Singing voice range profile: New objective evaluation methods for voice change after thyroidectomy

Background After surgery in the thyroid region, patients may present with phonation or singing difficulty, even within their vocal range. We designed a novel voice evaluation method that reflects subjective and objective voice complications of the surgery. Methods This tool recorded patients' voice ranges while singing, which was named the singing voice range profile (singing VRP). Patients were asked to sing “Happy Birthday,” which has a one‐octave scale, at a comfortable tone and intensity. The singing VRP, standard VRP and voice handicap index‐10 (VHI‐10) results were recorded before thyroidectomy and 1 and 3 months after thyroidectomy for 128 patients. For subgroup analysis, a group where the maximum F0 of standard VRP in 1 month postoperatively was lower than the highest singing F0 of the preoperative singing VRP was defined as “Collapsed group” and the other group was “Preserved group.” Results The changes in the highest, lowest and range of singing fundamental frequency (F0) had decreased at 1 month postoperatively. Subsequently, they had improved significantly at 3 months postoperatively but were lower than those preoperatively (all P