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Memory development for individuals with Down syndrome– An overview

Sue Buckley and Gillian Bird

Working memory is the system in the brain that supports the daily processing of visual and verbal information as individuals go about their lives. It has been described as ‘a mental workplace’, as it is not only essential for language processing, it also supports activities which involve holding and manipulating information such as reading a text with comprehension, planning and writing text or messages, doing mental arithmetic, and holding temporary information like a telephone number while dialling it. In addition to being a temporary storage and processing system essential to everyday functioning and to mental abilities, part of the working memory system which is specialised for holding verbal information - the phonological loop - is thought to be essential for learning a spoken language. The phonological loop holds the sound patterns for words. In order to learn a first language a child has to be able to store accurate representations of the sound patterns of words in order to link them to meaning and in order to be able to copy or produce the word when talking. If the phonological loop does not function well, speech and language will be delayed. There is evidence that there is a basic impairment in phonological loop functioning in children with Down syndrome. This is probably a major reason for their speech and language delays and difficulties and it also affects their ability to process spoken language and carry out cognitive tasks. Memory training studies indicate that it is possible to improve the short-term memory skills of children with Down syndrome. However, the biggest gains in short-term memory skills reported are linked to reading instruction and to being in a mainstream school. Reading activities may provide auditory training experiences which actually improve phonological coding (the accurate representation of the sound patterns of words) in the phonological loop. Memory training activities and support for weak auditory memory skills are discussed. However, a range of activities to improve speech sound and word discrimination are included, as they may improve basic phonological loop function and therefore result in the greatest gains for spoken language abilities and working memory.

Buckley SJ, Bird G. Memory development for individuals with Down syndrome– An overview. Down Syndrome Issues and Information. 2001.

doi:10.3104/9781903806081

Introduction

Memory - the ability to store and to recall events, actions and new information is clearly extremely important for all aspects of children's development. Memory is the storage system for all information and new learning. The human memory system is not fully understood and researchers have described and divided memory in a number of ways, sometimes based on whether the memories are being stored for seconds rather than days (short-term versus long-term memory systems) and sometimes based on the type of information being learned or stored (implicit/explicit, procedural/declarative - implicit or procedural memories are usually memories for skills and habits such as riding a bicycle or playing the piano and explicit or declarative memories are the recall of episodes, events or facts, typically involving verbal recall).

Research into the memory abilities of individuals with Down syndrome has mainly focused on short-term memory. There has been very little research into the long-term memory abilities of individuals with Down syndrome. A limited number of studies suggest that their implicit memory functions better than their explicit memory.[1] This could be because explicit memory usually involves language to a greater extent than implicit memory. Observational reports from parents and teachers suggest that the long-term memory abilities of individuals with Down syndrome, for skills learned and for events recalled, are good. However, this is an area needing more research.

The majority of the research into the memory skills of individuals with Down syndrome has focused on short-term memory abilities and the learning of new tasks. Much of the most recent work published has been based on the working memory model of short-term memory[2,3] and this work is the focus of this module because of its practical importance. The short-term memory and processing skills described as working memory have been shown to be important for learning to talk, for processing spoken language, for reading and mental arithmetic, and for the support of everyday tasks such as remembering a telephone number while dialling or a postcode while writing it.[see 4] Working memory measures are also associated with measures of general intelligence.[5]

Aspects of the working memory system seem to be specifically impaired in children and adults with Down syndrome[6,7] and these impairments could explain much of the difficulty that the children have in learning to talk, in general cognitive development and in learning in some classroom situations. It is possible that, conversely, over time, the speech and language difficulties of many children with Down syndrome limit the development of working memory capacities. It follows, then, that if it is possible to improve the functioning of working memory, this would have a major effect on the speech, language and cognitive difficulties associated with Down syndrome. For this reason, the working memory system is described in some detail in this module.

Drawing on research into the development of working memory in typically developing children, possible ways of improving basic memory function are discussed. Some of these have not yet been tried or evaluated. There have been a number of memory training studies with children, teenagers and adults with Down syndrome that have been published and the outcomes from these are discussed.

In the last section of this module, practical games and activities which may help memory development are described. It is not necessary to understand the research into working memory discussed in the next sections in order to use the practical activities, therefore some readers may wish to go straight to the practical section.