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18-08-2013 | Sleep medicine | Article

Hyperarousal impairs cognitive performance in insomnia

Abstract

Free abstract

medwireNews: Physiologic hyperarousal may make patients with insomnia more alert during the day but also less able to concentrate, investigators report.

They found that insomnia patients with physiologic hyperarousal logged fewer correct responses and had more errors on reaction time tests than did similarly alert healthy sleepers.

“Our results suggest that physiologic hyperarousal impairs rather than facilitates the cognitive performances of individuals with [primary insomnia],” says the team, led by Jack Edinger (National Jewish Health, Denver, Colorado, USA).

Following 3 nights of polysomnography and Multiple Sleep Latency Testing, 53 individuals with primary insomnia and 42 healthy sleepers were classified as alert (physiologically hyperaroused) during the day, while 36 and 53, respectively, were categorized as being sleepy during the day.

Both alert and sleepy individuals with insomnia reported greater daytime sleepiness than healthy sleepers; and alert participants – most notably those with insomnia – showed lower sleep efficiencies than those classified as sleepy, at 83.5% versus 86.2%.

This sleep disturbance appeared to impair participants’ performances on a simple reaction time test, a continuous performance test, and a switching attention task.

Alert insomnia patients performed significantly worse than alert healthy sleepers, logging 75.7 correct responses on average versus 77.5, and a mean of 4.5 errors versus 2.6.

The researchers note that, while alert insomnia patients appeared to have a similar error rate to that of the healthy sleepers with daytime sleepiness (mean 4.5 vs 4.4), they logged significantly fewer correct responses (mean 75.7 vs 77.7).

“Thus, of the various subgroups considered, our physiologically hyperaroused [primary insomnia] group seemed the most disposed to poor test performances,” they write in Sleep.

But they add that the findings indicate that healthy sleepers with daytime sleepiness also have a reduced ability to maintain normal physiologic arousal.

“The deleterious effects of this form of hyperarousal on performance among individuals with [primary insomnia] perhaps is not surprising,” the team comments.

“Human performance increases with physiological or mental arousal, but only up to a point,” they explain. “When levels of arousal become too high, performance decreases, particularly when complex tasks are considered.”

This is in line with evidence of increased risk for work and traffic accidents among those with insomnia, and of physiologic hyperarousal having deleterious cardiovascular and neurocognitive effects in such patients, say Edinger and colleagues.

medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013

By Lucy Piper, Senior medwireNews Reporter