Researchers at the Royal Netherlands Academy of Arts and Sciences have been looking into the effects of long-term insomnia on people's cognition. They compared a group of older adults with insomnia to a group of unaffected participants. The participants took four tests. In test one they had to press a button when they saw a star on the screen. In test two they had to press a button when they saw a 'p' on screen but not when they saw a 'd.' In test three they had to come up with as many words in a certain category, e.g. animals, as possible and in test four they had to come up with as many words beginning with a certain letter as possible. Surprisingly although the insomniacs performed worse in test two they performed better in tests one, three and four. The participants' brain activity was monitored while they carried out the tests and the insomniacs showed less activity in the regions needed to carry them out. Their superior performance was put down to them being in a state of extra vigilance, increased adrenalin and more stress known as hyperarousal. The participants with insomnia also had less grey matter in their orbitofrontal cortex. After six weeks of sleep therapy the insomniacs did less well in task one, better in task two and showed the same performance in tasks three and four. Their levels of brain activity while they carried out the tasks showed signs of improving but it could be that the state of hyperarousal experienced by the insomniacs leads to some of the physical and mental health problems associated with the condition.
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