[1] IMSS, Ctr Med Nacl Occidente, Dept Neurol, UMAE, Guadalajara 44340, Jalisco, Mexico
[2] Univ Guadalajara, Ctr Univ Ciencias Salud, Dept Neurosci, Guadalajara 44430, Jalisco, Mexico
[3] Novartis Mexico, Dept Hlth Econ, Mexico City, DF, Mexico
[4] IMSS, Hosp Reg 1, Dept Hlth Res, Chihuahua, Chi, Mexico
[5] Baylor Coll Med, Maxine Mesinger MS Comprehens Care Ctr, Houston, TX 77030 USA
[6] Inst Nacl Ciencias Med & Nutr Salvador Zubiran, Dept Neurol & Psychiat, Mexico City, DF, Mexico