[1] Univ Groningen, Univ Med Ctr Groningen, Dept Otorhinolaryngol Head & Neck Surg, POB 30-001,Hanzeplein 1, NL-9700RB Groningen, Netherlands
[2] Univ Chile, Fac Med, Dept Fonoaudiol, Santiago, Chile
[3] Univ Groningen, Univ Med Ctr Groningen, Dept Radiat Oncol, Groningen, Netherlands