Open-loop audiovisual stimulation induces delta EEG activity in older adults with osteoarthritis pain and insomnia

Objective: People with chronic insomnia tend to have cortical hyperarousal marked by excessive beta-/gamma-frequency brain activity during both wake and sleep. Currently, treatment options for managing hyperarousal are limited. Open-loop audiovisual stimulation (AVS) may be such a treatment. The purpose of this study was to provide a mechanistic foundation for future AVS research in sleep promotion by examining quantitative electroencephalogram (QEEG) responses to an AVS sleep-induction program. Method: Sixteen older adults with both chronic insomnia and osteoarthritis pain were randomly assigned to either active- or placebo-control AVS. Electroencephalogram (EEG) was collected during baseline (5 min, eyes closed/resting) and throughout 30 min of AVS. Results: Findings showed significantly elevated mean baseline gamma (35–45 Hz) power in both groups compared to an age- and gender-matched, noninsomnia normative database, supporting cortical hyperarousal. After 30 min of exposure to AVS, the active group showed significantly increased delta power compared to the placebo-control group, providing the first controlled evidence that active AVS induction increases delta QEEG activity in insomnia patients and that these changes are immediate. In the active group, brain locations that showed the most delta induction (Cz, Fp, O1, and O2) were associated with the sensory–thalamic pathway, consistent with the sensory stimulation provided by the active AVS program. Conclusions: Findings demonstrate that delta induction, which can promote sleep, is achievable using a 30-min open-loop AVS program. The potential for AVS treatment of insomnia in the general population remains to be demonstrated in well-designed clinical trials.