Noninvasive Acoustic Stimulation Effectively Reduced Insomnia Symptoms and Improved Cardiovascular Regulation

As effective insomnia interventions addressing autonomic dysregulation are lacking, investigators evaluated high-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM®) in a randomized, controlled clinical trial.

High-resolution, relational, resonance-based, electro-encephalic mirroring (HIRREM®) demonstrated, in a randomized, controlled clinical trial at Wake Forest Baptist Health, clinically relevant reduction of insomnia symptoms and improved autonomic cardiovascular regulation. These results were published in Brain and Behavior.

Individuals (N=107) with clinical diagnoses for insomnia without secondary causes were recruited for this study. In addition to current care, participants were randomized in a 1:1 ratio to receive tones linked to brainwaves (LB; n=56) or tones not linked to brainwaves (NL; n=51) during 10 sessions over 3 weeks. Participants had a brainwave assessment within 7 days of the study conclusion and were asked to respond to an Insomnia Severity Index (ISI) questionnaire at each visit.

At baseline, cohorts were balanced for all demographic and clinical characteristics and HIRREM session scheduling was similar. No significant difference was observed among participant expectation for the study outcome (P =.71).

A total of 3 participants in the treatment and 2 in the placebo groups dropped out of the study due to scheduling conflicts and 1 of the treatment participants did not return for the post-study assessment.

At the study conclusion, 46.9% of the treatment group and 22.4% of the placebo group believed they had received HIRREM therapy (P =.01). ISI scores were reduced by averages of -4.93 (standard error [SE], 0.76) points among the NL group and -2.05 (SE, 0.74) points among the LB group (P =.045). At a 16-18-week follow-up, an additional mean reduction of -2.30 (SE, 0.76) points was observed among the LB group (P =.058).

Heart rate variability (P <.001) and baroreflex sensitivity (P £.01) were observed to be significantly improved during all collection points compared between the treatment and placebo groups.

Compared with baseline, participants receiving LB treatment reported improved sleep quality (r=-0.54; P <.0001) and waking feeling rested (r=-.49; P <.0001).

No serious adverse events were reported, however, 10.7% of the LB and 13.7% of the NL group reported paradoxical side effects including heightened awareness of feelings or of others, changes in sleep, or of a mild headache.

A major limitation of this study was the lack of diversity. The majority of participants were younger White women. It remains unclear whether these results are translatable to a more general insomnia population.

The study authors concluded that noninvasive, acoustic stimulation with HIRREM was able to reduce symptoms of insomnia while improving autonomic cardiovascular regulation. These results warrant future studies into whether or not HIRREM may be a viable therapy option for those who suffer from sleep difficulties.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original study for a full list of disclosures.


Tegeler CL, Shaltout HA, Lee S W, Simpson SL, Gerdes L, Tegeler CH. High-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM) improves symptoms and autonomic function for insomnia: A randomized, placebo-controlled clinical trial. Brain Behav. 2020;e01826. doi: 10.1002/brb3.1826