Functional magnetic resonance imaging may avoid misdiagnosis of cochleovestibular nerve aplasia in congenital deafness

Citation
Ht. Van et al., Functional magnetic resonance imaging may avoid misdiagnosis of cochleovestibular nerve aplasia in congenital deafness, AM J OTOL, 21(5), 2000, pp. 663-670
Citations number
21
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Otolaryngology
Journal title
AMERICAN JOURNAL OF OTOLOGY
ISSN journal
0192-9763 → ACNP
Volume
21
Issue
5
Year of publication
2000
Pages
663 - 670
Database
ISI
SICI code
0192-9763(200009)21:5<663:FMRIMA>2.0.ZU;2-6
Abstract
Objective: To investigate a narrow internal auditory canal (IAC) syndrome u sing functional magnetic resonance imaging (fMRI) of the auditory cortex. Study Design: The study design was a case report. The follow-up period last ed 18 months. Setting: The study was carried out in the audiology clinic of an ear, nose, and throat department and in the department of pediatric neuroradiology at a university hospital. Main Outcome Measures: Age-appropriate observational audiometry, objective audiovestibular tests, computed tomography (CT), magnetic resonance imaging (MRI), and (fMRI) of the auditory cortex were performed to analyze in deta il the profound deafness of a young child. Results: Audiovestibular examination demonstrated both measurable hearing a nd normal vestibulo-ocular reflex, and CT showed narrow IACs combined with normal labyrinths. Axial MR images completed by sagittal sections perpendic ular to the IAC delineated a single nerve that was initially supposed to be the facial nerve. No cochleovestibular nerve was identified. However, fMRI performed with the patient under general anesthesia demonstrated activatio n of the primary auditory cortex during 1-kHz monaural stimulation on the l eft side. Conclusions: The absence of cochleovestibular nerve on MR studies cannot ex clude connections between the inner ear and the central auditory pathways. This might be caused by a lack of spatial resolution of anatomical MR studi es. The single nerve delineated within the IAC might also carry both facial and cochleovestibular fibers. Functional MRI can assess the cortical respo nse to acoustic stimuli when aplasia of the cochleovestibular nerve is susp ected. This case study illustrates a novel and atypical presentation of coc hlear nerve dysplasia.