Ecological momentary assessment of daytime symptoms during sleep restriction therapy for insomnia

Authors

  • Christopher B. Miller,

    Corresponding author
    1. Institute of Neuroscience and Psychology, University of Glasgow, Scotland, UK
    2. NHMRC Centre for Integrated Research and Understanding of Sleep (CIRUS), Woolcock Institute of Medical Research, University of Sydney, NSW, Australia
    • University of Glasgow Sleep Centre, Scotland
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  • Simon D. Kyle,

    1. University of Glasgow Sleep Centre, Scotland
    2. Institute of Neuroscience and Psychology, University of Glasgow, Scotland, UK
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  • Nathaniel S. Marshall,

    1. NHMRC Centre for Integrated Research and Understanding of Sleep (CIRUS), Woolcock Institute of Medical Research, University of Sydney, NSW, Australia
    2. Sydney Nursing School, University of Sydney, NSW, Australia
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  • Colin A. Espie

    1. University of Glasgow Sleep Centre, Scotland
    2. Institute of Neuroscience and Psychology, University of Glasgow, Scotland, UK
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Correspondence

Christopher B. Miller, Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia/Postal address: PO Box M77, Missenden Road, NSW, 2050, Sydney, Australia. Tel.: +61-(2)-9114-0451; fax: +61-(2)-9114-0014; e-mail: chris.miller@sydney.edu.au

Summary

This study profiles changes in self-reported daytime functioning during sleep restriction therapy (SRT) for insomnia. Ecological momentary assessment (EMA) captured point-in-time symptomatology to map the time–course of symptoms. We hypothesized a deterioration (week 1) followed by improvements at week 3 of therapy relative to baseline. Nine patients with psychophysiological insomnia completed the Daytime Insomnia Symptom Scale (DISS) at rise-time, 12:00 hours, 18:00 hours and bedtime for 1 week before and 3 weeks during SRT. Four validated factors from the DISS were analyzed (alert cognition, positive mood, negative mood and sleepiness/fatigue) across 28 days yielding 17 170 data points. Factors evaluated week (baseline versus weeks 1 and 3) and time of day symptomatology. Insomnia Severity Index scores decreased significantly pre-to-post treatment (mean 18 versus 7). Reflecting acute effects of SRT, significant differences were found for all factors, except negative mood, between baseline and week 1 of SRT, suggesting adverse effects. By week 3, sleepiness/fatigue and negative mood decreased significantly compared to baseline, and positive mood showed a trend towards improvement (= 0.06). Sleepiness/fatigue displayed a significant week × time of day interaction, explained by a reduction in sleepiness/fatigue at every daytime assessment point (except bedtime, which remained high). A significant interaction for alert cognition was associated with reduction in alertness at bedtime by week 3 and an increase in alertness at rise-time, suggesting that SRT not only improves sleep, but moderates alertness and sleepiness in therapeutic ways. Initial SRT is associated with an increase in sleepiness/fatigue and a decrease in alert cognition.

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