1. Department of Respiratory Therapy, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
2. King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
3. Rehabilitation Science, School of Health Professions, University of Alabama at Birmingham, Birmingham, AL, USA
4. Division of Pulmonary, Allergy, and Critical Care Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
5. Department of Physical Therapy, School of Health Professions, University of Alabama at Birmingham, Birmingham, AL, USA
6. Department of Health Behavior, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA