Children born prematurely benefit from memory training

In the last two decades interest in exercising the brain has increased rapidly. There are many different forms of cognitive training for children. Children born extremely and very prematurely (gestational age: 22-27 weeks and 28-31 weeks, respectively) are often at increased risk of cognitive deficits and behavioural problems. One cognitive domain that is frequently impaired is memory. Since memory functions are strongly related to scholastic performance, it is of crucial interest to prevent school problems by implementing memory training in at-risk children.

One approach for improving cognition is to train internal memory strategies, such as rehearsal or visualization. Rehearsal is a strategy involving the repetition of a piece of information over and over again so that it is processed and stored in your memory, while visualization involves creating mental pictures based on words you hear or a text you read.

Another way to improve your memory is to engage in intensive working memory training, so-called core working memory training. For the most part, core working memory training is conducted on a computer and requires you to recall a series of locations or reproduce a series of letters presented to you, in either the same or reverse order.

It seems obvious that training would improve the aspects of cognition it targets. A more important goal, however, is to improve related cognitive functions that are not the specific focus of the training. But only very few studies have shown stable transfer effects of memory training, and the underlying mechanisms in these cases are not yet fully understood.

When studying the effects of training, it is important to pay attention to a variety of factors that may influence the training effect. Researchers often fail to take into account the subject’s age, motivation and cognitive performance level, all of which might be expected to influence the impact of training.

Testing two kinds of memory training

The NEMO study group sought to determine whether two different types of memory training – namely memory strategy training and core working memory training – are able to improve cognitive functions in children between the ages of 7 to 12 who were born very prematurely (under 32 weeks of gestational age and/or with a birth weight below 1500g). The children underwent three neuropsychological assessments: one before training, one immediately after training and one six months after training.

And indeed, memory strategy training produced significant improvements in trained and non-trained cognitive functions immediately after memory training. In addition to improvement in memory domains, there was a significant increase in episodic memory and arithmetic performance. This transfer effect on non-trained tasks can be explained by the application of various memory strategies that require metamemory. Increased metamemory awareness, and thus also an increase in awareness and knowledge of one’s own cognitive functions, is likely to be related to the cognitive improvements found after memory strategy training.

“Memory strategy training produced significant improvements in trained and non-trained cognitive functions immediately after memory training.”

In keeping with the findings of studies of other populations (e.g. children with ADHD), in our sample core working memory training showed significant effects on short-term memory and working memory tasks immediately after training. However, we found no significant improvement in non-trained functions.

Even six months after training, children in both training groups showed better performance in trained functions such as working memory performance than children in the control group. Moreover, children born very prematurely whose memory performance was poor before training improved most after memory strategy training and after core working memory training – in keeping with the idea that weak performers are most likely to show gains.

These encouraging results suggest that various types of memory training can be effective in promoting the cognitive development of school-aged children. It is therefore essential to show parents, teachers, and therapists how to introduce memory training activities to children who were born very prematurely, but also to other children with atypical development (e.g. ADHD) who are at risk of cognitive problems.