Phonological Short-Term Memory Impairment in Children with Down Syndrome

Abstract

Background: Children with Down Syndrome commonly suffer from phonological and other language disorders which have been partly attributed to underlying deficit in phonological short term memory. Its evaluation was previously confined to non word repetition and/or forward digit span tasks. Aim of Study: To assess phonological short term memory in children with Down Syndrome with mild degree of intellectual disability in comparison with non syndromic children with mild degree of intellectual disability to find out any possible correlation between Down Syndrome and phonological short term memory deficits through comprehensive evaluation. Subjects and Methods: This case control study has been conducted on 40 children (20 Down Syndrome children with mild degree of intellectual disability, 20 non syndromic children with mild degree of intellectual disability with matched mental age). All of them underwent psychometric evaluation, audiological evaluation, language evaluation using Arabic version of Modified Preschool Language Scale-4 th edition (PLS-4), and Arabic version of Phonological Short Term Memory Test (PSTM). Results: Down Syndrome group scored significantly lower than non syndromic children with mild degree of intellectual disability in all items of phonological short term memory test; digit span, syllable repetition, non sense word repetition, dissimilar word set recall, similar word set recall, total score (p-value 0.000, 0.001, 0.004, 0.000, 0.000, 0.000 respectively) and language test; expressive abilities was lower in Down syndrome children (p-value 0.002) but both groups were equal in their receptive abilities (p-value 0.054). Conclusion: Children with Down Syndrome scored below expected for phonological short term memory and their phonological store was extensively impaired.