Acoustic neuromodulation with or without micro-voltage tACS reduces post-concussive symptoms

Objective: Persistent post-concussive symptoms (PPCS) are common and disruptive, particularly in military service members (SM), yet there are no approved therapies targeting underlying physiological processes. This study was designed to compare acoustic neuromodulation using Cereset Research™ Standard Operating Procedures (CR-SOP), with Cereset Research Cranial Electrical Stimulation (CR-CES), on PPCS. Methods: SM, veterans, or dependents with PPCS (Neurobehavioral Symptom Inventory [NSI] Score ≥23) were randomized to receive 10 sessions of engineered tones linked to brainwaves (CR-SOP) or 5 sessions of CR-CES, which adds intermittent low voltage transcranial alternating current stimulation (tACS) to CR-SOP. Designed to assess non-inferiority between varied doses of CR-SOP and CR-CES, the primary outcome was a change in post-concussive symptoms on the NSI, with secondary outcomes of heart rate variability (HRV) and self-report measures of PTSD, sleep, headaches, and depression. Results: Among study participants (n = 80, 21.3% female, mean age 40.2 [SD 13.2], 4.8 deployments, 3.2 TBIs), mean NSI declined from 45.6 to 29.5 after intervention (p < 0.0001), with gains sustained at 3 months (29.7). No significant between group differences for NSI (CR-SOP: baseline 43.9, post-intervention 26.0, 3-month 27.2, and CR-CES 46.4, 30.7, and 31.1, respectively), and no evidence of inferiority between the groups with respect to NSI. Similar improvements were seen on PCL-5, ISI, HIT-6, and PHQ-9, with no HRV differences between groups. Conclusion: Both acoustic neuromodulation alone (CR-SOP) and a lower dose of CR-SOP, with tACS added (CR-CES), significantly improved PPCS out to 3 months. Registration: ClinicalTrials.gov–NCT03649958.