Inclusion Criteria:  Male or female, at least 19 years of age or older Diagnosis of persistent post-concussional syndrome after ≥3 months of traumatic brain injury, based on the ICD-10 criteria. This diagnosis should be given to the patient from a clinical practitioner. ICD-10 clinical criteria require a history of TBI and the presence of three or more of the following eight symptoms: 1) headache, 2) dizziness, 3) fatigue, 4) irritability, 5) insomnia, 6) concentration or 7) memory difficulty, and 8) intolerance of stress, emotion, or alcohol. Current pharmacologic management can remain stable throughout the protocol. Fluent in English Able to understand the informed consent form, study procedures and willing to participate in study.  Exclusion Criteria:  Malignant skin carcinoma within the treatment area (neck and cranium) Intake of photosensitizing medication. Prior history of PBMT therapy Current diagnosis of severe anxiety (or score of ≥15 on the GAD-7), severe depression (or score of ≥20 on the PHQ-9), schizophrenia or bipolar disorder History of other major neurological disorder (brain cancer, dementia, multiple sclerosis, stroke) Diagnosed epilepsy or history of seizures not effectively controlled by medications Exposed to an investigational drug or device 30 days prior to starting the study, or concurrent use of an investigational drug or device while enrolled in the study Pregnant, suspected to be pregnant or planning to become pregnant during the study Contraindicated for the NeuroCatch® Platform 2, including:  9.1. Requires the use of hearing aids or a cochlear implant 9.2. Diagnosed with tinnitus that is currently active 9.3. Has temporary damage to hearing (e.g. punctured ear drum) 9.4. Unable to detect a 740Hz tone played at 85dB in both ears. 9.5. Implanted pacemaker or implanted electrical stimulators 9.6. Metal or plastic implants in the skull, excluding dental/facial implants 9.7. Unhealthy scalp (apparent open wounds and/or bruised or weakened skin) 9.8. Previous exposure to the NeuroCatch® Platform 2 audio sequences in the last 3 months