Predicting Speech Intelligibility With a Multiple Speech Subsystems Approach in Children With Cerebral Palsy

Abstract

Purpose Speech acoustic characteristics of children with cerebral palsy (CP) were examined with a multiple speech subsystem approach; speech intelligibility was evaluated using a prediction model in which acoustic measures were selected to represent three speech subsystems. Method Nine acoustic variables reflecting different subsystems, and speech intelligibility, were measured in 22 children with CP. These children included 13 with a clinical diagnosis of dysarthria (SMI), and nine judged to be free of dysarthria (NSMI). Data from children with CP were compared to data from age-matched typically developing children (TD). Results Multiple acoustic variables reflecting the articulatory subsystem were different in the SMI group, compared to the NSMI and TD groups. A significant speech intelligibility prediction model was obtained with all variables entered into the model (Adjusted R-squared = .801). The articulatory subsystem showed the most substantial independent contribution (58%) to speech intelligibility. Incremental R-squared analyses revealed that any single variable explained less than 9% of speech intelligibility variability. Conclusions Children in the SMI group have articulatory subsystem problems as indexed by acoustic measures. As in the adult literature, the articulatory subsystem makes the primary contribution to speech intelligibility variance in dysarthria, with minimal or no contribution from other systems.

Range and Precision of Formant Movement in Pediatric Dysarthria

“…Reduced vowel space area in adults with dysarthria has been found in single-word contexts (Liu et al, 2005), as well as in connected speech (Tjaden, Lam, & Wilding, 2013;Turner et al, 1995;Weismer et al, 2001). Studies of children have consistently found that reduced vowel space area is associated with dysarthria and correlated with reduced intelligiblity in pediatric populations (Higgins & Hodge, 2002;Hustad et al, 2010;J. Lee et al, 2014); however, to date, studies of vowel space area in children with CP have exclusively examined single-word productions, and it is currently unknown whether findings indicating reduced vowel space area also apply to connected speech.…”

“…For children with cerebral palsy (CP), articulatory imprecision is a common perceptual feature of dysarthria (Hustad, Gorton, & Lee, 2010;Nip, 2013Nip, , 2017Workinger & Kent, 1991). Prior research has identified acoustic correlates of reduced intelligibility in children with CP (Higgins & Hodge, 2002;Hsu, Chen, & Cheng, 2013;Hustad et al, 2010;J. Lee et al, 2014); however, little is known empirically about the movement characteristics underlying this imprecision in children with CP.…”

“…One study found that children with CP and dysarthria had shallower F2 slopes and shorter F2 extents than TD children in production of diphthongs (J. Lee et al, 2014). In contrast, kinematic studies have found that children with CP tend to use larger jaw excursions than typical children, possibly reflecting inefficient motor control or compensatory movement (R. Kent & Netsell, 1978;Nip, 2013).…”

“…Variability can result from individual differences in speech motor patterns (Allison & Hustad, 2014) as well as severity of speech motor involvement (J. Lee et al, 2014). Few studies have investigated these factors directly; however, larger standard deviations in F2 slope and vowel space area among children with CP and dysarthria compared to children without dysarthria have been reported (J.…”

“…Lee, Hustad, & Weismer, 2014;Weismer, Jeng, Laures, Kent, & Kent, 2001). For children with cerebral palsy (CP), articulatory imprecision is a common perceptual feature of dysarthria (Hustad, Gorton, & Lee, 2010;Nip, 2013Nip, , 2017Workinger & Kent, 1991).…”