الإتاحة: https://doi.org/10.1136/jnnp-2020-323079Testhttp://jnnp.bmj.com/cgi/content/short/91/8/840Test
الإتاحة: https://doi.org/10.1136/jnnp-2019-321774Testhttp://jnnp.bmj.com/cgi/content/short/91/3/298Test