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.     

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.     

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.     

A case of mixed transcortical aphasia with intact naming.

Altholgh Lichtheim recognized that Wernicke's 'reflex arch' (primary auditory area, to Wernicke's area, to Broca's area, to primary motor area) was important for repetition, he recognized that other areas of the brain (for example, area of concepts or semantic area) must be important in comprehension and voluntary speech. He suggested that Wernicke's area (phonemic area) not only projected to Broca's area (as Wernicke suggested) but that it also projected to the area of concepts. A lesion of this latter pathway or in the area of concepts would produce a syndrome where repetition was intact but comprehension was impaired (e.g. transcortical sensory aphasia). Lichtheim also thought that the area of concepts projected directly to Broca's area and that voluntary speech was mediated by this pathway. Although Lichtheim's model could explain the mechanism underlying transcortical aphasia, his schema could not explain anomic aphasia. Unlike Lichtheim's schema, Kussmaul's schema suggested that the area of concepts projects back to Wernicke's area before projecting to Broca's area. With this schema, a patient with a hypothetical lesion which interrupted the pathway from the area of concepts to Wernicke's area (but did not interrupt the pathway from Wernicke's area to the area of concepts) should be anomic, with normal comprehension and repetition. In order for this latter schema to be plausible there should also be a lesion which interrupts the pathway from Wernicke's area to the area of concepts but does not interrupt the pathway which goes from the area of concepts to Wernicke's area. A patient with this hypothetical lesion should comprehend poorly; however, in spite of poor comprehension, naming and repetition should be intact. We report a patient who demonstrates poor comprehension with intact naming and repetition. This patient could also read aloud but could not comprehend written language. Not only could this patient name objects but he could demonstrate their use. These observations suggest that comprehension of written language is mediated by a different pathway than the recognition of visually presented objects.     

The interactional organization of aphasia naming testing

Abstract

In this article, Conversation Analysis (CA) is used to investigate the nature of aphasia naming tests in terms of their properties as a specialized form of social interaction. The basic test-item sequence which occurs in these tests is shown to be made up of a three-part sequential structure consisting of (1) a testing prompt, (2) a proffered answer by the testee, and (3) an acceptance or declining of that proffered answer by the tester. A declining prompts a further answer to be proffered, and this cycle continues until either an answer is accepted by the tester or until the participants treat the testee as being unable to produce the relevant picture name. It is suggested that the results of the analysis have implications for understanding naming tests as instruments which generate theoretical and clinical findings through particular talk-in-interaction practices.     

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.     

Effects of phonological neighbourhood on the treatment of naming in aphasia

Background: Phonological treatments to improve naming ability in aphasia focus on re-strengthening connections within the phonological system. Nonetheless, the efficacy of phonological treatments is still being explored with particular consideration of cognitive neuropsychological perspectives. Clinicians may also need to consider lexical factors that interact with the word retrieval process. Researchers have shown that phonological neighbourhood density influences normal language recognition and production, but limited evidence exists for how phonological neighbourhoods may affect the treatment of word retrieval deficits in individuals with aphasia.

Aims: The present study explored if manipulating the emphasis on phonological neighbourhood during treatment has an effect on naming ability, particularly in an individual with predominantly phonologically based deficits. We hypothesised that training front- and end-matched words in a condition that emphasised phonological neighbourhood would result in greater naming improvements than training front- and end-matched words in a condition that does not emphasise neighbourhood.

Methods & Procedures: In this case study, participant AH had a moderate phonologically based word naming deficit following a stroke. He produced phonemic paraphasias and neologisms in spontaneous speech and other spoken word production tasks. In treatment, AH was asked to name triplets of pictures of items that were phonologically related, sharing initial or final phonemes, or unrelated. Items were from either high- or low-density phonological neighbourhoods. High-density items were trained largely in the context of neighbours, therefore emphasising neighbourhood. Low-density items were not trained within a condition that emphasise neighbourhood. The treatment was administered for 9 weeks (27 sessions), with each condition, front-matched, end-matched and unrelated, trained for 8 consecutive sessions. AH’s naming accuracy on training words was assessed using a basic withdrawal design with three probe naming tests during the treatment phase and at 1-month post-therapy. Naming accuracy was also recorded during treatment sessions.

Outcomes & Results: Front-matched words, in a condition that emphasises phonological neighbourhoods, had the greatest treatment effects, with a medium effect size when comparing pre- versus post-measures. A small treatment effect was observed for front-matched items where neighbourhood was not emphasised.

Conclusions: Results suggest that front-matched triplets trained within a condition that emphasises phonological neighbourhoods may lead to the greatest treatment effect. Clinicians should be aware that stimulus parameters, such as phonological neighbourhood, may interact with the effectiveness of treatment protocols.     

Phonological naming therapy in jargon aphasia: positive but paradoxical effects.

This article is a single-case investigation of phonological naming therapy. The individual involved had fluent jargon speech, with neologisms, verbal paraphasias, and paragrammatisms. The jargon was underpinned by a severe anomia. Content words were rarely accessed either in spontaneous speech or naming. Single word investigations highlighted some preserved skills. Auditory comprehension, at least for concrete words, was relatively intact and although nonwords could not be repeated, words could, and at a level which was far superior to naming. The patient also had some ability to respond to phonological cues. These results suggested that phonological representations were preserved and that there were some intact semantic abilities. It seemed that the naming disorder was primarily due to an inability to access phonology from semantics. Therapy took a phonological approach. The patient was encouraged to reflect upon the syllabic structure and first phoneme of pictured targets. Subsequently, she was required to use this partial phonological knowledge as a self-cue. It was hypothesized that this therapy might equip the subject with a self-cuing naming strategy. Posttherapy investigations of naming demonstrated dramatic improvements, which generalized to untreated items. However, there was little evidence that these were due to a self cuing strategy. Performance on phonological judgment and discrimination assessments, which required conscious phonological reflection, was unchanged, and there were no signs that the patient was self-cuing during naming. Reasons for these paradoxical results are discussed.     

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%).     

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.     

Deterioration of naming nouns versus verbs in primary progressive aphasia

Disproportionate impairment of naming nouns versus verbs and the opposite pattern have been reported in cases of focal brain damage or degenerative disease, indicating that processing of nouns and verbs may rely on different brain regions. However, it has not been clear whether it is the spoken word forms or the meanings (or both) of nouns and verbs that depend on separate neural regions. We tested oral and written naming of nouns and verbs, matched in difficulty, in patients with nonfluent primary progressive aphasia (nonfluent PPA; n = 15), fluent primary progressive aphasia (fluent PPA; n = 7), and amyotrophic lateral sclerosis with frontotemporal dementia (ALS-FTD; n = 6). Patients with nonfluent PPA and ALS-FTD, both individually and as groups, were significantly more impaired on verb naming than on noun naming and significantly more impaired on oral naming than written naming. Patients with fluent PPA showed the opposite pattern for both word class and modality, significantly more impaired naming of nouns versus verbs and significantly more impaired written versus oral naming. Results indicate that separate regions of the brain are essential for access to oral and written word forms of verbs and nouns, and that these neural regions can be differentially damaged in separate forms of PPA.     

Modality-specific deterioration in naming verbs in nonfluent primary progressive aphasia

A longitudinal study of oral and written naming and comprehension of nouns and verbs in an individual (M. M. L.) with nonfluent primary progressive aphasia (PPA) is reported. M. M. L. showed progressive deterioration of oral naming of verbs well before deterioration of written naming of verbs and before deterioration of oral or written naming of nouns. Her comprehension of both nouns and verbs remained intact, at least relative to oral naming of verbs. Her performance is compared to that of two other individuals with nonfluent PPA, who were tested at two time points. These patients showed similar patterns with respect to grammatical word class (verbs more impaired than nouns) and modality (spoken production more impaired than written production), but somewhat different courses of deterioration. The modality-specific nature of the observed verb production deficits rules out a semantic locus for the grammatical class effects. The results provide a new source of evidence for the hypothesis that there are distinct neural mechanisms for accessing lexical representations of nouns and verbs in language production.     

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.     

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.     

Therapy for naming deficits in two variants of primary progressive aphasia

Background: Primary progressive aphasia (PPA) refers to a progressive and selective decline in language due to neurodegenerative disease. There are three variants of PPA, progressive nonfluent aphasia (PNFA), semantic dementia (SD), and logopaenic progressive aphasia (LPA). All variants include impaired object naming, but distinct underlying deficits might interfere with naming. Therefore, individuals with different types of PPA may respond differently to naming therapy.

Aims: To identify differences in patterns of success and generalisation in response to the same treatment in patient with LPA and a patient with SD. Furthermore, we wished to identify whether the treatment effect was item specific (trained words) or generalised to untrained words in trained or untrained categories.

Methods & Procedures: Participants included an individual with LPA and one with SD. An assessment of lexical processing was administered before and after a naming treatment to assess underlying deficits and generalisation effects. Therapy consisted of a cueing hierarchy treatment. Treatment items consisted of pictured objects in the categories of fruits/vegetables and clothing.

Outcomes & Results: Two different patterns of performance were observed. The LPA participant improved in naming of treated items and untreated items in both treated and untreated categories. The participant with SD improved in naming treated items only, but showed less deterioration in untreated items in treated than untreated categories.

Conclusions: Individuals with PPA can show improved naming (at least temporarily) with therapy, but generalisation to untrained items may depend on the underlying cause of the naming deficit, which may differ across subtypes.     

Name it again! investigating the effects of repeated naming attempts in aphasia

ABSTRACT

Background: In the context of therapy for word retrieval in aphasia, the person with aphasia is often required to attempt to name treated items on multiple occasions. However, there is limited information about the impact of these repeated attempts at naming in and of themselves.

Aim: The aim of this study was to examine if repeated attempts at naming, with no treatment or feedback, improve naming accuracy in people with aphasia.

Methods & Procedures: 23 participants with stroke aphasia named 50 pictures on seven occasions, approximately six weeks apart. No support, cues (written or spoken) or feedback on accuracy was provided at the time or between naming attempts. This was part of a larger study investigating two different types of therapy on different items.

Outcomes & Results: After excluding any potential influence from treatment of other items, four participants showed significant improvements in accuracy and two participants showed a worsening of accuracy for the stimuli that received repeated naming attempts (but were untreated). We found evidence that significant change in accuracy was predicted by the variability of naming accuracy between sessions, executive functioning skills (as measured by the Wisconsin Card Sorting Task), and picture naming ability (Nickels’ Naming Test).

Conclusions: We hypothesised that in the context of variability in naming accuracy, intact executive functioning may help monitor responses, such that only correctly named items are reinforced. Critically, without the ability to monitor responses without feedback, incorrect responses may be reinforced, leading to a worsening of performance. The fact that four individuals with aphasia showed improved naming accuracy by naming items once every six weeks is striking and suggests that further investigation of effects of repeated naming at closer intervals is warranted, as for some participants any advantage from a naming attempt may have decayed by the time of repetition.     

Transcortical sensory aphasia: Dissociation between naming and comprehension

Abstract

Although anomia in transcortical sensory aphasia (TSA) is usually described as a semantically based deficit (naming and recognition are equally affected), dissociations in naming performance have occasionally been reported. We report a two-part study: in Study 1 the pattern of preserved and impaired language abilities was examined in five patients with TSA and intact object naming; in Study 2 the neural mechanism(s) underlying preserved visual confrontation naming in TSA was examined. Demographic factors, severity of language deficits, lesion volume and location, and cerebral asymmetries of patients with TSA and intact naming (TSA-intact) (n = 6) were compared with those of patients with TSA and impaired naming (TSA-impaired) (n = 6), anomic aphasia (Anomia) (n = 6), and left hemisphere damage without aphasia (Control). The results of Study 1 revealed that all five patients had a relative preservation of oral production (spontaneous speech, repetition, naming and reading aloud), but impaired auditory and written (sentence-level) comprehension. Object/picture naming was significantly better than auditory comprehension of the same targets, and naming was also preserved in tactile and auditory (verbal definitions and non-verbal sounds) modalites, but written naming was impaired. In four patients oral reading showed a pattern of phonological dyslexia. The results of Study 2 failed to demonstrate significant differences between the groups with preserved naming (TSA-intact and control) and those with impaired naming (TSA-impaired and anomia) in non-language variables that might explain the selective preservation or impairment of naming. These results are discussed in terms of the functional and anatomical independence of the neural systems responsible for object naming and comprehension.     

Patterns of decline in naming and semantic knowledge in primary progressive aphasia

Background: Individuals with primary progressive aphasia (PPA) and their caregivers want to know what to expect so that they can plan support appropriately. The ability to predict decline in naming and semantic knowledge, and advise individuals with PPA and their caregivers regarding future planning, would be invaluable clinically.

Aims: The aims of this study were to investigate patterns of decline in naming and semantic knowledge in each of the clinical variants of PPA (logopenic variant PPA, lvPPA; nonfluent agrammatic PPA, nfaPPA; and semantic variant PPA, svPPA) and to examine the effects of other variables on rate of decline. We hypothesized that speech-language rehabilitation, higher education, and higher baseline test scores would be associated with slower decline, and older age with faster decline.

Methods and Procedures: A total of 94 participants with PPA underwent language testing, including 36 participants with lvPPA, 31 participants with nfaPPA, and 27 participants with svPPA. All participant groups were similar in age and education. We focused on decline on three tests: the short form of the Boston Naming Test (BNT), the Hopkins Assessment of Naming Actions (HANA), and the short form of the Pyramids and Palm Trees Test (PPTT).

Outcome and Results: Across language tests, the most precipitous rates of decline (loss of points per month) occurred in nfaPPA, followed by svPPA, then lvPPA. Female sex, longer symptom duration, higher baseline test score, and speech-language rehabilitation were associated with slower decline.

Conclusions: PPA variants were distinguishable by rapidity of decline, with nfaPPA having the most precipitous decline. As hypothesized, higher baseline test scores and speech-language rehabilitation were associated with slower decline. Surprisingly, age and education were not important prognostically for individuals in this study. Further study of prognostically-relevant variables in PPA is indicated in this population.