aphasias with reduced initiation of spontaneous verbal messages. Dexamfetamine improves language function in subacute aphasia and the beneficial effect is maintained in the long term, but its use is restricted to highly selected samples. Pharmacological agents operating on the cholinergic system (e.g. donepezil) have shown promise. Data from single-case studies, case series and an open-label study suggest that donepezil may have beneficial effects on chronic poststroke aphasia. Preliminary evidence suggests that donepezil is well tolerated and its efficacy is maintained in the long term. Randomised controlled trials of donepezil and other cholinergic agents in poststroke aphasia are warranted.

Management of anomia

Anomia is a complex, commonly occurring symptom of aphasia with different underlying causes. A number of behavioral approaches to rehabilitation of anomia have been described. Some are restitutive in nature and attempt to reactivate lexical-semantic or phonological representations to improve word retrieval. Others are intended to reorganize language functions by engaging alternative cognitive systems to mediate word retrieval or by exploiting residual abilities to circumvent the impairment. A better appreciation of the characteristics of an individual's naming deficit may assist the clinician in selecting appropriate interventions for restitution or substitution of function in the management of this disorder.