Ear Preference and Interaural Threshold Asymmetry

Abstract

Objective: To define the relationships among ear preference strength, audiometric interaural asymmetry magnitude, and hearing impairment.

Study design: Prospective, cross-sectional.

Setting: Academic audiology clinic.

Patients: Adults.

Interventions: Diagnostic.

Main outcome measures: Patient-reported ear preference strength using a seven-category preference (no preference; left or right somewhat, strongly, or completely) scheme, hearing disability level on the Speech, Spatial, and Qualities of Hearing scale, and audiometric interaural threshold asymmetry were analyzed in three study cohorts: 1) normal hearing (thresholds ≤ 25 dB, n = 66), 2) symmetric hearing loss (any single threshold > 25 dB, n = 81), and 3) asymmetric hearing loss (maximum average interaural threshold difference at any two adjacent frequencies (IThrDmax2)≥ 15 dB, n = 112).

Results: Receiver operating characteristic curves for somewhat, strongly, and completely ear preference levels using IThrDmax2 cutoff values at 15, 30, and 45 dB showed good to excellent classifier performance (all curve areas ≥ 0.84). The mapping of ear preference strength to the most likely IThrDmax2 range by odds ratio analysis demonstrated: no preference (< 15 dB), somewhat (15-29 dB), strongly (30-44 dB), and completely (≥ 45 dB). Complete dependence on one ear was associated with the most severe degradation in spatial hearing function.

Conclusion: Categorical ratings of ear preference strength may be mapped to ranges of audiometric threshold asymmetry magnitude and spatial hearing disability level. Querying ear preference strength in routine clinical practice would enable practitioners to identify patients with asymmetric hearing more expeditiously and promote timely evaluation and treatment.