Non-invasive neuromodulation after repetitive head impacts: current evidence and a precision framework for circuit-based rehabilitation.

INTRODUCTION: Repetitive head impacts (RHIs) are associated with heterogeneous cognitive, behavioral, psychiatric, sleep-related, pain, and neurological symptoms. Chronic traumatic encephalopathy (CTE) remains a postmortem neuropathological diagnosis, whereas traumatic encephalopathy syndrome (TES) is a clinical research syndrome assessed during life. No intervention has been shown to modify CTE pathology, but neuromodulation may support the surviving neural circuits.

AREAS COVERED: PubMed/MEDLINE, Web of Science, Scopus and Google Scholar were searched from database inception to August 2026 for this narrative review. The author evaluates magnetic and electrical stimulation, low-intensity ultrasound, photobiomodulation and cranial nerve stimulation as adjuncts to rehabilitation after repetitive head impacts. Direct RHI/TES evidence is distinguished from findings in other traumatic brain injury and concussion populations, other clinical populations and experimental models. The author then proposes a phenotype- and circuit-guided framework for treatment development.

EXPERT OPINION: Neuromodulation should not be considered a disease-modifying treatment for CTE. Its most credible role is as a phenotype-led adjunct to rehabilitation. This approach requires identification of a viable circuit relevant to the dominant impairment, selection of an individualized stimulation dose, measurement of target engagement and pairing with symptom-relevant rehabilitation. Progress requires credible sham-controlled and factorial trials, multimodal biomarkers, clinically meaningful functional outcomes, and long-term follow-up.