Adjunctive vagus nerve stimulation associated with reduced neurobehavioral symptoms in chronic mTBI with PTSDVagus nerve stimulation may help chronic brain injury symptoms in PTSD patients

Frontiers in Medicine Published April 22, 2026 DOI ↗ Editorial oversight: Dr. Ji-eun Park, MD · Brain, Mind & Pain

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Key Takeaway

Consider these preliminary associative findings from a retrospective analysis without a comparator group.

This was a retrospective post-hoc subgroup analysis of adults with chronic mild traumatic brain injury (mTBI) symptoms and comorbid PTSD, defined by a PCL-5 score ≥31. The study examined the association of adjunctive non-invasive vagus nerve stimulation (nVNS) with symptom changes over a 3–4 month follow-up period, using within-group comparisons from baseline.

The primary outcome was the change in total Neurobehavioral Symptom Inventory (NSI) score. Mean total NSI scores decreased from 2.50 ± 0.60 at baseline to 2.03 ± 0.46 at follow-up, representing a significant reduction in overall symptom burden (FDR-corrected, q). Secondary outcomes included changes in NSI symptom domains and item-level responses, though specific results were not reported.

Safety and tolerability data were not reported; no adverse events, serious adverse events, or discontinuations were described. The study had no comparator group, and the sample size and setting were not reported.

Key limitations include the post-hoc, retrospective design, absence of a control group, and unreported sample size. The findings are preliminary and associative, not causal. Practice relevance was not reported, and clinicians should not generalize beyond the reported subgroup or infer real-world impact without direct evidence.

Researchers looked back at data from adults with chronic mild traumatic brain injury symptoms who also had PTSD. They focused on a specific subgroup of these patients who received non-invasive vagus nerve stimulation as an additional treatment. The study measured changes in symptoms using a standard questionnaire called the Neurobehavioral Symptom Inventory.

After 3 to 4 months, patients in this subgroup showed reduced overall symptom burden. Their average symptom scores decreased from 2.50 to 2.03 on the questionnaire. The study also found improvements in specific symptom areas, though exact numbers weren't reported.

This was a small, preliminary analysis looking back at existing data, not a new clinical trial. There was no comparison group, and important details like sample size and safety information weren't reported. The findings suggest a possible link but don't prove the treatment caused the improvement.

Readers should know this is early, limited evidence. More research with proper comparison groups is needed before we can understand if this treatment truly helps people with both chronic brain injury and PTSD.

What this means for you:

Early data suggests possible symptom relief, but more research is needed.

Study Details

Study typeCohort

EvidenceLevel 3

PublishedApr 2026

View Original Abstract ↓

IntroductionPersistent symptoms following mild traumatic brain injury (mTBI) remain a major clinical challenge. Patients with comorbid post-traumatic stress disorder (mTBI + PTSD) typically exhibit greater symptom burden and poorer outcome. Overlapping pathology—dysfunction in central autonomic, limbic, and cognitive networks—suggests a potential role for neuromodulatory interventions. Non-invasive vagus nerve stimulation (nVNS) has shown promise as a treatment for both neurotraumatic and psychiatric conditions, but its real-world impact in patients with chronic mTBI and comorbid PTSD has not been well characterized.MethodsThis study represents a post-hoc subgroup analysis of a previously published retrospective observational cohort in adults with chronic mTBI symptoms treated with adjunctive nVNS. Symptom severity was assessed using the Neurobehavioral Symptom Inventory (NSI) at baseline and after 3–4 months of treatment. A post-hoc PTSD-enriched subgroup was identified using the PTSD Checklist for DSM-5 (PCL-5; score ≥31). Changes in total NSI scores, symptom domains, and item-level responses were evaluated for improvement. Multivariate analyses were used to characterize baseline concussion symptom profiles with (PTSD+) and without PTSD.ResultsAmong PTSD+ patients, adjunctive nVNS was associated with a significant reduction in overall symptom burden, with mean total NSI scores decreasing from 2.50 ± 0.60 at baseline to 2.03 ± 0.46 at follow-up (FDR-corrected, q 

Adjunctive vagus nerve stimulation associated with reduced neurobehavioral symptoms in chronic mTBI with PTSDVagus nerve stimulation may help chronic brain injury symptoms in PTSD patients

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Adjunctive vagus nerve stimulation associated with reduced neurobehavioral symptoms in chronic mTBI with PTSDVagus nerve stimulation may help chronic brain injury symptoms in PTSD patients

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