Why insomniacs struggle to concentrate

A new study has tried to explain the reason behind people suffering from insomnia having trouble concentrating during the day even though objective evidence of a cognitive problem is lacking.

Lead author Sean P.A. Drummond, PhD, associate professor in the department of psychiatry at the University of California, San Diego, said that they found that insomnia subjects did not properly turn on brain regions critical to a working memory task and did not turn off 'mind-wandering' brain regions irrelevant to the task.

The research team led by Drummond and co-principal investigator Matthew Walker, PhD, studied 25 people with primary insomnia and 25 good sleepers.

The study subjects underwent a functional magnetic resonance imaging scan while performing a working memory task.

The results showed that participants with insomnia did not differ from good sleepers in objective cognitive performance on the working memory task.

However, the MRI scans revealed that people with insomnia could not modulate activity in brain regions typically used to perform the task.

As the task got harder, good sleepers used more resources within the working memory network of the brain, especially the dorsolateral prefrontal cortex.

Insomnia subjects, however, were unable to recruit more resources in these brain regions. Furthermore, as the task got harder, participants with insomnia did not dial down the "default mode" regions of the brain that are normally only active when our minds are wandering.

The study is set to be published online in journal Sleep.