Level of knowledge and quality of life among Saudi caregivers of Parkinson’s disease patients: A study from a tertiary hospital in Riyadh, Saudi Arabia oleh Abdulhadi A. Al Ofair, Muhanned Alamri, Sultan H. Alshehri, Ziyad A. Alzahrani, Alwaleed K. Alrumaih, Wajid Syed, Mohamed N. Al-Arifi, Moahmmed A. Assiri, Taim A. Muayqil, Abdulrahman Alwhaibi