Optimizing linguistic materials for feature-based intelligibility assessment in speech impairments.

Assessing the intelligibility of speech-disordered individuals generally involves asking them to read aloud texts such as word lists, a procedure that can be time-consuming if the materials are lengthy. This paper seeks to optimize such elicitation materials by identifying an optimal trade-off between the quantity of material needed for assessment purposes and its capacity to elicit a robust intelligibility metrics. More specifically, it investigates the effect of reducing the number of pseudowords used in a phonetic-acoustic decoding task in a speech-impaired population in terms of the subsequent impact on the intelligibility classifier as quantified by accuracy indexes (AUC of ROC, Balanced Accuracy index and F-scores). A comparison of obtained accuracy indexes shows that when reduction of the amount of elicitation material is based on a phonetic criterion-here, related to phonotactic complexity-the classifier has a higher classifying ability than when the material is arbitrarily reduced. Crucially, downsizing the material to about 30% of the original dataset does not diminish the classifier's performance nor affect its stability. This result is of significant interest to clinicians as well as patients since it validates a tool that is both reliable and efficient.

[Prosody and reading: Temporal and melodic characteristics in the dyslexic child in reading and narration]. / Prosodie et lecture: particularités temporelles et mélodiques de l'enfant dyslexique en lecture et en narration.

Dyslexia is widely associated to a massive phonological awareness deficit. This deficit leads to difficulties in grapheme to phoneme conversions in reading and difficulties in words and sentences productions. The origin of the phonological deficit is partially explained by the magnocellular, cerebellar and articulatory theories. Recently, an increasing number of studies demonstrated the relationship between prosody and reading and, more specifically, the potential key role of suprasegmental phonology in the healthy development of phonological representations. The aim of this study is to explore part of prosodic features in dyslexics and normal developing children in reading and narration tasks, in French. We examined reading accuracy, reading rate, pauses frequency and duration, inter-pausal units (IPUs) duration and instantaneous variations of F0. Results show correct decoding skills for all subjects but a lack of automation of this procedure for dyslexics. Differences in pauses frequency and duration, IPUS duration and F0 variations observed between dyslexics and controls confirm the link between prosodic reading and automaticity. The longer pause duration in narrative form a temporal feature of dyslexic's production. This temporal characteristic reflects the cognitive cost done by a speech generation task involving lexical selection, syntactic planning and articulatory programming processes. This result is a first step towards evidence of a suprasegmental phonological deficit in spoken language that could be an early marker of later reading difficulties.

Dyslexia: the articulatory hypothesis revisited.

Articulatory disorders have been associated with developmental phonological dyslexia in the literature. However, very few information is available about the articulatory movements involved in speech production in dyslexic children. This study uses aerodynamic/acoustic data to explore how dyslexic children produce bilabial stops in French (/b, p/) within a sentence where they occurred in two positions and in three vowel environments. Average durations of articulatory closure and release were calculated in 10 phonological dyslexic children and two groups of age-matched and reading age-matched controls. Moreover, deviation from a standard pronunciation of the same material was evaluated separately by blind examiners. Our results reveal differences in the timing of the articulatory movements between dyslexics and normal controls, as well as more deviations from the target consonant for the dyslexics than for the controls. These observations are consistent with recent findings pointing to a general deficit in fine motor control in dyslexia.