The effect of memory training on alchohol use.

Rationale:

Alcohol abuse causes disruptions in the human cognitive domain. For instance planning, attention, inhibition of inappropriate actions and working memory are affected by long-term alcohol abuse. It has been shown that an impairment of the aforementioned executive functions may result in maladaptive behaviour. For instance, drinking behaviour can get out of control, due to the fact that automatic impulses may not be suppressed appropriately. Working memory forms/is the basis for learning, planning, organizing, staying focused, control of impulses and reasoning. For this reason, the present study will investigate
whether working memory training can strengthen executive control and thereby maybe overcome the aforementioned deficits.



Objective:

The primary aim of this study is to investigate the effect of a computer-based
WMT on executive functioning (and especially WM performance) in a clinical sample of alcohol dependent subjects. Secondly, we will examine if an improvement in WM is related to
improved control over drinking behaviour (e.g. the amount of consumed alcohol beverages and alcohol cravings). Thirdly, we are interested whether this improvement in cognitive functioning is additional to the effect of the regular treatment, especially in the long run.



Study design:

Split-plot design (double-blind randomized trial).



Study population:

A minimal total of 125 alcohol dependent subjects.



Intervention:

The experimental group and one of the two control groups will receive working memory training for 25 consecutive days.



Main study parameters/endpoints:

The difference in working memory performance, automatic preferences for alcohol, alcohol cravings, executive functioning, relapse rate and
alcohol use between patients who will receive working memory training and patients who will not receive working memory training.
Nature and extent of the burden and risks associated with participation, benefit and
group relatedness
Working memory training is an intervention that is used to strengthen executive functions. It is found that working memory training is highly relevant for reducing
clinical symptoms and to improve working memory capacity and other cognitive abilities in a variety of clinical samples. The study holds no direct risks for the participants.

The primary aim of this study is to investigate the effect of a computer-based WMT on executive functioning (and especially WM performance) in a clinical sample of alcohol dependent subjects. Secondly, we will examine if an improvement in WM is related to improved control over drinking behaviour (e.g. the amount of consumed alcohol beverages and alcohol cravings). Thirdly, we are interested whether this improvement in cognitive functioning is additional to the effect of the regular treatment, especially in the long run.

Neuropsychological assessment before the start of the experiment. At pretest, posttest and follow-up, several questionnaires and tests will be administered.

The working memory training (WMT) used in the present study is based on the exact same tasks used in the study of Houben, Wiers and Jansen (2011) and the results of this study were promising. The participants in this study showed an improvement in WM performance after WMT. Their WMT was based on the ideas, tasks and studies of Klingberg and associates (e.g. 2002). The daily exercises are designed to train both the visuo-spatial and verbal WM.

All participants (in both the training and control conditions) will be tested during the WMT on three kind of WM tests: the visuospatial WM span task, the backwards digit span task, and the letter span task (based on Klingberg et al., 2002). All three tasks consist of 30 trials.

1. Visuospatial WM task: During this task, a certain number of squares in a 4x4 grid
changed in colour on the computer screen. Participants have to reproduce this
sequence by clicking on the squares that have changed colour in the correct order
using the computer mouse;

2. Backward digit span: During this task, a sequence of numbers will be presented on
the computer screen. Participants have to reproduce this sequence in reversed order,
using either the computer mouse or the number keys on the keyboard;

3. Letter span task: During this task, a sequence of letters will be presented on the
computer screen in a circle. One of the positions in this circle is the be indicated and participants have to reproduce the corresponding letter using the keyboard.



In the training condition (participants in the experimental group (group 3)), the difficulty level of all three WM tasks will be automatically adjusted on a trial-by-trial basis. Initially, each task involved sequences of three items. The length of the sequences will increase and decrease
according to participants’ performance. When participants correctly reproduce the sequences on two consecutive trials, one item will be added to the sequence on the next trial. When participants are not able to correctly reproduce the sequences on two consecutive trials, the sequence in the next trial will contain one item fewer.



In the control condition (participants in group 2), the difficulty level of the WM tasks will not be adjusted, remaining at the initial, easy level throughout each task (i.e., three items in each sequence).