Memory training for children with Down syndrome
Frances Conners, Celia Rosenquist and Lori Taylor
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
Conners FA, Rosenquist CJ, Taylor LA. Memory training for children with Down syndrome. Down Syndrome Research and Practice. 2001;7(1);25-33.
For some time now it has been understood that, in spite of general low intellectual
functioning, individuals with intellectual disabilities have relative strengths
and weaknesses (Dykens,
Hodapp & Finucane, 2000;
Pennington & Bennetto, 1998; Pulsifer, 1996).
This is true for individuals with Down syndrome. Relative strengths in Down syndrome
may be in the areas of implicit memory (Carlesimo,
Marotta & Vicari, 1997; Vicari, 2001;
& Carlesimo, 2000) and visual-motor processing (Silverstein,
Legutki, Friedman & Takayama, 1982; see Wang, 1996).
Relative weaknesses are in language processing (Abbeduto,
2001; Chapman, 1995;
Gelman & Gleitman, 1994) and in working memory (Jarrold
& Baddeley, 2001; Marcell
& Weeks, 1988; McDade &
Adler, 1980). The present paper is concerned with the
relative weakness in working memory and prospects for ameliorating it. It begins
with a brief discussion of the problem of poor working memory in Down syndrome and
continues with a discussion of rehearsal training as a potential solution to this
problem. Research has shown that rehearsal training can improve working memory in
individuals with Down syndrome. However, three important issues are as yet unresolved—(1)
Can auditory working memory be improved reliably?, (2) Can improvement
be maintained over the long term?, and (3) Can improvements hold up to more stringent
control comparisons? The last section of the paper is a description of our own in-progress
rehearsal training study, which was designed with these three issues in mind. Preliminary
results from the study allow us to address the first and third of these issues.
The Problem: Poor Auditory Working Memory
Working memory refers to the memory system that deals immediately with newly encoded
information from the environment as well as information from long-term memory that
is currently active. It includes short-term memory and largely determines one's
memory span - the number of items one can recall immediately. It is known to be
limited in capacity and is considered a critical component in information processing.
A prominent model of working memory is Baddeley's multicomponent model (Baddeley,
1986; Baddeley & Hitch, 1974;
1994). In Baddeley's model,
there are three components- the central executive, the phonological loop, and the
visuo-spatial sketchpad. The central executive coordinates activities of the phonological
loop and the visuo-spatial sketchpad, monitors automatic routines, and provides
general attentional resources where needed. The phonological loop processes verbal
sequential information. It includes a capacity- and time-limited acoustic storage
and articulatory control processes that refresh stimulus traces being stored. These
articulatory control processes carry out the rehearsal function of the phonological
loop. The visuo-spatial sketchpad processes visual/spatial information in a capacity-
and time-limited visual buffer.
Working memory plays a central and extremely important role in almost every conscious
cognitive activity. Because it is capacity- and time-limited and is involved in
the control of current processing of activated codes, working memory sets limits
on higher-level processing, such as those involved in language (Gathercole
& Baddeley, 1990,
1993), reading (Baddeley, 1982;
Kintsch & van Dijk, 1978),
and mathematics (Adams & Hitch,
1997; Logie, Gilhooly
& Wynn, 1994). For example, when listening to a spoken message,
a person hears sounds in a particular order and must somehow interpret their meaning.
Working memory coordinates the moment-to-moment processing whereby incoming sounds
are interpreted into words, word meanings are accessed, grammatical structures are
interpreted, and the meaning of the message is understood. If working memory is
extremely limited, then the comprehension process might break down, particularly
for long messages.
Researchers have shown that memory span is shorter in individuals with Down syndrome
than in typically developing individuals of equivalent mental age (Hulme
& Mackenzie, 1992;
Kay-Raining Bird & Chapman, 1994;
Mackenzie & Hulme, 1987) and also shorter than in individuals
with unspecified causes of intellectual disability who are of equivalent chronological
age and mental age (Marcell,
Harvey & Cothran, 1988;
Marcell, Ridgeway, Sewell & Whelan, 1995;
Marcell & Weeks, 1988; McDade
& Adler, 1980). Mackenzie and Hulme (1987;
Hulme & Mackenzie, 1992)
showed that memory span increased at a slower rate than mental age in adolescents
with Down syndrome. Considering that mental age increases more slowly for those
with Down syndrome than for those who are typically developing (Wishart,
1996), the memory span development findings are very compelling. They indicate
that, with age, the memory span impairment in Down syndrome becomes more and more
Memory span is limited in Down syndrome especially when materials are presented
auditorily rather than visually (Broadley,
MacDonald & Buckley, 1995;
Jarrold, Baddeley & Hewes, 1999;
Marcell et al., 1988;
McDade & Adler, 1980) even when thorough hearing screenings
have been made (Kay-Raining
Bird & Chapman, 1994;
Marcell & Armstrong, 1982). The memory span impairment seems unrelated
to a general sequential processing impairment (Kay-Raining
Bird & Chapman, 1994; Marcell
& Weeks, 1988), to distractibility (Marcell
et al., 1988), to storage capacity limitations (McDade
& Adler, 1980), or to oral responding demands (Marcell
& Weeks, 1988). It has been suggested that the impairment
is related to poor long-term retrieval of phonological codes (Varnhagan,
Das & Varnhagen, 1987), to weakness in the rehearsal function of the
phonological loop (Hulme & Mackenzie,
1992, but see Jarrold &
Jarrold, Baddeley & Hewes, 2000), and/or to poor central executive
Carlesimo & Caltagirone, 1995).
Given the critical role of working memory in so many aspects of cognition, it is
extremely important to examine ways in which individuals with Down syndrome can
improve their working memory function. Auditory working memory, which involves the
functioning of the phonological loop, supports the development of language comprehension
and expression as well as reading. As such, it is very important to the daily functioning
and quality of life of individuals with Down syndrome.
A Potential Solution: Rehearsal Training
In typical development, there is clear improvement in working memory functioning
through childhood. One reason for this improvement is that children develop more
effective rehearsal strategies (see Cowan, 1997;
and Chinsky, 1966;
Ornstein, Naus & Stone, 1977). For example, Ornstein, et al.
second graders rehearsed only one or two items together whereas sixth graders rehearsed
more than two items together (see also
Ornstein, Naus & Liberty, 1975). When trained, second graders were able
to learn to rehearse more items together and when they did, their recall became
similar to that of sixth-graders. Fergusen and Bray (1976)
suggested that the ordered repetition of items involved in rehearsal was key to
memory improvement. They found that first graders who were trained to repeat items
in order did better on the memory test than those trained to repeat items one at
a time, to simply label items, or to use their own method. Many other studies have
shown that children and adults can improve their immediate memory performance by
adopting active rehearsal strategies (e.g.,
Ford, Pelham & Ross, 1984; Henry, 1991;
Ornstein & Naus, 1983)
There has been great interest in applying rehearsal strategies to the training of
individuals with intellectual disabilities. Rehearsal training studies have shown
that, when instructed to use a rehearsal strategy, individuals with intellectual
disabilities can use it and their short-term memory performance improves (e.g.,
Wambold & Belmont, 1973;
Brown, Campione, Bray & Wilcox, 1973; Conroy,
1978; Hulme & Mackenzie, 1992;
& Johnson, 1974; Turnbull, 1974).
Brown, Campione and Murphy, (1974)
found that the effects of their 10-day training lasted over a six-month period.
The most commonly used rehearsal strategy in this research is the overt cumulative
rehearsal strategy, in which participants receive one new list item at a time, and
each time they receive a new list item they repeat the entire list from the beginning.
For example, suppose participants view a set of four pictures- car, tree, book,
and chair. They see car first and say, "car." Then they see tree and say, "car,
tree." Then they see book and say, "car, tree, book." Finally, they see chair and
say, "car, tree, book, chair."
It is also now clear that rehearsal training can improve working memory in individuals
with Down syndrome (Broadley &
MacDonald, 1993; Comblain, 1994;
Laws, MacDonald & Buckley, 1996). For example, Broadley and MacDonald
(1993) showed that, after
12 20-minute sessions of rehearsal training over 6 weeks, children with Down syndrome
(mean age = 8.4) performed better than no-training controls (mean age = 9.5) on
most word span measures administered. Using a slightly older group with 18 15-minute
sessions of rehearsal training over 6 weeks, Laws et al., (1996)
found small but significant gains on some though not all span measures. Finally,
Comblain (1994) found that, after eight 30-minute
training sessions over eight weeks, rehearsal-trained individuals with Down syndrome
improved on memory span tests, whereas untrained controls did not. This study included
children, adolescents, and adults (mean age = 16.9, mean mental age = 4.07). Trends
suggested that the training was more effective for the children and adolescents
than the adults, but only 4 in each age group received training, so this is difficult
As part of their study, Broadley and MacDonald (1993)
compared rehearsal training with organisation training. The organisation training
involved teaching category names and exemplars and providing practice on them in
a game context (see Broadley, 1994). Half
their training group received six weeks of rehearsal training followed by six weeks
of organisation training, whereas the other half received the opposite schedule.
Assessments taken before the switch indicated that rehearsal training was more effective
in increasing memory span, whereas organisation training was more effective in increasing
categorization. Thus, improvements were training-specific. This suggests that to
improve auditory working memory, a rehearsal strategy would be more desirable than
an organisation strategy. However, it also suggests that different types of training
are not necessarily redundant, and using more than one type can enhance the breadth
of improvement. At the end of the two six-week training periods, the trained children
performed better at both word span and categorization measures than untrained children.
Issue 1: Auditory modality
In early rehearsal training studies involving individuals with intellectual disabilities,
little attention was paid to modality. In these studies, etiology of intellectual
disability was either unknown or mixed and there was no special reason to make a
distinction between auditory and visual working memory. In most of these studies,
visual materials were used for both training and test. Thus, we know little about
the prospects of using rehearsal training to improve auditory working memory per
se. In one study in which auditory materials were used, results were equivocal.
Hulme and Mackenzie (1992)
used a totally auditory cumulative rehearsal training routine to boost the auditory
memory span of adolescents with intellectual disabilities of mixed aetiology. Over
the 10-day training period, the training group improved significantly on word span
but not on digit span. On word span, the training group improved significantly more
than an idle control group, but not more than a "repeatedly tested" control group.
The failure to find significant improvement in digit span may have been due to a
small sample size (n = 8) and a limited training period.
For individuals with Down syndrome, there is a special concern for improving auditory
working memory because it tends to be weaker than visual working memory. Thus, one
important issue in memory training for individuals with Down syndrome is whether
rehearsal training can be effective in improving auditory working memory.
Broadley and MacDonald (1993)
reported that, although rehearsal training was more effective than organisation
training in increasing memory span measures, this did not apply to the auditory-only
measures- on these there was no difference between the groups. Also, both trained
groups improved more than the control group on all measures of visual memory. However,
only the trained group that had rehearsal training second improved more than the
control group on measures of auditory memory, and only on a few of the auditory
The greater improvements for visual than auditory working memory in the Broadley
and MacDonald (1993) study
may be due to the fact that auditory working memory is particularly weak individuals
with Down syndrome and may be more resistant to training. However, the cumulative
rehearsal training in the study used pictures heavily, making the training activities
more similar to the visual memory tests than to the auditory memory tests. In other
words, the training may have prepared children better to perform well on visual
memory tests than to perform well on auditory memory tests. Laws et al.
(1996) also used
visual training materials, and found modest improvement in auditory word span but
not auditory digit span. For both word span and digit span, there was a trend toward
less improvement in the auditory than the visual modality, though the differences
were not significant.
Comblain's (1994) study involved cumulative rehearsal
training that began with pictures but phased them out over sessions until children
were left with only finger cues to mark new items. Using this training, Comblain
found clear and significant differences between trained and untrained groups on
a composite auditory memory span measure. Visual memory was not measured. Possibly,
improvements in auditory working memory are more likely if the training relies on
auditory processing moreso than visual processing. In the present study we were
especially interested in improving auditory working memory, and we set up the training
to be totally auditory with no visual materials at all. To compensate for the lack
of visual assistance in the training, we set up a longer training period than has
Issue 2: Maintenance
If rehearsal training is to make an impact on learning and communication in the
lives of individuals with Down syndrome, we need to know how long the impact of
the training can last and what must be done to achieve really meaningful effects.
Follow-up assessments to date have shown that the effects of rehearsal training
can last several months. Two and eight-months following the training in the Broadley
and MacDonald (1993) study,
trained children generally maintained their levels of improvements, and were still
performing better than the control children who were still in the study (18 of the
original 26). Improvements in visual working memory seemed to maintain better than
those in auditory working memory (Broadley,
MacDonald & Buckley, 1994). Six-weeks and six months following the training
in the Comblain (1994) study, trained individuals
declined from posttest, but they still performed better than at pretest. Untrained
individuals did not change over the various assessments.
Although training effects can last for several months, they may dissipate eventually.
Only one follow-up study has examined maintenance over a period of time greater
than one year. Laws, MacDonald, Buckley and Broadley (1995)
reported that three years after training in the Broadley and MacDonald (1993)
study, gains made had subsided. Fourteen of the original 25 trained children performed
similarly to a same-age matched untrained group. Their memory performance was above
what it was pretraining, but it dropped from earlier assessments, and the difference
between pretraining and 3-year follow-up was more likely due to development than
to the training. One of the most important next steps in research on rehearsal training
of individuals with Down syndrome is to find a way to make improvements last years
rather than months. Periodic maintenance activities may be the answer.
One way to encourage maintenance activities is to teach parents the training routine
so they can use it with their children at home. After the intensive period of memory
training, parents can work with their children from time to time so that any gains
in working memory and related abilities will be maintained. Broadley and MacDonald
(1993) had this idea in
mind in their training study (see also Laws et al., 1996). Eleven of their
26 trained children received their training from a "keyworker, " who was either
a teacher, a non-teaching assistant, or a parent. In fact, there was some evidence
that keyworker-trained children maintained improvements over eight months better
than the experimenter-trained children (Broadley
et al., 1994); however, the keyworker-trained children were higher
in general ability at the beginning of the training. Thus, it is difficult to know
whether the difference in maintenance was due to the type of trainer or the difference
in general ability. Further, it is not clear how many of the 11 keyworkers were
parents and how many were teachers and non-teaching-assistants. Laws et al.
(1996) found that,
though teacher-trained children at two schools improved in word span, those from
a third school who were parent-trained did not. The parent training was set up because
teachers at the third school declined to participate. It is possible that children
did not benefit from the training because they were different in some way from the
children at the other schools, or because they were being trained by their parents
in their home. Thus, there is still a need to investigate the feasibility of parents
as trainers. The present study was designed to be totally parent-oriented, with
parents as the only trainers.
Issue 3: Control comparisons
A very powerful test of the effectiveness of a training routine is to compare the
training group to a group that is similar in the number of contacts, amount of special
attention, practice on focusing attention, and positive reinforcement. Without this
type of comparison, some of the improvement on assessments may be due to increased
familiarity and comfort with the experimenter, motivation, and ability to complete
tasks. Most of the rehearsal training studies described in the present paper did
not use this type of control comparison. Most used an idle control group which only
completed assessments at various intervals. In one exception from the studies using
mixed-aetiology studies, Hulme and Mackenzie (1992)
used a "repeatedly tested" control group as well as an idle control group. Adolescents
in the repeatedly tested control group met with the experimenter the same amount
of time as those in the rehearsal group, but rather than use an overt cumulative
rehearsal procedure, they simply repeated back lists. The rehearsal and repeatedly
tested groups performed similarly, showing improvement on word span but not on digit
span. Thus, it appeared that there was no great advantage of the cumulative rehearsal
training over simple practice. Next, we would like to know if there is any advantage
of either of these methods beyond the adult attention and reinforcement afforded
In Broadley and MacDonald's (1993)
study involving children with Down syndrome, the rehearsal training group was compared
with the organisation training group after six weeks of training. As noted already,
their organisation training involved teaching category names and exemplars. It was
less similar to the rehearsal training than was Hulme and Mackenzie's (1992)
repeated testing condition, yet it involved one-on-one adult attention and reinforcement.
The finding that the rehearsal training group performed better on several memory
span tests than the organisation training group is very important because it indicates
that it is indeed the training itself that resulted in the improvements. In our
in-progress study, we are using a "visual activities" comparison condition, in which
there was no memory training, but instead, parents work with their children on various
visual activities for the same amount of time as they would work on memory training.
The present study: In-progress
In the present section, we describe our own in-progress study, and use the preliminary
results to address two of the three issues raised earlier in the paper. One is the
issue of whether auditory working memory can be improved in individuals with Down
syndrome. Our training and tests are auditory. The other is the issue of whether
improvements related to rehearsal training will hold up to more stringent control
comparisons. Our control comparison involves roughly equivalent contact time and
one-on-one attention from a parent, but no memory activities. The study addresses
the remaining issue of whether memory improvements can be lasting by having parents
be the trainers. We present anecdotal information on whether parents can be good
trainers. However, the preliminary results can not address the effectiveness of
this approach in producing working memory improvements that last.
In the present study, parents learn to follow a totally auditory overt cumulative
rehearsal training routine with their children with Down syndrome. Half the families
are in the "Memory-first" condition and half are in the "Visual-first" condition.
The Memory-first families begin with 3 months of memory training, then switch to
3 months of visual activities, and then return to 3 months of memory training. The
Visual-first families have the opposite schedule. The visual activities serve as
a control condition in which the amount of one-on-one time and attentional requirements
are similar to the memory training. They include a variety of visually-based workbook
activities, such as colouring, shape matching, and connect-the-dots. Before the
first 3-month period and after each following 3-month period, parents bring their
children to the lab for memory/language assessment. These assessments serve as pre-
and posttests. Because the study is ongoing, we can only report preliminary data
here. We can report early results from the first 3-month period, which has been
completed by six Memory-first families and five Visual-first families. For the present
report, we address two questions- (1) Can parents be good trainers? and (2) Can
auditory working memory improve with parents as trainers?
Children were eligible for the study if they were between 6 and 14 years old, could
imitate verbally at least one word at a time, had no more than a mild hearing loss
in the better ear, lived at home within a 2-hours drive of our laboratory, had a
telephone at home and a parent who was willing to participate. All children had
Down syndrome verified by chromosomal analysis. Table 1 contains
characteristics of the sub-sample reported here. In the sub-sample, there were two
girls and four boys in the Memory-first group, and five boys in the Visual-first
Memory-first Group (n = 6)
Visual-first Group (n = 5)
Digit span a
Sentence memory c
Digit span a
Sentence memory c
a number of items repeated back. b number of trials correct
of 15. c Age-equivalent score in years. In parenthesis is the age-equivalent
score converted to years and months.
Table 1 | Group Characteristics and Performance on Pre/posttest
Memory Measures over 3 months.
Children complete the following pre/posttests.
1. Digit span
Adapted from the Digit span subtest of the Wechlser Intelligence Scale for Children,
3rd ed. (WISC-III), this test measures
auditory working memory. It requires children to listen to increasingly long lists
of digits and repeat back verbatim. Scoring was reflected as the length of list
the participant could repeat back reliably.
2. Counting span
Modelled after a task used by Case, Kurland and Goldberg (1982),
this task taps more general working memory, and reflects both storage and processing
aspects of working memory. Children count the green dots on an index card, turn
it over, and report the number of green dots. If they can do that, they advance
to two index cards. They count the dots on the first card, turn it over, count the
dots on the second card, turn it over, then report the number of dots from the first
card followed by the number of dots from the second card. The task goes up to five
cards, but testing is discontinued if a child misses all three trials at a particular
level. The task combines both visual and auditory presentation, in that the dots
are presented visually but are counted aloud by the children. Scores are number
of trials correct of 15 (3 trials at each level x 5 levels).
3. Sentence memory
From the Woodcock-Johnson Psychoeducational Battery, this test reflects auditory
working memory as assisted by language processing. Children listen to increasingly
long phrases and sentences, and repeat them back verbatim. Scores are expressed
4. Other tasks
Not included in this report are Listening comprehension, Phonological similarity,
Day/Night central executive task, and Category fluency. We hope to use them eventually
to address questions regarding the impact of training on specific aspects of working
memory and on language processing.
Working memory training
The training involves overt cumulative rehearsal. Children listen to a list of unrelated
digits or words. Each time they hear a new digit or word, they repeat the list from
the beginning. For example, the parent begins the list 4-7-2 by saying, "4." The
child repeats, "4". The parent gives the next list item, "7." The child repeats,
"4-7." The parent gives the final list item, "2." The child repeats, "4-7-2."
Each child begins with a Learning Phase in which he or she simply learns the repeating-back
procedure. In this phase, the parent demonstrates using a favourite stuffed animal,
and there are only two items in each list. When the child meets a criterion of 3
in a row correct without prompts, he or she advances to the Memory Phase. In the
Memory Phase, the number of items per list increases to 3. When a criterion of 3
in a row correct is achieved, the number of items per list increases to 4 and, when
applicable, to 5. Each new session begins with a Learning Phase as a review of the
procedure. During the sessions, if the child is struggling to remember an item,
the parent can give an auditory prompt (the first sound of the item). For each list
attempted, the parent records "correct," "correct with prompts," or "incorrect."
The parent follows a reinforcement schedule that includes response-level, session-level,
and criterion-level reinforcers chosen by the parent based on the child's interests.
There are 5 10-minute sessions per week for 3 months. The parent records the data
and tape records the sessions.
Can parents be good trainers?
The parents' data sheets and the tape-recordings of training sessions allow us to
answer this question. Indeed, parents have been successful at following the training
procedure, though most have needed minor corrections at the beginning. They have
followed the reinforcement procedure, but some have needed correction. They have
recorded data diligently and when they have followed the procedure and reinforcement
routine, the data appear to be very accurate. We are currently working on a data-based
reliability study so that we can answer this question more precisely. Finally, as
might be expected, there is some variability in how closely parents have kept to
the 5-sessions-per-week schedule. The range is 2.5 to 5.1 sessions per week. Thus,
the Memory-first children did not all have the same amount of training. Our study
sacrifices a degree of experimental control in order to find out whether training
can be effective in the real world of family life.
Can auditory working memory improve with parents as trainers?
We present two forms of data relevant to whether auditory working memory improved
during the first 3-month period of the study. First, we present the session-to-session
data from the training for the first child to complete the training period (Figure
1). In Figure 1, the number of trials needed to meet criterion in the Learning
phase and Memory phase (with 3 and with 4 items per list) are shown for each training
session completed in the 3-month period. Points that are above 24 represent failure
to meet criterion during the session. With this type of data, improvement in auditory
working memory would be indicated by a decrease over sessions in the number of trials
to criterion and advancement from one phase to the next (Learning Memory-3 to Memory-4).
As shown in Figure 1, Participant number 1 met criterion in the Learning phase in
the first session, indicating that she learned the repeating back procedure easily.
However, it took her about 13 sessions before she met criterion in the Memory phase
with 3-item lists. She had a period in which she sometimes met criterion and sometimes
did not. Finally, she met criterion consistently and easily. At this point she began
4-item lists, but she did not meet criterion before her 3-month training period
ended. Each child has a unique pattern of progress, with some showing faster progress
than others. Although this child is not unusual in her rate of progress, her pattern
may be more stable than many of the others.
Figure 1 | Trials needed to reach criterion for Learning
and Memory phases for participant no.1 in each 10 minute training session
(criterion = 3 trials or lists in a row correctly repeated back without prompts.
Points above 24 indicate failure to meet criterion in the designated training session.
The second type of data we present is the pretest-posttest assessments of auditory
working memory. It is in this comparison that we can say whether improvements hold
up to our relatively rigorous control comparison. Table 1
provides pre- and posttest group means and standard deviations for the Digit span,
Counting span, and Sentence memory tasks. On Digit span, the Memory-first group
improved significantly by almost a whole digit, which represents about a 50% gain,
t(5) = 2.86, SEM = 0.32, p < .05. The Visual-first
group did not improve significantly. On Counting span, the Memory-first group improved
a bit, whereas the Visual-first group decreased a bit. These changes are not statistically
significant, and we will have to wait for data from more children to assess the
effect of the memory training on this task. On Sentence memory, age-equivalent scores
increased by approximately 2 months over the 3-month period. This amount of gain
is impressive for the children in the study who, at 10 years old are only doing
as well as a 2-year-old on this task. Because the gain is present for both groups,
however, it cannot be attributed to the memory training. It could be related to
increased demand in both conditions for listening to instructions, or it could be
a testing effect.
Previous research has indicated that rehearsal training can improve working memory
in individuals with Down syndrome. We designed the present study in part to address
three issues that are still not resolved- targeting auditory working memory, maintenance
of improvement, and control comparisons. Unlike in most previous studies, the rehearsal
training in the present study was totally auditory, it was administered only by
parents, and an alternate-activity control comparison was used. Our preliminary
results suggest that dedicated parents can be good trainers and auditory working
memory can improve with parents as trainers. This improvement is above and beyond
any advantage related to parents sitting down with their children one-on-one on
a regular basis to do instructional activities (e.g. increased practice in, attention
for, and praise for focusing attention, following instructions, and engaging in
conversation). The most reliable improvements and those most clearly linked to the
rehearsal training are in digit span, the task most similar to the training. Any
gain in sentence memory (nonsignificant at this point) appears to be equivalent
in both groups. These conclusions are highly tentative, however, because our data
collection is not yet complete.
If improvements in auditory working memory are to have any utility, they will enable
higher-order cognitive functions such as language processing. In our preliminary
data, however, there is no evidence yet that improvements in auditory working memory
lead to improvements in language processing. Even our measure of language-assisted
auditory working memory (sentence memory) shows no improvement that is specifically
related to the training. However, our samples are very small and improvements in
memory/language measures may emerge as more children complete the first phase of
the study. Still, for language improvements that are enabled specifically by improvements
in auditory working memory, it may be that a time lag is to be expected. The language
improvement may not emerge until several months after the initial improvement in
auditory working memory. If so, we may see some improvement in sentence memory and
other memory/language tasks at the 6- and 9-month assessments.
The challenge today in research and practice is to find ways of turning improvement
in working memory into long-lasting and meaningful improvements in general areas
of functioning. In the field of intellectual disabilities, it has been relatively
easy to train a skill or expand a cognitive capacity. It has been very difficult,
however, to train transfer of the skill to meaningful domains. To accomplish this
task, we will need to examine the time lag relations between improvements in working
memory and improvements in higher-order functioning such as language, reading, calculation,
reasoning, and spatial processing. We will also need to examine the impact of maintenance
activities and schedules on continued improvement of working memory as well as on
improvement in higher-order functioning.
The research described in this paper is currently supported by Grant HD37445 from
the National Institute of Child Health and Human Development, jointly with the National
Down Syndrome Society. This article is based on a presentation at the 3rd
International Conference on Language and Cognitive Development in Down Syndrome,
2000, Portsmouth, UK.
Frances A. Conners • Box 870348, Tuscaloosa, AL 35487-0348 USA • Email
- Abbeduto, L. (2001). The language and cognitive
profile in Down syndrome: Evidence from a comparison with fragile-X syndrome. Down
Syndrome Research and Practice, 7(1), 9-15. [Open
Access Full Text
- Adams, J. W., & Hitch, G.
J. (1997). Working memory and children's mental addition. Journal of Experimental
Child Psychology, 67, 21-38.
- Baddeley, A. D. (1982). Reading and working
memory. Bulletin of the British Psychological Society, 35, 414-417.
- Baddeley, A. D. (1986). Working Memory.
Oxford: Oxford University Press.
- Baddeley, A. D., & Hitch,
G. (1974). Working memory. In G. H. Bower (Ed.), Recent Advances in Learning
and Motivation (Vol. 8, pp. 47-89). New York: Academic Press.
- Baddeley, A. D., & Hitch,
G. (1994). Developments in the concept of working memory. Neuropsychology,
- Broadley, I. W. (1994). Teaching short-term
memory skills to children with Down syndrome. Unpublished Ph.D. thesis, University
of Portsmouth, Portsmouth, UK.
- Broadley, I., & MacDonald,
J. (1993). Teaching short term memory skills to children with Down syndrome.
Down Syndrome Research and Practice, 1, 56-62. [Open
Access Full Text
- Broadley, I., MacDonald,
J., & Buckley, S. (1994). Are children with Down syndrome able to maintain
skills learned from a short-term memory training programme? Down Syndrome Research
and Practice, 2, 116-122. [Open
Access Full Text
- Broadley, I., MacDonald,
J. & Buckley, S. (1995). Working memory in children with Down syndrome.
Down Syndrome Research and Practice, 3, 3-8. [Open Access Full Text
Brown, A. L., Campione, J. C., Bray, N. W., & Wilcox, B. L (1973). Keeping
track of changing variables: Effects of rehearsal training and rehearsal prevention
in normal and retarded adolescents. Journal of Experimental Psychology,
- Brown, A. L.,
Campione, J. C., and Murphy, M. D. (1974). Keeping track of changing variables:
Long-term retention of a trained rehearsal strategy by retarded adolescents. American
Journal of Mental Deficiency, 78, 446-453.
E. C., Wambold, C., & Belmont, J. M. (1973). On the theory and practice
of improving short-term memory. American Journal on Mental Retardation,
- Carlesimo, G. A.,
Marotta, L., & Vicari, S. (1997). Long-term memory in mental retardation:
Evidence for a specific impairment in subjects with Down syndrome. Neuropsychologia,
- Case, R., Kurland, M.,
& Goldberg, J. (1982). Operational efficiency and the growth of short-term
memory span. Journal of Experimental Child Psychology, 33, 386-404.
- Chapman, R. S. (1995). Language development
in children and adolescents with Down syndrome. In P. Fletcher, & B. MacWhinney
(Eds.), The Handbook of Child Language (pp. 641-663). Cambridge, MA: Blackwell.
- Chapman, R. S. (2001). Language, cognition and
short-term memory in individuals with Down syndrome. Down Syndrome Research and
Practice, 7(1), 1-7. [Open
Access Full Text
- Comblain, A. (1994). Working memory in Down syndrome:
Training the rehearsal strategy. Down Syndrome Research and Practice, 2,
123-126. [Open Access Full Text
- Conroy, R. L. (1978). Facilitation of serial
recall in retarded children and adolescents: Verbal and kinesthetic strategies.
American Journal of Mental Deficiency, 82, 410-413.
- Cowan, N. (1997). The development of working memory.
In N. Cowan (Ed.), The Development of Memory in Childhood (pp. 163-199).
Hove, England: Psychology Press/Erlbaum.
- Dykens, E.
M., Hodapp, R. M., & Finucane, B. M. (2000). Genetics and Mental Retardation
Syndromes. Baltimore: Paul H. Brookes.
- Fergusen, R. P., & Bray,
N. W. (1976). Component processes of an overt rehearsal strategy in young children.
Journal of Experimental Child Psychology, 21, 490-506.
- Flavell, J.
H., Beach, D. R., & Chinsky, J. H. (1966). Spontaneous verbal rehearsal
in a memory task as a function of age. Child Development, 37, 283-299.
- Ford, C. E., Pelham,
W. E., & Ross, A. O. (1984). Selective attention and rehearsal in the auditory
short-term memory task performance of poor and normal readers. Journal of Abnormal
Child Psychology, 12, 127-141.
- Fowler, A. E.,
Gelman, R., & Gleitman, L. R. (1994). The course of language learning in
children with Down syndrome. In H. Tager-Flusberg (Ed.), Constraints on Language
Acquisition: Studies of Atypical Children (pp. 91-140). Hillsdale, NJ:
- Gathercole, S. E., &
Baddeley, A. D. (1990). Phonological memory deficits in language disordered
children: Is there a causal connection? Journal of Memory and Language,
- Gathercole, S. E., &
Baddeley, A. D. (1993). Working Memory and Language. Hillsdale, NJ:
- Henry, L. A. (1991). Development of auditory memory
span: The role of rehearsal. British Journal of Developmental Psychology,
- Hulme, C., & Mackenzie, S. (1992).
Working Memory and Severe Learning Difficulties. Hillsdale, NJ: Erlbaum.
- Jarrold, C. & Baddeley, A.
D. (2001). Short-term memory in Down syndrome: Applying the working memory model.
Down Syndrome Research and Practice, 7(1), 17-23. [Open
Access Full Text
- Jarrold, C., Baddeley,
A. D., & Hewes, A. K. (1999). Genetically dissociated components of working
memory: Evidence from Down's and Williams syndrome. Neuropsychologia, 37,
- Jarrold, C., Baddeley,
A. D., & Hewes, A. K. (2000) Verbal short-term memory deficits in Down syndrome:
A consequence of problems in rehearsal? Journal of Child Psychology and Psychiatry,
- Kay-Raining Bird, E.,
& Chapman, R. S. (1994). Sequential recall in individuals with Down syndrome.
Journal of Speech and Hearing Research, 37, 1369-1380.
- Kellas, G., Ashcraft,
M. H., & Johnson, N. S. (1974). Rehearsal processes in the short-term memory
performance of mildly retarded adolescents. American Journal of Mental Deficiency,
- Kintsch, W., & van Dijk,
T. A. (1978). Toward a model of text comprehension and production. Psychological
Review, 85, 363-394.
- Laws, G., MacDonald,
J., & Buckley, S. (1996). The effects of a short-term training in the use
of a rehearsal strategy on memory for words and pictures in children with Down syndrome.
Down Syndrome Research and Practice, 4, 70-78. [Open
Access Full Text
G., MacDonald, J., Buckley, S., & Broadley, I. (1995). Long-term maintenance
of memory skills taught to children with Down syndrome. Down Syndrome Research and
Practice, 3, 103-109. [Open
Access Full Text
- Logie, R. H., Gilhooly,
K. J., & Wynn, V. (1994). Counting on working memory in arithmetic problem
solving. Memory and Cognition, 22, 395-410.
- Mackenzie, S., & Hulme, C. (1987).
Memory span development in Down syndrome, severely subnormal, and normal subjects.
Cognitive Neuropsychology, 4, 303-319.
- Marcell, M. M., & Armstrong,
V. (1982). Auditory and visual sequential memory of Down syndrome and nonretarded
children. American Journal of Mental Deficiency, 87, 86-95.
- Marcell, M. M.,
Harvey, C. F., & Cothran, P. (1988). An attempt to improve auditory short-term
memory in Down's syndrome individuals through reducing distractions. Research in
Developmental Disabilities, 9, 405-417.
Marcell, M. M., Ridgeway, M. M., Sewell, D. H., & Whelan, M. L. (1995).
Sentence imitation by adolescents and young adults with Down's syndrome and other
intellectual disabilities. Journal of Intellectual Disability Research,
- Marcell, M. M., & Weeks,
S. L. (1988). Short-term memory difficulties and Down's syndrome. Journal of
Mental Deficiency Research, 32, 153-162.
- McDade, H. L., & Adler, S. (1980).
Down syndrome and short-term memory impairment: A storage or retrieval deficit?
American Journal of Mental Deficiency, 84, 561-567.
- Ornstein, P. A., & Naus,
M. J. (1983). "Rehearsing" according to artificially generated rehearsal patterns:
An analysis of active rehearsal. Bulletin of the Psychonomic Society, 21,
- Ornstein, P. A.,
Naus, M. J., & Liberty, C. (1975). Rehearsal and organizational processes
in children's memory. Child Development, 46, 818-830.
- Ornstein, P.
A., Naus, M. J., & Stone, B. P. (1977). Rehearsal training and developmental
differences in memory. Developmental Psychology, 13, 15-24.
- Pennington, B. F., &
Bennetto, L. (1998). Toward a neuropsychology of mental retardation. In J. A.,
Burack, R. M. Hodapp, & E. Zigler (Eds.), Handbook of Mental Retardation and
Development (pp. 80-114). New York: Cambridge University Press.
- Pulsifer, M. B. (1996). The neuropsychology
of mental retardation. Journal of the International Neuropsychological Society,
Silverstein, A. B., Legutki, G., Friedman, S. L., & Takayama, D. L. (1982).
Performance of Down syndrome individuals on the Stanford-Binet Intelligence Scale.
American Journal of Mental Deficiency, 86, 548-551.
- Turnbull, A. (1974). Teaching retarded persons
to rehearse through cumulative overt labeling. American Journal of Mental Deficiency,
- Varnhagan, C.
K., Das, J. P., & Varnhagan, S. (1987). Auditory and visual memory span:
Cognitive processing by TMR individuals with Down syndrome or other etiologies.
American Journal of Mental Deficiency, 91, 398-405.
- Vicari, S. (2001). Implicit versus explicit memory
function in children with Down and Williams syndrome. Down Syndrome Research and
Practice, 7(1), 35-40. [Open
Access Full Text
- Vicari, S., Bellucci,
S., & Carlesimo, G. A. (2000). Implicit and explicit memory: A functional
dissociation in persons with Down syndrome. Neuropsychologia, 38, 240-251.
- Vicari, S.,
Carlesimo, G. A., & Caltagirone, C. (1995). Short-term memory in persons
with intellectual disabilities and Down's syndrome. Journal of Intellectual Disability
Research, 39, 532-537.
- Wang, P. (1996). A neuropsychological profile of Down
syndrome: Cognitive skills and brain morphology. Mental Retardation and Developmental
Disabilities Research Reviews, 2, 102-108.
- Wishart, J. (1996). Learning in young children
with Down's syndrome: Developmental trends. In J. A. Rondal, J. Perera, L. Nadel,
& A. Comblain (Eds.), Down's Syndrome: Psychosocial, Psychobiological, and Socio-Educational
perspectives. San Diego: Singular Publishing Group.