The purpose of this study is to determine whether the application of virtual reality (VR) is effective in reducing training pain in robot-assisted gait training (RAGT) in patients with lower extremity burn. The investigators investigated through an analysis of the activation status over time in the prefrontal cortex using functional near-infrared spectroscopy (NIRS).

Burn injuries and their treatment are considered to be among the most painful a person can endure. Therefore, new modalities that prove effective with burn patients are expected to improve clinical outcomes when applied to painful therapies. The purpose of this study is to determine whether the application of virtual reality (VR) is effective in reducing training pain in robot-assisted gait training (RAGT) in patients with lower extremity burn. The investigators investigated through an analysis of the activation status over time in the prefrontal cortex using functional near-infrared spectroscopy (NIRS). RAGT was performed 10 times for 2 weeks from Monday to Friday, and the cerebral blood flow measurement using NIRS was measured 3 times each while applying or not applying VR for 30 minutes as long as the RAGT is in progress. The VR program provided non-immersive VR walking along a forest path or a coastal path according to the walking speed while the RAGT was in progress. For each physical therapy session, each patient spent equal amounts of time in VR and in the control condition (without VR). The average of oxy-Hb and deoxy-Hb of each session was measured for 10 days. In the prefrontal cortex, the levels of hemoglobin (Hb) were measured using the fNIRS measurement system. Average values of both oxy-Hb and deoxy-Hb were calculated at four stages : temporal delay time with RAGT, RAGT without VR, temporal delay time with VR, RAGT with VR. Before training, all patients verbally rated their most severe pain during physical training as a score of 5 or higher on a visual analog scale (VAS) of 0 to 10, where 0 presents " no pain at all" and 10 presents " worst pain". Pain, the primary dependent variable, was measured immediately after each experimental treatment. Patient rated (1) their worst pain (no pain to worst pain), and (2) their average pain ( no pain or worst pain).

Inclusion Criteria:

• partial-to-full-thickness burns that had spontaneously healed or required skin grafting
• all patients rated their most severe pain during robot assisted gati training (RAGT) as a score 5 or higher on a visual analog scale of 0 to 10, where 0 represents no pain at all, and 10 represents worst pain.
• 1 ≤ functional ambulation category (FAC) score ≤ 3

Exclusion Criteria:

• patients with history of brain injury
• cognitive disorders, intellectual impairment before burn injury
• problems with weight bearing due to unstable fractures
• body weight ≥100 kg
• severe fixed contracture
• skin disorders that could be worsened by RAGT and conventional rehabilitation