Inclusion Criteria  patients with significant difficulty in communication, such as severe cognitive impairment (MMSE <10) or speech-language impairment patients with ataxia patients with spasticity of the affected lower extremity of measured by Modified Ashworth scale (Modified Ashworth Scale (MAS) ≥ 2) patients with severe musculoskeletal disorder in the lower limbs patients with a contracture that limits the lower limb range of motion patents with apparent leg length discrepancy of 2 cm or more (Rt: cm / Lt: cm) patients with a lower limb fracture or open wound or unhealed ulcer patients to whom robot-assisted gait rehabilitation cannot be applied due to a severe cardiovascular or pulmonary disease patients with a history of osteoporotic fracture patients with a neurological disorder that may affect the ambulatory function (e.g. Parkinson disease, multiple sclerosis, etc.) patients determined to be ineligible by the investigator  Exclusion Criteria  patients who express a desire to drop out of treatment patients who do not comply with the guidelines provided by the investigator patients who require a treatment outside the scope of the present clinical study patients who show a severe injury due to an accident such as a fall patients who participate in < 80% of training sessions patients who show a new major condition and consequently require absolute rest for recovery (e.g. another incidence of stroke, aggravation of stroke, myocardial infarction, any other neurological, internal, or musculoskeletal condition, etc.)