Study objectives: To determine if vestibular stimulation is an effective therapy for transient insomnia in a sleep phase advance model.
Design: Multi-site, double-blind, randomized, parallel-group, sham-controlled trial
Setting: This study was carried out at 6 sites in the United States.
Participants: 198 healthy normal sleepers.
Interventions: Bilateral electrical stimulation of the vestibular apparatus of the inner ear via electrodes on the skin of the mastoid process at a frequency of 0.5 Hz vs. sham stimulation.
Results: We did not find a significant effect of treatment on our primary outcome variable, latency to persistent sleep onset (LPS). However, our planned analysis identified that the mean latency to sleep onset on the multiple sleep latency test was a significant covariate. This led us to carry out post hoc analyses, which showed a significant effect of treatment on LPS in those subjects with a mean MSLT sleep onset latency > or = 14 minutes.
Conclusions: Vestibular stimulation did not have a therapeutic effect in a model of transient insomnia in the overall population studied. However, this study provides preliminary evidence that vestibular stimulation may shorten sleep onset latency compared with sham therapy in the subset of subjects with mean MSLT sleep onset latency > or = 14 minutes.