Dysgraphia in primary progressive aphasia: Characterisation of impairments and therapy options

This is an Accepted Manuscript of an article published by Taylor & Francis in Aphasiology on January 3, 2014, available online: http://www.tandfonline.com/10.1080/02687038.2013.869308.Background: Spelling impairment is common in primary progressive aphasia (PPA). Although behavioural interventions tend to focus on spoken language, remediation of written language may be desirable, either because an individual’s regular use of writing makes it a priority or because writing is needed for communication in cases where it is better preserved than spoken language. Aims: This paper has three aims: (1) to provide an up-to-date survey of spelling and handwriting impairments in each variant of PPA, (2) to provide guidance on characterisation of dysgraphia and identification of loci of impairment, and (3) to outline possible interventions. Because the number of studies which have specifically evaluated therapy for dysgraphia in PPA is small, this paper also reviews relevant studies of therapy in non-progressive dysgraphia. Main Contribution: Review of the literature indicated that the most common pattern of spelling impairment in the semantic variant of PPA is surface dysgraphia (impairment in lexical spelling). The profile is more variable in the non-fluent and logopenic variants of PPA, but most commonly there is impairment in lexical spelling and in phoneme-to-grapheme conversion. Review of the literature on therapy for dysgraphia indicated that four main types of therapy have been evaluated and shown to improve spelling performance: (1) training of spelling of specific target words (used to ameliorate lexical and graphemic buffer impairments), (2) training of sound-to-spelling correspondence rules (used to treat impairment in assembled spelling), (3) training in segmentation of stimulus words into smaller chunks (to make them manageable for a damaged graphemic buffer, or as a first stage in applying sound-to-spelling correspondence rules), and (4) learning to identify and self-correct errors (used in treatment of graphemic buffer disorder). Conclusions: It is likely that spelling impairment in PPA would be responsive to treatment, although this has only been demonstrated in the logopenic variant. Reported improvements following therapy for anomia demonstrate that relearning is possible in PPA, despite the progressive nature of the condition. This gives reason for optimism regarding a positive response to therapy for dysgraphia in all variants of PPA

Automatic speech recognition in the diagnosis of primary progressive aphasia

Narrative speech can provide a valuable source of information about an individual’s linguistic abilities across lexical, syntactic, and pragmatic levels. However, analysis of narrative speech is typically done by hand, and is therefore extremely time-consuming. Use of automatic speech recognition (ASR) software could make this type of analysis more efficient and widely available. In this paper, we present the results of an initial attempt to use ASR technology to generate transcripts of spoken narratives from participants with semantic dementia (SD), progressive nonfluent aphasia (PNFA), and healthy controls. We extract text features from the transcripts and use these features, alone and in combination with acoustic features from the speech signals, to classify transcripts as patient versus control, and SD versus PNFA. Additionally, we generate artificially noisy transcripts by applying insertions, substitutions, and deletions to manually-transcribed data, allowing experiments to be conducted across a wider range of noise levels than are produced by a tuned ASR system. We find that reasonably good classification accuracies can be achieved by selecting appropriate features from the noisy transcripts. We also find that the choice of using ASR data or manually transcribed data as the training set can have a strong effect on the accuracy of the classifiers. Index Terms: automatic speech recognition, classification, progressive aphasi

Impaired coherence for semantic but not episodic autobiographical memory in semantic variant primary progressive aphasia

Language deficits, including word-finding difficulties and impaired single-word comprehension, have been found in patients with semantic variant primary progressive aphasia (svPPA). These deficits characterize the linguistic abilities of patients with svPPA on a micro-linguistic level (word and sentence level). On a macro-linguistic level (discourse level), svPPA patients’ discourse has been described as “empty”. Few studies have considered the contribution of a linguistic impairment to the difficulty of producing autobiographical narratives. In the present study, we assessed svPPA patients’ discourse coherence during autobiographical narratives in order to characterize the nature of their speech on a macro-linguistic level and to investigate the relationship between discourse production and memory in a naturalistic context. We collected samples of discourse in which svPPA patients and healthy controls (matched in age, education, sex and handedness) reported autobiographical events. Their narratives were assessed with a rating scale to evaluate global coherence of discourse. The protocols were also analysed using the Autobiographical Interview method (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002) and categorized as episodic (information about events at a specific time and place), semantic (general knowledge), or supplementary details (metacognitive statements, repeated information, editorializing). Where possible, patients were assessed longitudinally at three time points over two years. Patients with svPPA produced a reduced number of episodic details, while the number of semantic details produced was comparable to controls. However, the episodic information produced by patients was coherent with the topic of discourse, while semantic information was not. These results suggest that svPPA patients produce semantic information comparable to controls in quantity but not quality, whereas the opposite is the case for episodic information

Automated classification of primary progressive aphasia subtypes from narrative speech samples

The final version of this article from Elsevier can be found at http://dx.doi.org/10.1016/j.cortex.2012.12.006In the early stages of neurodegenerative disorders, individuals may exhibit a decline in language abilities that is difficult to quantify with standardized tests. Careful analysis of connected speech can provide valuable information about a patient's language capacities. To date, this type of analysis has been limited by its time-consuming nature. In this study, we present a method for evaluating and classifying connected speech in primary progressive aphasia using computational techniques. Syntactic and semantic features were automatically extracted from transcriptions of narrative speech for three groups: semantic dementia (SD), progressive nonfluent aphasia (PNFA), and healthy controls. Features that varied significantly between the groups were used to train machine learning classifiers, which were then tested on held-out data. We achieved accuracies well above baseline on the three binary classification tasks. An analysis of the influential features showed that in contrast with controls, both patient groups tended to use words which were higher in frequency (especially nouns for SD, and verbs for PNFA). The SD patients also tended to use words (especially nouns) that were higher in familiarity, and they produced fewer nouns, but more demonstratives and adverbs, than controls. The speech of the PNFA group tended to be slower and incorporate shorter words than controls. The patient groups were distinguished from each other by the SD patients' relatively increased use of words which are high in frequency and/or familiarity

Lack of Frank Agrammatism in the Nonfluent Agrammatic Variant of Primary Progressive Aphasia

Background/Aims: Frank agrammatism, defined as the omission and/or substitution of grammatical morphemes with associated grammatical errors, is variably reported in patients with nonfluent variant primary progressive aphasia (nfPPA). This study addressed whether frank agrammatism is typical in agrammatic nfPPA patients when this feature is not required for diagnosis. Method: We assessed grammatical production in 9 patients who satisfied current diagnostic criteria. Although the focus was agrammatism, motor speech skills were also evaluated to determine whether dysfluency arose primarily from apraxia of speech (AOS), instead of, or in addition to, agrammatism. Volumetric MRI analyses provided impartial imaging-supported diagnosis. Results: The majority of cases exhibited neither frank agrammatism nor AOS. Conclusion: There are nfPPA patients with imaging-supported diagnosis and preserved motor speech skills who do not exhibit frank agrammatism, and this may persist beyond the earliest stages of the illness. Because absence of frank agrammatism is a subsidiary diagnostic feature in the logopenic variant of PPA, this result has implications for differentiation of the nonfluent and logopenic variants, and indicates that PPA patients with nonfluent speech in the absence of frank agrammatism or AOS do not necessarily have the logopenic variant