Agrammatic Aphasia Research Articles

Preserved processing of musical structure in a person with agrammatic aphasia

ABSTRACTEvidence for shared processing of structure (or syntax) in language and in music conflicts with neuropsychological dissociations between the two. However, while harmonic structural processing can be impaired in patients with spared linguistic syntactic abilities (Peretz, I. (1993). Auditory atonalia for melodies. Cognitive Neuropsychology, 10, 21–56. doi:10.1080/02643299308253455), evidence for the opposite dissociation–preserved harmonic processing despite agrammatism–is largely lacking. Here, we report one such case: HV, a former musician with Broca’s aphasia and agrammatic speech, was impaired in making linguistic, but not musical, acceptability judgments. Similarly, she showed no sensitivity to linguistic structure, but normal sensitivity to musical structure, in implicit priming tasks. To our knowledge, this is the first non-anecdotal report of a patient with agrammatic aphasia demonstrating preserved harmonic processing abilities, supporting claims that aspects of musical and linguistic structure rely on distinct neural mechanisms.

Predicting Decline in Agrammatism, Apraxia of Speech and Parkinsonism in Agrammatic Primary Progressive Aphasia (P4.030)

Predicting Decline in Agrammatism, Apraxia of Speech and Parkinsonism in Agrammatic Primary Progressive Aphasia (P4.030)

Frontotemporal Dementias.

This article reviews the common behavioral and cognitive features of frontotemporal dementia (FTD) and related disorders as well as the distinguishing clinical, genetic, and pathologic features of the most common subtypes. Advances in clinical phenotyping, genetics, and biomarkers have enabled improved predictions of the specific underlying molecular pathology associated with different presentations of FTD. Evaluation of large international cohorts has led to recent refinements in diagnostic criteria for several of the FTD subtypes. The FTDs are a group of neurodegenerative disorders featuring progressive deterioration of behavior or language and associated pathology in the frontal or temporal lobes. Based on anatomic, genetic, and neuropathologic categorizations, the six clinical subtypes of FTD or related disorders are: (1) behavioral variant of FTD, (2) semantic variant primary progressive aphasia, (3) nonfluent agrammatic variant primary progressive aphasia, (4) corticobasal syndrome, (5) progressive supranuclear palsy, and (6) FTD associated with motor neuron disease. Recognition and accurate diagnoses of FTD subtypes will aid the neurologist in the management of patients with FTD.

Grammatical Encoding and Learning in Agrammatic Aphasia: Evidence from Structural Priming.

The present study addressed open questions about the nature of sentence production deficits in agrammatic aphasia. In two structural priming experiments, 13 aphasic and 13 age-matched control speakers repeated visually- and auditorily-presented prime sentences, and then used visually-presented word arrays to produce dative sentences. Experiment 1 examined whether agrammatic speakers form structural and thematic representations during sentence production, whereas Experiment 2 tested the lasting effects of structural priming in lags of two and four sentences. Results of Experiment 1 showed that, like unimpaired speakers, the aphasic speakers evinced intact structural priming effects, suggesting that they are able to generate such representations. Unimpaired speakers also evinced reliable thematic priming effects, whereas agrammatic speakers did so in some experimental conditions, suggesting that access to thematic representations may be intact. Results of Experiment 2 showed structural priming effects of comparable magnitude for aphasic and unimpaired speakers. In addition, both groups showed lasting structural priming effects in both lag conditions, consistent with implicit learning accounts. In both experiments, aphasic speakers with more severe language impairments exhibited larger priming effects, consistent with the "inverse preference" prediction of implicit learning accounts. The findings indicate that agrammatic speakers are sensitive to structural priming across levels of representation and that such effects are lasting, suggesting that structural priming may be beneficial for the treatment of sentence production deficits in agrammatism.

The effect of syntactic frequency on sentence comprehension in standard Indonesian Broca’s aphasia

ABSTRACTBackground: Comprehension of reversible sentences that have derived word order has often been reported as impaired in agrammatic aphasia. Most accounts of this phenomenon refer to the syntactic differences between derived and base word order of the arguments. However, it has been demonstrated that in agrammatic spontaneous speech in standard Indonesian (SI) passives are produced at a rate that is proportional to that of healthy speakers. The main difference between passives in SI and in other languages is the frequency with which passives are used: passives in SI are highly frequent. The high frequency can be explained by the fact that passives are used for politeness reasons, saliency of the passive morphology, earlier acquisition, and formal simplicity of the passive structure.Aims: The purpose of the current study is to investigate comprehension of the passive as a derived structure in SI and the influence of frequency.Methods & Procedures: A sentence-to-picture matching task was developed to test four reversible sentence types (active, passive, subject cleft and object cleft). There are three variables that are of interest, that is, word order, embedding and relative frequency of structures. Eleven agrammatic speakers classified as suffering from Broca’s aphasia were tested.Outcomes & Results: The passive sentences were comprehended equally well as the active sentences. Embedding had limited effects: subject clefts were understood as well as actives and passives. Object clefts, however, were understood poorly and significantly worse than the three other sentence types.Conclusions: The sentence comprehension deficit pattern shown in SI individuals with Broca’s aphasia introduces frequency of a syntactic structure as an additional factor to consider. Whether frequency or pragmatic constraints protects against erosion of the passive in Broca’s aphasia in SI remains an open question.

Implicit learning and implicit treatment outcomes in individuals with aphasia

ABSTRACTBackground: Implicit learning is a process of learning that occurs outside of conscious awareness and may be involved in implicit, exposure-based language training. However, research shows that implicit learning abilities are variable among individuals with aphasia, and it remains unknown whether individuals who show basic implicit learning abilities also benefit from implicit language training.Aims: The aims of this series of experiments were to test implicit learning in individuals with agrammatic aphasia, examine the effects of a novel implicit language treatment, and investigate whether individuals with aphasia who show implicit learning ability also benefit from implicit treatment focused on passive sentence comprehension.Methods & Procedures: Nine participants with chronic agrammatic aphasia and 21 neurologically intact participants completed a visuomotor serial reaction time test of implicit learning (Experiment 1). The participants with aphasia also completed a short-term novel implicit sentence comprehension treatment (Experiment 2) that consisted of five sessions of repeated exposure to grammatically correct passive sentences and matching photographs. Sentence comprehension was tested in multiple baseline sessions and on each day of training using a sentence–picture matching task. The relation between participants’ learning patterns across experiments was also examined.Outcomes & Results: Individuals with agrammatic aphasia as well as neurologically intact adults demonstrated significant implicit sequence learning in the serial reaction time task. However, the participants with aphasia did not show concomitant improvement in sentence comprehension as a result of the implicit treatment protocol.Conclusions: This study suggests that individuals with agrammatic aphasia demonstrate implicit learning ability; however, this ability does not necessarily promote successful outcomes in treatment that is based solely on implicit training methods.

Agrammatic Aphasia following Right versus Left Basal Ganglia Lesions: case reports and review of the literature

Agrammatic Aphasia following Right versus Left Basal Ganglia Lesions: case reports and review of the literature

Language recovery in aphasia following implicit structural priming

Language recovery in aphasia following implicit structural priming

Subject�Verb Agreement in Turkish Agrammatic Broca�s Aphasia: Comparison of Person and Number Features

Subject�Verb Agreement in Turkish Agrammatic Broca�s Aphasia: Comparison of Person and Number Features

Manifestation of Agrammatism in Hindi-English Bilingual Aphasia

Manifestation of Agrammatism in Hindi-English Bilingual Aphasia

Online Syntactic Prediction in Agrammatic Aphasia: Evidence from ERPs

Online Syntactic Prediction in Agrammatic Aphasia: Evidence from ERPs

Corticobasal Degeneration Presenting as Non-Fluent/Agrammatic Primary Progressive Aphasia: A Case Report

BackgroundNon-fluent agrammatic primary progressive aphasia (naPPA) is characterized by progressive non-fluent speech disorder and might be associated with taupathy such as corticobasal degeneration (CBD) and progressive supranuclear palsy. We report a case of overlap syndrome presented with language impairment, and diagnosed as naPPA with possible CBD.Case ReportA 58-year-old woman visited a memory and dementia clinic, with a 10-month history of progressive language disturbance. She was diagnosed as naPPA and overlapping CBD, based on the clinical features and neuroimaging findings including florbetaben PET.ConclusionsnaPPA is pathologically caused by taupathy, and might progress to asymmetrical parkinsonism and apraxia, suggestive of CBD. Overlapping clinical features in our case represent various phenotypes of taupathy.

Verb-production treatment in multilingual aphasia: Cross-linguistic generalization or inhibition?

Verb-production treatment in multilingual aphasia: Cross-linguistic generalization or inhibition?

Frequency, activation, and the production of verb inflection in agrammatic aphasia

ABSTRACTBackground: The production of verb inflectional morphology has been shown to be differentially impaired in agrammatic aphasia: agreement is preserved relative to tense. The consistency with which this pattern has been observed across a wide range of typologically diverse languages should be viewed as surprising, given that language-specific characteristics have been demonstrated to correlate with differences in agrammatic performance on various grammatical constructions. In addition, the preservation of agreement, a primarily syntactic inflection, over tense, a semantic inflection, appears to run counter to previous research showing impairments of syntactic processing in agrammatic aphasia. Representational and processing-based accounts have attempted to explain the dissociation of agreement and tense morphology in agrammatic speech, but have neglected these two points.Aims: The purpose of this review is to investigate the degree to which current theories can account for the differential impairment of agreement and tense, and to propose a new theory that is situated in the larger context of language production models. Discussion will explore the role of frequency and the activation effects of elements that frequently co-occur during language production. Based on this review, the Grammatical Encoding Co-Occurrence (GECO) Frequency Hypothesis will be proposed. This hypothesis attributes the preservation of agreement over tense to the co-occurrence of grammatical features at the stage of language production when inflectional morphology is encoded. Main Contribution: The GECO Frequency Hypothesis accounts for the preservation of agreement relative to tense in the context of cross-linguistic differences by making reference to aspects of inflectional morphology and language production that are common across languages. It is compatible with the results obtained from previous studies, and adds precision and clarity to the previous accounts of the differential impairment of agreement and tense. More generally, the hypothesis contributes to an understanding of the role of frequency at different stages in language production. Implications of the GECO Frequency Hypothesis for both agrammatic and normal language production include that language production is an activation-based process rather than one involving syntactic operations per se.Conclusions: The differential impairment of agreement and tense morphology in agrammatic aphasia is a result of the co-occurrence frequency of grammatical features activated during the language production process, rather than impairments to specific morphological representations or syntactic processes.

Morpho-syntactic processing of Arabic plurals after aphasia: dissecting lexical meaning from morpho-syntax within word boundaries

Within the domain of inflectional morpho-syntax, differential processing of regular and irregular forms has been found in healthy speakers and in aphasia. One view assumes that irregular forms are retrieved as full entities, while regular forms are compiled on-line. An alternative view holds that a single mechanism oversees regular and irregular forms. Arabic offers an opportunity to study this phenomenon, as Arabic nouns contain a consonantal root, delivering lexical meaning, and a vocalic pattern, delivering syntactic information, such as gender and number. The aim of this study is to investigate morpho-syntactic processing of regular (sound) and irregular (broken) Arabic plurals in patients with morpho-syntactic impairment. Three participants with acquired agrammatic aphasia produced plural forms in a picture-naming task. We measured overall response accuracy, then analysed lexical errors and morpho-syntactic errors, separately. Error analysis revealed different patterns of morpho-syntactic errors depending on the type of pluralization (sound vs broken). Omissions formed the vast majority of errors in sound plurals, while substitution was the only error mechanism that occurred in broken plurals. The dissociation was statistically significant for retrieval of morpho-syntactic information (vocalic pattern) but not for lexical meaning (consonantal root), suggesting that the participants' selective impairment was an effect of the morpho-syntax of plurals. These results suggest that irregular plurals forms are stored, while regular forms are derived. The current findings support the findings from other languages and provide a new analysis technique for data from languages with non-concatenative morpho-syntax.

A Computational Evaluation of Sentence Processing Deficits in Aphasia.

Individuals with agrammatic Broca's aphasia experience difficulty when processing reversible non-canonical sentences. Different accounts have been proposed to explain this phenomenon. The Trace Deletion account (Grodzinsky, 1995, 2000, 2006) attributes this deficit to an impairment in syntactic representations, whereas others (e.g., Caplan, Waters, Dede, Michaud, & Reddy, 2007; Haarmann, Just, & Carpenter, 1997) propose that the underlying structural representations are unimpaired, but sentence comprehension is affected by processing deficits, such as slow lexical activation, reduction in memory resources, slowed processing and/or intermittent deficiency, among others. We test the claims of two processing accounts, slowed processing and intermittent deficiency, and two versions of the Trace Deletion Hypothesis (TDH), in a computational framework for sentence processing (Lewis & Vasishth, 2005) implemented in ACT-R (Anderson, Byrne, Douglass, Lebiere, & Qin, 2004). The assumption of slowed processing is operationalized as slow procedural memory, so that each processing action is performed slower than normal, and intermittent deficiency as extra noise in the procedural memory, so that the parsing steps are more noisy than normal. We operationalize the TDH as an absence of trace information in the parse tree. To test the predictions of the models implementing these theories, we use the data from a German sentence-picture matching study reported in Hanne, Sekerina, Vasishth, Burchert, and De Bleser (2011). The data consist of offline (sentence-picture matching accuracies and response times) and online (eye fixation proportions) measures. From among the models considered, the model assuming that both slowed processing and intermittent deficiency are present emerges as the best model of sentence processing difficulty in aphasia. The modeling of individual differences suggests that, if we assume that patients have both slowed processing and intermittent deficiency, they have them in differing degrees.

Classification and clinicoradiologic features of primary progressive aphasia (PPA) and apraxia of speech

The consensus criteria for the diagnosis and classification of primary progressive aphasia (PPA) have served as an important tool in studying this group of disorders. However, a large proportion of patients remain unclassifiable whilst others simultaneously meet criteria for multiple subtypes. We prospectively evaluated a large cohort of patients with degenerative aphasia and/or apraxia of speech using multidisciplinary clinical assessments and multimodal imaging. Blinded diagnoses were made using operational definitions with important differences compared to the consensus criteria. Of the 130 included patients, 40 were diagnosed with progressive apraxia of speech (PAOS), 12 with progressive agrammatic aphasia, 9 with semantic dementia, 52 with logopenic progressive aphasia, and 4 with progressive fluent aphasia, while 13 were unclassified. The PAOS and progressive fluent aphasia groups were least impaired. Performance on repetition and sentence comprehension was especially poor in the logopenic group. The semantic and progressive fluent aphasia groups had prominent anomia, but only semantic subjects had loss of word meaning and object knowledge. Distinct patterns of grey matter loss and white matter changes were found in all groups compared to controls. PAOS subjects had bilateral frontal grey matter loss, including the premotor and supplementary motor areas, and bilateral frontal white matter involvement. The agrammatic group had more widespread, predominantly left sided grey matter loss and white matter abnormalities. Semantic subjects had bitemporal grey matter loss and white matter changes, including the uncinate and inferior occipitofrontal fasciculi, whereas progressive fluent subjects only had left sided temporal involvement. Logopenic subjects had diffuse and bilateral grey matter loss and diffusion tensor abnormalities, maximal in the posterior temporal region. A diagnosis of logopenic aphasia was strongly associated with being amyloid positive (46/52 positive). Our findings support consideration of an alternative way of identifying and categorizing subtypes of degenerative speech and language disorders.

Argument structure deficit in aphasia: it’s not all about verbs

Background: Verb difficulties in aphasia often co-occur with difficulties specifying argument structure of the sentence. Recent exploration of verb and argument structure deficits has shown dissociations between lexical semantic information, argument structure information, and production of the argument structure. There is currently limited evidence regarding the implications of these dissociations for treatment.Aims: This paper explores the patterns of generalisation following intervention to increase access to verb argument structure for a 62-year-old woman (YR) with chronic agrammatic aphasia. YR had good access to nouns and verbs in picture naming alongside severe sentence production difficulties characterised by difficulty specifying argument structure.Methods & Procedures: Detailed pre-therapy language assessment investigated single word and sentence comprehension and production, with a specific focus on whether YR could produce argument structure. Intervention targeted verb retrieval, awareness of argument structure information, cueing of arguments, and production of argument and syntactic structure involving transitive verbs. A single-subject multiple baseline design was used to monitor the effectiveness of treatment. The primary outcome measure was accuracy of two-argument structures in sentence production to picture and sentence generation to written word tasks, with effects on treated and untreated verbs considered. Other measures of sentence comprehension and production were also obtained to determine any further generalisation.Outcomes & Results: Following the first phase of therapy, YR showed a significant improvement in the production of two-argument structures across both treated and untreated verbs in sentence production to pictures, with a corresponding significant reduction in incomplete argument structures. No change was seen in two-argument structures in sentence generation to written words. After the second phase of therapy, significant gains were seen in two-argument structures with both treated and untreated verbs in the sentence generation task while sentence production to picture performance maintained. Gains in sentence generation were more vulnerable following the cessation of therapy. Other tasks of sentence production also improved with no change seen on a control task.Conclusions: Argument structure can be selectively impaired in aphasia, in the presence of good verb and noun access at the single word level, and targeted in therapy to improve sentence production. The study highlights the complexity of the relationship between verbs and argument structure and that argument structure difficulties are not always a consequence of a semantic verb deficit. Generalised improvement in argument structure production provides evidence that therapy targeted general processes rather than lexically specified argument structure information.

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

Background: Phonological priming has been shown to facilitate naming in individuals with aphasia, as well as healthy speakers, resulting in faster naming latencies. However, the mechanisms of phonological facilitation (PF) in aphasia remain unclear.Aims: Within discrete vs. interactive models of lexical access, this study examined whether PF occurs via the sub-lexical or lexical route during noun and verb naming in agrammatic and anomic aphasia.Methods & Procedures: Thirteen participants with agrammatic aphasia and 10 participants with anomic aphasia and their young and age-matched controls (n = 20/each) were tested. Experiment 1 examined noun and verb naming deficit patterns in an off-line confrontation naming task. Experiment 2 examined PF effects on naming both word categories using eyetracking priming paradigm.Outcomes & Results: Results of Experiment 1 showed greater naming difficulty for verbs than for nouns in the agrammatic group, with no difference between the two word categories in the anomic group. For both participant groups, errors were dominated by semantic paraphasias, indicating impaired lexical selection. In the phonological priming task (Experiment 2), young and age-matched control groups showed PF in both noun and verb naming. Interestingly, the agrammatic group showed PF when naming verbs, but not nouns, whereas the anomic group showed PF for nouns only.Conclusions: Consistent with lexically mediated PF in interactive models of lexical access, selective PF for different word categories in our agrammatic and anomic groups suggest that phonological primes facilitate lexical selection via feedback activation, resulting in greater PF for more difficult (i.e., verbs in agrammatic and possibly nouns in anomic group) lexical items.

Grammatical Planning Units During Real-Time Sentence Production in Speakers With Agrammatic Aphasia and Healthy Speakers.

Grammatical encoding (GE) is impaired in agrammatic aphasia; however, the nature of such deficits remains unclear. We examined grammatical planning units during real-time sentence production in speakers with agrammatic aphasia and control speakers, testing two competing models of GE. We queried whether speakers with agrammatic aphasia produce sentences word by word without advanced planning or whether hierarchical syntactic structure (i.e., verb argument structure; VAS) is encoded as part of the advanced planning unit. Experiment 1 examined production of sentences with a predefined structure (i.e., "The A and the B are above the C") using eye tracking. Experiment 2 tested production of transitive and unaccusative sentences without a predefined sentence structure in a verb-priming study. In Experiment 1, both speakers with agrammatic aphasia and young and age-matched control speakers used word-by-word strategies, selecting the first lemma (noun A) only prior to speech onset. However, in Experiment 2, unlike controls, speakers with agrammatic aphasia preplanned transitive and unaccusative sentences, encoding VAS before speech onset. Speakers with agrammatic aphasia show incremental, word-by-word production for structurally simple sentences, requiring retrieval of multiple noun lemmas. However, when sentences involve functional (thematic to grammatical) structure building, advanced planning strategies (i.e., VAS encoding) are used. This early use of hierarchical syntactic information may provide a scaffold for impaired GE in agrammatism.