The role of auditory stimulation in the maturation of the auditory pathway

Abstract

Problem: To compare the maturation of the auditory pathway, as shown by electrical brainstem auditory potentials (EABR), in ears in which there had been prior auditory stimulation and ears in which no prior auditory stimulation had occurred. Methods: Electrophysiological data were collected prospectively from ears that had received cochlear implants. ImpEABR were recorded. Thirty children, implanted after January 2000, were selected according to a strict inclusion-exclusion protocol. All the children had received a 22-channel Nucleus cochlear implant (CI24 series). Intraoperatively, ImpEABR were recorded using the Medelec Synergy® system in conjunction with the Nucleus NRT® software. The ImpEABR latencies of wave eII, eIII, eV, and the morphology of wave eV were assessed. Results: The ImpEABR alter during the first 12 months of life. The latency becomes shorter during this period and the morphology of eV alters from a broad shape to a more distinct waveform. This appears to occur independently even in the absence of auditory stimulation. Conclusion: The development of the electrical brainstem auditory potentials is not dependent on auditory stimulation. Significance: Commonly, it has been supposed that prior exposure to acoustic stimulus is a prerequisite for maturation of the auditory neural pathway. However, recent works have indicated that this precondition may not be an absolute necessity and the peripheral auditory pathways may develop despite auditory acoustic deprivation. This paper is an attempt to assess the role of auditory stimulation in the maturation of the auditory pathway. Support: This work was made possible by the Graham Fraser Memorial Fellowship (UK).