[1] Pontificia Univ Catolica Chile, Dept Enfermedades Resp, Fac Med, Santiago, Chile
[2] Pontificia Univ Catolica Chile, Fac Med, Dept Neurol, Santiago, Chile
[3] Univ Chile, Fac Med, Med, Santiago, Chile
[4] Pontificia Univ Catolica Chile, Fac Med, Med, Santiago, Chile