Memory & Down Syndrome Abstracts

J Exp Child Psychol 91 (1): 1-23 (2005 May)

Impaired verbal short-term memory in Down syndrome reflects a capacity limitation rather than atypically rapid forgetting

Purser HR, Jarrold C
Department of Experimental Psychology, University of Bristol, Bristol BS8 1TN, UK

Individuals with Down syndrome suffer from relatively poor verbal short-term memory. Recent work has indicated that this deficit is not caused by problems of audition, speech, or articulatory rehearsal within the phonological loop component of Baddeley and Hitch's working memory model. Given this, two experiments were conducted to investigate whether abnormally rapid decay underlies the deficit. In a first experiment, we attempted to vary the time available for decay using a modified serial recall procedure that had both verbal and visuospatial conditions. No evidence was found to suggest that forgetting is abnormally rapid in phonological memory in Down syndrome, but a selective phonological memory deficit was indicated. A second experiment further investigated possible problems of decay in phonological memory, restricted to item information. The results indicated that individuals with Down syndrome do not show atypically rapid item forgetting from phonological memory but may have a limited-capacity verbal short-term memory system.
J Child Psychol Psychiatry 46 (3): 304-16 (2005 Mar)

Serial order reconstruction in Down syndrome: evidence for a selective deficit in verbal short-term memory

Brock J, Jarrold C
Department of Experimental Psychology, University of Bristol, Bristol, UK

BACKGROUND: Individuals with Down syndrome consistently perform less well than appropriately matched comparison groups on tests of verbal short-term memory, despite performing relatively well on non-verbal short-term memory tasks. However, it is not clear whether these findings constitute evidence for a selective deficit in verbal short-term memory, or whether they instead reflect the influence of non-central factors such as speech difficulties or poor number knowledge. METHODS: Twenty-six individuals with Down syndrome and 32 typically developing children were tested on a digit reconstruction task in which participants were presented with auditory digit sequences and responded by pressing the corresponding digits on a touch-screen in the correct serial order. Background measures were performance on a closely matched visuo-spatial reconstruction task, reaction time on a simple digit identification task, receptive vocabulary age and non-verbal ability (Raven's matrices). Participants were also tested on a conventional digit recall task. RESULTS: All four background measures accounted for significant individual variation in digit reconstruction performance, but there remained a significant effect of group that reflected relatively poor performance of individuals with Down syndrome. Hierarchical regression showed that group membership accounted for unique variation in both digit reconstruction and recall performance, even after all group differences on background measures had been accounted for. CONCLUSIONS: The results provide strong evidence that Down syndrome is associated with a selective deficit in verbal short-term memory, and a deficit in verbal serial order memory in particular. Implications for the language difficulties associated with Down syndrome are discussed.
Am J Ment Retard 109 (6): 456-66 (2004 Nov)

Verbal and visuospatial working memory deficits in children with Down syndrome

Lanfranchi S, Cornoldi C, Vianello R
Dipartimento di Psicologia della Sviluppo, University of Padua, Via Venezia 8, 35131 Padua, Italy

The hypothesis that deficits of children with Down syndrome on working memory tasks are more evident the higher the control required and for verbal than visuospatial tasks was tested. Two groups of children, one with Down syndrome, who ranged in age from 7 to 18, and a control group were assessed with batteries of verbal and visuospatial working memory tests requiring different levels of control. On tasks requiring low control, children with Down syndrome showed impairment of verbal but not visuospatial working memory tasks. As the requirement for control increased, they showed greater impairment on both tasks. Children with Down syndrome were comparatively better in visuospatial than verbal tasks. Implications of these results for working memory models and the role of working memory in intelligence were discussed.
J Child Psychol Psychiatry 45 (6): 1085-95 (2004 Sep)

Contributions of phonological memory, language comprehension and hearing to the expressive language of adolescents and young adults with Down syndrome

Laws G
Department of Experimental Psychology, University of Oxford, UK

BACKGROUND: Expressive language constitutes a major challenge to the development of individuals with Down syndrome. This paper investigates the relationships between expressive language abilities, language comprehension and the deficits in verbal short-term memory and hearing which are also associated with the syndrome. METHODS: Tests of nonverbal ability, expressive language, verbal short-term memory, visuo-spatial memory, language comprehension and hearing were administered. RESULTS: Phonological memory, measured by nonword repetition, was significantly correlated with expressive language abilities measured by MLU and sentence recall. Adjusting for word repetition skills did not reduce this correlation, suggesting that the relationship did not depend on the fact that both tests required spoken output. Hearing did not contribute significantly to expressive language scores of participants who provided an intelligible narrative. However, level of hearing loss as well as other language and memory measures did differentiate these participants from those who were unable to produce an intelligible narrative. CONCLUSION: Phonological memory was closely associated with the expressive language abilities of individuals with Down syndrome. Hearing loss appeared to be less closely related except that individuals with uncorrected mild to moderate hearing loss had difficulty with the narrative task. Further research is necessary to establish the nature of these relationships.
J Intellect Disabil Res 48 (2): 80-92 (2004 Feb)

Verbal short-term memory in Down's syndrome: an articulatory loop deficit?

Vicari S, Marotta L, Carlesimo GA
IRCCS, Ospedale Pediatrico Bambino Gesu, Santa Marinella, Rome, Italy IRCCS, Fondazione Santa Lucia, Rome, Italy

BACKGROUND: Verbal short-term memory, as measured by digit or word span, is generally impaired in individuals with Down's syndrome (DS) compared to mental age-matched controls. Moving from the working memory model, the present authors investigated the hypothesis that impairment in some of the articulatory loop sub-components is at the base of the deficient maintenance and recall of phonological representations in individuals with DS. METHODS: Two experiments were carried out in a group of adolescents with DS and in typically developing children matched for mental age. In the first experiment, the authors explored the reliance of these subjects on the subvocal rehearsal mechanism during a word-span task and the effects produced by varying the frequency of occurrence of the words on the extension of the word span. In the second experiment, they investigated the functioning of the phonological store component of the articulatory loop in more detail. RESULTS: A reduced verbal span in DS was confirmed. Neither individuals with DS nor controls engaged in spontaneous subvocal rehearsal. Moreover, the data provide little support for defective functioning of the phonological store in DS. CONCLUSIONS: No evidence was found suggesting that a dysfunction of the articulatory loop and lexical-semantic competence significantly contributed to verbal span reduction in subjects with DS. Alternative explanations of defective verbal short-term memory in DS, such as a central executive system impairment, must be considered.
J Child Psychol Psychiatry 45 (2): 326-37 (2004 Feb)

Phonological memory as a predictor of language comprehension in Down syndrome: a five-year follow-up study

Laws G, Gunn D
Department of Experimental Psychology, University of Oxford, UK

BACKGROUND: This study reports the language and memory progress over five years of 30 adolescents and young adults with Down syndrome, and investigates the relationship of earlier phonological memory abilities to later language development. METHODS: Tests of nonverbal ability, receptive vocabulary, grammar comprehension, digit span and nonword repetition were administered at two points in time. RESULTS: For the sample as a whole, there were significant gains in nonverbal ability, receptive vocabulary and grammar comprehension, but no increases in phonological memory measured by nonword repetition or digit span. However, there were considerable individual differences in progress which, in part, were related to chronological age. Phonological memory improved in many younger participants but there were signs of decline in some older ones. Partial correlations between earlier nonword repetition scores and later language scores, controlling for nonverbal ability and earlier language scores, indicated a significant role for phonological memory in the acquisition of vocabulary knowledge. There was similar evidence of a role for phonological memory in grammar comprehension, but only for younger participants. Earlier receptive vocabulary also predicted later nonword repetition scores, particularly for participants with higher levels of vocabulary knowledge. CONCLUSION: Relationships among the processes involved in language and memory development in Down syndrome may be similar to those established for typical development.
Journal of Intellectual Disability Research 48 (2): 160-71 (2004 Feb)

Sentence memory of individuals with Down's syndrome and typically developing children

Seung, H-K., Chapman, R.S.
University of Florida, Department of Communicative Disorders, College of Health Professions, PO Box 100174, Gainesville, FL

Background. Individuals with Down's syndrome (DS) have an auditory short-term memory span disproportionately shorter than the non-verbal mental age (MA). This study evaluated the Baddeley model's claim that verbal short-term memory deficits might arise from slower speaking rates (and thus less material rehearsed in a 2 s passive store) by using the sentence memory subtest of the Stanford-Binet. Previous work had shown digit span recall speaking rate to be comparable to the examiner's slow rate (one syllable per second) for both DS and language-matched participants.
Method. Thirty individuals with DS were compared to two control groups [non-verbal MA-matched and mean length of utterance (MLU)-matched] on the sentence span and speaking rate for the longest verbatim recalled sentence. Sentence stimuli were presented at a normal speaking rate.
Results. The DS group had shorter sentence memory span than the MA-matched group and a faster, rather than slower, speaking rate (syllables per second) than the MLU-matched controls.
Conclusions. Language production level accounted for a substantial portion of the variance in the sentence memory span in the DS group. Thus, language production skill, rather than speaking rate, predicts variability in verbal memory span.
J Speech Lang Hear Res 45 (3): 531-44 (2002 Jun)

Verbal short-term memory in Down syndrome: a problem of memory, audition, or speech?

Jarrold C; Baddeley AD; Phillips CE
Centre for the Study of Memory and Learning, Department of Experimental Psychology, University of Bristol, UK

The current study explored three possible explanations of poor verbal short-term memory performance among individuals with Down syndrome in an attempt to determine whether the condition is associated with a fundamental verbal short-term memory deficit. The short-term memory performance of a group of 19 children and young adults with Down syndrome was contrasted with that of two control groups matched for level of receptive vocabulary. The specificity of a deficit was assessed by comparing memory for verbal and visuo-spatial information. The effect of auditory problems on performance was examined by contrasting memory for auditorily presented material with that for material presented both auditorily and visually. The influence of speech-motor difficulties was investigated by employing both a traditional recall procedure and a serial recognition procedure that reduced spoken response demands. Results confirmed that individuals with Down syndrome do show impaired verbal short-term memory performance for their level of receptive vocabulary. The findings also indicated that this deficit is specific to memory for verbal information and is not primarily caused by auditory or speech-production difficulties.
J Child Psychol Psychiatry 43 (3): 533-64 (2002 Mar)

Working memory in children and adolescents with Down syndrome: evidence from a colour memory experiment

Laws G
Department of Experimental Psychology, University of Oxford, UK

BACKGROUND: This paper reports information on the visual and verbal short-term memory of individuals with Down syndrome. METHODS: Colour memory in 16 children and adolescents with Down syndrome was compared with that of 16 typically developing children matched for receptive vocabulary. It was suggested that focal colours should be remembered more successfully than non-focal colours on the basis that the former could be remembered using a verbal recoding strategy. However, children with Down syndrome, for whom a deficit in verbal short-term memory makes the use of such a strategy unlikely, should remember focal and non-focal colours equally well. More importantly, if individuals with Down syndrome have more developed visual memory abilities than control children, they should outperform them in recognising non-focal colours. RESULTS: Although the group with Down syndrome demonstrated significantly better Corsi blocks performance than controls, and displayed similar levels of colour knowledge, no advantage for colour memory was found. Non-focal colours were remembered by individuals with Down syndrome as successfully as focal colours but there was no indication of a visual memory advantage over controls. Focal colours were remembered significantly more successfully than non-focal colours by the typically developing children. CONCLUSION: Their focal colour memory was significantly related to digit span, but only Corsi span was related to focal colour memory in the group with Down syndrome.
Down's Syndrome: Research and Practice 7 (1): 25-33 (2001)

Memory training for children with Down syndrome

Conners F.A., Rosenquist C.J., and Taylor L.A.
Psychology Department, University of Alabama

One well-established fact concerning cognitive and language development in individuals with Down syndrome is that working memory is particularly poor, with auditory working memory worse than visual working memory. Working memory serves the functions of control, regulation, and active maintenance of information and is critical in daily complex cognitive activities. Thus, there is a strong need to find effective and practical interventions targeted at improving working memory in individuals with Down syndrome. The present paper reviews research on rehearsal training and concludes that it can be used successfully to increase working memory in individuals with Down syndrome. However, there are still questions about whether auditory working memory can be improved reliably, whether improvement can be maintained over the long term, and whether improvement exists beyond any effect of increased attention. We describe our in-progress study which addresses these concerns.
Journal of Intellectual Disability Research 45 (2): 157 (2001 Apr)

Working memory and everyday cognition in adults with Down's syndrome

H. Numminen, E. Service, T. Ahonen & I. Ruoppila

A number of previous studies have suggested that young people with Down's syndrome (DS) have a specific deficit of the phonological loop component of the working memory. However, there have also been studies which have proposed a specific deficit of the central executive component of working memory and suggested similarities of working memory functioning with patients with Alzheimer's disease. Fifteen middle-aged people with DS were matched for their individual scores of non-verbal intelligence to 15 individuals with mixed aetiology of intellectual disability. A versatile range of tasks was used in order to evaluate the functioning of working memory components. In addition, several everyday cognition skills were assessed. The subjects with DS performed significantly more poorly in all tasks assessing the phonological loop. Performance in other working memory tasks and compound variables representing different working memory components was equal in the groups. In addition, both groups had equal everyday cognition skills. The functioning of the phonological loop seems to be clearly deficient in people with DS. Interestingly, the deficit does not seem to affect the vocabulary or other everyday cognition skills in individuals with DS. No signs of specific deficit of the central executive component of working memory were found.
Journal of Speech, Language, and Hearing Research 43 (3): 609-620 (2000 Jun)

Digit Span in Individuals With Down Syndrome and in Typically Developing Children: Temporal Aspects

Seung, H-K., Chapman, R.S.

This study explored factors influencing digit span performance in individuals with Down syndrome. The following questions were asked: Is there a deficit in the phonological loop, either in articulatory rehearsal (measured in speaking rate and recall latency) or in the passive store (measured in recall duration)? Is reduced auditory short-term memory associated with a language production deficit? Thirty five adolescents with trisomy 21 Down syndrome were compared to 35 mental-age-matched and 35 language-production-matched controls. There was no group difference in speaking rate. The DS group had shorter digit spans than the MA controls. Language production level accounted for substantial variance in digit span in individuals with Down syndrome.
Journal of Child Psychology and Psychiatry 41 (2): 233-44 (2000 Feb)

Verbal Short-term Memory Deficits in Down Syndrome: A Consequence of Problems in Rehearsal?

Christopher Jarrold, Alan D. Baddeley, Alexa K. Hewes
Centre for the Study of Memory and Learning, Department of Experimental Psychology, University of Bristol, 8 Woodland Road, Bristol BS8 1TN, U.K.

Individuals with Down syndrome suffer from relatively poor verbal short-term memory. Previous explanations of this deficit have been framed in terms of inefficient or absent rehearsal of verbal material in Down syndrome within the phonological loop component of Baddeley and Hitch's (1974) working memory model. Two experiments are presented which test this explanation by looking for the markers of rehearsal in children with Down syndrome and verbal mental age matched controls. Both experiments confirm that individuals with Down syndrome show poorer verbal short-term memory performance than controls. However, they rule out rehearsal as an explanation of these deficits because the evidence suggests that neither individuals with Down syndrome nor matched controls are engaging in spontaneous subvocal rehearsal. Other explanations of poor verbal short-term memory performance in Down syndrome, in terms of impairments both within and outside of the phonological loop system, are discussed. Practical implications for intervention strategies aimed at improving verbal short-term memory skills in Down syndrome are also outlined.
Down's Syndrome: Research and Practice 6 (2): 61-75 (1999)

Down Syndrome and the Phonological Loop: The Evidence for, and Importance of, a Specific Verbal Short-Term Memory Deficit

Christopher Jarrold, Alan D. Baddeley, Caroline Phillips
Centre for the Study of Memory and Learning, Department of Experimental Psychology, University of Bristol, 8 Woodland Road, Bristol BS8 1TN, U.K.

Individuals with Down syndrome are thought to perform poorly on tests of verbal short-term memory, such as measures of word span or digit span. This review critically examines the evidence for a specific deficit in verbal short-term memory in Down syndrome, and outlines a range of possible explanations for such a deficit. The potential implications of a verbal short-term memory impairment for broader aspects of development are outlined, in particular with respect to vocabulary development. Possible intervention strategies, which might improve verbal short-term memory performance in Down syndrome are also considered. However, we argue that further research is needed to fully clarify the nature of a verbal short-term memory deficit in Down syndrome, before the merits of these various intervention approaches can be properly evaluated.
Down's Syndrome: Research and Practice 6 (2): 76-84 (1999)

The relevance of a nonword repetition task to assess phonological short-term memory in individuals with Down syndrome

Comblain, Annick
Laboratoire de Psycholinguistique, Université de Liège, Liège, Belgium

Phonological short-term memory capacity is generally measured with a word span task or a digit span task. Another way to measure it is to use a nonword repetition task. Gathercole and Adams (1993) claimed that this procedure can be used with children as young as two-years old. It seems that in normally developing children the quality of nonword repetition is influenced both by the length of nonwords and by the degree of wordlikeness. Can the phonological short-term memory of individuals with Down syndrome be assessed with a nonword repetition task? In order to answer this question, we decided to replicate Gathercole and collaborators' experiments (1991,1993) but with individuals with Down syndrome. The quality of nonword repetition in individuals with Down syndrome is, as in normally developing children, influenced both by the length of nonwords and by their degree of wordlikeness. Furthermore, our results seem to confirm the hypothesis which states that nonwords are temporarily stored in the phonological short-term memory system. As this system has a limited capacity, both normally developing children and people with Down syndrome recall more short nonwords than long nonwords. In conclusion, nonword repetition is a reliable task with which to assess phonological short-term memory in individuals with Down syndrome as well as in normally developing children.
Journal of Child Psychology and Psychiatry 39 (8): 1119-30 (1998)

The Use of Nonword Repetition as a Test of Phonological Memory in Children with Down Syndrome

Laws, Glynis
Department of Psychology, University of Surrey, Guildford, Surrey GU2 5XH, U.K.

Recent research suggests a significant relationship between verbal short-term memory and normal language development. Although poor short-term memory and impaired language are features of Down syndrome there has been little investigation of the relationship between these functions in this population, and no studies have included the nonword repetition test devised by Gathercole and Baddeley on which much of the evidence from normal development is based. This study reports the use of nonword repetition with 33 children and teenagers with Down syndrome aged from 5 to 18 years, and investigates the relationship between this test and other memory and language measures. Word repetition was included as an indirect control for the perceptual and speech impairments often associated with this group. Words were repeated significantly more successfully than nonwords and both these tasks were sensitive to word length. Nonword repetition was significantly correlated with age, and when age and nonverbal cognitive ability were controlled, nonword repetition was significantly correlated with all other language-based memory measures, i.e. auditory digit span, word span, sentence repetition, and fluency, and also with memory for a sequence of hand movements, but not with memory for faces or a visual digit span task. There was also a significant relationship between nonword repetition and receptive vocabulary, language comprehension, and reading. When performance on the word repetition task was controlled in addition to age and nonverbal ability, significant correlations between nonword repetition and word span, sentence memory, hand movements, language comprehension, and reading remained. Fewer relationships between auditory digit span and these other measures were established; in particular, there was no association between digit span and the language and reading measures. Results suggest that nonword repetition is a reliable measure of phonological memory in Down syndrome and can predict language comprehension and reading ability.
Neuropsychologia 35 (1): 71-9 (1997)

Long-term memory in mental retardation: evidence for a specific impairment in subjects with Down's syndrome

Carlesimo GA, Marotta L, Vicari S
Clinica Neurologica, Universita di Roma, Tor Vergata, Italy

This study aimed at investigating long-term memory functioning in Down's syndrome subjects (DS) as compared to individuals with mental retardation of different etiology (MR) and mental-age matched normal children (MA). For this purpose, tests of verbal and visuo-perceptual explicit memory and a verbal repetition priming task were administered to 15 DS, 15 MR and 30 MA subjects. Our results document comparable verbal priming in the three groups. As for explicit memory, normal children performed better than MR individuals, and these, in turn, better than DS subjects. Compared to MR subjects, DS subjects were particularly deficient in organizing verbal material according to its categorical structure and in actively retrieving stored information. These results support a view positing heterogeneity of neuropsychological deficits across distinct etiology MR groups.
American Journal on Mental Retardation 100 (4): 418-23 (1996 Jan)

Effortful and Automatic Processes Associated with Down Syndrome and Nonspecific Mental Retardation

Dulaney, Cynthia L. et al.

This study examined recognition memory for items and their location among adults with Down syndrome (n=24), adults with nonspecific mental retardation (n=22), and community volunteers (n=20). No differences in memory for spatial location were found between the two groups with mental retardation, though both groups performed worse than control subjects.
Down's Syndrome: Research and Practice 4 (2): 70-7 (1996)

The Effects of a Short Training in the Use of Rehearsal Strategy on Memory for Words and Pictures in Children with Down Syndrome

Laws, Glynis; MacDonald, John; Buckley, Sue
Department of Psychology, University of Portsmouth, UK and The Down Syndrome Educational Trust

This study describes the effects of using a memory training programme with children with Down syndrome at schools for children with severe learning difficulties. The results suggest a small but significant improvement in memory spans for children at schools where they were trained by teachers or teaching assistants. There were no significant differences between auditory or visual stimulus presentation or between manual or verbal responses, but a three-way interaction between assessment point, stimulus presentation and response mode showed that memory and verbal recall of longer words particularly improved. Responses demonstrated a classic word length effect. One further finding was a significant correlation between reading and memory scores after the training.
J Intellect Disabil Res 39 (6): 532-7 (1995 Dec)

Short-term memory in persons with intellectual disabilities and Down's syndrome

Vicari S, Carlesimo A, Caltagirone C
Servizio di Neurologia e Riabilitazione, Ospedale Pediatrico Bambino Gesu, I.R.C.C.S., Santa Marinella, Rome, Italy

The present study was designed to investigate verbal and spatial short-term memory abilities in persons with Down's syndrome (DS) and intellectual disability (ID) of different aetiology. For this purpose, we compared performances of DS (n = 15; mean mental age = 5.2 years; SD = 1.2 years; mean chronological age = 16.6 years; SD = 2.9 years) and ID subjects (n = 14; mean mental age = 5.8 years; SD = 2.1 years; mean chronological age = 16.4 years; SD = 2.5 years) with those of normally developed subjects matched for mental age (n = 24) on tasks of forward and backward immediate recall of verbal and spatial sequences. Our results are discussed in the light of the Working Memory model developed by Baddeley (1986, 1990). Altogether, our data documents a deficit of verbal and spatial backward spans in persons with DS. The deficit seems to be specific for this particular aetiology group, confirming the hypothesis that ID is not a uniform condition, characterized by an undifferentiated delay of the cognitive development, but rather that it is characterized by a deficit in a complex cognitive system in which some cognitive abilities can be disrupted more than others (Detterman 1987; Vicari et al. 1992).
J Intellect Disabil Res 39 (3): 215-32 (1995 Jun)

Sentence imitation by adolescents and young adults with Down's syndrome and other intellectual disabilities

Marcell MM, Ridgeway MM, Sewell DH, Whelan ML
Department of Psychology, College of Charleston, South Carolina 29424, USA

Sentence imitation performance was evaluated longitudinally in 26 adolescents and young adults with Down's syndrome (DS), and 26 age- and IQ-matched non-DS individuals with other causes of intellectual disability (ID). In each of three annual assessments, the DS group began sentence repetitions more slowly and imitated sentences less accurately than the ID group. DS sentence repetition accuracy was equivalent to the ID group only for two-word sentences and was poorer for every other sentence length. Comparisons of sentence imitation and auditory digit span scores suggested that only ID subjects benefitted from the additional meaning and structure provided by sentences. Correlational analyses performed between each year's sentence imitation score and a set of language, memory and hearing measures revealed that sentence imitation was related to grammatical comprehension, auditory short-term memory and IQ in both groups, and to expressive language ability, speed of spoken word processing, speech discrimination and acoustic reflexes in the DS group only. A significant relationship between sentence imitation and middle-ear functioning was further supported by a categorical analysis in which DS subjects with bilateral abnormal tympanograms tended to perform more poorly on sentence imitation tasks than DS subjects with at least one normal tympanogram. It was concluded that sentence imitation is a task that is sensitive to the auditory-perceptual, cognitive and expressive difficulties evidenced by individuals with DS.
Australia and New Zealand Journal of Developmental Disabilities 20 (2): 113-25 (1995)

Memory Performance in Adults with Down Syndrome

Simon, Elliott W.; Rappaport, David A.; Agriesti, Michael

The memory abilities of adults (N=20) with Down Syndrome (DS) were compared to subjects matched on age and IQ and on age alone. Three memory tasks were employed: facial recognition, free recall of pictures and words, and cued recall of separate or interacting pictures. In DS individuals, memory was improved primarily by practice and interactive stimuli.
Down's Syndrome: Research and Practice 3 (3): 103-109 (1995)

Long-term maintenance of memory skills taught to children with Down's Syndrome

Laws, G.; MacDonald, J.; Buckley, S.J.; Broadley, I.
Department of Psychology, University of Portsmouth, U.K.

Children with Down syndrome who had followed a memory training programme were reassessed three years later. The programme, which involved training rehearsal and organisation strategies to improve short term memory, had resulted in significant gains on tests of auditory and visual memory skills. These gains were maintained for at least eight months after the end of the training period. However, after three years, memory capacity was found to have declined, although word spans were still significantly greater than those found before the training programme began. By comparing the performance of the children in the follow-up study with an untrained group matched for age, vocabulary and grammar understanding, it was concluded that this increase could be attributed to developmental progress and not to any residual effects of training. None of the children had continued to practice the memory training routines resulting in the loss of the trained memory skills over time.
Down's Syndrome: Research and Practice 3 (2): 59-64 (1995 June)

The influence of reading instruction on language and memory development in children with Down's Syndrome

Laws, G.; Buckley, S.J.; Bird, G.; MacDonald, J.; Broadley, I.

Department of Psychology, University of Portsmouth, UK and The Down Syndrome Educational Trust
This paper reports evidence for the importance of reading instruction for memory and language development in children with Down syndrome. Language and memory measures for 14 children were obtained over nearly four years as part of our research investigating the effect of teaching memory strategies. Half of the children were readers or became readers in the course of the study. At the start of the study, there were no significant differences between readers and non-readers in vocabulary and grammar understanding, or in auditory and visual memory performance. By the end of the study, a significant advantage for the readers was noted for all language and memory measures. Possible reasons for these findings are discussed, as well as the implications for educational intervention.
Down's Syndrome: Research and Practice 3 (1): 3-8 (1995)

Working memory in children with Down's Syndrome

Broadley, I.; MacDonald, J.; Buckley, S.J.
University of Southampton and University of Portsmouth, UK

A group of 4 to 18 year old children with Down syndrome (N=62) was presented with a set of working memory tasks, including auditory and visual serial recall of words; standardised digit span tasks and a rhyme judgement task. The serial recall tasks involved pictures of common objects or the spoken names of these objects and the children had to recall lists which varied on a number of parameters, including word length and the acoustic similarity of the object names. It was found that contrary to expectation the children's performance showed significant effects of word length and acoustic similarity, which are normally taken to indicate phonological storage and speech based rehearsal. These effects were found in both the auditory and visual presentation conditions and for the youngest age group. In addition to this evidence for speech based storage in short-term memory there was also evidence of the children utilising visual information in the serial recall tasks. The results are discussed in terms of working memory operation and the implications for memory remediation strategies in children with Down syndrome.
Down's Syndrome: Research and Practice 2 (3): 116-122 (1994)

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

Broadley, I.; MacDonald, J.; Buckley, S.J.
University of Southampton, UK University Portsmouth, UK

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.
Down's Syndrome: Research and Practice 2 (3): 123-126 (1994)

Working memory in Down syndrome: Training the rehearsal strategy

Comblain, Annick
Laboratoire de Psycholinguistique, Université de Liège, Liège, Belgium

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.
Journal of Speech and Hearing Research 37 (6): 1369-80 (1994 Dec)

Sequential Recall in Individuals With Down Syndrome

Kay-Raining Bird, E.; Chapman, R.
School of Human Communication Disorders, Dalhousie University, 5599 Fenwick Street, Halifax, Nova Scotia B3H 1R2 Canada

This study investigated whether memory for item order is selectively impaired in a group of individuals with Down syndrome. The ability to recall correctly ordered information was examined using two auditory tasks—narrative recall (Time 1) and digit span (Time 2)—and a nonverbal, visual task (Time 2) on which mental age (MA) matching was partially determined. Although subjects with Down syndrome recalled significantly less information than MA-matched controls on both auditory tasks, replicating previous findings of auditory memory span deficits, no differences in the ordering of recalled information were found. Nor did the groups differ in the relative frequency of ordering errors in the visual task. Neither a pervasive deficit in sequential processing nor a specific difficulty in recalling the order of information is supported. Alternative accounts are discussed.
Down's Syndrome: Research and Practice 2 (2): 47-50 (1994 June)

Short term memory deficits and Down syndrome: A comparative study

Bower, Anna; Hayes, Alan
School of Early Childhood, Queensland University of Technology and Schonell Special Education Research Centre, The University of Queensland, Australia

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.
Down's Syndrome: Research and Practice 1 (2): 56-62 (1993)

Teaching short term memory skills to children with Down's Syndrome

Broadley, I.; MacDonald, J.
Sarah Duffen Centre and Department of Psychology, University of Portsmouth

This study investigates a range of short term memory skills and the effectiveness of memory training procedures in improving these skills. The initial sample was 63 children with Down syndrome, aged 4-18 years, from two geographical areas in the UK. Phase 1 of the study assessed each child on a battery of tests including short term memory skills in different modalities, language skills, speech rate, word identification and a number of general IQ measures. Two groups were formed, one from one geographical area identified as the experimental group (n=25). A control group was formed from a subset of the remainder of children (n=26). Analysis verified that the two groups were similar and matched in terms of age and abilities. Phase 2 of the research consisted of a longitudinal training study of two memory strategies (rehearsal and organisation) which lasted for six weeks. For the experimental group (n=25), a cross-over design was employed to assess the effect of each strategy independently. Half the group received the rehearsal training first and the other half, the organisation-based training. Fifteen children from the group were taught by the first author and the rest by "keyworkers". In Phase 3 the initial assessment battery was repeated. The results demonstrated that each training programme was effective and enhanced only those specific memory skills addressed.
Cortex 29 (3): 467-483 (1993)

Preserved Vocabulary Acquisition in Down's Syndrome: The Role of Phonological Short Term Memory

Vallar, G.; Papagno, C.
Dipartimento di Psicologia, Universita di Roma La Sapienza

We report the study of a 23-year-old Italian girl, FF, with Down's syndrome (trisomy 21). FF showed a remarkably good developmental acquisition of Italian language and vocabulary and was able to learn English and French, although the latter with less proficiency. FF showed an entirely preserved function of the phonological short-term store and articulatory rehearsal components of verbal short-term memory. By contrast, she was impaired in a wide range of tasks assessing verbal and non-verbal reasoning, visuo-spatial perception and memory, and verbal long-term memory. These findings, in line with evidence from brain-damaged patients, normal subjects and children, suggest that phonological short-term memory plays a crucial role in vocabulary acquisition, which may occur in the presence of substantial deficits of general intelligence and episodic memory.
Journal of Mental Deficiency Research 32 (2): 153-162 (1988 Apr)

Short-term memory difficulties in Down's syndrome

Marcell, M.M.; Weeks, S.L.
The College of Charleston, Charleston, South Carolina, USA

Nonretarded (NR) individuals typically show better short-term memory for brief sequences of auditory than visual information (the modality effect). The present study attempted to determine whether the failure of Down's syndrome (DS) individuals to show the modality effect is due to the verbal-expressive demands of oral responding in memory tasks. DS, NR and MR (non-DS mentally retarded) subjects listened to or looked at increasingly long sequences of digits and attempted to recall them either orally or manually (through placement of items). Analyses suggested the following: (1) manual responding failed to enhance auditory recall in either DS or any other subjects; and (2) difficulty in recalling auditory stimuli was greatest for DS mentally retarded subjects. An additional assessment of DS, MR and NR subjects on a standardized auditory short-term memory test requiring a nonverbal pointing response replicated the above findings.
Research in Developmental Disabilities 9 (4): 405-17 (1988)

An attempt to improve auditory short-term memory in Down's syndrome individuals through reducing distractions

Marcell, M.M.; Harvey, C.F., Cothran, L.P.
Department of Psychology, College of Charleston, SC 29424

Down's syndrome (DS) individuals, relative to nonretarded individuals, have greater difficulty remembering brief sequences of verbal information presented auditorily. Previous research suggests at least two possible attentional explanations of their difficulty: They are especially susceptible to both auditory distraction and off-task glancing during laboratory tasks. DS, non-DS mentally retarded and nonretarded persons listened to, looked at, and attempted to remember sequences of digits. Although the three groups did not differ in their recall of visually-presented stimuli, DS subjects showed significantly poorer recall of auditorially-presented stimuli than the other two groups (which did not differ). Furthermore, the poor auditory memory of DS subjects did not improve under testing conditions designed to minimize auditory and visual distractions. It was suggested that poor auditory short-term memory for verbal information is tied more closely to Down's syndrome than to low intelligence and does not seem to be caused by a special susceptibility of Down's syndrome individuals to attentional distractors.
American Journal of Mental Deficiency 91 (4): 398-405 (1987)

Auditory and visual memory span: Cognitive processing by TMR individuals with Down syndrome or other etiologies

Varnhagen, C.; Das, J.; Varnhagen, S.

Auditory and visual memory span for letters and component memory processes of TMR young adults with Down syndrome or other etiologies was examined. Component processes of the span task included long-term memory access for labels for the stimuli and memory for the order in which the stimuli were presented. Results indicated that although all subjects had relatively poor auditory memory spans, the Down syndrome group was especially poor at long-term memory access for stimulus identification and at short-term storage and processing of auditory information. Lexical storage and retrieval deficiencies were isolated, accounting for the verbal difficulties experienced by the individuals with Down syndrome, leading to their deficiency in processing lexical information.
Cognitive Neuropsychology 4 (3): 303-319 (1987)

Memory span development in Down's syndrome, severely subnormal and normal subjects

Mackenzie, S.; Hulme, C.
University of York, U.K.

The devevelopment of digit span was studied in relation to mental age in two large groups of severely subnormal (SSN) individuals, one diagnosed as suffering from Down's syndrome and the other of mixed aetiology, and a group of normal subjects matched for mental age. Digit span in the Down's syndrome and SSN mixed aetiology groups were generally lower than that expected on the basis of mental age. A cross-sectional and longitudinal study showed a failure of development of digit span in both SSN groups which resulted in an increasing lag between digit span as mental age increased. Some possible explanations for the lack of short-term memory development in Down's syndrome and other SSN subjects are discussed, together with the possible implications of this for other aspects of cognitive development.
American Journal of Mental Deficiency 87 (1): 86-95 (1982)

Auditory and visual sequential memory of Down syndrome and nonretarded children

Marcell, M.M.; Armstrong, V.

The study was designed to investigate auditory and visual sequential memory of mentally retarded individuals. Experiment 1, conducted with Down syndrome children and adolescents, replicated previous findings of poor auditory sequential memory on the Illinois Test of Psycholinguistic Abilities. In Experiment 2, nonretarded kindergarteners showed superior recall of auditory items on a more comparable set of auditory and visual tasks. These same tasks, administered to the Down syndrome sample in Experiment 3, supported the earlier finding that retarded individuals have difficulty recalling auditorially presented verbal material. Their difficulty, however, did not appear to be linked to the sequential nature of recall. We suggested that the auditory-visual recall difference evidenced by nonretarded but not by retarded subjects may have been due to the differential use of information in echoic memory.
American Journal of Mental Deficiency 84 (6): 561-7 (1980)

Down syndrome and short-term memory impairement: a storage or retrieval deficit?

McDade, H.L; Adler, S.

The majority of researchers investigating the memory skills of retarded individuals have utilized heterogeneous samples of subjects whose sole criteria for grouping was either IQ or MA. The present experiment was designed to evaluate the short-term memory performance of subjects representing a specific type of retardation. Three groups of subjects (Down syndrome, CA control, and MA control) received a battery of tests designed to assess recall and recognition memory utilizing either auditory or visual input with verbal and nonverbal responses. Results indicated that the Down syndrome group possessed deficits in both storage and retrieval abilities, with storage of visually presented stimuli being particularly impaired.
Journal of Applied Behavioural Analysis 11 (3): 413-9 (1978 Fall)

Improving the generalized mnemonic performance of a Down's syndrome child

Farb, J.; Throne, J.

A training program was conducted to improve the generalized mnemonic performance, or memory, of a Down's Syndrome child. Training was directed at digit-span performance with generalization from training determined by responses to untrained mnemonic performance probes. The digit-span items varied in length from three to five digits. Each length constituted an item class, with each class trained within the framework of a multiple-baseline design. Probes consisted of untrained digit-span items, grammatical sentences, nongrammatical sentences, and match-to-sample items. A training procedure, in which 15 items from each class varied continually from trial to trial and from day to day, resulted in the percentage of correct responses to both training and probe items increasing to levels substantially above baseline. The results demonstrate the effectiveness of the training procedure in improving the generalized mnemonic performance of a Down's Syndrome child.
Br J Psychol 68 (2): 223-8 (1977 May)

Pattern detection by mongol and non-mongol subnormals

McDonald G, Mackay DN

Ten mongols and ten clinically heterogeneous subnormals matched on chronological age, mental age and digit span took part in an experiment in which tape-recorded supra-span digit sequences with different patterns were presented. There were six patterns: random, mirror (e.g. 583385); same-digit pairs (e.g. 558833), same-digit throughout (e.g. 333333), couplet repetition (e.g. 585858) and triplet repetition (583583). The numbers of digits correctly recalled in any order by the mongols in the various conditions ranked from least to most were: random, mirror, same-digit pairs, same-digit messages, triplet repetition and couplet repetition. The rank order for the non-mongols was the same except that the positions of couplet and triplet repetition were reversed. Mongols had significantly poorer recall for random, mirror and same-digit pair messages than non-mongols but were their equals in other conditions. The mongols' performance was more sensitive to pattern than the performance of the other subjects. There was some evidence that, in the messages with same-digit pairs and the same digit throughout, all subjects (but mongols in particular) tended to insert new digits into the response sequence and that the digit introduced was the next one in simple arithmetic progression. It would appear that the hypothesis about poor auditory-vocal channelling capacities of mongols needs qualification.
Journal of Mental Deficiency Research 20 (3): 191-6 (1976 Sep)

The effects of varying digit message structures on their recall by Mongols and nonmongol subnormals

MacKay, D.N.; McDonald, G.
Muckamore Abbey Hosp, Northern Ireland

24 mongoloid, epileptic, and undifferentiated subnormal adults matched on CA, MA, and digit span, took part in 2 experiments, in which tape-recorded digit messages were relayed over earphones. Both item recall (the number of digits correctly reproduced irrespective of order) and order recall (the number of digits correctly reproduced in the right order) were examined. It was found that item and order recall scores of the mongoloids were comparable to those of the nonmongoloids for redundant, mirror and regular sequences but were significantly lower for other types of messages. The mongoloids' item and order recall of redundant and mirror messages in Exp I was significantly better than their recall of partly redundant and mixed messages, while in Exp II their item and order recall of regular sequences was significantly better than that of near-regular or mixed messages. Order scores of epileptics and undifferentiated Ss for redundant messages were significantly higher than those for mixed messages in Exp I, and their order scores for regular sequences were significantly higher than those for near-regular and mixed messages in Exp II. It is concluded that severely subnormal adults are able to discern and utilize certain patterns in the material of a learning task.
American Journal of Mental Deficiency 70 (1): 78-82 (1965 Jul)

The ITPA and Down's Syndrome: An Exploratory Study

Bilovsky, D; Share, S.
California State College at Los Angeles and Mental Retardation Community Service Center, Childrens Hospital of Los Angeles

The identification of the psychological characteristics basic to successful learning is a role of the psychologists working with retarded children. An attempt to ascertain if there is a characteristic cognitive style for retarded children thus becomes the general purpose of this exploratory paper. Twenty-four non-institutionalized Down's Syndrome subjects were administered the Illinois Test of Psycholinguistic Abilities (ITPA). The subjects were analyzed in terms of their performance on the nine subtests of the ITPA. The subjects of the study responded in what appeared to be a consistent cognitive style. The development of educational programs appropriate to these results is encouraged.