Cochlear Implantation in the Cochlear Nerve Hypoplasia or Aplasia as Suggested by Temporal Bone Magnetic Resonance Imaging / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Identifying cochlear nerve hypoplasia or aplasia is dependent on temporal bone magnetic resonance imaging (TBMRI) providing information on the cochlea, internal auditory canal, and the cochlear nerve. The purpose of this study was to review the results of cochlear implantation (CI) in ears with cochlear nerve hypoplasia or aplasia as suggested by TBMRI. SUBJECTS AND METHOD: From April 1999 to April 2005, 321 patients were fitted with cochlear implants in our department by two surgeons. The present study focused on four prelingual patients who underwent CI in ears with cochlear nerve hypoplasia or aplasia as suggested by TBMRI. The perceptive and linguistic results were evaluated based on speech perception and production at preimplantation and at 1, 3, 6, 9, 12, and 24 months postimplantation. RESULTS: Pre-operative auditory brainstem responses were absent at 90 dB nHL in all patients. At least 10 months after implantation all patients were able to detect consonants and vowels in 100% and their categories of auditory performance scores were 4 or above. CONCLUSION: We confirmed cochlear nerve presence in cases of cochlear nerve hypoplasia or aplasia as suggested by TBMRI and made their auditory habilitation possible with cochlear implantation. However, even in cases of cochlear nerve hypoplasia or aplasia suggested by TBMRI, physicians need to confirm cochlear nerve presence before implantation and to predict the outcome of cochlear implantation.