A randomized controlled trial investigating a wearable device for treatment of insomnia

J. Kent Werner, PhD, Ethan Cheraghpour, Angeliki Pollatou, PhD, Adriana Penafiel, Colin Dawkins, Sujasha Gupta, PhD, Lilly Skeiky, PhD, Maria Provo

Introduction: Insomnia is a huge problem in the military with over 50% of warfighters chronically sleep less than 6 hours per night while on deployment or in garrison. Consequently, they are predisposed to workplace injury, cognitive and physical health compromise, poor morale, immune compromise/infection, and fatal/costly accidents. We performed a clinical trial to investigate a new wearable device to improve outcomes for those suffering from insomnia by attempting to enhance the brain rhythms within the frontal lobe implicated in slow wave generation during the transition from wake to sleep. 

Materials & Methods: Our trial design is a two condition, within-subjects cross-over comparing active treatment with 0.75 Hz frontal transcranial direct current stimulation (tDCS) to same-subject pre-treatment baselines and a 25 Hz tDCS active control with the same device. The trial enrolled active-duty US military or veterans (N=48) with at least moderate insomnia as measured by the Insomnia Severity Index (ISI). Brain stimulation was delivered with the wearable device at home, over 30-minutes immediately before sleep. Trial outcomes were: sleep onset latency (SOL) measured with actigraphy, total sleep time, wake after sleep onset, changes in ISI scores, and neural biomarkers of frontal brain activity measured with EEG. Treatment-dependent hypothesis testing was done using a repeated measures, 3-factor ANOVA test, while between groups testing was performed using paired student t-tests.

Results: SOL was reduced from 90 minutes (baseline) to 51 minutes following 0.75 Hz treatment, and 62 minutes in response to active control stimulation (F=7.6, p=0.0005). 90% of patients realized a reduction in their SOL with 0.75Hz stimulation. No significant differences were observed in total sleep time or wake after sleep onset. Changes in SOL were strongly correlated to pre-treatment baselines (r = -0.71, p<<0.001) with the strongest reductions from 0.75 Hz treatment occurring in patients with the most severe insomnia pathology. ISI scores were reduced in both groups from 20.4 (baseline) to 16.5 (treatment, p<0.001) or 16 (active control, p<0.001). Treatment with 0.75 Hz stimulation evoked strong increases in slow wave spectral power (0.5 – 1.2 Hz) and left/right EEG coherence.

Conclusions: This trial confirms the efficacy of a new wearable device to combat sleep onset insomnia and provides support for its use as a safe, and effective therapeutic tool in a military population.