Targeted multidomain intervention for complex mTBI: protocol for a multisite randomized controlled trial in military-age civilians

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.

Role of anxiety in exercise intolerance and autonomic nervous system dysfunction post-concussion

OBJECTIVE

To compare autonomic nervous system (ANS) response using the Buffalo Concussion Bike Test (BCBT) between adult post-concussion patients with and without pre-existing and post-injury anxiety.

DESIGN

Cross-sectional cohort study of participants from the Targeted, Multidomain (T-MD) Treatment for Concussion Randomized Controlled Trial.

SETTING

Two concussion specialty clinics.

PARTICIPANTS

Ages 18-49 years, 8 days to 6 months from injury, without a history of cardiovascular/neurological/vestibular disorders. 256 participants were eligible, 120 declined, 136 enrolled, and 30 were excluded.

EXPOSURES

Participants completed the BCBT at a baseline study visit following initial clinical evaluation.

MAIN OUTCOMES AND MEASURES

Number of BCBT stages completed and Visual Analogue Scale (VAS), heart rate (HR), blood pressure (BP), and Ratings of Perceived Exertion (RPE) pre- and post-BCBT.

RESULTS

106 participants (age = 25.5 [12.5], 66 [62.3%] female) were included, 44 (41.5%) with pre-existing anxiety, 61 (57.6%) without pre-existing anxiety, 33 (31.1%) with post-injury anxiety, and 73 (68.9%) without post-injury anxiety. Eighteen (17.0%) were in both anxiety groups. Results supported a significant group x time interaction in participants with pre-existing anxiety for increased diastolic BP (F[1,97] = 5.03, p = 0.03) and VAS (F[1,99] = 5.05, p = 0.03) while controlling for covariates. Participants with pre-existing anxiety (median = 8[4]) and post-injury anxiety (median = 8[5]) completed fewer BCBT stages than those without pre-existing (median = 11[6], p < 0.01) and post-injury (median = 10[6], p = 0.03) anxiety.

CONCLUSIONS

Adults with pre-existing and post-injury anxiety experienced altered physiological responses to exercise post-concussion and completed fewer stages of the BCBT. Anxiety should be considered by clinicians when interpreting findings from exercise intolerance tests such as the BCBT.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov ; identifier: NCT04549532; https://clinicaltrials.gov/study/NCT04549532.

White Matter Alterations in Military Service Members With Remote Mild Traumatic Brain Injury

Importance

Mild traumatic brain injury (mTBI) is the signature injury experienced by military service members and is associated with poor neuropsychiatric outcomes. Yet, there is a lack of reliable clinical tools for mTBI diagnosis and prognosis.

Objective

To examine the white matter microstructure and neuropsychiatric outcomes of service members with a remote history of mTBI (ie, mTBI that occurred over 2 years ago) using diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI).

Design, Setting, and Participants

This case-control study examined 98 male service members enrolled in a study at the National Intrepid Center of Excellence. Eligible participants were active duty status or able to enroll in the Defense Enrollment Eligibility Reporting system, ages 18 to 60 years, and had a remote history of mTBI; controls were matched by age.

Exposures

Remote history of mTBI.

Main Outcomes and Measures

White matter microstructure was assessed using a region-of-interest approach of skeletonized diffusion images, including DTI (fractional anisotropy, mean diffusivity, radial diffusivity and axial diffusivity) and NODDI (orientation dispersion index [ODI], isotropic volume fraction, intra-cellular volume fraction). Neuropsychiatric outcomes associated with posttraumatic stress disorder (PTSD) and postconcussion syndrome were assessed.

Results

A total of 65 male patients with a remote history of mTBI (mean [SD] age, 40.5 [5.0] years) and 33 age-matched male controls (mean [SD] age, 38.9 [5.6] years) were included in analysis. Compared with the control cohort, the 65 service members with mTBI presented with significantly more severe PTSD-like symptoms (mean [SD] PTSD CheckList-Civilian [PCL-C] version scores: control, 19.0 [3.8] vs mTBI, 41.2 [11.6]; P < .001). DTI and NODDI metrics were altered in the mTBI group compared with the control, including intra-cellular volume fraction of the right cortico-spinal tract (β = -0.029, Cohen d = 0.66; P < .001), ODI of the left posterior thalamic radiation (β = -0.006, Cohen d = 0.55; P < .001), and ODI of the left uncinate fasciculus (β = 0.013, Cohen d = 0.61; P < .001). In service members with mTBI, fractional anisotropy of the left uncinate fasciculus was associated with postconcussion syndrome (β = 5.4 × 10-3; P = .003), isotropic volume fraction of the genu of the corpus callosum with PCL-C (β = 4.3 × 10-4; P = .01), and ODI of the left fornix and stria terminalis with PCL-C avoidance scores (β = 1.2 × 10-3; P = .02).

Conclusions and Relevance

In this case-control study of military-related mTBI, the results suggest that advanced magnetic resonance imaging techniques using NODDI can reveal white matter microstructural alterations associated with neuropsychiatric symptoms in the chronic phase of mTBI. Diffusion trends observed throughout widespread white matter regions-of-interest may reflect mechanisms of neurodegeneration as well as postinjury tissue scarring and reorganization.