Cochlear nerve deficiency

Cochlear nerve deficiency (CND) is defined as a small or absent cochlear nerve. It is most often diagnosed in the setting of congenital sensorineural hearing loss and represents around 1?% of cases within this population. It is associated with a recognized syndrome in 30-50?% of cases, most commonly CHARGE syndrome. Treatment planning requires a combination of anatomic and functional assessments using both electrophysiologic and behavioral testing of hearing and imaging of the temporal bones, and central nervous system with MRI and CT. Treatment poses many management challenges and should be tailored to the families’ expectations and those options which provide the greatest chance for success while minimizing risk. For bilateral cases, options include manual/visual communication modes, amplification, cochlear implantation, and auditory brainstem implantation. Overall the results from cochlear implantation are significantly poorer than age-matched controls with normal imaging and there is a higher rate of non-auditory stimulation. Auditory brainstem implantation may be considered in cases where cochlear implantation has been demonstrated unsuccessful or impossible.