Research Reports - Can impaired working memory functioning be improved by Training? A Meta-Analysis With a Special Focus on Brain Injured Patients
Neuropsychology. 2015 Aug 3. [Epub ahead of print]
Weicker J, Villringer A, Thöne-Otto A.
OBJECTIVE: Deficits in working memory (WM) are commonly observed after brain
injuries and cause severe impairments in patients' everyday life. It is still
under debate if training can enhance or rehabilitate WM in case of malfunction.
The current meta-analysis investigates this issue from a clinical point of view.
It addresses under which conditions and for which target group WM training may be
METHOD: Relevant WM training studies were identified by searching electronic
literature databases with a comprehensive search term. In total, 103 studies,
which added up to 112 independent group comparisons (N = 6,113 participants),
were included in the analysis.
RESULTS: Overall, WM training caused a moderate and long-lasting improvement in
untrained WM tasks. Moreover, improvement of WM functioning led to sustainable
better evaluation of everyday life functioning, however, effect sizes were small.
Concerning transfer effects on other cognitive domains, long-lasting improvements
with small effect sizes were observed in cognitive control and
reasoning/intelligence. In contrast, small immediate, but no long-term effects
were found for attention and long-term memory. Studies with brain injured
patients demonstrated long-lasting improvements in WM functions with moderate to
large effect sizes. A main moderator variable of intervention efficacy is the
number of training sessions applied.
CONCLUSION: WM training produces long-lasting beneficial effects which are
strongly pronounced in patients with acquired brain injuries. This finding
supports the application of WM training in clinical settings. To determine
optimal training conditions, future studies must systematically investigate the
characteristics of interventions as they are at present inevitably confounded.