Temporal and spectral aspects of coarticulation in ataxic dysarthria: an acoustic analysis.
In order to analyze the impact of cerebellar disorders on temporal and spectral aspects of coarticulation, 9 individuals with cerebellar dysfunction and 9 controls were asked to produce test sentences comprising a target vowel (V = ['ah'], [i], or [u]) within a schwa-t-V-t-schwa environment. The con...
| Publicado en: | Journal of Speech, Language & Hearing Research Vol. 42; no. 2; pp. 367 - 382 |
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| Autores principales: | , |
| Formato: | equations & formulas research tables/charts tracings Journal Article |
| Publicado: |
American Speech-Language-Hearing Association
Apr1999
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=107211692&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 107211692 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 10924388 1SM jtl: Journal of Speech, Language & Hearing Research issn: 10924388 maglogo: N pubinfo: dt: Apr1999 vid: 42 iid: 2 pid: 42 pub: American Speech-Language-Hearing Association place: Rockville, Maryland artinfo: ui: 107211692 107211692 1999061887 10.1044/jslhr.4202.367 NLM10229453 107211692 ppf: 367 ppct: 15 formats: fmt: – @attributes: type: T – @attributes: type: P tig: atl: Temporal and spectral aspects of coarticulation in ataxic dysarthria: an acoustic analysis. aug: au: Hertrich I Ackermann H affil: Department of Neurology, University of Tubingen, Hoppe-Seyler-Str. 3, D-72076 Tubingen, Germany. E-mail: ingo.hertrich@uni-tuebingen.de sug: subj: Dysarthria Speech Production Measurement Case Control Studies Time Factors Speech Rate Acoustics Female Male Adult Middle Age Aged Multivariate Analysis of Variance Sound Spectrography Descriptive Statistics Human Adult: 19-44 years Middle Aged: 45-64 years Aged: 65+ years Female Male ab: In order to analyze the impact of cerebellar disorders on temporal and spectral aspects of coarticulation, 9 individuals with cerebellar dysfunction and 9 controls were asked to produce test sentences comprising a target vowel (V = ['ah'], [i], or [u]) within a schwa-t-V-t-schwa environment. The control speakers were investigated both at their habitual speech tempo and under a slow speaking condition. The squared distances between averaged FFT spectra served as a quantitative estimate of target-induced coarticulation, a method that can be applied to consonants as well as vowels, and which avoids the shortcomings of formant analysis. In order to test the significance of coarticulation effects at the level of individual speakers and to obtain F values as a further measure of the strength of coarticulation, multivariate tests of target effects were performed, with the first 6 principal components derived from the spectra of each speaker. First, inconsistent patterns of anticipatory vowel-to-vowel (VV) interactions emerged across individuals, and neither significant group differences nor any effects of speech rate could be detected. The underlying control mechanisms thus seem to be segment-linked subject-specific specifications of the pretarget vowel, uncompromised by cerebellar dysfunction. Second, all participants exhibited highly significant anticipatory [th]-to-vowel (CV) coarticulation. This effect was slightly smaller in the cerebellar group than in the control group, which can be at least partially explained by reduced spectral distances among the 3 target vowels. Speech rate did not influence the CV effects of the control group. As concerns temporal aspects of coarticulation, no significant group differences emerged in terms of length adjustments of the pretarget consonant to the intrinsic duration of the target vowel. Third, ataxic speakers showed a tendency toward enlarged perseverative vowel-to-[th] (VC) and VV effects if their slow speech rate was taken into account. Retentive coarticulation turned out to be similar in slow ataxic speakers and in fast-speaking controls. However, significant attenuation of these effects emerged in the latter group under the condition of decreased speech tempo. In summary, these results corroborate the suggestion of different mechanisms of gestural overlap in the temporal domain: Whereas perseverative coarticulation, presumably, reflects biomechanical or motor constraints, anticipation seems to represent higher level phonetic processing. pubtype: Academic Journal doctype: equations & formulas research tables/charts tracings Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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