Background: Expressive language constitutes a major challenge to the development of individuals with Down syndrome. This paper investigates the relationships between expressive language abilities, language comprehension and the deficits in verbal short-term memory and hearing which are also associated with the syndrome.
Methods: Tests of nonverbal ability, expressive language, verbal short-term memory, visuo-spatial memory, language comprehension and hearing were administered.
Results: Phonological memory, measured by nonword repetition, was significantly correlated with expressive language abilities measured by MLU and sentence recall. Adjusting for word repetition skills did not reduce this correlation, suggesting that the relationship did not depend on the fact that both tests required spoken output. Hearing did not contribute significantly to expressive language scores of participants who provided an intelligible narrative. However, level of hearing loss as well as other language and memory measures did differentiate these participants from those who were unable to produce an intelligible narrative.
Conclusion: Phonological memory was closely associated with the expressive language abilities of individuals with Down syndrome. Hearing loss appeared to be less closely related except that individuals with uncorrected mild to moderate hearing loss had difficulty with the narrative task. Further research is necessary to establish the nature of these relationships.