Connected speech production in three variants of primary progressive aphasia

Abstract

Primary progressive aphasia is a clinical syndrome defined by progressive deficits isolated to speech and/or language, and can be classified into non-fluent, semantic and logopenic variants based on motor speech, linguistic and cognitive features. The connected speech of patients with primary progressive aphasia has often been dichotomized simply as 'fluent' or 'non-fluent', however fluency is a multidimensional construct that encompasses features such as speech rate, phrase length, articulatory agility and syntactic structure, which are not always impacted in parallel. In this study, our first objective was to improve the characterization of connected speech production in each variant of primary progressive aphasia, by quantifying speech output along a number of motor speech and linguistic dimensions simultaneously. Secondly, we aimed to determine the neuroanatomical correlates of changes along these different dimensions. We recorded, transcribed and analysed speech samples for 50 patients with primary progressive aphasia, along with neurodegenerative and normal control groups. Patients were scanned with magnetic resonance imaging, and voxel-based morphometry was used to identify regions where atrophy correlated significantly with motor speech and linguistic features. Speech samples in patients with the non-fluent variant were characterized by slow rate, distortions, syntactic errors and reduced complexity. In contrast, patients with the semantic variant exhibited normal rate and very few speech or syntactic errors, but showed increased proportions of closed class words, pronouns and verbs, and higher frequency nouns, reflecting lexical retrieval deficits. In patients with the logopenic variant, speech rate (a common proxy for fluency) was intermediate between the other two variants, but distortions and syntactic errors were less common than in the non-fluent variant, while lexical access was less impaired than in the semantic variant. Reduced speech rate was linked with atrophy to a wide range of both anterior and posterior language regions, but specific deficits had more circumscribed anatomical correlates. Frontal regions were associated with motor speech and syntactic processes, anterior and inferior temporal regions with lexical retrieval, and posterior temporal regions with phonological errors and several other types of disruptions to fluency. These findings demonstrate that a multidimensional quantification of connected speech production is necessary to characterize the differences between the speech patterns of each primary progressive aphasic variant adequately, and to reveal associations between particular aspects of connected speech and specific components of the neural network for speech production.

Can MRI Visual Assessment Differentiate the Variants of Primary-Progressive Aphasia?

“…This finding is not unexpected because, though not always assessed systematically, atrophy of rostral-inferior temporal structures has been consistently reported in svPPA (also known as semantic dementia) both at a group level and individually. 7,10,[30][31][32][33][34][35] Given the uniform pattern of atrophy seen in this consecutively recruited cohort of 21 patients with svPPA, it can be argued that the diagnosis of svPPA should be seriously questioned in the absence of this atrophy pattern. Gil-Navarro et al 36 found the same consistent presence of anterior temporal lobe atrophy in a study of 29 patients with PPA that included 5 with svPPA.…”

“…6 Degeneration of the left frontal operculum and rostral insula is the culprit lesion in nfvPPA. More recent studies have also highlighted involvement of premotor 32 and basal ganglia 37 regions. Like svPPA, the group-average voxel-based morphometry findings in our nfvPPA cohort were largely compatible with the proposed diagnostic recommendations.…”

Preservation of passive constructions in a patient with primary progressive aphasia

“…The nature of WR's language impairment was categorized as that of logopenic PPA (Gorno-Tempini et al, 2011;Wilson et al, 2010). In logopenic PPA cell loss is initially apparent in posterior-superior temporal lobe structures (Wilson et al, 2010).…”

“…The nature of WR's language impairment was categorized as that of logopenic PPA (Gorno-Tempini et al, 2011;Wilson et al, 2010). In logopenic PPA cell loss is initially apparent in posterior-superior temporal lobe structures (Wilson et al, 2010). The behavioral profile is considered similar to that of vascular conduction aphasia (Gorno-Tempini, Dronkers, Rankin, Ogar, La Phengrasamy, Rosen, … Miller, 2004), although Rohrer, Rossor and Warren (2010) (Howard, Swinburn, & Porter, 2004)).…”

Avaliação fonoaudiológica da deglutição na demência frontotemporal

“…No discurso dos pacientes com APP-L, Wilson et al (2010) reconheceram as mesmas características dos demais subtipos da APP, porém em menor gravidade. Foram observados erros sintáticos e fonológicos vistos na APP-G, e a dificuldade de acesso lexical que é característica da APP-S.…”