Retraining speech production and fluency in non-fluent/agrammatic primary progressive aphasia

Abstract

The non-fluent/agrammatic variant of primary progressive aphasia (nfvPPA) presents with a gradual decline in grammar and motor speech resulting from selective degeneration of speech-language regions in the brain. There has been considerable progress in identifying treatment approaches to remediate language deficits in other primary progressive aphasia variants; however, interventions for the core deficits in nfvPPA have yet to be systematically investigated. Further, the neural mechanisms that support behavioural restitution in the context of neurodegeneration are not well understood. We examined the immediate and long-term benefits of video implemented script training for aphasia (VISTA) in 10 individuals with nfvPPA. The treatment approach involved repeated rehearsal of individualized scripts via structured treatment with a clinician as well as intensive home practice with an audiovisual model using 'speech entrainment'. We evaluated accuracy of script production as well as overall intelligibility and grammaticality for trained and untrained scripts. These measures and standardized test scores were collected at post-treatment and 3-, 6-, and 12-month follow-up visits. Treatment resulted in significant improvement in production of correct, intelligible scripted words for trained topics, a reduction in grammatical errors for trained topics, and an overall increase in intelligibility for trained as well as untrained topics at post-treatment. Follow-up testing revealed maintenance of gains for trained scripts up to 1 year post-treatment on the primary outcome measure. Performance on untrained scripts and standardized tests remained relatively stable during the follow-up period, indicating that treatment helped to stabilize speech and language despite disease progression. To identify neural predictors of responsiveness to intervention, we examined treatment effect sizes relative to grey matter volumes in regions of interest derived from a previously identified speech production network. Regions of significant atrophy within this network included bilateral inferior frontal cortices and supplementary motor area as well as left striatum. Volumes in a left middle/inferior temporal region of interest were significantly correlated with the magnitude of treatment effects. This region, which was relatively spared anatomically in nfvPPA patients, has been implicated in syntactic production as well as visuo-motor facilitation of speech. This is the first group study to document the benefits of behavioural intervention that targets both linguistic and motoric deficits in nfvPPA. Findings indicate that behavioural intervention may result in lasting and generalized improvement of communicative function in individuals with neurodegenerative disease and that the integrity of spared regions within the speech-language network may be an important predictor of treatment response.

Interpersonal prosodic correlation in frontotemporal dementia

“…This result may seem surprising in nfvPPA, which is partially defined by nonfluency. The sustained ability of nonfluent patients with left frontal damage to mimic fluent speech stimuli, however, is sufficiently well established to be the basis of therapeutic trials in nfvPPA. In addition, contrary to some prior research on bvFTD, we found no diagnostic group differences in standard deviation of fundamental frequency.…”

Multimodal 18F-AV-1451 and MRI Findings in Nonfluent Variant of Primary Progressive Aphasia: Possible Insights on Nodal Propagation of Tau Protein Across the Syntactic Network

“…Although in our nfvPPA sample we did not find significant tau deposition in other regions of the brain connected with the anterior node of the syntactic network, such as the supplementary motor area or anterior cingulate area, which is connected to the anterior node through the aslant tract (37), these other regions could show abnormal deposition with lower thresholds or in other samples. In nfvPPA, another group has found increased tau deposition in the supplementary motor area, but the sample showed heterogeneous findings (42), which suggests that this unusual and still poorly understood syndrome may have various underlying neuroanatomic substrates loading differently in different patient samples.…”

“…Because the disease begins with impairment of functions such as verbal fluency ( Fig. 2A), mediated by the anterior node, it is logical to postulate that the anterior node is the epicenter of damage (37,38) and that tau buildup starts there. Clinically detectable impairment, as we found in our patients, begins when anterior node neurons become dysfunctional or die.…”

Ethical and Practical Challenges of the Communication and Behavioral Manifestations of Primary Progressive Aphasia

“…6 Sebastian et al 31 found that rates of decline in oral naming were more precipitous in nfaPPA than other variants in part because of apraxia of speech. Education about apraxia of speech, highlighting that speech production is no longer a reliable means of communication despite spared ability to formulate communicative intentions and understand others, may facilitate insight regarding needed therapy and supports, such as structured oral reading, 32 script training with speech entrainment, 33 phonological and orthographic speech and language treatment, 34 and implementation of personalized communication aids and assistive devices/apps. 35 In this case, helping Ms. B's The ethical dilemma in this case arises because Mr. C's wife was concerned about Mr. C's safety when traveling to therapy appointments (nonmaleficence principle) while simultaneously wanting to support his desire to participate in therapy (autonomy principle).…”