Longitudinal Growth in Single-Word Intelligibility Among Children With Cerebral Palsy From 24 to 96 Months of Age: Effects of Speech-Language Profile Group Membership on Outcomes

Abstract

Purpose We examined whether there were differences among speech-language profile groups of children with cerebral palsy (CP) in age of crossing 25%, 50%, and 75% intelligibility thresholds; age of greatest intelligibility growth; rate of intelligibility growth; maximum attained intelligibility at 8 years; and how well intelligibility at 36 months predicts intelligibility at 96 months when group membership is accounted for. Profile groups were children with no speech motor impairment (NSMI), those with speech motor impairment and language comprehension that is typically developing (SMI-LCT), and those with speech motor impairment and language comprehension impairment (SMI-LCI). Method Sixty-eight children with CP were followed longitudinally between 24 and 96 months of age. A total of 564 time points were examined across children ( M = 8.3 time points per child, SD = 2.6). We fitted a nonlinear random effects model for longitudinal observations, allowing for differences between profile groups. We used the fitted model trajectories to generate descriptive analyses of intelligibility growth by group and to generate simulations to analyze how well 36-month intelligibility data predicted 96-month data accounting for profile groups. Results Children with CP who have NSMI have different growth and better intelligibility outcomes than those with speech motor impairment. Children with SMI-LCT tend to have better outcomes but similar intelligibility growth as children with SMI-LCI. There may be a subset of children that cut across SMI-LCI and SMI-LCT groups who have severe speech motor involvement and show limited growth in intelligibility. Conclusions Intelligibility outcomes for children with CP are affected by profile group membership. Intelligibility growth tends to be delayed in children with speech motor impairment. Intelligibility at 3 years is highly predictive of later outcomes regardless of profile group. Intervention decision making should include consideration of early intelligibility, and treatment directions should include consideration of augmentative and alternative communication.

Speech Development Between 30 and 119 Months in Typical Children I: Intelligibility Growth Curves for Single-Word and Multiword Productions

“…A second key finding from this study is that intelligibility peaks in its rate of growth at very early ages and that children in lower developmental percentiles tend to be older when they experience their peak in growth rate. The finding that children with lower levels of speech performance experience peak growth later than children with higher levels of performance is generally consistent with findings from our research on children with cerebral palsy (Hustad, Mahr, Broman, & Rathouz, 2020). Interestingly, findings from this study indicate that the 5th percentile of typical children demonstrate peak growth at the same time as children with cerebral palsy who have no evidence of speech motor involvement, providing an important point of convergence for these two groups of children.…”

“…In our work on speech intelligibility development in children with cerebral palsy with and without dysarthria, we found that children experienced maximum intelligibility growth between the ages of 36 and 60 months ( Hustad, Sakash, Natzkie, et al, 2019 ). However, for children who had deficits in speech and language ability, results suggested that the age of maximum growth occurred in the later months of this time frame ( Hustad, Mahr, Broman, & Rathouz, 2020 ). To our knowledge, analogous studies have not been performed on typically developing children, so we do not know about growth rates or the timing of peak growth in speech intelligibility.…”

Speech Treatment Effects on Narrative Intelligibility in French-Speaking Children With Dysarthria

“…Speech intelligibility in children with dysarthria due to CP is reduced compared to that of typically-developing children (Braza et al, 2019;Hustad et al, 2010;Hustad et al, 2012) and of children with CP with no speech motor impairment (Hustad et al, 2020). Moreover, intelligibility in children with CP with no speech motor deficits is also reduced compared to that of typically developing children (Hustad et al, 2019).…”

Spoken Vocabulary Outcomes of Toddlers With Developmental Delay After Parent-Implemented Augmented Language Intervention

“…These difficulties may result in vowel distortions, consonant errors, and difficulty with multisyllabic words (Allison et al, 2017;Bauman-Waengler, 2012). Additionally, children diagnosed with CP, even without dysarthria, have been reported to have reduced intelligibility compared to typically developing peers (Hustad et al, 2019). The genotype of Down syndrome may result in decreased muscle tone of the tongue, lips, soft palate, and jaw (Kumin, 1996;Romski, Sevcik, Barton-Hulsey, et al, 2020).…”