Speech intelligibility in individuals with Down’s syndrome and its relations to motor oral praxis, verbal auditory memory, age, gender and intellectual level

Abstract

45 individuals with Down’s syndrome, their ages ranging from 5 to 13, were studied as to speech intelligibility. Over 70% of non-repetitive utterances were intelligible in 16 subjects, less than 40% were intelligible in 17, and 12 subjects were in intermediate positions. The two extreme groups, with good and bad intelligibility – Groups I and II respectively – were then compared as to their responses in two oral motor tests and two verbal memory tests. Group I did significantly better on all 4 tests. Both groups were also studied as to gender, age and intelligence tests results. Statistical tests showed a significant difference in the frequency on unintelligibility according to gender as well as the influence of the intellectual level on the quality of speech. There was no relation between age and intelligibility. These results support the presence of specific factors interfering in intelligibility, unequally distributed in the syndrome, as well as the relative, non consistent, influence of the intellectual level on the quality of speech, and a greater tendency towards unintelligibility in boys. Such findings point to the possibility of an early identification of individuals with Down’s syndrome with a greater risk of unintelligibility, as well as to the relevance of deeper studies on the genesis of speech unintelligibility in Down’s syndrome.