Objective: To investigate the changes in sound localization ability in the horizontal plane after canaloplasty in unilateral congenital aural atresia (CAA) patients.
Study design: Prospective interventional study.
Setting: Tertiary referral center.
Patients: Twenty-eight patients with unilateral CAA were enrolled. All patients had unilateral conductive hearing loss.
Interventions: Canaloplasty.
Main outcome measures: Pure tone audiometry, sound localization test, and the Speech, Spatial, and Quality questionnaire (SSQ) were administered preoperatively, 6 and 12 months postoperatively. For the sound localization test, 8 loudspeakers were positioned in a circle at 45-degree intervals, and patients were instructed to identify the speaker from which sound was coming. Mean correct response rate and mean error degree were calculated for each patient. The correct lateralization rate to the ipsilesional/contralesional stimuli was also calculated.
Results: Mean hearing threshold decreased from preoperatively 63.8 to 39.4 dB 12 months after canaloplasty. Mean correct response rate and error degree at preoperative evaluation were 26.0% and 60.7 degrees, respectively, and these were respectively improved to 58.5% and 27.8 degrees postoperatively. Respective mean correct lateralization rate to ipsilesional stimuli after canaloplasty improved from 20.6% to 84.0%, and that to contralesional stimuli slightly improved from 93.8% to 98.8%. Patients with good postoperative hearing (<40 dBHL) showed better sound localization results. In addition, self-assessment scores of spatial domain in the SSQ questionnaire were significantly improved after the operation.
Conclusion: Sound localization performance improved significantly after canaloplasty. Canaloplasty could provide better localization benefit and subjective improvement in spatial sensation to unilateral CAA patients.