The Oxford-Durham study: a randomized controlled trial of dietary supplementation with fatty acids in children with developmental coordination disorder.

Abstract:

Background: Developmental coordination disorder (DCD) affects around 5% of school age children. In addition to the core deficits in motor function, this condition is commonly associated with difficulties in learning, behavior and psychosocial adjustment that persist into adulthood. Mounting evidence suggests that a relative lack of certain polyunsaturated fatty acids may contribute to related neurodevelopmental and psychiatric disorders such as dyslexia and AD/HD. Given the current lack of effective evidence-based treatment options for DCD, the use of fatty acid supplements merits investigation.

Methods: A randomized controlled trial of dietary supplementation with omega-3 and omega-6 fatty acids versus placebo was conducted in 117 children with DCD aged 5-12 years. Treatment for 3 months in parallel groups was followed by a one-way crossover from placebo to active treatment for a further 3 months.

Results: No effect of treatment on motor skills was apparent, but significant improvements for active treatment versus placebo were found in reading, spelling and behavior over 3 months of treatment in parallel groups (p< 0.01 in each case). Following the crossover, similar changes were seen in the placebo-active group, while children continuing with active treatment maintained or improved their progress.

Conclusions: These results indicate that fatty acid supplementation may offer a safe and efficacious treatment option for educational and behavioral problems in children with DCD. Additional work is needed to investigate whether our inability to detect any improvement in motor skills reflects the measures used and to assess the durability of treatment effects on behavior and academic progress.

NON-TECHNICAL SUMMARY

Background

Developmental coordination disorder (DCD) – sometimes known as developmental dyspraxia - affects around 5% of school age children. By definition, children with DCD /dyspraxia show specific difficulties with motor coordination, but they also often have associated difficulties in learning, behaviour and social or psychological adjustment. The DCD / dyspraxia syndrome usually persists into adulthood, and the associated difficulties represent a huge cost not only to the individuals and families affected, but to society as a whole.

There is increasing evidence that nutrition could play a role in DCD/dyspraxia. In particular, it has been suggested that a relative lack of certain polyunsaturated fatty acids (particularly the omega-3 fatty acids found in fish oil) could contribute to dyspraxic difficutleis. These fatty acids are essential for brain development and function, and treatment studies have already shown that dietary supplementation with omega-3 can be of benefit in related conditions such as dyslexia and ADHD.

Few of the current treatment options for DCD/dyspraxia are backed by any firm evidence of their effectiveness, so the use of fatty acid supplements in this condition is worthy of investigation.

Methods

This was a randomized, double-blind, placebo-controlled trial, the only kind of study that can provide clear evidence of cause and effect.

117 children with DCD (all aged between 5 and 12 years) received dietary supplementation for 3 months. Half of them received a supplement containing 80% fish oil and 20% evening primrose oil (providing omega-3 and some omega-6 fatty acids). The other half received an identical-looking placebo supplement (containing olive oil), which was not expected to be of any benefit. Each child had an equal chance of receiving the fatty acid supplement being tested (the ‘active treatment’), and until the whole study had finished, no-one involved knew which children were receiving which treatment.

The study also involved an additional follow-up period of 3 months, during which the children who had been receiving the placebo ‘crossed over’ to treatment with the fatty acid supplement, while those who were already receiving this continued to do so. Although this part of the study was irrelevant to the main statistical analyses, it provided additional information that was of use both for interpreting the main results and for planning future studies.

During the main 3-month study period, the progress of children taking the fatty acid supplement (the ‘active treatment’) was compared with the progress of those on placebo treatment to find out if the supplement had any effects. Because children with DCD/dyspraxia usually show at least some features of either dyslexia or ADHD, progress in all three of these areas was assessed using age-standardised tests. Before treatment, and at the 3- and 6-month follow-up points, the children were therefore assessed not only for motor coordination skills, but also for both reading and spelling achievement and teacher ratings of behaviour and learning difficulties usually associated with ADHD.

Results

After 3 months of treatment in parallel groups, the changes in motor skills did not differ between the two groups on objective testing. However, children who received the fatty acid supplement showed significantly better progress in both reading and spelling than children who received the placebo. Similarly, active treatment was associated with highly significant reductions in ADHD-related symptoms according to teacher ratings of the childrens’ behaviour.

Following the one-way treatment crossover, similar improvements in behaviour, reading and spelling were observed for the children who crossed from placebo to active treatment, while children continuing with active treatment maintained or improved their progress.

Conclusions

This is the largest study to date of fatty acid supplementation in children with specific learning difficulties. Results indicate that fatty acid supplementation may offer a safe and efficacious treatment option for educational and behavioral problems in children with DCD/dyspraxia.

No advantages of fatty acid treatment were found, however, for the core deficits in motor skills. Instead, significant improvements in motor function were found for both groups of children over the 3-month study period. Additional studies would be needed to find out whether this large placebo effect arose from the particular test battery used to assess motor function, or some other factors. (No such placebo effects were found for reading, spelling or ADHD-type symptoms).

Further work is also needed to investigate the durability of the treatment effects that were seen on behavior and academic progress, and to find out whether these results may generalise to other age groups and populations. Previous studies have shown similar behavioural improvements in children identified with dyslexic or ADHD-type difficulties. Given the prevalence of these kinds of difficulties in the general population, large-scale controlled trials involving mainstream children are now warranted.