Vowel Intelligibility in Children With and Without Dysarthria

Abstract

Children with dysarthria due to cerebral palsy (CP) present with decreased vowel space area and reduced word intelligibility. Although a robust relationship exists between vowel space and word intelligibility, little is known about the intelligibility of vowels in this population. This exploratory study investigated the intelligibility of American English (AE) vowels produced by children with dysarthria and typically developing children (TD). Three CP and five TD repeated words with contrastive vowels /i-ɪ/, /æ-ɛ/, /ɑ-ʌ/, /o-u/ produced by a native AE adult. Adult listeners transcribed the utterances orthographically and rated their ease of understanding. Overall, CP presented with less-intelligible vowels than TD. For CP, a trend was found with the lowest intelligibility for /ɑ/ (CP = 7%, TD = 66%), /ɪ/ (CP = 30%, TD = 82%), and /ʌ/ (CP = 38%, TD = 99%), and more heterogeneous vowel confusions; however, intelligibility differences between vowels did not reach statistical significance. Clinical implications include that, unless further studies show vowel-specific effects, treatment targeting the entire vowel system may be warranted for increasing intelligibility.

Children's Perception of Conversational and Clear American-English Vowels in Noise

“…Thus, children and adults demonstrated consistent difficulty perceiving the back vowel /A/ and perceived the other target vowels (/ɛ, ae, Ã/) with variable difficulty. Particular difficulty perceiving low back vowels has also been documented crosslinguistically and across listener populations (e.g., Bion, Escudero, Rauber, & Baptista, 2006;Higgins & Hodge, 2002;Levy et al, 2014;Lin, 2013), but is poorly understood, attributed variably to the cross-linguistic salience of high front vowels and the extremities of F2 frequencies.…”

Acoustic vowel analysis and speech intelligibility in young adult Hebrew speakers: Developmental dysarthria versus typical development

“…Impaired production of vowel contrasts has been reported as a contributing factor to the speech intelligibility deficit of individuals with CP, including both high–low and front–back contrasts (Ansel and Kent 1992, Levy et al . 2016). These difficulties can be attributed to the motor control impairment demonstrated by individuals with CP, which affects accurate lingual positioning necessary for production of speech sounds (Nip et al .…”

Speech treatment for Hebrew‐speaking adolescents and young adults with developmental dysarthria: A comparison of mSIT and Beatalk

“…Resonance and prosodic impairment have also been documented among individuals with CP, characterized by hyper‐ or hypo‐nasality (Schölderle et al., 2016), as well as reduced speech rate and impaired intonational patterns (Allison & Hustad, 2018; Kuschmann et al., 2017), respectively. Articulatory deficits are typically characterized by impaired production of both consonants (Allison & Hustad, 2018; Ansel & Kent, 1992) and vowels (Higgins & Hodge, 2002; Levy et al., 2016). Specifically, several consonantal errors have been documented as contributing to the intelligibility deficit, including voicing errors (Nordberg et al., 2014), weak stop consonant production (Allison & Hustad, 2018) and difficulty with the fricative–affricate consonant contrast (Ansel & Kent, 1992).…”