The purpose of this research study is to test the effectiveness of virtual reality (VR) based treadmill training on walking ability. The study will also help to understand the changes in cognitive ability and brain activity as a result of VR-based treadmill training after a brain injury.

The study will include 3 groups: C-MILL training group (CTG), Treadmill training group (TTG), and healthy control group (HCG).

Individuals with brain injury will be randomly assigned to C-MILL training group, or Treadmill training group.

The CTG and TTG will participate in up to 13 sessions. The participants will be screened for the inclusion/exclusion criteria and consented during the first session. They will participate in two data collection sessions, one before the training and one after the training. The participants will undergo 10 training sessions. Individuals in the CTG will receive gait and balance training sessions with the virtual reality and auditory cues using C-MILL (such as walking on a pathway, obstacle avoidance, lateral balance etc.) to provide task specific training. C-Mill (Motekforce Link, Amsterdam, The Netherlands) is an instrumented treadmill that uses visual (on the screen as well on the treadmill) and acoustic cues for gait and balance training. The C-Mill allows for gait and balance adaptability strategy as it can provide obstacle avoidance environments, change in speed and various walking pathways in a safe and controlled environment.

Individuals in TTG group will walk on the treadmill (C-MILL) or stand on the treadmill (C-MILL) with no visual or auditory cues.

HCG will participate in up to four sessions. The participants will be screened for the inclusion/exclusion criteria and consented during the first session. They will participate in two data collection sessions and one C-MILLsession.

Each training session will last for 45 minutes. During the 45 minutes, the participants will perform the task for approximately 1 minute. Participants will be allowed as much rest as needed by them.

During the training all participants will wear the safety harness to protect from falling. In addition spotter will be present with the participants to prevent falls.

Data Collection:

Each participant's baseline and follow up data will be collected for a) functional b) neuromechanical c) cortical and d) cognitive outcomes. During walking on treadmill data will also be collected with instrumented C- MILL. C-MILL can provide gait parameters such as step length, width, frequency, speed and symmetry in addition to center of pressure for evaluation of gait and balance.

During Training Sessions: The instrumented treadmill will collect force data during training.

Inclusion/exclusion criteria for TBI:

Inclusion Criteria:

Participants must:

• Be TBI survivors > 6 months post TBI
• Be able to tolerate upright standing for up to 30 minutes.
• Have joint range of motion within normal functional limits for walking as determined by study staff.
• Be between 13-35 years of age.
• Be able to follow directions and commands.
• Be able to communicate in English.
• Have stable blood pressure.
• Not been diagnosed with any cognitive (thinking) deficits.

Exclusion Criteria:

• Weight above 300lbs.
• Joint contracture or spasticity of any limb that limits normal range of motion during ambulation with assistive devices.
• Have any medical issue that prevents from supporting his/her weight (e.g. orthopedic injuries, pain, or severe spasticity).
• Have pre-existing condition that causes exercise intolerance (e.g. documented uncontrolled hypertension, coronary artery disease, irregular heart rate or rhythm, or congestive heart failure).
• Skin issues that would prevent from wearing a harness.
• Have been hospitalized for heart attack, heart surgery or acute heart failure within 3 months of enrollment in study.
• Have uncontrolled seizure disorder.
• Have uncontrolled spasticity that would interfere with walking.
• Diagnosed with cognitive (thinking) problems prior to TBI.
• Have neuromuscular or neurological issues (e.g. spinal cord injury, multiple sclerosis, or Parkinson's disease)

Inclusion/exclusion criteria for Healthy controls:

Inclusion Criteria:

Participants must:

• Be able to tolerate upright standing for up to 30 minutes.
• Have joint range of motion within normal functional limits for ambulation.
• No history of orthopedic, neuromuscular, cognitive or neurological disorders.
• Be between 13-35 years of age.
• Have stable blood pressure; no diagnosis of persistent orthostatic hypotension (blood pressure drop of more than 30 millimeters of Mercury in body weight support system).
• No diagnosed cognitive deficits.

Exclusion Criteria:

• Weight above 300lbs
• Joint contracture or spasticity of any limb that limits normal range of motion during ambulation with assistive devices.
• Any medical issue that precludes full weight bearing and ambulation (e.g. orthopedic injuries, pain, severe spasticity).
• Pressure sore that would negatively affect weight bearing, or harness fit.
• Pre-existing condition that causes exercise intolerance.(Documented uncontrolled hypertension, coronary artery disease, cardiac arrhythmia, or congestive heart failure)
• Hospitalization for heart attack, heart surgery or acute heart failure within 3 months of enrollment in study.
• Uncontrolled seizure disorder.
• Uncontrolled spasticity that would interfere with walking due to neuromuscular or neurological pathologies (e.g., Parkinson's disease, spinal cord injury, or multiple sclerosis) that will interfere with ambulation, or limit the range of motion of the lower limbs
• Diagnosed with cognitive deficits.