Relationship between kinematics, F2 slope and speech intelligibility in dysarthria due to cerebral palsy

a,bPurpose: We examined variability of speech intelligibility scores and how well intelligibility scores predicted group membership among 5-year-old children with speech motor impairment (SMI) secondary to cerebral palsy and an agematched group of typically developing (TD) children. Method: Speech samples varying in length from 1-4 words were elicited from 24 children with cerebral palsy (mean age 60.50 months) and 20 TD children (mean age 60.33 months). Two hundred twenty adult listeners made orthographic transcriptions of speech samples (n = 5 per child). Results: Variability associated with listeners made a significant contribution to explaining the variance in intelligibility scores for TD and SMI children, but the magnitude was greater for TD children. Intelligibility scores differentiated very well between children who have SMI and TD children when intelligibility was at or below approximately 75% and above approximately 85%. Conclusions: Intelligibility seems to be a useful clinical tool for differentiating between TD children and children with SMI at 5 years of age; however, there is considerable variability within and between listeners, highlighting the need for more than one listener per child to ensure validity of an intelligibility measure.

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confidence: 99%

Variability and Diagnostic Accuracy of Speech Intelligibility Scores in Children

Hustad

Oakes

Allison

2015

“…All kinematic data on both typical speakers (Weismer, Yunusova, & Westbury, 2003) and speakers with disorders (Rong et al, 2012) showed reasonable correlations between F2 slope measures and measures of articulatory movement and timing within each subject. However, high variability between subjects was reported in all three studies.…”

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confidence: 75%

“…X-ray microbeam and electromagnetic articulography data have been used to determine the relationship of F2 measures to vocal tract kinematics (Rong, Loucks, Kim, & Hasegawa-Johnson, 2012;Weismer, Yunusova, & Westbury, 2003). All kinematic data on both typical speakers (Weismer, Yunusova, & Westbury, 2003) and speakers with disorders (Rong et al, 2012) showed reasonable correlations between F2 slope measures and measures of articulatory movement and timing within each subject.…”

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confidence: 99%

A Modeling Study of the Effects of Vocal Tract Movement Duration and Magnitude on the F2 Trajectory in CV Words

Neely

Bunton

Story

2016

Purpose: This study used a computational vocal tract model to investigate the relationship of diphthong duration and vocal tract movement magnitude to measures of the F2 trajectory in CV words. Method: Three words (bough, boy, and buy) were simulated on the basis of an adult female vocal tract model, in which the model parameters were estimated from audio recordings of a female talker. Model parameters were then modified to generate 35 simulations of each word corresponding to 7 different durations and 5 movement magnitude settings. In addition, these simulations were repeated with vocal tract lengths representative of an adult male and an approximately 6-year-old child.Results: On the basis of univariate analysis, measures of frequency predicted changes in magnitude, and temporal measures predicted changes in speaking rate consistent with the hypothesis. The combined effects of duration and magnitude showed that F2 was more sensitive to changes in magnitude at shorter word durations compared with longer word durations. This finding held across words and vocal tract length. Conclusions: Results suggest that there is an interaction between duration and magnitude that affects the slope of the F2 trajectory. The next step is to relate kinematics to F2 trajectory output using real speakers.T he trajectory of the second formant (F2) has been studied as an index of gesture overlap in studies of speaking rate and contrastive stress as well as studies of disordered speech production (cf. Liss & Weismer, 1994;Tjaden & Weismer, 1998;Weismer & Berry, 2003;Weismer, Tjaden, & Kent, 1995). F2 trajectories have shown a reasonable correlation with presumed articulatory movement during transitions; however, determining specifically how rate and movement magnitude individually contribute to F2 trajectory measures has been inconclusive (Liss & Weismer, 1994;Tjaden, 1999;Tjaden & Weismer, 1998;Weismer & Berry, 2003).Coarticulation is thought to be reflected in measures of the F2 transition and thus can be a useful measure for studying speech production in populations with speech disorders. Weismer, Kent, Hodge, and Martin (1988) devised a definition to index the beginning and end of F2 transitions by marking F2 transition onsets (points in time at which a 20-ms segment occurs in conjunction with a 20-Hz minimal change) and transition offsets (points in time at which a 20-ms segment does not co-occur with a change of 20 Hz or more), allowing investigators to obtain a measure of slope. Steeper F2 slope and F2 onset values that are close to the steady-state target vowel frequency are considered indicators of articulatory overlap. For example, in vowel F2 trajectories that increase in frequency following a consonant release, higher F2 onset values and steeper F2 slope values are believed to suggest more overlap between neighboring consonant-vowel gestures.Several studies have investigated the effect of speaking rate changes on F2 onset and F2 slope produced by typical adult speakers; for example, Tjaden and Weismer (1998) and Weismer a...

“…Although formants do not directly measure articulatory movement, many studies have demonstrated strong correspondence between acoustic measurements and articulatory movements (Fant, 1960;Mefferd & Green, 2010;Rong, Loucks, Kim, & Hasegawa-Johnson, 2012;Stevens & House, 1961;Wang, Green, Samal, & Yunusova, 2013). In speakers with dysarthria, various formant measures have been used to quantify vowel distinctiveness as an indicator of the precision of vowel articulation.…”

Section: Acoustic Indicators Of Articulatory Imprecisionmentioning

confidence: 99%

Range and Precision of Formant Movement in Pediatric Dysarthria

Allison

Annear

Policicchio

et al. 2017

Purpose: This study aimed to improve understanding of speech characteristics associated with dysarthria in children with cerebral palsy by analyzing segmental and global formant measures in single-word and sentence contexts. Method: Ten 5-year-old children with cerebral palsy and dysarthria and 10 age-matched, typically developing children participated in this study. Vowel space area and second formant interquartile range were measured from children's elicited productions of single words and sentences. Results: Results showed that the children with dysarthria had significantly smaller vowel space areas than typically developing children in both word and sentence contexts; however, overall ranges of second formant movement did not differ between groups in word or sentence contexts. Additional analysis of single words revealed that, compared to typical children, children with dysarthria had smaller second formant interquartile ranges in single words with phonetic contexts requiring large changes in vocal tract configuration, but not in single words with monophthongs. Conclusions: Results of this study suggest that children with dysarthria may not have globally reduced ranges of articulatory movement compared to typically developing peers; however, they do exhibit reduced precision in producing phonetic targets.