Assessing Phonological Profiles in Children and Adolescents With Down Syndrome: The Effect of Elicitation Methods

Abstract

In the context of comparing linguistic profiles across neurodevelopmental disorders, Down syndrome (DS) has captured growing attention for its uneven profile. Although specific weaknesses in grammatical and phonological processing have been reported, research evidence on phonological development remains scarce, particularly beyond early childhood. The purpose of this study was to explore the phonological profiles of children and adolescents with Down syndrome. The profiles were based on the frequency and relative proportion of the processes observed by classes, and they were compared to those of typically developing preschool children of similar verbal age. A complementary goal was to assess the effect of two different methods of elicitation: a test of articulation and spontaneous speech sampling. Finally, intergroup and intragroup differences in full match percentages between three positions at syllable-level (complex onset, medial coda, and final coda) were assessed. The results of the present study confirmed that the frequency of phonological processes in children and adolescents with DS is atypically high and is above what is expected for lexical age and at the same level as grammatical age. Highly increased frequency of processes, consistent in all kinds of processes and positions at the syllable-level, and asynchronous with verbal age and mental age suggest atypical developmental trajectories of phonological development in the Down syndrome population.

Late phonological development in Williams syndrome

“…In this group, frequency of omissions of voiceless stop, nasal and fricative consonants may be interpreted as reconverging with the normative group, thus also following a non-linear trajectory of phonological development. The results of this study were partially consistent with those of Diez-Itza et al (2021) who observed that children and adolescents with Down syndrome presented atypically more omission processes than their 3-year-old TD controls. A substantial portion of the segmental omissions corresponded to codas in medial and final position, which were significantly more frequent in participants with Down syndrome.…”

“…This rate of phonological development would compensate for the delay in language onset, which in turn has been related to delayed babbling ( Masataka, 2001 ) and auditory-visual integration difficulties observed in infants and toddlers with WS and other neurodevelopmental syndromes ( D’Souza et al, 2015 ). However, it remains unclear why syndromes follow quite different trajectories of phonological development ( Huelmo et al, 2017 ; Hidalgo and Garayzábal, 2019 ; Diez-Itza et al, 2021 ).…”

“…It is important to point out the possible effect of the elicitation method, as Diez-Itza et al (2021) observed that children and adolescents with Down syndrome presented a higher tendency for the omission of segments in spontaneous speech than in articulation tests. Conversely, they found a lower tendency for substitutions in spontaneous speech, consistent with the findings of the present study, where participants with WS did not differ from TD children in consonant substitutions.…”

“…In general, both direct studies of production and those of phonological processing or prosody show that these skills are not fully preserved and that difficulties persist into adolescence and adulthood. However, in late phonological development, individuals with WS reach more advanced stages than other neuroevolutionary genetic syndromes, such as WS duplication syndrome, Smith Magenis syndrome, Down syndrome, and Fragile X syndrome ( Mervis et al, 2015 ; Huelmo et al, 2017 ; Hidalgo and Garayzábal, 2019 ; Diez-Itza et al, 2021 ).…”

Defining Expressive Language Benchmarks for Children with Down Syndrome

“…In youth with DS, multiple factors make the perception and production of speech more challenging (e.g., cognitive limitations, hearing loss, anatomical/physiological differences) [ 10 ]. As a result, phonological skills remain an area of clinical focus often into adulthood [ 10 , 11 , 12 ]. Research suggests that the sequence of vocal development is similar in infants with DS and infants with TD [ 10 , 13 ], but delays become more apparent as children age.…”