Research into the effects of memory training on behavior and cognitive performance of ADHD children.

Attention-Deficit Hyperactivity Disorder (ADHD) is one of the most prevalent
developmental disorders. The De DSM-IV discriminates three ADHD subtypes; the
inattentive subtype, the hyperactivy/impulsive subtype and the combined subtype
with both attention and hyperactivity/impulsivity problems. Recently there is
accumulating evidence for memory problems in children with ADHD, like low
working memory capacity (for review see Martinussen et al, 2005; Diamond et
al., 2005). Suficient working memory capacity is crucial for efficient
performance in tasks that require both processing and stoarge of information
for a short period of time. Examples of such activities are calulation and
reading.
Recent studies ahve demonstrated that low working memory capacity is an
imporatnt mediating factor in attention regulation and attent problems in
adults as well as children. In light of these findings is is highly likely that
low working memory capacity in ADHD children plays an imprtant role in the
attention problems. One effective way to increase the capacity of working
memory is through training of memory strategies to cause better storage and
retrieval of information. Positieve effects of memory strategy training on
working memory capacity have been established in studies including healthy
adults. In a previous study by the applicant we have shown positive effects of
memory strategy training in children with ADHD (Jonkman & Hurks, submitted).
The present study is a follow-up of the previous study in which the long-term
effects of the memory strategy training and the far transfer effects on ADHD-
and executive daily behavior and academic performance are investigated. Also,
effects of simple memory strategies like rehearsal and more complex encoding
strategies like clustering on semantic category are compared, because
differences in effectivity have been deminstated in adults depending on Working
Memory capacity.

Studying and comparing the short and long-term effects of two different memory
trainings on the behavior and cognitive performance of children with ADHD
within a controled design. Training excersizes are dereived from a published
training from Timmerman & van de Schoot (2000) that is applied in clinical and
school settings.

There is a double-blind- controlled between-subjects design. Children that
fullfill the inclusion criteria are assigned to either the two training groups
or a control group, matching as much as possible on factors like age, IQ and
medication use. Effects of the trainings are measured by comparing
questionnaire scores from parents and teachers and performance of the children
on neuropsychological tests between a pre- and a post session. Tto measure
long-term effects a follow-up session follows 2,5 months after the first
post-session. In the control group, children only perform pre- and post
sessions without training. This control group is necessary to control for
practice effects on the tasks due to repeated performance. Children in the
control group will get the opportunity to follow the training after the last
post-session.

The memory trainings consist of 6 1-hour, weekly ,sessions and will be given to
groups of 4 children. Memory training-1 is similar to the memory training used
in an earlier study (Jonkman & Hurks, submitted;MEC 06-3-012.2) in which
children learn to apply different strategies (naming, rehearsal, semantic
grouping, mental imagery). In memory training-2 exactly the same excersizes
and materials are used, but only the most simple rehearsal strategy is trained.
All excersizes used in the trainings are derived from a published training by
Timmerman & van der Schoot, (2000), that is applied at schools and clinical
settings.

There are no risks attached to participation in the present study. The total
burden posed on the participants is 12 hours spread out over circa 4 months; 6
weekly training sessons of 1 hour , and 1 pre-session and two post-sessions of
2 hours duration. Children in the control group participate for 6 hours (only
pre and post-sessions). Parents and teachers will have to fill in
questionnaires at three different times (duration per session 25 minutes).