medwireNews: Preoperative assessment of the cochlear nerve can predict postoperative outcome in patients undergoing cochlear implantation (CI) for postlingual deafness, research suggests.
Parasagittal magnetic resonance imaging (MRI) measurements of the cochlear nerve in 68 adults, aged an average of 49 years, that were taken before CI revealed a significant negative correlation between the cross-sectional area (CSA) of the cochlear nerve and duration of deafness, report Jae Young Choi and co-workers, from Yonsei University College of Medicine in Seoul, South Korea.
Further analysis of the cochlear nerve of five patients with at least a 9-year difference in the duration of deafness between each ear revealed that the CSA was significantly smaller in the ear with the longest duration versus the ear with the shorter period of deafness.
There was also a trend toward decreasing CSA with increasing hearing loss, with a significant difference in the CSA of the ears with hearing loss of no more than 80 dB compared with ears with at least 101 dB loss.
Moreover, CSA of the cochlear nerve significantly and positively predicted postoperative auditory performance 3 months after surgery, as measured using the Korean version of the Central Institute for the Deaf test under auditory-only listening conditions.
By contrast, there was no significant correlation between CSA and patient age, or between cochlear nerve size and the cause of deafness, which included sudden sensorineural hearing loss, chronic otitis media, genetic hearing loss, and other causes.
Because the hearing loss of the patients resulted from multiple causes, additional investigations are needed to analyze the correlation of the [cochlear nerve] size with auditory performance in more homogeneous patient groups," the researchers write in JAMA Otolaryngology Head & Neck Surgery.
"However, our study suggests that measuring the size of the [cochlear nerve] with parasagittal MRI may provide useful information for preoperative counseling of patients."
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