medwireNews: A study assessing cognitive ability in older adults with insomnia has failed to detect any reduction in working memory, despite consistent subjective reports of daytime impairment.
Writing in the Journal of Sleep Research, Nicole Lovato (Flinders University, Adelaide, South Australia, Australia) say that their findings add weight to the hypothesis that insomnia per se does not impair cognition.
"Recent neuroimaging studies have demonstrated frontal lobe hypo-activation among insomniac populations when compared with healthy, good sleepers," the authors write.
"However, research is yet to confirm whether frontal lobe hypo-activation translates into objective declines when performing tasks hypothesized to draw upon this brain region."
Lovato's team used the Double Span Memory Task (DSMT) to assess working memory performance in 49 individuals with sleep maintenance and/or early morning awakening insomnia and 49 self-reported good sleepers matched for age and gender. The mean age of participants was 70 years.
Patients with insomnia reported significantly more problems with their cognitive functioning, memory, ability to organize thoughts, and ability to concentrate compared with good sleepers. Insomniacs also scored significantly lower on the Wechsler Abbreviated Scale of Intelligence when compared with good sleepers.
And, patients with insomnia self-reported poorer overall sleep quality, greater levels of fatigue and sleepiness, and greater impairment of overall daytime functioning when compared with the good sleepers.
After controlling for intelligence, however, there was no significant difference between insomniacs and good sleepers with regard to any of the recall types (objects, locations, double, and overall) assessed by the DSMT.
Lovato et al conclude that insomnia is not associated with any observable deficits when performing tasks that rely heavily upon frontal lobe functioning, despite the subjective experience of patients.
"If individuals suffering from insomnia are not cognitively impaired, treatment would benefit from emphasizing the use of cognitive therapy to challenge how individuals with insomnia conceptualize the consequences of poor sleep," the authors conclude.
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013
By Joanna Lyford, Senior medwireNews Reporter