1. Department of Motor & Cognition Rehabilitation, Korean National Rehabilitation Research Institute, 111 Gaorigil, Gangbuk-gu, Seoul 142-884, Republic of Korea
2. College of Korean Medicine, Kyung Hee University, 23 Kyungheedae-ro, Dongdaemun-gu, Seoul 130-872, Republic of Korea
3. Institute for Evidence-Based Medicine, Department of Preventive Medicine, College of Medicine, Korea University, 126-1 Anam-dong, Seongbuk-gu, Seoul 136-705, Republic of Korea