Quantitative Analysis of Agrammatism in Agrammatic Primary Progressive Aphasia and Dominant Apraxia of Speech

Neural basis of speech and grammar symptoms in non-fluent variant primary progressive aphasia spectrum

The non-fluent/agrammatic variant of primary progressive aphasia (nfvPPA) is a neurodegenerative syndrome primarily defined by the presence of apraxia of speech (AoS) and/or expressive agrammatism. In addition, many patients exhibit dysarthria and/or receptive agrammatism. This leads to substantial phenotypic variation within the speech-language domain across individuals and time, in terms of both the specific combination of symptoms as well as their severity. How to resolve such phenotypic heterogeneity in nfvPPA is a matter of debate. 'Splitting' views propose separate clinical entities: 'primary progressive apraxia of speech' when AoS occurs in the absence of expressive agrammatism, 'progressive agrammatic aphasia' (PAA) in the opposite case, and 'AOS + PAA' when mixed motor speech and language symptoms are clearly present. While therapeutic interventions typically vary depending on the predominant symptom (e.g. AoS versus expressive agrammatism), the existence of behavioural, anatomical and pathological overlap across these phenotypes argues against drawing such clear-cut boundaries. In the current study, we contribute to this debate by mapping behaviour to brain in a large, prospective cohort of well characterized patients with nfvPPA (n = 104). We sought to advance scientific understanding of nfvPPA and the neural basis of speech-language by uncovering where in the brain the degree of MRI-based atrophy is associated with inter-patient variability in the presence and severity of AoS, dysarthria, expressive agrammatism or receptive agrammatism. Our cross-sectional examination of brain-behaviour relationships revealed three main observations. First, we found that the neural correlates of AoS and expressive agrammatism in nfvPPA lie side by side in the left posterior inferior frontal lobe, explaining their behavioural dissociation/association in previous reports. Second, we identified a 'left-right' and 'ventral-dorsal' neuroanatomical distinction between AoS versus dysarthria, highlighting (i) that dysarthria, but not AoS, is significantly influenced by tissue loss in right-hemisphere motor-speech regions; and (ii) that, within the left hemisphere, dysarthria and AoS map onto dorsally versus ventrally located motor-speech regions, respectively. Third, we confirmed that, within the large-scale grammar network, left frontal tissue loss is preferentially involved in expressive agrammatism and left temporal tissue loss in receptive agrammatism. Our findings thus contribute to define the function and location of the epicentres within the large-scale neural networks vulnerable to neurodegenerative changes in nfvPPA. We propose that nfvPPA be redefined as an umbrella term subsuming a spectrum of speech and/or language phenotypes that are closely linked by the underlying neuroanatomy and neuropathology.

Neural mechanisms of sentence production: a volumetric study of primary progressive aphasia

Studies on the neural bases of sentence production have yielded mixed results, partly due to differences in tasks and participant types. In this study, 101 individuals with primary progressive aphasia (PPA) were evaluated using a test that required spoken production following an auditory prime (Northwestern Assessment of Verbs and Sentences-Sentence Production Priming Test, NAVS-SPPT), and one that required building a sentence by ordering word cards (Northwestern Anagram Test, NAT). Voxel-Based Morphometry revealed that gray matter (GM) volume in left inferior/middle frontal gyri (L IFG/MFG) was associated with sentence production accuracy on both tasks, more so for complex sentences, whereas, GM volume in left posterior temporal regions was exclusively associated with NAVS-SPPT performance and predicted by performance on a Digit Span Forward (DSF) task. Verb retrieval deficits partly mediated the relationship between L IFG/MFG and performance on the NAVS-SPPT. These findings underscore the importance of L IFG/MFG for sentence production and suggest that this relationship is partly accounted for by verb retrieval deficits, but not phonological loop integrity. In contrast, it is possible that the posterior temporal cortex is associated with auditory short-term memory ability, to the extent that DSF performance is a valid measure of this in aphasia.

Automated analysis of written language in the three variants of primary progressive aphasia

Despite the important role of written language in everyday life, abnormalities in functional written communication have been sparsely investigated in primary progressive aphasia. Prior studies have analysed written language separately in each of the three variants of primary progressive aphasia-but have rarely compared them to each other or to spoken language. Manual analysis of written language can be a time-consuming process. We therefore developed a program that quantifies content units and total units in written or transcribed language samples. We analysed written and spoken descriptions of the Western Aphasia Battery picnic scene, based on a predefined content unit corpus. We calculated the ratio of content units to units as a measure of content density. Our cohort included 115 participants (20 controls for written, 20 controls for spoken, 28 participants with nonfluent variant primary progressive aphasia, 30 for logopenic variant and 17 for semantic variant). Our program identified content units with a validity of 99.7% (95%CI 99.5-99.8). All patients wrote fewer units than controls (P < 0.001). Patients with the logopenic variant (P = 0.013) and the semantic variant (0.004) wrote fewer content units than controls. The content unit-to-unit ratio was higher in the nonfluent and semantic variants than controls (P = 0.019), but no difference in the logopenic variant (P = 0.962). Participants with the logopenic (P < 0.001) and semantic (P = 0.04) variants produced fewer content units in written compared to spoken descriptions. All variants produced fewer units in written samples compared to spoken (P < 0.001). However, due to a relatively smaller decrease in written content units, we observed a larger content unit-to-unit ratio in writing over speech (P < 0.001). Written and spoken content units (r = 0.5, P = 0.009) and total units (r = 0.64, P < 0.001) were significantly correlated in patients with nonfluent variant, but this was not the case for logopenic or semantic. Considering all patients with primary progressive aphasia, fewer content units were produced in those with greater aphasia severity (Progressive Aphasia Severity Scale Sum of Boxes, r = -0.24, P = 0.04) and dementia severity (Clinical Dementia Rating scale Sum of Boxes, r = -0.34, P = 0.004). In conclusion, we observed reduced written content in patients with primary progressive aphasia compared to controls, with a preference for content over non-content units in patients with the nonfluent and semantic variants. We observed a similar 'telegraphic' style in both language modalities in patients with the nonfluent variant. Lastly, we show how our program provides a time-efficient tool, which could enable feedback and tracking of writing as an important feature of language and cognition.

Assistive Completion of Agrammatic Aphasic Sentences: Amalgamation of NLP and Neurolinguistics-based Synthetic Dataset

Damage to the inferior frontal gyrus (Broca's area) can cause agrammatic aphasia wherein patients, although able to comprehend, lack the ability to form complete sentences. This inability leads to communication gaps which cause difficulties in their daily lives. The usage of assistive devices can help in mitigating these issues and enable the patients to communicate effectively. However, due to lack of large scale studies of linguistic deficits in aphasia, research on such assistive technology is relatively limited. In this work, we present two contributions that aim to re-initiate research and development in this field. Firstly, we propose a model that uses linguistic features from small scale studies on aphasia patients and generates large scale datasets of synthetic aphasic utterances from grammatically correct datasets. We show that the mean length of utterance, the noun/verb ratio, and the simple/complex sentence ratio of our synthetic datasets correspond to the reported features of aphasic speech. Further, we demonstrate how the synthetic datasets may be utilized to develop assistive devices for aphasia patients. The pre-trained T5 transformer is fine-tuned using the generated dataset to suggest 5 corrected sentences given an aphasic utterance as input. We evaluate the efficacy of the T5 model using the BLEU and cosine semantic similarity scores. Affirming results with BLEU score of 0.827/1.00 and semantic similarity of 0.904/1.00 were obtained. These results provide a strong foundation for the concept that a synthetic dataset based on small scale studies on aphasia can be used to develop effective assistive technology.Clinical relevance- We demonstrate the utilization of Natural Language Processing (NLP) for developing assistive technology for Aphasia patients. While disorders like Broca's aphasia offer a small sample size of patients and data, synthetic linguistic models like ours offer extensive scope for developing assistive technology and rehabilitation monitoring.

The Apraxia of Speech Rating Scale: Reliability, Validity, and Utility

PURPOSE

The purpose of this study was to examine the interrater reliability and validity of the Apraxia of Speech Rating Scale (ASRS-3.5) as an index of the presence and severity of apraxia of speech (AOS) and the prominence of several of its important features.

METHOD

Interrater reliability was assessed for 27 participants. Validity was examined in a cohort of 308 participants (120 with and 188 without progressive AOS) through item analysis; item-Total score correlations; correlations among ASRS Total score and component subscores and independent clinical ratings of AOS, dysarthria and aphasia severity, intelligibility, and articulatory errors, as well as years postonset and age; and regression models assessing item and Total score prediction of AOS presence.

RESULTS

Interrater reliability was good or excellent for most items and excellent for the Total score. Item and Total score analyses revealed good separation of participants with versus without AOS. Inter-item and item-Total score correlations were generally moderately high as were correlations between the ASRS Total score and independent ratings of AOS severity, intelligibility, and articulatory errors. The Total score was not meaningfully correlated with ratings of aphasia and dysarthria severity, years postonset, or age. Total scores below 7 and above 10 revealed excellent diagnostic sensitivity and specificity for AOS. The presence of eight or more abnormal features was also highly predictive of AOS presence.

CONCLUSIONS

The ASRS-3.5 is a reliable and valid scale for identifying the presence and severity of AOS and its predominant features. It has excellent sensitivity to AOS presence and excellent specificity relative to aphasia and dysarthria in patients with neurodegenerative disease.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21817584.

Association of Long-Term Speech Therapy and Neuromodulation in Primary Progressive Aphasia: Lessons from a Case Report

Primary progressive aphasia (PPA) is a neurodegenerative disorder with a progressive loss of language. Long-term support requires speech therapy but also individually set training programs. Here we propose an 8-month individualized speech-training program which alternates 3-week periods of transcranial direct current stimulation (tDCS) treatment with intensive daily language exercises and a 3-week period without tDCS treatment and a less intensive language exercise from home in a patient with non-fluent variant PPA (nfvPPA). The endpoints were the following: adherence to this program, language data after 8 months, questionnaires related to emotional valence, and brain volume changes. The results showed a persistent adherence after 8 months and a positive compliance reported by both the patient and the partner. The language evaluation showed a clinical stabilization. Moreover, a significant and positive influence of tDCS on mood was observed. This is, to our knowledge, the first ever published report of a combined neuromodulation and language training during the course of 8 months. Our finding suggests the feasibility of programs integrating hospital speech therapy, home training, and tDCS modulation in PPA. Further studies should be conducted in order to disentangle the contextual influences on language performance from the tDCS intervention effects and to address the observation of an initial improvement and a subsequent stabilization effect of language performances.

Tractography of supplementary motor area projections in progressive speech apraxia and aphasia

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Degeneration of SMA white matter tracts occurs in progressive apraxia of speech.

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SMA commissural, putamen and precentral tracts were associated with speech apraxia.

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Agrammatism was associated with SMA-prefrontal and frontal aslant tracts.

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Tract profile analysis suggests different disease epicenters across syndromes.

Progressive apraxia of speech (AOS) is a motor speech disorder affecting the ability to produce phonetically or prosodically normal speech. Progressive AOS can present in isolation or co-occur with agrammatic aphasia and is associated with degeneration of the supplementary motor area. We aimed to assess breakdowns in structural connectivity from the supplementary motor area in patients with any combination of progressive AOS and/or agrammatic aphasia to determine which supplementary motor area tracts are specifically related to these clinical symptoms. Eighty-four patients with progressive AOS or progressive agrammatic aphasia were recruited by the Neurodegenerative Research Group and underwent neurological, speech/language, and neuropsychological testing, as well as 3 T diffusion magnetic resonance imaging. Of the 84 patients, 36 had apraxia of speech in isolation (primary progressive apraxia of speech, PPAOS), 40 had apraxia of speech and agrammatic aphasia (AOS-PAA), and eight had agrammatic aphasia in isolation (progressive agrammatic aphasia, PAA). Tractography was performed to identify 5 distinct tracts connecting to the supplementary motor area. Fractional anisotropy and mean diffusivity were assessed at 10 positions along the length of the tracts to construct tract profiles, and median profiles were calculated for each tract. In a case-control comparison, decreased fractional anisotropy and increased mean diffusivity were observed along the supplementary motor area commissural fibers in all three groups compared to controls. PPAOS also had abnormal diffusion in tracts from the supplementary motor area to the putamen, prefrontal cortex, Broca’s area (frontal aslant tract) and motor cortex, with greatest abnormalities observed closest to the supplementary motor area. The AOS-PAA group showed abnormalities in the same set of tracts, but with greater involvement of the supplementary motor area to prefrontal tract compared to PPAOS. PAA showed abnormalities in the left prefrontal and frontal aslant tracts compared to both other groups, with PAA showing greatest abnormalities furthest from the supplementary motor area. Severity of AOS correlated with tract metrics in the supplementary motor area commissural and motor cortex tracts. Severity of aphasia correlated with the frontal aslant and prefrontal tracts. These findings provide insight into how AOS and agrammatism are differentially related to disrupted diffusivity, with progressive AOS associated with abnormalities close to the supplementary motor area, and the frontal aslant and prefrontal tracts being particularly associated with agrammatic aphasia.

Neuropsychological Profiles of Patients with Progressive Apraxia of Speech and Aphasia

OBJECTIVE

To characterize and compare the neuropsychological profiles of patients with primary progressive apraxia of speech (PPAOS) and apraxia of speech with progressive agrammatic aphasia (AOS-PAA).

METHOD

Thirty-nine patients with PPAOS and 49 patients with AOS-PAA underwent formal neurological, speech, language, and neuropsychological evaluations. Cognitive domains assessed included immediate and delayed episodic memory (Wechsler Memory Scale-Third edition; Logical Memory; Visual Reproduction; Rey Auditory Verbal Learning Test), processing speed (Trail Making Test A), executive functioning (Trail Making Test B; Delis-Kaplan Executive Functioning Scale - Sorting), and visuospatial ability (Rey-Osterrieth Complex Figure copy).

RESULTS

The PPAOS patients were cognitively average or higher in the domains of immediate and delayed episodic memory, processing speed, executive functioning, and visuospatial ability. Patients with AOS-PAA performed more poorly on tests of immediate and delayed episodic memory and executive functioning compared to those with PPAOS. For every 1 unit increase in aphasia severity (e.g. mild to moderate), performance declined by 1/3 to 1/2 a standard deviation depending on cognitive domain. The degree of decline was stronger within the more verbally mediated domains, but was also notable in less verbally mediated domains.

CONCLUSION

The study provides neuropsychological evidence further supporting the distinction of PPAOS from primary progressive aphasia and should be used to inform future diagnostic criteria. More immediately, it informs prognostication and treatment planning.

Contribution of the Cognitive Approach to Language Assessment to the Differential Diagnosis of Primary Progressive Aphasia

Diagnosis of primary progressive aphasia (PPA) is essentially based on the identification of progressive impairment of language abilities while other cognitive functions are preserved. The three variants of PPA are characterized by core and supportive clinical features related to the presence or absence of language impairment in different linguistic domains. In this article, we review the cognitive neuropsychological approach to the assessment of PPA and its contribution to the differential diagnosis of the three variants. The main advantage of this assessment approach is that it goes beyond the mere description and classification of clinical syndromes and identifies impaired and preserved cognitive and linguistic components and processes. The article is structured according to the main language domains: spoken production, language comprehension, and written language. Each section includes a brief description of the cognitive processes involved in the assessment tasks, followed by a discussion of typical characteristics for each PPA variant and common pitfalls in the interpretation of the results. In addition, the clinical benefit of the cognitive neuropsychological approach for the behavioral management of PPA is briefly sketched out in the conclusion.

A Preliminary Look Into the Clinical Evolution of Motor Speech Characteristics in Primary Progressive Apraxia of Speech in Québec French

Purpose This study aimed to track changes in acoustical and perceptual features of motor speech in patients with phonetic and prosodic primary progressive apraxia of speech (PPAOS) in Québec French over an 18-month period. Method A prospective multiple-case series with multiple testing periods, including four participants with a diagnosis of PPAOS, was conducted. Participants were 0.5-4 years postonset of disease at baseline. They underwent comprehensive motor speech and language assessments and cognitive screening every 6 months for up to 18 months. Acoustical and perceptual analyses of motor speech were conducted. Results Results showed a considerable impairment in motor speech abilities for patients with PPAOS at all time points and a significant decrease in performance for almost all articulatory and prosodic measures over time. Passage reading and diadochokinesis seemed particularly promising for the tracking of changes in PPAOS motor speech characteristics and PPAOS classification. Quantifying length of speech runs made it possible to distinguish phonetic from prosodic PPAOS. Finally, the patients who evolved to phonetic PPAOS developed aphasia, and the two with prosodic PPAOS showed greater motor symptoms such as unequivocal dysarthria. Conclusion This study extends the growing literature on PPAOS and its subtypes by describing specific changes in articulatory and prosodic abilities over a period of at least 6 months, which are important for the diagnosis and management of PPAOS.

Progressive apraxia of speech: delays to diagnosis and rates of alternative diagnoses

BACKGROUND

Progressive apraxia of speech (PAOS) is a neurodegenerative disorder of speech programming distinct from aphasia and dysarthria, most commonly associated with a 4-repeat tauopathy. Our objective was to better understand the reasons for possible delays or diagnostic errors for patients with PAOS.

METHODS

Seventy-seven consecutive PAOS research participants from the Neurodegenerative Research Group were included in this study. The medical records for these patients were reviewed in detail. For each speech-related visit, data such as the chief complaint, clinical findings, and neuroimaging findings were recorded.

RESULTS

Apraxia of speech was the initial diagnosis in 20.1% of participants at first evaluation noted in the historical record. Other common diagnoses included primary progressive aphasia (PPA) (20.1%), dysarthria (18.18%), MCI/Dementia (6.5%), and motor neuron disease (3.9%). It took a median of 2.02 (range: 0.16-8.18) years from symptoms onset for participants to receive an initial diagnosis and 3.00 (range: 0.49-9.42) years to receive a correct diagnosis. Those who were seen by a speech-language pathologist (SLP) during their first documented encounter were more likely to be correctly diagnosed with PAOS (37/48) after SLP consultation than those who were not seen by an SLP on initial encounter (5/29) (p < 0.001).

CONCLUSION

Approximately 80% of patients with PAOS were imprecisely diagnosed at their first visit, with it taking a median of 3 years from symptom onset to receiving a diagnosis of PAOS. Being seen by a speech-language pathologist during the initial evaluation increased the likelihood of a correct apraxia of speech diagnosis.

Progressive apraxia of speech in Quebec French speakers: A case series

BACKGROUND

The term progressive apraxia of speech (PAOS) is used to describe speakers presenting with isolated or dominant apraxia of speech in the context of a neurodegenerative syndrome, including primary progressive apraxia of speech (PPAOS) and dominant progressive apraxia of speech (DAOS), respectively. Its motor speech profile has been increasingly explored in the last decade, but description remains vague and very English oriented, although the effect of speakers' language on motor speech phenotypes is increasingly recognized. Although some studies suggest that speakers presenting with isolated PAOS (PPAOS) versus dominant PAOS with concomitant aphasia (DAOS) should be differentiated, distinct characteristics of the two presentations are unclear. Furthermore, a careful description of their clinical presentation in languages other than English is required.

AIMS

To describe the motor speech characteristics of Quebec French-speaking participants with prominent PAOS and to explore the communication profile of those presenting more specifically with isolated PAOS (PPAOS), and with dominant PAOS and concomitant aphasia (DAOS).

METHODS & PROCEDURES

A thorough effort to recruit all speakers presenting with PAOS in the larger population areas of the province of Quebec was conducted over a 3-year span. A total of nine participants with PAOS (pwPAOS; PPAOS = 5, DAOS = 4) underwent a comprehensive language and motor speech assessment, and a cognitive screening. Their performance was compared with 30 matched healthy controls.

OUTCOMES & RESULTS

As a group, pwPAOS differed from healthy speakers on all acoustic and perceptual measures. The PPAOS and PAOS subgroups were similar on several measures, but participants from the PPAOS subgroup tended to perform better on articulatory measures and maximum speech rate tasks.

CONCLUSIONS & IMPLICATIONS

This study provides an in-depth analysis of motor speech characteristics of PAOS in Quebec French speakers and adds further evidence for the differentiation of PPAOS and DAOS. Combining simple perceptual and acoustic analyses represent a promising approach to distinguish the two variants and identify treatment targets. What this paper adds What is already known on this subject Progressive apraxia of speech (PAOS) is a neurodegenerative syndrome characterized by progressive and initially isolated or dominant apraxia of speech (primary progressive apraxia of speech [PPAOS] and dominant progressive apraxia of speech [DAOS], respectively). Studies mostly report articulatory and prosodic deficits in PAOS, but concomitant deficits such as dysarthria and executive dysfunction are also reported. The description of motor speech skills in PAOS remains vague and English-oriented. Studies suggest that speakers presenting with isolated PAOS vs dominant PAOS with concomitant aphasia should be differentiated, but distinct characteristics of the two presentations are unclear. What this study adds to existing knowledge To the best of the authors' knowledge, this study is the first to report transversal data of Quebec-French participants with PPAOS and DAOS. Moreover, this study is a first step towards identifying potential characteristics that could facilitate the diagnosis of PPAOS and DAOS in Quebec French. It makes a significant contribution to our understanding of progressive apraxia of speech in different cultural languages. What are the potential or actual clinical implications of this work? This study also initiates the search for sensitive tasks for the diagnosis of those speakers (which is an important process), in addition to identifying the core characteristics of PAOS, DAOS, and PPAOS in the development of an assessment battery for this population.

Brain atrophy patterns in patients with frontotemporal dementia: voxel-based morphometry

Frontotemporal dementia (FTD) is a neurodegenerative disorder characterized by language and behaviour deficits, which is considered the second most common cause of early-onset dementia. Detection of brain atrophy patterns is important for FTD diagnosis. However, the visual assessment of magnetic resonance imaging data may not be sensitive enough requiring the use of objective gray matter (GM) volume determination method. The study was aimed to assess the GM atrophy pattern in patients with FTD compared to control group patients using voxel-based morphometry (VBM). The study included 16 patients with FTD (12 patients with nonfluent agrammatic variant primary progressive aphasia (nfvPPA), three patients with behavioral variant of FTD, and one patient with logopenic variant PPA) and 10 healthy volunteers. VBM of patients with FTD and healthy controls revealed three significant (pFWE-corr < 0.05) atrophy areas in the left inferior frontal, left fusiform, and left supramarginal gyri. Taking into account the predominance of patients with nfvPPA in the group of FTD patients, the additional VBM of this group and control group was carried out, which revealed a distinct atrophy pattern: the reduced GM volume was detected in the left inferior frontal and left middle frontal gyri (pFWE-corr < 0.05). The results obtained indicate that regardless of the clinical variant, there is a certain atrophy pattern characteristic of FTD, which involves both frontotemporal areas and parietal lobe. The example of nfvPPA shows that each variant of the disease is associated with distinct localization of atrophy.

Progressive agrammatic aphasia without apraxia of speech as a distinct syndrome

Agrammatic aphasia affects grammatical language production and can result from a neurodegenerative disease. Although it typically presents with concomitant apraxia of speech, this is not always the case. Little is known about the clinical course and imaging features of patients that present with agrammatism in the absence of apraxia of speech, which we will refer to as progressive agrammatic aphasia. We aimed to make a detailed description of the longitudinal clinical, linguistic, and neuroimaging features of a cohort of 11 patients with progressive agrammatic aphasia to provide a complete picture of this syndrome. All patients underwent detailed speech and language, neurological and neuropsychological assessments, 3 T structural and diffusion tensor imaging MRI, 18F-fluorodeoxyglucose and Pittsburgh compound B PET. The 11 patients were matched by age and gender to 22 patients who had mixed apraxia of speech and agrammatism. The progressive agrammatic aphasia patients performed abnormally on tests of language, general cognition, executive function, and functional ability at baseline and declined in these measures over time. Only two patients eventually developed apraxia of speech, while parkinsonism was absent-to-mild throughout all visits for all patients. When compared to the patients with mixed apraxia of speech and agrammatism, the patients with progressive agrammatic aphasia performed better on tests of motor speech and parkinsonism but more poorly, and declined faster over time, on tests of general aphasia severity, agrammatism, and naming. The patients with progressive agrammatic aphasia also showed different neuroimaging abnormalities, with greater atrophy, hypometabolism and white matter tract degeneration in the prefrontal and anterior temporal lobes compared to patients with mixed apraxia of speech and agrammatism. These differences were more pronounced as the disease progressed. These results demonstrate that progressive agrammatic aphasia has a different clinical disease course and different underlying neuroanatomical abnormalities than patients with the more common syndrome of mixed agrammatism and apraxia of speech. This supports the distinction of progressive agrammatic aphasia and has implications for the classification of patients with agrammatic aphasia.

Western Aphasia Battery-Revised Profiles in Primary Progressive Aphasia and Primary Progressive Apraxia of Speech

Purpose The primary aim was to examine the utility of the Western Aphasia Battery-Revised (WAB-R; Kertesz, 2007) for classifying variants of primary progressive aphasia (PPA). Traditional WAB-R metrics of Aphasia Quotient (AQ), subtest scores, WAB-R classification, and several novel metrics were examined. A secondary aim was to examine these same WAB-R metrics in individuals with primary progressive apraxia of speech (PPAOS). Method A retrospective analysis of WAB-R records from 169 participants enrolled in a study of neurodegenerative speech and language disorders was conducted. PPA/PPAOS classification was determined by consensus review of speech, language, and cognitive profiles. Scores on each of the WAB-R subtests were obtained to derive AQ, WAB-R aphasia profile, and 3 ratios reflecting relative performance on subtests. Results Mean AQ was significantly higher in the PPAOS group compared to all PPA variants except primary fluent aphasia. AQ above the normal cutoff was observed for 20% of participants with PPA. Significant main effects of group were noted for each of the subtests. Follow-up comparisons most frequently discriminated PPAOS, primary agrammatic aphasia (PAA), and logopenic progressive aphasia. Primary fluent aphasia and semantic dementia (SD) subtest scores were less distinctive, with the exception of Naming for SD, which was significantly lower than for PAA and PPAOS. When the WAB-R AQ detected aphasia, a classification of anomic aphasia was most frequently observed; this pattern held true for each of the PPA variants. The mean Information Content:Naming ratio was highest for SD, and the mean Comprehension:Fluency ratio was highest for PAA. Conclusions In the current study, AQ underestimated the presence of PPA and WAB-R classification did not distinguish among PPA classification determined by consensus. Performance on individual subtests and relative performance across subtests demonstrated inconsistent alignment with PPA classification. We conclude the WAB-R in isolation is inadequate to detect or characterize PPA. We instead suggest utilizing the WAB-R as 1 component of a comprehensive language and motor speech assessment when PPA is suspected.

Quantitative assessment of grammar in amyloid-negative logopenic aphasia

Logopenic primary progressive aphasia (lvPPA) typically results from underlying Alzheimer's disease, but subjects have been reported that do not show beta-amyloid (Aβ) deposition. These subjects do not differ on neurological and speech-language testing from Aβ-positive lvPPA, but they impressionistically show increased grammatical deficits. We performed a quantitative linguistic analysis of grammatical characteristics in Aβ-negative lvPPA compared to Aβ-positive lvPPA and agrammatic PPA, which is characterized by increased grammatical difficulties. Aβ-negative lvPPA used fewer function words and correct verbs but more syntactic and semantic errors compared to Aβ-positive lvPPA. These measures did not differ between Aβ-negative lvPPA and agPPA. Both lvPPA cohorts showed a higher mean length of utterance, more complex sentences, and fewer nouns than agPPA. Aβ-negative lvPPA subjects appear unique and share linguistic features with both agPPA and Aβ-positive lvPPA. Quantitative language analysis in lvPPA may be able to distinguish those with and without Aβ deposition.