Improved naming after transcranial direct current stimulation in aphasia

Transcranial direct current stimulation (tDCS) has been proposed as an adjuvant technique to improve functional recovery after ischaemic stroke. This study evaluated the effect of tDCS over the left frontotemporal areas in eight chronic non-fluent post-stroke aphasic patients. The protocol consisted of the assessment of picture naming (accuracy and response time) before and immediately after anodal or cathodal tDCS (2 mA, 10 minutes) and sham stimulation. Whereas anodal tDCS and sham tDCS failed to induce any changes, cathodal tDCS significantly improved the accuracy of the picture naming task by a mean of 33.6% (SEM 13.8%).     

Dexamphetamine boosts naming treatment effects in chronic aphasia.

To date, minimal research has investigated the effect of combining dexamphetamine with standard naming therapy after stroke. The present study used a double-blind, placebo-controlled, multiple baseline, crossover design with two individuals in the chronic stage of stroke recovery. Each individual attended two 4-week blocks of naming therapy (two to three treatment sessions per week). Dexamphetamine (10 mg) was administered at the start of each session during one therapy block, while a placebo was administered during the other therapy block. Therapy progress on treated and untreated items was assessed by a confrontation naming task during and after each therapy block. Both individuals showed greater progress in therapy and maintenance of therapy gains when behavioral treatment was combined with dexamphetamine rather than placebo, although this gain was only statistically significant in one individual. There was no significant improvement on a control task (nonword reading) in either individual. The results provide preliminary evidence that dexamphetamine paired with combined semantic and phonological therapy may be beneficial for the treatment of naming disorders in chronic aphasia.     

Treatment-induced neuroplasticity following intensive naming therapy in a case of chronic Wernicke's aphasia

Background: Renewed interest in the effects of intensity on treatment has led to development of short-term, intensive treatment protocols, such as Constraint-Induced Language Therapy (CILT), in which participants with chronic aphasia begin to show statistically significant language improvements in as little as 2 weeks. Given its relatively short treatment cycle, CILT is also a good choice of treatment methodology for studying brain/behaviour plasticity in post-stroke aphasia.

Aims: This study aimed to examine differences between two short, intensive treatment protocols in a participant with chronic Wernicke's aphasia both in terms of treatment outcomes and changes in patterns of BOLD signal activation.

Methods & Procedures: The participant (ACL) participated in language testing and an fMRI overt speech confrontation-naming paradigm pre and post 2 weeks of CILT, post 2 weeks of unconstrained language therapy (PACE), and 6 months post-CILT. He named 48 black/white line drawings from each of four conditions: treated (CILT or PACE), untreated, or consistently correctly named pictures.

Outcomes & Results: Naming treated pictures improved, even in the scanner, while naming untreated pictures did not. About one third of PACE and three-fourths of CILT gains were maintained. Rather than a distinct pattern of activation distinguishing treated from untreated or CILT from PACE pictures, ACL recruited a frontal network during naming of all pictures that included left middle and inferior frontal cortex, SMA and pre-SMA, and that varied in spatial extent and degree of activation according to accuracy and performance expectation. In post-hoc analyses of accuracy, this frontal network was most active during incorrect trials. At 6 months post-CILT, compared to controls, incorrect naming recruited a large and significant bilateral network including right Wernicke's area homologue.

Conclusions: Results suggest that short, intensive therapy can improve naming and jumpstart language recovery in chronic aphasia, whether responses are constrained to the speech modality or not. Modulation of a left frontal network was associated with accuracy in naming and may represent compensatory adaptation to improve response selection, self-monitoring, and/or inhibition.     

Effect of propranolol on naming in chronic Broca's aphasia with anomia

Previous research suggests that the noradrenergic system modulates flexibility of access to the lexical-semantic network, with propranolol benefiting normal subjects in lexical-semantic problem solving tasks. Patients with Broca's aphasia with anomia have impaired ability to access appropriate verbal output for a given visual stimulus in a naming task. Therefore, we tested naming in a pilot study of chronic Broca's aphasia patients with anomia after propranolol and after placebo in a double-blinded crossover manner. Naming was better after propranolol than after placebo, suggesting a potential benefit from propranolol in chronic Broca's aphasia with anomia. Larger follow-up studies are necessary to further investigate this effect.     

Noun-verb naming in aphasia: a voxel-based lesion-symptom mapping study

Single case and anatomo-correlative studies of aphasic participants have indicated that lesions in temporal regions cause predominant noun impairment, whereas lesions in frontal areas affect verb processing. These studies, however, relied mostly on arbitrary cut-offs, grouping participants according to whether or not they showed a noun or a verb deficit. Here, instead, we applied a recent anatomo-correlation technique, voxel-based lesion symptom mapping (VLSM) to a group of 16 left-hemisphere stroke participants tested on noun and verb naming tasks. Behavioral and lesion data were collected continuously without establishing a priori two different groups of participants. Noun naming was associated with regions located in the left superior temporal areas, whereas verb naming involved a larger region extending from the left prefrontal to the superior temporal areas. The differences and similarities of the two networks are discussed.     

Cortical mapping of naming errors in aphasia

Persons with aphasia vary greatly with regard to clinical profile; yet, they all share one common feature—anomia—an impairment in naming common objects. Previous research has demonstrated that particular naming errors are associated with specific left hemisphere lesions. However, we know very little about the cortical activity in the preserved brain areas that is associated with aphasic speech errors. Utilizing functional magnetic resonance imaging (fMRI), we show for the first time that specific speech errors are associated with common cortical activity in different types and severities of aphasia. Specifically, productions of phonemic errors recruited the left posterior perilesional occipital and temporal lobe areas. A similar pattern of activity was associated with semantic errors, albeit in the right hemisphere. This study does not discount variability in cortical activity following left hemisphere stroke; rather, it highlights commonalities in brain modulation in a population of patients with a common diagnosis but vastly different clinical profiles. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.     

Compounds in different aphasia categories: a study on picture naming

This study investigated the production of compounds in Italian-speaking patients affected by different aphasia categories (i.e., Broca's, Wernicke's, and anomic aphasia) in a confrontation naming task. Questions of theoretical interest concerning the processing of compounds within the framework of the "lemma theory" as well as the role of morphological productivity in compound processing are addressed. Results indicate that all persons with aphasia retain knowledge of the morphological status of words, even when they fail to retrieve the corresponding phonological form (the "compound effect"). A difference was found among aphasia categories in the type of errors produced (omission vs. substitution) and in the position (first or second) of these errors within the compound words. In Broca's aphasia, the first component is omitted more frequently than the second one, but only in verb-noun compounds. Anomic and Wernicke's aphasia, unlike in Broca's aphasia, seem to retain sensitivity to morphological productivity.     

Using a written cueing hierarchy to improve verbal naming in aphasia

Background: For some individuals with aphasia, writing has been used as an alternative modality for communicating (e.g., Clausen & Beeson, 2003 Clausen, N. S. and Beeson, P. M. 2003. Conversational use of writing in severe aphasia: A group treatment approach.. Aphasiology, 17: 625–644. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]; Lustig & Tompkins, 2002 Lustig, A. P. and Tompkins, C. A. 2002. A written communication strategy for a speaker with aphasia and apraxia of speech: Treatment outcomes and social validity.. Aphasiology, 16(4/5/6): 507–521. [Taylor & Francis Online] , [Google Scholar]). In some investigations where writing ability was treated; post‐treatment and/or anecdotal reports indicated that verbal naming ability also improved for participants with aphasia (e.g., Beeson, Rising, & Volk, 2003 Beeson, P. M., Rising, K. and Volk, J. 2003. Writing treatment for severe aphasia: Who benefits?. Journal of Speech, Language, and Hearing Research, 46(5): 1038–1060.  [Google Scholar]; Kiran, 2005 Kiran, S. 2005. Training phoneme to grapheme conversion for patients with written and oral production deficits: A model‐based approach.. Aphasiology, 19: 53–76. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). In some recent studies, investigators have reported that written naming cueing can improve verbal naming ability (DeDe, Parris, & Waters, 2003 DeDe, G., Parris, D. and Waters, G. 2003. Teaching self‐cues: A treatment approach for verbal naming.. Aphasiology, 17(5): 465–480. [Taylor & Francis Online] , [Google Scholar]; Hillis, 1989 Hillis, A. E. 1989. Efficacy and generalisation of treatment for aphasic naming errors.. Archives of Physical Medicine and Rehabilitation, 70(8): 632–636.  [Google Scholar]).

Aims: The purpose of the present study was to examine the effects of a written cueing treatment programme on verbal naming ability in two adults with aphasia.

Method & Procedures: Treatment involved using a written cueing hierarchy, which was modelled after Copy and Recall Treatment (CART; Beeson, 1999 Beeson, P. M. 1999. Treating acquired writing impairment: Strengthening graphemic representations.. Aphasiology, 13(9–11): 767–785.  [Google Scholar]) and included verbal and writing components. A modified multiple probe across behaviours design was used to document individual participants' response to treatment. The design was replicated across each participant and included baseline, treatment, probe, and maintenance conditions.

Outcomes & Results: Both participants improved their verbal naming ability for the target items over the course of treatment, but they responded differently to the treatment. One participant (P2) maintained verbal naming performance for the treated items 4 weeks after treatment ended and generalised to the untrained items; whereas the other participant (P1) did not.

Conclusions: Results support and extend previous findings that treating in one modality improves performance in a different modality. Further, participants responded differently to the treatment, suggesting that underlying differences in the participants' deficits may account for why they responded differently to the same treatment.     

Anosognosia and self-correction of naming errors in aphasia

ABSTRACT

Background: There has been comparatively little research into anosognosia for aphasia (a lack of awareness of acquired language deficits). Direct assessments of metacognitive awareness tend to rely on high levels of verbal competence and are difficult for people with aphasia to complete. Therefore, indirect measures of awareness have been considered, notably the person’s self-correction of his or her naming errors. Different mechanisms for self-correction based in comprehension or production skills have been proposed. In addition, in other areas of cognition, the relationships between direct and indirect measures and underlying forms of awareness have not been clearly established.

Aims: The aims of this study were: (a) to investigate the relationship between a direct and an indirect measure of awareness of aphasia, (b) to examine the role of executive functioning in performance on both assessment types, and (c) to examine the relationship between these measures and underlying language comprehension and production skills.

Methods & Procedures: A total of 48 people with aphasia participated, drawn from rehabilitation hospital caseloads. Participants were assessed on a language battery, a non-verbal test of executive function, a direct measure of awareness (ratings of difficulties), and had self-correction behaviour examined in a 40-item naming test.

Outcomes & Results: There was a trend relationship between performance on the direct and indirect measures. Both related to overall severity of language impairment, with more severely impaired people being less aware of their difficulties. The two measures, however, dissociated with respect to single-word production and comprehension scores: the direct measure related to production and not comprehension, while the indirect measure related to comprehension and not production. Executive functioning related only to the direct measure of metacognitive awareness. Within production scores, the rate of correction success rather than pre-correction naming rate was associated with metacognitive awareness.

Conclusions: This study revealed different underlying bases, in language processes and executive function, for two measures of anosognosia for aphasia. When used to assess awareness of deficits, direct and indirect methods should not be regarded as equivalent.     

Modelling confrontation naming and discourse performance in aphasia

Background: It is well documented in the literature that the ability to produce discourse is what matters most to people with aphasia (PWA) and their families. However, quantifying discourse in typical clinical settings is a challenging task due to its dynamic and multiply determined nature. As a result, professionals often depend on confrontation naming tests to identify and measure impaired underlying cognitive mechanisms that are also hypothesised to be important for discourse production.

Aims: The main goals of the study were to investigate the extent to which confrontation naming test (CNT) scores are predictive of (i) the proportion of paraphasias in connect speech, and (ii) the amount of information PWA can effectively communicate.

Methods & Procedures: Data from 98 monolingual PWA were retrieved from AphasiaBank and analysed using structural equation modelling. Performance in CNTs was modelled as a latent variable based on the Boston Naming Test, the Western Aphasia Battery–R Naming Subtest, and the Verb Naming Test. Performance at the discourse level was modelled based on the observed proportions of paraphasias in three discourse tasks (free speech, eventcasts, and story retell). Informativeness was quantified using the percentage of Correct Information Units based on story re-tell.

Outcomes & Results: For the first question, the regression coefficient between the two latent factors was estimated to be –0.52. When the latent factor based on the CNTs was regressed on informativeness, the estimated regression coefficient was equal to 0.68.

Conclusions: Performance on CNTs was not a strong predictor of the proportion of paraphasias produced in connected speech but was substantially higher for the amount of information communicated by PWA. Clinicians are cautioned not to predict a speaker’s performance at the discourse level after establishing CNT performance. Other anomic behaviours (e.g., pauses) during discourse production may be associated with CNT performance and should be considered in future investigations.     

Influence of rate of treatment on the naming abilities of adults with chronic aphasia

Abstract

There is a lack of empirical evidence on which clinicians can base their daily decisions about aphasia treatment rate and duration. The purpose of this series of studies was to review the outcomes of various rates of speech/language therapy on the naming performances of adults with aphasia. A retrospective pre/post design was employed with a total of 40 subjects across studies. Results revealed the significant positive effects of intensive speech/language therapy on the naming skills of adults with aphasia, and that these improvements were greater than those obtained during non-intensive treatment, Although there are limitations of the treatment-based, retrospective research design, this line of research contributes to the ability of rehabilitation professionals to make appropriate treatment recommendations regarding treatment rate.     

On the nature of naming difficulties in aphasia.

An extensive naming battery was administered to ten patients representing classical aphasia syndromes. The battery included traditional performance measures and error scoring, phonological cuing, multiple-choice tasks tapping semantic and phonological knowledge, and word repetition tests. Differences in the patients' performance profiles were interpreted as reflecting lexical-phonological, phoneme assembly or multiple deficits. The results suggest that the hypothesized naming deficits have complex relationships to classical aphasia syndromes.     

Treatment of naming in nonfluent aphasia through manipulation of intention and attention: a phase 1 comparison of two novel treatments.

Twenty-three chronic nonfluent aphasia patients with moderate or severe word-finding impairments and 11 with profound word-finding impairments received two novel picture-naming treatments. The intention treatment initiated picture-naming trials with a complex left-hand movement and was designed to enhance right frontal participation during word retrieval. The attention treatment required patients to view visual stimuli for picture-naming trials in their left hemispace and was designed to enhance right posterior perisylvian participation during word retrieval. Because the intention treatment addressed action mechanisms and nonfluent aphasia reflects difficulty initiating or maintaining action (i.e., language output), it was hypothesized that intention component of the treatment would enhance re-acquisition of picture naming more than the attention component. Patients with moderate and severe word-finding impairment showed gains with both treatments but greater incremental improvement from one treatment phase to the next with the intention than the attention treatment. Thus, the hypothesis that intention component would be a more active constituent than the attention component was confirmed for these patients. Patients with profound word-finding impairment showed some improvement with both treatments but no differential effects for the intention treatment. Almost all patients who showed treatment gains on either treatment also demonstrated generalization from trained to untrained items.     

The utility of computerized visual communication for improving natural language in chronic global aphasia: Implications for approaches to treatment in global aphasia

A computerized communication system (C-VIC) was employed as a diagnostic and therapeutic tool to identify propositional language abilities in a chronic, globally aphasic patient. The patient demonstrated the ability to construct sentences during training according to abstract syntax-like rules by manipulating iconic symbols representing nouns and verbs. Further, he produced correct symbolic order to express the thematic relationships in sentences. The effect of C-VIC as a therapeutic intervention to improve the patient's natural language abilities was examined using pre- and post-training assessments. Improvements specific to training were observed but neither improvements in natural language nor generalization to production of multiple sentences using C-VIC was found. The results are discussed with regard to current debates concerning treatment approaches and the use of augmentative communication devices for globally aphasic patients.     

Decreasing and increasing cues in naming therapy for aphasia

Background : Applying a hierarchy of cues is a well-established method in therapy for aphasic naming disorders (see overview in Nickels, 2002b; and Hillis & Caramazza, 1994; Wambaugh, 2003). Usually, cues are used in the increasing direction. Giving assistance as sparsely as possible, the naming of an individual item remains effortful which enhances the chance to recall it later on. But the high opportunity to make errors may be disadvantageous. As an alternative, the method of vanishing cues (see Glisky, 1992), which was designed for treatment of memory disorders, provides as much assistance as needed, thereby helping patients to avoid errors (see Riley & Heaton, 2000). Therefore, this method complies with “errorless learning” (see Baddeley & Wilson, 1994). It is favoured when amnesic patients have to learn new information. In aphasia therapy, the errorless learning procedure may be interesting for patients with severe naming disorders because it prevents them from producing frequent errors. Aims : The purpose of this study was to compare the effectiveness of increasing and vanishing cues for aphasic patients with naming disorders in a 4-week therapy programme. As patients may differ in the underlying mechanism of impairment, we expected a different therapy effect among and within patients. Furthermore, the importance of errorless learning should increase with severity of impairment because of error opportunity. Methods & Procedures : A total of 100 line drawings were selected and split into four sets of 25 items each. The sets were assigned to four conditions: control (no training), vanishing cue, increasing cue, and both-cue condition (training with both methods). Then 20 therapy sessions were ordered according to the alternating treatments design. During treatment, the patient's attempts to name a picture were assisted by a hierarchy of oral cues given by the therapist. Treatment methods differed in order of application but not in the type of cues used. Outcomes & Results : Cueing therapy in general was effective for 8 of 10 patients. Those patients with moderate naming disorders profited less than those with severe naming disorders. Both methods differed among and within patients. However, in contrast to our prediction, we found no patient who improved only under vanishing cues but several who showed positive effects with increasing cues alone or with both, increasing and vanishing cues. Conclusions : Unlike patients with amnesia, patients with aphasia do not seem to be troubled by their errors and may not require the vanishing cue method.