Insomnia Symptoms May Not Reflect Objective Sleep Measurements

MedicalResearch.com Interview with:
Jen-Hao Chen, Ph.D.
Assistant Professor, Department of Health Sciences
University of Missouri, Columbia, MO 65211

Medical Research: What are the main findings of the study?

Dr. Chen: In this study, we mapped four commonly-reported insomnia symptoms (feeling rested when waking up, having trouble falling asleep, waking up during the night, waking up too early and not being able to fall asleep again) to direct assessment of sleep characteristics in the general population of U.S. older adults. While we know older adults frequently complain about their sleep, we know little about how these complain reflect older adults’ actual sleep outcomes.

Using innovative actigraphy data of 727 older adults aged 62-91 from the National Social Life, Health and Aging Project, we found that two of these four common report of insomnia symptoms did not match specific objective sleep characteristics as these questions intends to index. The question of feeling rested was not related to any objective sleep characteristic. The question of difficulty falling asleep was not related to the objective measure of time to fall sleep but was related to other objective sleep characteristics. For waking up during the night question, high frequency was associated with more wake time after sleep onset and numbers of wake bout (but was also related to other objective sleep characteristics). For waking up too earlier question, answer of this question was related to earlier wake up time. But again, other objective sleep characteristics also predicted frequency of waking up earlier.

In sum, many of the relationships and non-relationships found in this study were unexpected. Findings suggested that these widely used questions did not related to older adults’ sleep outcomes as exactly as the wording suggested. Thus, while older adults’ report of these questions are related to objective sleep characteristics in some ways, insomnia symptoms and objective sleep characteristics did not complete match each other as expected.


Medical Research: What was most surprising about the results?

Dr. Chen: While many of the relationships (and non-relationships) between report of insomnia symptoms and objective sleep characteristics were not expected, the most surprising finding to us is the no relationship between the question of “how often do you feel really rested when you wake up in the morning” and any of the actigraphic sleep characteristics. This question is widely used in survey research as to tap into the overall sleep quality of respondents. It is also often used as a question to tap into the degree of non-restorative sleep in clinical settings. Despite the prevalence of the use of this question in science and in practice, this question was the only question (among four questions of insomnia symptoms) that had nothing to do with objective sleep characteristics assessed by actigraphy. In other words, the result suggested that feeling rested when waking up was not influenced by actual sleep outcomes. This result really surprised us.

Medical Research: What should clinicians and patients take away from your report?

Dr. Chen: For clinicians, it is clear from our study that insomnia questions are not good proxies of direct assessment of sleep properties. Psychiatrists should be aware that how well a patient feel about their sleep may not be equivalent to how well a patient actually sleep. The report also implies that to know how well a patient sleep, a direct assessment of sleep properties is needed because till now self-report of insomnia symptoms (instead of objective assessment of sleep outcomes) remain the sole criteria for diagnosis of insomnia in clinical settings.

For patients, if they did not feel having a good night of sleep, it might not mean that their sleep quality was poor or duration was inadequate. In fact, people may have adequate and quality sleep from objective assessment but still not feeling rested or having trouble falling asleep. So patients may want to treat see their sleep problems not mere a pure sleep issue (i.e., caused by not having adequate sleep and poor sleep quality) but also look for other social and psychological factors that may cause the feeling not having a good night sleep instead of thinking purely of your problem as a sleep issue. If you yourself are having trouble getting a good nights sleep and believe it’s because of surrounding noise, check out the soundproofexpert blog for advice on how to keep your bedroom quieter.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Chen: We definitely recommend future research on sleep should carefully interpret people’s answer of survey questions about insomnia symptoms, especially the general question asking whether the respondent feels rested when waking up. We recommend researcher should not treat survey questions about insomnia symptoms as proxies of objective sleep characteristics. Instead, these questions simply reflect people’s subjective experience of their sleep that could be influenced by their actual sleep outcomes and numerous other social and psychological factors. Treating answers of insomnia symptoms as actual sleep outcomes can lead to incorrect interpretation of the results and mask the true reasons that leads to report of insomnia symptoms.

Citation:
Insomnia Symptoms and Actigraph-Estimated Sleep Characteristics in a Nationally Representative Sample of Older Adults

Jen-Hao Chen, Linda Waite, Lianne M. Kurina, Ronald A. Thisted, Martha McClintock and Diane S. Lauderdale

J Gerontol A Biol Sci Med Sci first published online September 8, 2014 doi:10.1093/gerona/glu144

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