Preparing an E-learning-based Speech Therapy (EST) efficacy study: Identifying suitable outcome measures to detect within-subject changes of speech intelligibility in dysarthric speakers.

We explored the suitability of perceptual and acoustic outcome measures to prepare E-learning based Speech Therapy (EST) efficacy tests regarding speech intelligibility in dysarthric speakers. Eight speakers with stroke (n=3), Parkinson's disease (n=4) and traumatic brain injury (n=1) participated in a 4 weeks EST trial. A repeated measures design was employed. Perceptual measures were (a) scale ratings for "ease of intelligibility" and "pleasantness" in continuous speech and (b) orthographic transcription scores of semantically unpredictable sentences. Acoustic measures were (c) "intensity during closure" (ΔIDC) in the occlusion phase of voiceless plosives, (d) changes in the vowel space of /a/, /e/ and /o/ and (e) the F0 variability in semantically unpredictable sentences. The only consistent finding concerned an increased (instead of the expected decreased) ΔIDC after EST, possibly caused by increased speech intensity without articulatory adjustments. The importance of suitable perceptual and acoustic measures for efficacy research is discussed.

Auditory discrimination as a condition for E-learning based Speech Therapy: a proposal for an auditory discrimination test (ADT) for adult dysarthric speakers.

BACKGROUND: Web based speech training for dysarthric speakers, such as E-learning based Speech Therapy (EST), puts considerable demands on auditory discrimination abilities. AIMS: To discuss the development and the evaluation of an auditory discrimination test (ADT) for the assessment of auditory speech discrimination skills in Dutch adult dysarthric speakers as a prelude to EST. METHOD: Five ADT subtests were developed, each addressing a vital speech dimension in speech therapy: articulation (segmental elements), intensity, overall pitch, speech rate and intonation. A healthy control group of 36 participants performed a 'same-different task' in each subtest. ADT items yielding scores of at least 80% but below 100% correctly responding healthy controls were considered sensitive to diminished auditory discrimination. Subsequently, the ADT was carried out by 14 neurological patients with dysarthric speech and 14 matched healthy controls. Score percentages, sensitivity indices and reaction times (ms) on only sensitive items were compared. RESULTS: The majority of the ADT items met the 'minimal 80% to below 100% criterion' in the healthy control group. The neurological participants performed lower on all outcome measures across all subtests than the healthy controls, although not all of these differences achieved statistical significance. CONCLUSIONS: The results of the healthy control group show that the majority of the ADT items meet our criterion for sensitivity to diminished auditory discrimination. The poorer performance of dysarthric patients across all subtests supports the sensitivity of the ADT. However, further research involving larger and more homogeneous groups of neurological patients is required. LEARNING OUTCOMES: Readers will be encouraged to (1) identify potential factors that may hinder web based speech training and (2) estimate the value of assessing auditory discrimination skills as a vital condition for (web based) speech training in dysarthric patients.

Advantage of bimodal fitting in prosody perception for children using a cochlear implant and a hearing aid.

Cochlear implants are largely unable to encode voice pitch information, which hampers the perception of some prosodic cues, such as intonation. This study investigated whether children with a cochlear implant in one ear were better able to detect differences in intonation when a hearing aid was added in the other ear ("bimodal fitting"). Fourteen children with normal hearing and 19 children with bimodal fitting participated in two experiments. The first experiment assessed the just noticeable difference in F0, by presenting listeners with a naturally produced bisyllabic utterance with an artificially manipulated pitch accent. The second experiment assessed the ability to distinguish between questions and affirmations in Dutch words, again by using artificial manipulation of F0. For the implanted group, performance significantly improved in each experiment when the hearing aid was added. However, even with a hearing aid, the implanted group required exaggerated F0 excursions to perceive a pitch accent and to identify a question. These exaggerated excursions are close to the maximum excursions typically used by Dutch speakers. Nevertheless, the results of this study showed that compared to the implant only condition, bimodal fitting improved the perception of intonation.