1/2. Increased amplitudes of distortion product otoacoustic emissions in patients with unilateral acoustic neuroma.We present a case series of 4 patients with a unilateral acoustic neuroma and increased amplitudes of the distortion products of otoacoustic emissions (DPOAEs) at the low- and middle- frequency bandwidth on the involved side compared to the uninvolved side despite a 28-dB hearing level (HL) worse (compared to the uninvolved side) pure-tone hearing threshold average for standard audiometric frequencies between 1 and 6 kHz at the involved side. In 3 of these patients, 2 with an inferior vestibular nerve origin of the acoustic neuroma and one in whom the nerve of origin could not be unequivocally defined, the tumor was extending extrameatally. One patient had a purely intrameatal acoustic neuroma of superior vestibular nerve origin. Moreover, notable was the presence of the DPOAEs in all of the involved ears despite elevated pure-tone hearing thresholds (pure- tone averages for the standard audiometric frequencies between 1 and 6 kHz ranging between 36 and 62 dB HL).- - - - - - - - - - ranking = 1keywords = nerve (Clic here for more details about this article) |
2/2. Nonsyndromic isolated unilateral cochlear nerve aplasia without narrow internal auditorymeatus: a previously overlooked cause of unilateral profound deafness in childhood.OBJECTIVES: Juvenile or adolescent unilateral profound sensorineural deafness (worldwide prevalence, 0.1% to 0.2%) has been attributed to postnatal viral infection, sudden deafness, prenatal and perinatal problems including maternal rubella and viral infections, congenital innerear anomalies, and other factors. Herein, 2 cases are reported and another potentially important cause of unilateral profound hearing loss is proposed. methods: Two nonsyndromic cases of a presently "very rare" cause of pediatric unilateral deafness are presented as a retrospective case study. RESULTS: The 2 patients showed isolated aplasia of the cochlear nerve; other branches of the eighth cranial nerve, the seventh nerve, and the inner ear were spared,and there was no anomaly of the internal auditory meatus. Both functional and imaging studies confirmed the isolated lesion (absence) of the cochlear nerve. CONCLUSIONS: Because of the absence of bony abnormalities, such cases may have been overlooked. The authors would like to advocate this isolated anomaly of thecochlear nerve as an important cause of juvenile or adolescent unilateral profound deafness.- - - - - - - - - - ranking = 3keywords = nerve (Clic here for more details about this article) |