Department of Communicative Disorders & Sciences, University at Buffalo, Buffalo, New York, USA.
Ear Hear. 2011 Feb;32(1):2-15. doi: 10.1097/AUD.0b013e3181e8534c.
A great amount of variability is observed in speech perception outcomes with cochlear implants. The mechanisms behind the observed variability need to be elucidated. One possible mechanism contributing to the observed variability is the development of cross-modal plasticity. This study examines the association between visual/auditory cross-modal plasticity and speech perception with a cochlear implant in individuals with pre- and postlingual onset of severe to profound hearing loss.
The N1 visual evoked potential (VEP) in response to peripheral visual motion stimuli was recorded in individuals with pre- (N = 10) and postlingual (N = 12) onset of severe to profound hearing loss who use a cochlear implant. The association between the amplitude of the N1 VEP response over the right temporal lobe and sentence and word perception scores obtained with the cochlear implant was examined through linear regression analyses. In addition, the association between the duration of auditory deprivation and the amplitude of the N1 VEP response was examined.
As the amplitude of the N1 VEP recorded over the right temporal lobe increased, speech perception scores in individuals with prelingual onset of severe to profound hearing loss decreased. However, a clear association between the amplitude of the N1 VEP over the right temporal lobe and speech perception scores was not observed for individuals with postlingual onset of severe to profound hearing loss. Neither group demonstrated an association between the amplitude of the VEP over the right temporal lobe and the duration of auditory deprivation before cochlear implantation.
The results suggest that cross-modal plasticity accounts for a significant amount of the variability observed in speech perception performance with a cochlear implant in individuals with prelingual onset of severe to profound hearing loss but not in individuals who acquire severe to profound hearing loss later in life. Furthermore, the results suggest that the influence of cross-modal plasticity on speech perception ability is more greatly influenced by when (pre- or postlingually) a person acquires a severe to profound hearing impairment rather than the duration of auditory deprivation before receipt of a cochlear implant.
人工耳蜗植入后，言语感知结果存在很大的可变性。需要阐明观察到的可变性背后的机制。一种可能导致观察到的可变性的机制是跨模态可塑性的发展。本研究探讨了在语前和语后重度至极重度听力损失个体中，视觉/听觉跨模态可塑性与人工耳蜗植入后的言语感知之间的关系。
记录了使用人工耳蜗的语前（N=10）和语后（N=12）重度至极重度听力损失个体对周围视觉运动刺激的 N1 视觉诱发电位（VEP）。通过线性回归分析，研究了右颞叶 N1 VEP 反应幅度与人工耳蜗获得的句子和单词感知得分之间的关系。此外，还研究了听觉剥夺时间与 N1 VEP 反应幅度之间的关系。
随着右颞叶记录的 N1 VEP 幅度增加，语前重度至极重度听力损失个体的言语感知得分下降。然而，对于语后重度至极重度听力损失个体，右颞叶 N1 VEP 幅度与言语感知得分之间没有明显的关联。两组个体均未显示右颞叶 VEP 幅度与人工耳蜗植入前听觉剥夺时间之间存在关联。
结果表明，跨模态可塑性解释了语前重度至极重度听力损失个体人工耳蜗植入后言语感知表现中观察到的大量可变性，但对于后来获得重度至极重度听力损失的个体则不然。此外，结果表明，跨模态可塑性对言语感知能力的影响更多地受到个体获得重度至极重度听力损失的时间（语前或语后）的影响，而不是人工耳蜗植入前听觉剥夺的时间。
