Noninvasive Neuromodulation for Treatment of Symptoms Due to Mild or Moderate Traumatic Brain Injury

The investigators hypothesis is that electrical stimulation to the tongue that directly stimulates two cranial nerve nuclei (Trigeminal and Facial Nerve Nuclei), will excite neural impulses to the brainstem and cerebellum. The investigators call this cranial nerve non-invasive neuromodulation (CN-NINM). The activation of these structures induces neuroplasticity when combined with specific physical, cognitive and/or mental exercises, promoting recovery of selected functional damage such as problems with balance or walking.

44 subjects will be recruited for 2 weeks of intensive In-Lab Balance and Gait Training followed by 12 weeks of intensive Home Training with weekly In-Lab check sessions. Half of the subjects will use CN-NINM in conjunction with the exercise. Half of the subjects will use very low level stimulation in conjunction with the exercise, and will serve as a control group.

* Based on the results of the investigators pilot study in moderate traumatic brain injury (M-TBI), the investigators will conduct a randomized, controlled study of cranial nerve non-invasive neuromodulation (CN-NINM) in individuals with chronic symptoms of mild to moderate traumatic brain injury (mTBI), post-concussive sequelae, (PCS) and post-traumatic stress (PTS).
* The study will involve training of both balance and gait, with assessments using standardized and relevant metrics to monitor changes in these indications, as well as cognitive function, sleep, headache, anxiety, mood, and eye-movement control.
* The training regimen involves using a neurostimulation intervention that addresses primary and secondary symptoms associated with mTBI, PCS, and PTS.
* This randomized double blind controlled study will enroll a total of 44 subjects (M \& F) in 2 equal subgroups: 22 with an Active PoNS™, and 22 with a Control (non-zero, minimally perceivable stimulation) device.
* Subjects will participate in a 3-phase intervention beginning with a 2-week in-lab training program (ITP) (2 in-lab training sessions and 1 home training session daily), followed by 12 weeks of training at home (HTP) (3 home training sessions daily), and a 12-week withdrawal period (no training). Subjects will return to the clinic weekly during the at-home phase for a single session of retraining and progression, and participate in periodic retesting.
* All training and testing will be performed uniformly across all subjects in both groups. Multiple assessment metrics will capture data at the beginning and end of the 2-week in-lab CN-NINM intervention period and at 3-week intervals. After completion of the formal training period, subjects will stop using the device (withdrawal stage) and will be tested every 3 weeks over an additional 12 weeks to monitor and assess changes due to withdrawal of the PoNS. This will yield a total of 10 data points for each subject.
* If successful, this study would indicate that CN-NINM may improve rehabilitation outcomes and reduce time required to improve function.

Eligibility Criteria:
Inclusion Criteria:

* All candidates will have a balance disorder as a result of a traumatic brain injury (TBI).
* All candidates will have a NeuroCom® Sensory Organization Test (SOT) composite score at least 8 points below normal after adjustment for age and height \[based on normative data\].
* All candidates will be between the ages of 18 and 65 (at the time of screening).
* If female of childbearing potential, the candidate agrees to use adequate contraception throughout participation in the study (from enrollment to completion).
* All candidates must have access to a treadmill.
* All candidates will be at least 1 year post-injury.
* All candidates will have a neuroradiologic scan and report after their most recent TBI.
* All candidates will be ambulatory and able to walk for 20 minutes.
* All candidates, if on medications, will not have had any major changes in type or dosage within 3 months of enrollment.
* All candidates will have participated in a focused physical rehabilitation program for their TBI and feel that they have reached a plateau.
* All candidates will be able to understand and willing to give informed consent.

Exclusion Criteria:

* All candidates that have oral health problems (e.g. gum disease, active cankers, piercings, oral surgery within the previous 3 months).
* All candidates with non-removable metal orthodontic devices (e.g., braces) or oral cavity piercings that could interfere with PoNS™ use.
* All candidates who have chronic infectious diseases (e.g. hepatitis, HIV, TB).
* All candidates with unmanaged hypertension.
* All candidates with unmanaged diabetes, or complications due to diabetes (e.g. retinopathy, neuropathy, renal disease).
* All candidates with neurological disorders other than those attributed to their primary diagnosis (e.g., MS, PD, ALS, AD or other dementia, uncontrolled pain).
* All candidates with a history of oral cancer.
* All candidates who have been treated for any type of cancer other than basal cell carcinoma within the past year.
* All candidates who have had a penetrating injury, craniotomy (with the exception of a burr hole \[trephination\] for resolution of acute subdural hematoma), or refractory subdural hematoma.
* Exceptions for other abnormalities identified in neuroradiologic scan reports that are asymptomatic and not expected to change may be made on a case by case basis by the Medical Advisor.
* All candidates with chronic use of psychoactive or psychostimulant medications that, in the opinion of the investigators, would compromise the subject's ability to comprehend and perform the study activities.
* All candidates who have a pacemaker, or are identified as at-risk for cardiovascular events.
* All candidates who are pregnant or lactating.
* All candidates with a lower extremity biomechanical prosthetic.
* All candidates with a history of seizures (except those in the acute or post-acute phases, and are controlled).
* All candidates who who experienced a loss of consciousness greater than 24 hours as a result of their TBI.
* All candidates with a "severe" score in any of the Attention, Memory, or Executive Functions categories on the Cognitive Linguistic Quick Test (CLQT).
* All candidates who, in the opinion of the investigators, are unable to feel the stimulation and successfully complete the device level setting procedure.