Actions Speak Louder than Words: Signing and Speech Intelligibility in Adults with Down Syndrome

Previous studies into the use of key-word signing with people with a learning disability have concentrated on its contribution to the development of speech and language. The few studies focusing on its relationship to actual speech production and intelligibility were based on taught target words or phrases. This study, which was of quasi-experimental design, looked at whether reported improvements in intelligibility were supported in spontaneous speech production. Communication samples were collected by video recording 'good' and 'poor' speakers under 'high' and 'low' signing conditions. 'Skilled' and 'naive' raters assigned intelligibility ratings under 'seen' and 'unseen' conditions. It was predicted that speech from the 'high' signing condition would be rated more highly than that from the 'low' signing condition. This was supported. The iconicity of signs was shown to have a positive effect for 'naive' raters when rating the 'poor' speakers, which may counter previous arguments that the general public would be unable to understand communication attempts by people using key-word signing.

Are children with Down's syndrome able to maintain skills learned from a short-term memory training programme?

The ability of children with Down syndrome to maintain a set of trained short-term memory skills was assessed by follow up of a group who had previously undergone training in using rehearsal and organisation based memory strategies. That first study (Broadley and MacDonald, 1993) found that training in rehearsal and organisation skills led to an improvement in short-term memory ability in children with Down syndrome. That study also found that the effects applied across a wide age range; that the training could be conducted effectively by different people and that the type of training (rehearsal or organisation) acts independently, affecting only the targeted memory measures. The study reported here assesses the trained children's short-term memory abilities, 2 months and 8 months after the training had ended. Comparison with their own baseline performance and with a group of untrained children allowed assessment of the long and short term gains in memory performance. It was found that the trained children maintained the level of performance attained at the end of the training study. Training by keyworkers showed advantages for maintenance of some of the gains.

Working memory in Down syndrome: Training the rehearsal strategy

Verbal short term memory skills of individuals with Down syndrome are very poor (Hulme and MacKenzie, 1992; Bower and Hayes, 1994). This study reports on the verbal short term memory skills of individuals with Down syndrome and on the possibility of increasing memory span durably by using a rehearsal training strategy. Three tasks (letter span, digit span and word span) were presented to two groups of 12 individuals with Down syndrome as a pre-test. A global span measure was established for each individual. Each group contained four children, four teenagers and four young adults. The groups had similar memory span and mental age at the beginning of the study. None of these individuals seemed to clearly rehearse. One group of 12 was exposed to an intensive rehearsal training during eight weeks (half an hour a week). The methodology was inspired from that used by Hulme and MacKenzie (1992), and partially from that used by Broadley and MacDonald (1993). The other group of 12 received no training. After the training, the three initial memory tasks were presented again to the two groups as a post-test. The trained participants significantly improved their memory span, whereas the non-trained participants did not improve at all. Only the trained individuals showed, at this time, clear signs of systematic rehearsal. Two other post-tests were presented to them, one six weeks and the other six months after the first post-test. The trained participants did not seem, at these times, to rehearse systematically any more. Their memory performances fell significantly lower than after the first post-test but remained significantly higher than at the beginning of the study.

Short term memory deficits and Down syndrome: A comparative study

This study provides an evaluation of the short-term memory performance of children with Down syndrome (DS) and children with intellectual disability of other etiologies (ID/OE) on the Stanford-Binet 4th Edition (SB4). Results revealed a significant difference between the two groups for short term memory scores on the SB4, indicating that on short-term memory tasks children with Down syndrome function at a significantly lower level, than a group of intellectually disabled peers with other etiologies. Differences between visual and auditory short-term memory sub-scores for the two groups also were identified, with significantly lower scores for auditory short-term memory for the group with Down syndrome. Finally it was established that while the SB4 appears to be a suitable instrument for the identification of intellectual disability, the test is limited in its range of short-term memory subtests for young children with Down syndrome.