An Investigation of Neural Mechanisms Underlying Verb Morphology Deficits in Aphasia

Agrammatic aphasia is an acquired language disorder characterized by slow, non-fluent speech that include primarily content words. It is well-documented that people with agrammatism (PWA) have difficulty with production of verbs and verb morphology, but it is unknown whether these deficits occur at the single word-level, or are the result of a sentence-level impairment. The first aim of this paper is to determine the linguistic level that verb morphology impairments exist at by using magnetoencephalography (MEG) to analyze neural response to two language tasks (one word-level, and one sentence-level). It has also been demonstrated that PWA benefit from a morphosemantic intervention for verb morphology deficits, but it is unknown if this therapy induces neuroplastic changes in the brain. The second aim of this paper is to determine whether or not neuroplastic changes occur after treatment, and explore the neural mechanisms by which this improvement occurs.

Survival analysis in primary progressive apraxia of speech and agrammatic aphasia

ABSTRACTObjective:To compare survival among patients with different combinations of apraxia of speech (AOS) and agrammatic aphasia, including those with isolated AOS (primary progressive apraxia of speech, PPAOS), both AOS and agrammatic aphasia (AOS+PAA) and isolated agrammatic aphasia (progressive agrammatic aphasia, PAA).Methods:One-hundred-and-nine patients were recruited who had any combination of AOS and agrammatic aphasia (42 PPAOS, 56 AOS+PAA and 11 PAA) and were followed longitudinally, with 57 patients having since died. Cox proportional hazards models were used to quantify the relative risk of death across diagnoses. Adjusted survival curves are presented based on this model. We also assessed the influence of AOS and aphasia severity on survival.Results:PPAOS had the longest survival (median survival of 5.97 years from baseline visit), followed by PAA (5.26 years) and then AOS+PAA (4.33 years). AOS+PAA had a greater risk of death than PPAOS, with a hazard ratio of 3.01 (Lower/upper CI= 1.66/5.46, p<0.001). Risk of death did not differ between PAA and the other groups. All results accounted for age and time from onset to baseline visit. AOS severity, independent of syndromic diagnosis, was associated with greater risk of death, with a hazard ratio of 1.35 for a one-point increase in severity. Aphasia severity was not associated with risk of death.Conclusions:Individuals with PPAOS have better survival and reduced risk of death compared to AOS+PAA individuals. This finding will help improve prognostic estimates for these patients and supports the value of distinguishing PPAOS from AOS+PAA.

NOUN AND VERB PRODUCTION IN UZBEK NON-FLUENT APHASIA

Noun and verb retrieval in Uzbek agrammatic aphasia is studied through picture naming experiment. Healthy and brain-damaged individuals participated in the study. Neuro linguistic studies showed difference in noun and verb impairment in aphasia. Majority of studies reported that noun processing is easier than verb processing for aphasic speakers. The results of the current study showed no noun-verb dissociation in Uzbek agrammatic aphasia. However, a small effect of age of acquisition on noun production and image ability effect on verb production is observed.

Neurocognitive Recovery of Sentence Processing in Aphasia

Purpose Reorganization of language networks in aphasia takes advantage of the facts that (a) the brain is an organ of plasticity, with neuronal changes occurring throughout the life span, including following brain damage; (b) plasticity is highly experience dependent; and (c) as with any learning system, language reorganization involves a synergistic interplay between organism-intrinsic (i.e., cognitive and brain) and organism-extrinsic (i.e., environmental) variables. A major goal for clinical treatment of aphasia is to be able to prescribe treatment and predict its outcome based on the neurocognitive deficit profiles of individual patients. This review article summarizes the results of research examining the neurocognitive effects of psycholinguistically based treatment (i.e., Treatment of Underlying Forms; Thompson & Shapiro, 2005 ) for sentence processing impairments in individuals with chronic agrammatic aphasia resulting from stroke and primary progressive aphasia and addresses both behavioral and brain variables related to successful treatment outcomes. The influences of lesion volume and location, perfusion (blood flow), and resting-state neural activity on language recovery are also discussed as related to recovery of agrammatism and other language impairments. Based on these and other data, principles for promoting neuroplasticity of language networks are presented. Conclusions Sentence processing treatment results in improved comprehension and production of complex syntactic structures in chronic agrammatism and generalization to less complex, linguistically related structures in chronic agrammatism. Patients also show treatment-induced shifts toward normal-like online sentence processing routines (based on eye movement data) and changes in neural recruitment patterns (based on functional neuroimaging), with posttreatment activation of regions overlapping with those within sentence processing and dorsal attention networks engaged by neurotypical adults performing the same task. These findings provide compelling evidence that treatment focused on principles of neuroplasticity promotes neurocognitive recovery in chronic agrammatic aphasia. Presentation Video https://doi.org/10.23641/asha.10257587