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Perception of binaural cues develops in children who are deaf through bilateral cochlear implantation.

Gordon KA, Deighton MR, Abbasalipour P, Papsin BC - PLoS ONE (2014)

Bottom Line: There are significant challenges to restoring binaural hearing to children who have been deaf from an early age.They were asked on which side of their head they heard unilaterally or bilaterally presented click- or electrical pulse- trains.Interaural timing cues were not detected by new bilateral adolescent users, consistent with previous evidence.

View Article: PubMed Central - PubMed

Affiliation: Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Ontario, Canada.

ABSTRACT
There are significant challenges to restoring binaural hearing to children who have been deaf from an early age. The uncoordinated and poor temporal information available from cochlear implants distorts perception of interaural timing differences normally important for sound localization and listening in noise. Moreover, binaural development can be compromised by bilateral and unilateral auditory deprivation. Here, we studied perception of both interaural level and timing differences in 79 children/adolescents using bilateral cochlear implants and 16 peers with normal hearing. They were asked on which side of their head they heard unilaterally or bilaterally presented click- or electrical pulse- trains. Interaural level cues were identified by most participants including adolescents with long periods of unilateral cochlear implant use and little bilateral implant experience. Interaural timing cues were not detected by new bilateral adolescent users, consistent with previous evidence. Evidence of binaural timing detection was, for the first time, found in children who had much longer implant experience but it was marked by poorer than normal sensitivity and abnormally strong dependence on current level differences between implants. In addition, children with prior unilateral implant use showed a higher proportion of responses to their first implanted sides than children implanted simultaneously. These data indicate that there are functional repercussions of developing binaural hearing through bilateral cochlear implants, particularly when provided sequentially; nonetheless, children have an opportunity to use these devices to hear better in noise and gain spatial hearing.

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Experienced bilateral CI users and normal hearing peers perceived changes in ILDs as these cues moved from left to right weighted.Interaural level differences (ILDs) in CI users represent differences in CU and dB re: 20 Pa in the normal hearing group (∼0.08 dB re: 100 µA per acoustic dB change in ILD, see Table 3 for additional details). Significant effects of ILD were found across groups (p<0.0001). Rate of change in ILDs delivered by CIs (CU) was reduced relative to acoustic ILD (dB) (p<0.05) with no significant difference between the 2 implanted groups (p>0.05).
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pone-0114841-g003: Experienced bilateral CI users and normal hearing peers perceived changes in ILDs as these cues moved from left to right weighted.Interaural level differences (ILDs) in CI users represent differences in CU and dB re: 20 Pa in the normal hearing group (∼0.08 dB re: 100 µA per acoustic dB change in ILD, see Table 3 for additional details). Significant effects of ILD were found across groups (p<0.0001). Rate of change in ILDs delivered by CIs (CU) was reduced relative to acoustic ILD (dB) (p<0.05) with no significant difference between the 2 implanted groups (p>0.05).

Mentions: Given that perception of binaural level cues appeared so early in bilateral implant use and even in children who had very long delays between implantations, we asked whether there was an effect of the timing of implantation on this perception. In this part of the study, we measured proportion of responses to the left and right sides of the head in response to bilateral input in 3 groups of children matched for bilateral hearing age: 1) 29 children receiving bilateral implants simultaneously (unilateral implant use  = 0 years, bilateral implant use mean ± SD  = 4.31±1.10 years); 2) 16 children receiving bilateral implants sequentially (unilateral implant use  = 4.10±2.17 years, bilateral implant use  = 5.30±1.55 years); and 3) 16 children with normal hearing (age/bilateral hearing age  = 9.16±2.19 years). Mean (SE) responses in the 3 groups are plotted in Fig. 2A. Responses at ILD = 0 are not significantly different from the expected 0.50 in any group (Simultaneous: t(28) = 0.39, p = 0.70; Sequential: t(15) = 0.84, p = 0.42; Normal hearing: t(15) = 1.36, p = 0.20) indicating bilateral input in this condition was perceived as balanced for level. Proportion of responses to either side increased as ILDs weighted to that side increased. Binary logit regression curves fit to responses to the right/first implanted side are shown in Fig. 2B and revealed significant detection of ILDs in all (thin grey lines) but 4 children tested (dashed lines). All 4 of the children with non-significant changes were in the simultaneous group but were of similar ages (6.99±1.65 years) and had similar durations of bilateral implant use (4.08±0.92 years) as the other children in this group. Note that the ILD on x-axis is in CU for CI groups and dB re: sound pressure (20 µPa) for the normal hearing group. Table 3 indicates the current provided to each device/ear at each ILD for each group. Each change in ILD of acoustic stimuli by 1 dB is compared to ∼0.08 dB re: 100 µA of ILD change in CI stimulation. Diamond symbols in Fig. 2B denote mean (SE) data predicted by significant regression curves. Data from those children who showed significant changes in response with ILD are compared by group in Fig. 3. Repeated measures ANOVA testing revealed a significant effect of ILD on proportion of right/first implant responses as expected (F(6,49) = 189.8, p<0.0001), with no significant differences in responses between the groups (F(2,54) = 0.52, p = 0.60) or interaction between ILD and group (F(12,100) = 1.14, p = 0.34). The rate of ILD change was further calculated using a bias reduced general linear model. Comparisons by group with ANOVA showed a significant effect of group on the rate of change in proportion of right responses with ILD (F(2,54) = 7.07, p = 0.002). Post-hoc comparisons (Bonferroni) indicated that the rate of change in ILDs delivered by CIs was reduced relative to ILDs delivered by acoustic input (Simultaneous vs Normal: p = 0.002; Sequential vs Normal: p = 0.02) but that there was no difference between the CI groups regardless of prior unilateral implant exposure (p = 1.00).


Perception of binaural cues develops in children who are deaf through bilateral cochlear implantation.

Gordon KA, Deighton MR, Abbasalipour P, Papsin BC - PLoS ONE (2014)

Experienced bilateral CI users and normal hearing peers perceived changes in ILDs as these cues moved from left to right weighted.Interaural level differences (ILDs) in CI users represent differences in CU and dB re: 20 Pa in the normal hearing group (∼0.08 dB re: 100 µA per acoustic dB change in ILD, see Table 3 for additional details). Significant effects of ILD were found across groups (p<0.0001). Rate of change in ILDs delivered by CIs (CU) was reduced relative to acoustic ILD (dB) (p<0.05) with no significant difference between the 2 implanted groups (p>0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4273969&req=5

pone-0114841-g003: Experienced bilateral CI users and normal hearing peers perceived changes in ILDs as these cues moved from left to right weighted.Interaural level differences (ILDs) in CI users represent differences in CU and dB re: 20 Pa in the normal hearing group (∼0.08 dB re: 100 µA per acoustic dB change in ILD, see Table 3 for additional details). Significant effects of ILD were found across groups (p<0.0001). Rate of change in ILDs delivered by CIs (CU) was reduced relative to acoustic ILD (dB) (p<0.05) with no significant difference between the 2 implanted groups (p>0.05).
Mentions: Given that perception of binaural level cues appeared so early in bilateral implant use and even in children who had very long delays between implantations, we asked whether there was an effect of the timing of implantation on this perception. In this part of the study, we measured proportion of responses to the left and right sides of the head in response to bilateral input in 3 groups of children matched for bilateral hearing age: 1) 29 children receiving bilateral implants simultaneously (unilateral implant use  = 0 years, bilateral implant use mean ± SD  = 4.31±1.10 years); 2) 16 children receiving bilateral implants sequentially (unilateral implant use  = 4.10±2.17 years, bilateral implant use  = 5.30±1.55 years); and 3) 16 children with normal hearing (age/bilateral hearing age  = 9.16±2.19 years). Mean (SE) responses in the 3 groups are plotted in Fig. 2A. Responses at ILD = 0 are not significantly different from the expected 0.50 in any group (Simultaneous: t(28) = 0.39, p = 0.70; Sequential: t(15) = 0.84, p = 0.42; Normal hearing: t(15) = 1.36, p = 0.20) indicating bilateral input in this condition was perceived as balanced for level. Proportion of responses to either side increased as ILDs weighted to that side increased. Binary logit regression curves fit to responses to the right/first implanted side are shown in Fig. 2B and revealed significant detection of ILDs in all (thin grey lines) but 4 children tested (dashed lines). All 4 of the children with non-significant changes were in the simultaneous group but were of similar ages (6.99±1.65 years) and had similar durations of bilateral implant use (4.08±0.92 years) as the other children in this group. Note that the ILD on x-axis is in CU for CI groups and dB re: sound pressure (20 µPa) for the normal hearing group. Table 3 indicates the current provided to each device/ear at each ILD for each group. Each change in ILD of acoustic stimuli by 1 dB is compared to ∼0.08 dB re: 100 µA of ILD change in CI stimulation. Diamond symbols in Fig. 2B denote mean (SE) data predicted by significant regression curves. Data from those children who showed significant changes in response with ILD are compared by group in Fig. 3. Repeated measures ANOVA testing revealed a significant effect of ILD on proportion of right/first implant responses as expected (F(6,49) = 189.8, p<0.0001), with no significant differences in responses between the groups (F(2,54) = 0.52, p = 0.60) or interaction between ILD and group (F(12,100) = 1.14, p = 0.34). The rate of ILD change was further calculated using a bias reduced general linear model. Comparisons by group with ANOVA showed a significant effect of group on the rate of change in proportion of right responses with ILD (F(2,54) = 7.07, p = 0.002). Post-hoc comparisons (Bonferroni) indicated that the rate of change in ILDs delivered by CIs was reduced relative to ILDs delivered by acoustic input (Simultaneous vs Normal: p = 0.002; Sequential vs Normal: p = 0.02) but that there was no difference between the CI groups regardless of prior unilateral implant exposure (p = 1.00).

Bottom Line: There are significant challenges to restoring binaural hearing to children who have been deaf from an early age.They were asked on which side of their head they heard unilaterally or bilaterally presented click- or electrical pulse- trains.Interaural timing cues were not detected by new bilateral adolescent users, consistent with previous evidence.

View Article: PubMed Central - PubMed

Affiliation: Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Ontario, Canada.

ABSTRACT
There are significant challenges to restoring binaural hearing to children who have been deaf from an early age. The uncoordinated and poor temporal information available from cochlear implants distorts perception of interaural timing differences normally important for sound localization and listening in noise. Moreover, binaural development can be compromised by bilateral and unilateral auditory deprivation. Here, we studied perception of both interaural level and timing differences in 79 children/adolescents using bilateral cochlear implants and 16 peers with normal hearing. They were asked on which side of their head they heard unilaterally or bilaterally presented click- or electrical pulse- trains. Interaural level cues were identified by most participants including adolescents with long periods of unilateral cochlear implant use and little bilateral implant experience. Interaural timing cues were not detected by new bilateral adolescent users, consistent with previous evidence. Evidence of binaural timing detection was, for the first time, found in children who had much longer implant experience but it was marked by poorer than normal sensitivity and abnormally strong dependence on current level differences between implants. In addition, children with prior unilateral implant use showed a higher proportion of responses to their first implanted sides than children implanted simultaneously. These data indicate that there are functional repercussions of developing binaural hearing through bilateral cochlear implants, particularly when provided sequentially; nonetheless, children have an opportunity to use these devices to hear better in noise and gain spatial hearing.

Show MeSH
Related in: MedlinePlus