Effect of age at onset of deafness on binaural sensitivity in electric hearing in humans

Abstract

Sensitivity to binaural cues was studied in 11 bilateral cochlear implant users, all of whom received both of their cochlear implants as adults, but who varied in the age at onset of deafness, from pre-lingual to childhood-onset to adult-onset. Sensitivity to interaural timing difference ͑ITD͒ and interaural level difference ͑ILD͒ cues was measured at basal, middle, and apical pitch-matched places of stimulation along the cochlear arrays, using a stimulation rate of 100 Hz. Results show that there is a trend for people whose onset of deafness occurred during adult life or late childhood to retain at least some sensitivity to ITDs, whereas people with onset of deafness earlier in life were insensitive to ITDs. In contrast, ILD cue sensitivity was present in all subjects. There were no effects of place of stimulation on binaural sensitivity, suggesting that there is no indication of a dependence of ITD sensitivity on apical vs basal electrode location.

Modulation Enhancement in the Electrical Signal Improves Perception of Interaural Time Differences with Bimodal Stimulation

“…This is comparable to the best thresholds found in our previous studies with single and 3-channel stimuli (Francart et al 2009. The thresholds are also comparable to thresholds found for the best bilateral CI listeners with single-channel stimuli (Laback et al 2007(Laback et al , 2004Lawson et al 1998;Litovsky et al 2010Litovsky et al , 2012Long et al 2003;Majdak et al 2006;Senn et al 2005;van Hoesel 2004van Hoesel , 2007van Hoesel and Tyler 2003). That sensitivity with multiple-channel stimuli is comparable to performance with single-channel stimuli is unlike performance often reported for NH listeners, for whom sensitivity increases with increasing bandwidth.…”

Congenital and Prolonged Adult-Onset Deafness Cause Distinct Degradations in Neural ITD Coding with Bilateral Cochlear Implants

“…This finding is consistent with psychophysical data indicating that prelingually deaf bilateral CI users who were implanted as adults are unable to lateralize sounds based on ITD, even though most are able to utilize ILDs (Litovsky et al 2010). Even when they are bilaterally implanted at a relatively young age (G 5 years) and use their implants daily, most prelingually deaf subjects still do not acquire ITD sensitivity (Salloum et al 2010).…”

“…Bilateral CI users who were implanted as adults can lateralize electric pulse trains based on ITD if they lost hearing in late childhood or later, but not if they lost hearing earlier in life (Litovsky et al 2010). Most congenitally deaf children who use their implants daily do not learn to lateralize based on ITD, even though they do lateralize based on ILD (Salloum et al 2010).…”

Sensitivity to interaural envelope correlation changes in bilateral cochlear-implant users

“…In conditions where PC ¼ 70.7% was not achieved, the JND was set to a value of Da ¼ 1.1, corresponding to the value used in previous studies that performed similar measurements in NH listeners (Goupell, 2012;Goupell and Litovsky, 2014). In all analyses, we did not take into account the cochlear place of stimulation because of the large variability across place within single CI listeners, which often results in a lack of significant effect of place (e.g., Litovsky et al, 2010;Lu et al, 2010).…”