BACKGROUND: Postlingual single-sided deafness (SSD) is defined as normal hearing in one ear and severely impaired hearing in the other ear. A right ear advantage and dominance of the left hemisphere are well established findings in individuals with normal hearing and speech processing. Therefore, it seems plausible that a right ear advantage would exist in patients with SSD.
METHODS: The audiometric database was searched to identify patients with SSD. Results from the German monosyllabic Freiburg word test and four-syllabic number test in quiet were evaluated. Results of right-sided SSD were compared with left-sided SSD. Statistical calculations were done with the Mann-Whitney U test.
RESULTS: Four hundred and six patients with SSD were identified, 182 with right-sided and 224 with left-sided SSD. The two groups had similar pure-tone thresholds without significant differences. All test parameters of speech audiometry had better values for right ears (SSD left) when compared with left ears (SSD right). Statistically significant results (p < 0.05) were found for a weighted score (social index, 98.2 ± 4% right and 97.5 ± 4.7% left, p < 0.026), for word understanding at 60 dB SPL (95.2 ± 8.7% right and 93.9 ± 9.1% left, p < 0.035), and for the level at which 100% understanding was reached (61.5 ± 10.1 dB SPL right and 63.8 ± 11.1 dB SPL left, p < 0.022) on a performance-level function.
CONCLUSION: A right ear advantage of speech audiometry was found in patients with SSD in this retrospective study of audiometric test results.