| Decades of research have established exceptional benefit of binaural hearing for understanding speech in noise. Less is known, however, about the value of binaural hearing for understanding speech when signals have been degraded asymmetrically between the two ears. A few previous studies have demonstrated a phenomenon known as binaural interference. Binaural interference occurs when speech perception is poorer when listening binaurally than monaurally to the better of the two signals. The purpose of the current study was to examine the effect of asymmetrical signal degradation on binaural speech perception in children and adults with normal hearing. Specifically, the purpose was to ascertain if individuals experience binaural interference or, at a minimum, lose their binaural advantage when presented asymmetrically-degraded signals. In addition, the current study sought to determine whether the effect of asymmetric signal degradation on speech perception was influenced by the listener's age or which ear (right or left) received the more degraded signal.; Two groups of children, age 5–6.5 years (N = 14) and 10–11.5 years (N = 14), and one group of adults, age 24–29 years (N = 14) participated in the project. Sentence recognition ability amidst multi-talker babble was assessed in three listening conditions: (1) monaurally, with mild degradation in one ear, (2) binaurally with mild degradation in both ears, and (3) binaurally with mild degradation in one ear and severe degradation in the other ear. Sentence materials and babble noise were digitally degraded to simulate the perceptual effects of mild and severe cochlear hearing loss.; Results demonstrated that participants in all three age groups exhibited considerable binaural advantage when listening to symmetrically-degraded signals. In contrast, participants achieved no binaural benefit, on average, when listening to asymmetrically-degraded signals. Child participants exhibited binaural indifference. That is, children demonstrated no significant increments or decrements in performance when listening binaurally to asymmetrically-degraded signals than when listening monaurally to the better of the two signals. Adults, however, demonstrated slight evidence of binaural interference. That is, adults exhibited greater difficulty, on average, when listening binaurally to asymmetrically-degraded signals than when listening monaurally to the better signal. Findings are discussed in light of previous studies, clinical implications, and future research. |
