Volume 134, Issue 3, September 2013
Index of content:
- SPEECH PRODUCTION 
Imprecise vowel articulation as a potential early marker of Parkinson's disease: Effect of speaking task134(2013); http://dx.doi.org/10.1121/1.4816541View Description Hide Description
The purpose of this study was to analyze vowel articulation across various speaking tasks in a group of 20 early Parkinson's disease (PD) individuals prior to pharmacotherapy. Vowels were extracted from sustained phonation, sentence repetition, reading passage, and monologue. Acoustic analysis was based upon measures of the first (F1) and second (F2) formant of the vowels /a/, /i/, and /u/, vowel space area (VSA), F2i/F2u and vowel articulation index (VAI). Parkinsonian speakers manifested abnormalities in vowel articulation across F2u, VSA, F2i/F2u, and VAI in all speaking tasks except sustained phonation, compared to 15 age-matched healthy control participants. Findings suggest that sustained phonation is an inappropriate task to investigate vowel articulation in early PD. In contrast, monologue was the most sensitive in differentiating between controls and PD patients, with classification accuracy up to 80%. Measurements of vowel articulation were able to capture even minor abnormalities in speech of PD patients with no perceptible dysarthria. In conclusion, impaired vowel articulation may be considered as a possible early marker of PD. A certain type of speaking task can exert significant influence on vowel articulation. Specifically, complex tasks such as monologue are more likely to elicit articulatory deficits in parkinsonian speech, compared to other speaking tasks.
Accounting for the listener: Comparing the production of contrastive intonation in typically-developing speakers and speakers with autism134(2013); http://dx.doi.org/10.1121/1.4816544View Description Hide Description
The present research investigates what drives the prosodic marking of contrastive information. For example, a typically developing speaker of a Germanic language like Dutch generally refers to a pink car as a “PINK car” (accented words in capitals) when a previously mentioned car was red. The main question addressed in this paper is whether contrastive intonation is produced with respect to the speaker's or (also) the listener's perspective on the preceding discourse. Furthermore, this research investigates the production of contrastive intonation by typically developing speakers and speakers with autism. The latter group is investigated because people with autism are argued to have difficulties accounting for another person's mental state and exhibit difficulties in the production and perception of accentuation and pitch range. To this end, utterances with contrastive intonation are elicited from both groups and analyzed in terms of function and form of prosody using production and perception measures. Contrary to expectations, typically developing speakers and speakers with autism produce functionally similar contrastive intonation as both groups account for both their own and their listener's perspective. However, typically developing speakers use a larger pitch range and are perceived as speaking more dynamically than speakers with autism, suggesting differences in their use of prosodic form.