1. Department of Physical Therapy, Faculty of Allied Health Sciences, Chulalongkorn University, Pathumwan, Bangkok, Thailand.
2. Department of Preventive and Social Medicine, Faculty of Medicine, Chulalongkorn University, Pathumwan, Bangkok, Thailand.
3. Department of Physical Therapy and Rehabilitation, Central Chest Institute of Thailand, Nonthaburi, Thailand.
4. Department of Physical Therapy, California State University, Northridge, Northridge, CA USA.