[1] Akershus Univ Hosp, Head & Neck Res Grp, Nordbyhagen, Norway
[2] Univ Oslo, Fac Div, Nordbyhagen, Norway
[3] Akershus Univ Hosp, Dept Ear Nose & Throat Surg, Lorenskog, Norway
[4] Univ Oslo, Dept Special Needs Educ, Blindern, Norway
[5] Akershus Univ Hosp, Res Ctr, Oslo, Norway
[6] Akershus Univ Hosp, Dept Neurol, Oslo, Norway