It is with great excitement that we are assuming our roles as co-editors of the journal, Augmentative and Alternative Communication. As we embark on this new journey, we would like to take a moment...

The Changing Face of Augmentative and Alternative Communication: Past, Present, and Future Challenges

Improvement or maintenance of speech intelligibility is a central aim in a whole range of conditions in speech-language therapy, both developmental and acquired. Best clinical practice and pursuance of the evidence base for interventions would suggest measurement of intelligibility forms a vital role in clinical decision-making and monitoring. However, what should be measured to gauge intelligibility and how this is achieved and relates to clinical planning continues to be a topic of debate. This review considers the strengths and weaknesses of selected clinical approaches to intelligibility assessment, stressing the importance of explanatory, diagnostic testing as both a more sensitive and a clinically informative method. The worth of this, and any approach, is predicated, though, on awareness and control of key design, elicitation, transcription and listening/listener variables to maximize validity and reliability of assessments. These are discussed. A distinction is drawn between signal-dependent and -independent factors in intelligibility evaluation. Discussion broaches how these different perspectives might be reconciled to deliver comprehensive insights into intelligibility levels and their clinical/educational significance. The paper ends with a call for wider implementation of best practice around intelligibility assessment.

Measuring up to speech intelligibility.

In motor speech disorders, dysarthric features impacting intelligibility, articulation, fluency and voice emerge more saliently in conversation than in repetition, reading or singing. A role of the basal ganglia in these task discrepancies has been identified. Further, more recent studies of naturalistic speech in basal ganglia dysfunction have revealed that formulaic language is more impaired than novel language. This descriptive study extends these observations to a case of severely dysfluent dysarthria due to a parkinsonian syndrome. Dysfluencies were quantified and compared for conversation, two forms of repetition, reading, recited speech and singing. Other measures examined phonetic inventories, word forms and formulaic language. Phonetic, syllabic and lexical dysfluencies were more abundant in conversation than in other task conditions. Formulaic expressions in conversation were reduced compared to normal speakers. A proposed explanation supports the notion that the basal ganglia contribute to formulation of internal models for execution of speech.

Dramatic effects of speech task on motor and linguistic planning in severely dysfluent parkinsonian speech

Background: Acquired progressive dysarthria is traditionally assessed, rated, and researched using measures of speech perception and intelligibility. The focus is commonly on the individual with dysarthria and how speech deviates from a normative range. A complementary approach is to consider the features and consequences of dysarthric speech as it is produced as a turn‐at‐talk in everyday interaction and in particular the ways in which this talk may be identified by its recipient as problematic to understand.Aims: To investigate how dysarthric turns‐at‐talk in everyday conversation may be problematic to understand. Further, to describe how recipients of dysarthric talk identify the source of problematic understandings to the dysarthric speaker.Methods & Procedures: Video data of natural conversation from two dyads were selected for this paper. The dyads were video‐recorded at home, at 3‐monthly intervals, over a maximum period of 18 months. Using the methods of conversation analysis a collection of seque...

Acquired dysarthria in conversation: identifying sources of understandability problems.

OBJECTIVEPatients with Parkinson disease (PD) who undergo subthalamic nucleus (STN) deep brain stimulation (DBS) often develop a deterioration in speech performance, but there is no clear consensus on the specific effects seen or the mechanism involved and little description of the impact of DBS on conversational speech. Furthermore, there has been no fiber tract connectivity analysis to identify the structures potentially modulated by DBS to cause such deficits. The main objective of this study was to quantify spontaneous speech performance and identify potential involvement of the dentatorubrothalamic tract (DRTt) in patients who underwent STN DBS, because this tract has been implicated in speech deterioration.METHODSSpontaneous speech samples were obtained with STN DBS in both on and off modes in 35 patients with PD and assessed across multiple domains. Diffusion tensor imaging tractography seeded from the therapeutic DBS contacts was performed to identify the fiber tracts involved and, specifically, t...

Speech changes induced by deep brain stimulation of the subthalamic nucleus in Parkinson disease: involvement of the dentatorubrothalamic tract

This study examined the independent and interactive effects of visual information and linguistic class of words on intelligibility of dysarthric speech. Seven speakers with dysarthria participated in the study, along with 224 listeners who transcribed speech samples in audiovisual (AV) or audio-only (AO) listening conditions. Orthographic transcriptions from listeners were scored for the number of words identified correctly. Correctly identified words were then coded into two linguistic classes, open and closed. Results showed that across all speakers and listeners, the AV presentation mode resulted in significantly higher intelligibility scores than the AO mode. However, the difference was significant for only three of seven individual speakers. Results also showed that across all speakers and listeners, closed class words were more intelligible than open class words. The difference between linguistic classes was significant for six of seven individual speakers. The interaction between linguistic class and mode of presentation was not significant, indicating that the margin of benefit for closed class words was consistent across presentation modalities.

Effects of visual information on intelligibility of open and closed class words in predictable sentences produced by speakers with dysarthria

This study examined listeners' endorsement of cognitive, linguistic, segmental, and suprasegmental strategies employed when listening to speakers with dysarthria. The study also examined whether strategy endorsement differed between listeners who earned the highest and lowest intelligibility scores. Speakers were eight individuals with dysarthria and cerebral palsy. Listeners were 80 individuals who transcribed speech stimuli and rated their use of each of 24 listening strategies on a 4-point scale. Results showed that cognitive and linguistic strategies were most highly endorsed. Use of listening strategies did not differ between listeners with the highest and lowest intelligibility scores. Results suggest that there may be a core of strategies common to listeners of speakers with dysarthria that may be supplemented by additional strategies, based on characteristics of the speaker and speech signal.

Caitlin M. Dardis

Papers

Effects of visual information on intelligibility of open and closed class words in predictable sentences produced by speakers with dysarthria

Use of Listening Strategies for the Speech of Individuals with Dysarthria and Cerebral Palsy