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An Investigation Into The Effects Of Central Executive Deficits On Word Recognition Abilities Of Dyslexic Teenagers
Sue Palmer investigated the way the central executive in working memory affects word recognition in dyslexic teenagers. Working memory is the system that holds and manipulates information for a short period of time. One current theory suggests that there are two 'slave' systems: one holds roughly a few seconds worth of sound and the other deals with visual information. The Central Executive directs and controls which information should be held and attended to, it is also thought to control the strategy for storing memories. Palmer suggested that part of the problems in dyslexia may be related to developing the system that allows the central executive to control which storage information would best suit a particular stimulus. For example, the word "duck" can be held visually (the pattern for the printed word duck) or as a sound bite. Some developmental studies have shown that in young children the strategy used to store information is primarily visual. This is effective for small amounts of information but children need to develop a sound based, phonological system in order to cope with the storage and manipulation demands of reading.
The main part of Palmer's study was related to the central executive's ability to switch quickly between retrieval strategies: visual or phonological. The Wisconsin Card Sort Task allows researchers to gauge how quickly the central executive can switch between visual and sound strategies. It was shown that the dyslexic participants took longer and made more errors in the task, suggesting the role of the central executive, which is a poorly understood part of working memory, and its role in dyslexia needs further investigation.
Patterns Of Long-Term Memory Deficit In Learning Disorders Clinic Cohort
Wayne Levick's talk concerned the study of a group of children with learning disabilities and whether the inability to store information in long term memory might be a contributing factor in some of the problems these children have. He tested participants with tasks which involved recollection of information from memory after a specified delay. The results suggest that difficulties do exist in some of the children's abilities to store and retrieve verbal or phonological information. There was also a sub type who showed a general inability to store information reliably in long term memory. This was discussed in terms of implications for the current understanding of dyslexia's phonological processing and future research into underlying impairments in dyslexia.
Everyday Memory And Dyslexia
James Smith-Spark set out to examine how memory used in everyday life might go astray in dyslexics; this is an often overlooked area as the majority of researchers tend to examine memory in the laboratory. Participants were asked to fill out questionnaires relating to things they have tended to forget in the recent past, for example, whether they forgot names of people when introduced to them, or whether they wondered if they had used words correctly in conversation. In addition, he compared these accounts with accounts of the dyslexic's close friend's evaluation of his or her forgetfulness. The final aspect involved asking participants to keep a diary. The results showed that dyslexics did generally seem more "forgetful" than their non dyslexic friends. James Smith-Spark went on to conclude that this certainly showed that the problems in dyslexia go beyond just reading and helped confirm that the results found in laboratory studies of memory in dyslexics do have a real world underpinning.
Dyslexia And Deficits In Short-Term Memory: Phonological Versus Sequential Explanations
Dyslexic children and adults have often shown problems in digit span tasks, a task where the researcher says a short list of numbers and the respondent has to reply with the same numbers in the same order. John Everatt's talk was concerning the research into why this may be the case. They found that whilst dyslexics had trouble with both recalling words and numbers, both of which require verbal, phonological skills, a problem which has been implicated in a number of studies in the past. They did not have trouble where the task required recall of purely visual, non verbal information. He argued that studies that had suggested that non verbal memory was impaired had used tasks which had an implicit phonological component. He continued that this had implications for the understanding of the role of the working memory 'slave' systems in dyslexia.
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