Phonetic variation in dysarthric speech as a function of sampling task

Abstract

S Previous studies have demonstrated a number of ways in which normal speakers' phonetic performance varies across reading and spontaneous speech tasks. This study set out to investigate whether similar differences across speech sampling tasks were found in a mixed group of dysarthric subjects. A selection of segmental and prosodic parameters were investigated acoustically in the performance of five mild dysarthric speakers and five matched control subjects. The results demonstrated that breath–pause position, unstressed vowel duration and voice‐onset time were subject to variation across sampling task in the speech produced by different types of dysarthric speaker. The results suggest that read material produced by dysarthric speakers may not be wholly representative of those speakers' spontaneous speech. Preliminary implications for clinical practice are discussed. The findings point to the need for further research to investigate the extent of such differences and their implications for dysarthria assessment, which up to the present has relied predominantly on read material. Des études précédentes ont démontré que la performance phonétique du locuteur normal peut varier d'un certain nombre de façons selon qu'il est amené à lire ou à s'exprimer spontanément. Cette étude a cherché à determiner si l'on pouvait trouver des différences analogues chez un groupe mixte de sujets dysarthriques lors de différentes tåches d'échantillonnages de la parole. L'on a fait l'analyse acoustique d'un choix de paramètres segmentaux et prosodiques récoltés chez cinq locuteurs souffrant de dysarthrie légère et cinq sujets de contro̊le appariés. Les résultats montrent que dans le langage produit par différents types de locuteurs dysarthriques l'on pouvait observer des variations chez selon les types de tåches linguistiques dans la position de la pause d'inhalation, la durée des voyelles atones et le délai de voisement après les occlusives sourdes. Ces résultats suggérent que la lecture à haute voix chez les locuteurs dysarthriques n'est peut‐e̊tre pas entièrement représentative de la parole spontanée chez ces me̊mes locuteurs. La discussion porte sur la portée préliminaire de ces résultats pour la pratique clinique. Ils montrent la nécessité de faire des recherches ultérieures en vue d'examiner l'importance de ces différences et leurs conséquences pour le traitement de la dysarthrie qui jusqu'ici a reposé principalement sur la lecture de textes écrits. Frühere Studien haben demonstriert, wie die phonetische Performanz normaler Sprecher in verschiedener Weise beim Lesen und bei spontansprachlichen Äußerungen variiert. Hier war es das Ziel festzustellen, ob in einer gemischten Gruppe dysarthrischer Personen ähnliche Unterschiede zwischen verschiedenen Sprechbedingungen zu beobachten sind. Eine Anzahl segmenteller und prosodischer Parameter wurde in der Sprache von fünf leicht dysarthrischen Sprechern und fünf mit ihnen gepaarten Kontrollpersonen akustisch untersucht. Die Ergebnisse zeigten, daß bei d...

An acoustic investigation of Parkinsonian speech in linguistic and emotional contexts

“…It also bears noting that our present speech samples were derived from non-spontaneous conditions; the prosodic alterations that we found may thus not be fully comparable to changes found in the conversational speech of PD patients (Brown & Docherty, 1995;Kempler & Van Lancker, 2002). Two patterns of findings have bearing on this matter.…”

“…First, acoustic changes have been found in both non-spontaneous Parkinsonian speech samples collected from reading or repetition tasks (e.g., Forrest, Weismer, & Turner, 1989) and in spontaneous speech tokens (e.g., Illes, 1989). Second, in studies where both types of speech tokens were collected from a single sample of patients, the spontaneous speech tokens were found to be even more significantly acoustically altered than non-spontaneous tokens (Brown & Docherty, 1995;Kempler & Van Lancker, 2002). Thus, while the prosodic shifts in the present elicited Parkinsonian speech may not be equivalent to (potential) changes in the unprompted verbalizations of the PD speakers, there is nonetheless a good possibility that the acoustic distinctions we found reflect genuine alterations in the PD patients' spontaneous speech.…”

Information status marking in spontaneous vs. read speech in story-telling tasks – Evidence from intonation analysis using GToBI

“…Reading aloud can only be used if it has been established that it yields the same results as spontaneous speech. This has been shown to be the case in voice onset time production, for instance (Brown & Docherty, 1995). But it is evidently not true for (at least certain aspects of) intonation.…”

Cross-language differences in fundamental frequency range: A comparison of English and German

“…Apart from the word list, every speaker also recorded the Dog and Duck story (Brown and Docherty, 1995)-which we translated into German for the NSG speakersand some further material for future studies. The first five sentences of the Dog and Duck story were selected for further analysis.…”