Speech not memory deficit underlies teen nonword repetition problems
MedWire News: Nonword repetition (NWR) difficulties seen in adolescents with specific language impairment (SLI) may indicate problems with phonology itself, not with memory or storage of phonologic information, study results show.
Indeed, when NWR was assessed among teenagers with SLI, phonologic complexity correlated with NWR accuracy, say Susan Ebbels (Moor House School, Oxted, UK) and co-authors.
The study, published in the International Journal of Language and Communication Disorders, involved 15 individuals with SLI and aged 11-15 years. All underwent a NWR test known as the Test of Phonologic Structure.
Tests, assessing literacy, verb agreement, and tense marking were also performed.
Analysis of the test results revealed two distinct groups among adolescents with SLI: those with difficulties repeating nonwords and those without.
Specifically, when compared with SLI-free age- and language-matched controls, approximately half of the study cohort had age-appropriate NWR, whereas the other half had significantly worse NWR scores.
Test results for language and literacy were similar among all participants with SLI.
NWR showed strong positive correlation with verb agreement and tense marking, as reflected by respective correlation coefficients of 0.97 and 0.89.
Ebbels and team highlight that factors such as difficulties with phonologic short-term memory or storage, which have been hypothesized as causes of NWR difficulties, "cannot account for the language difficulties of half of the participants who had no detectable difficulties with NWR."
However, the authors say that these factors "may account for some of the difficulties with verb tense and particularly agreement marking of the other half."
The study also demonstrated that although phonologic complexity correlated with NWR score, nonword length did not.
"We propose that all participants with SLI have impairments in syntax and morphology which affect their general language abilities, including marking of agreement and tense," say Ebbels and co-authors.
"However, we propose that the SLI-low group have an additional phonological impairment (which the SLI-high group do not have) which greatly affects their ability to repeat the non-words on the [Test of Phonologic Structure] and further impairs their ability to mark tense and particularly agreement in sentences accurately."
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By Lauretta Ihonor