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OBJECTIVE: Comparison of asymmetric hearing in patients with severe-to-profound hearing loss (STPHL) and those with less pronounced or no hearing loss. The influence of asymmetric hearing on cochlear implantation (CI) was also analyzed.

STUDY DESIGN: Retrospective cohort.

SETTING: Hearing clinics across all regions in Sweden.

PATIENTS: This study included 898,421 adult patients identified using the audiometric software Auditbase and 4286 adult patients from the Swedish National Quality Register for STPHL.

MAIN OUTCOME MEASURES: Proportion of patients with asymmetric hearing according to 11 different asymmetry criteria. Adjusted odds ratios for the presence of cochlear implants, adjusted for age, sex, and the highest level of education.

RESULTS: Across the different criteria, asymmetric hearing ranged from 20% to 59% in STPHL patients and 14% to 46% in those with better hearing. Adjusted odds ratios showed that cochlear implants were more common in patients with >15 dB asymmetry in the pure tone average at the base and mid-range frequencies.

CONCLUSION: This study of national audiogram data from Sweden showed that asymmetric hearing was more common in patients with STPHL. The higher proportion of CI in patients with asymmetric hearing indicates that asymmetric hearing is a complicating factor that must be considered in the rehabilitation of STPHL.