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Cochlear Nerve Deficiency

Aplasia or hypoplasia of cochlear nerve, MRI cisternal segment, cochlear implant outcomes, ABI candidacy

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our KBB (Kulak Burun Boğaz) department. Book Appointment →

What is Cochlear Nerve Deficiency?

Cochlear nerve deficiency is a structural anomaly where the cochlear branch of the eighth cranial nerve is absent or smaller than normal, often associated with inner ear malformations such as cochlear hypoplasia, common cavity, or vestibular aqueduct enlargement. It is found in 12 to 18 percent of children with congenital severe to profound sensorineural hearing loss.

Diagnosis requires high-resolution three-dimensional T2-weighted magnetic resonance imaging of the internal auditory canal, with oblique sagittal reformats comparing the cochlear nerve to the facial nerve in cross-section. Computed tomography evaluates bony cochlear malformations and the bony cochlear nerve canal width.

Cochlear nerve hypoplasia may still permit cochlear implantation with variable benefit, while complete aplasia generally indicates auditory brainstem implantation. Surgical decision-making is multidisciplinary, includes electrically evoked auditory brainstem response testing, and balances family expectations with realistic prognosis. Pediatric outcomes depend on age at intervention and associated cochlear anomalies.

Symptoms

Profound hearing loss in newborn screening
No response to cochlear implant in trial
Bilateral severe-profound deafness
Associated inner ear malformations
Failure to develop spoken language

Risk Factors

Congenital inner ear malformation
Narrow bony cochlear nerve canal
Family history of CN deficiency
Syndromic hearing loss (CHARGE)
Cochlear hypoplasia or common cavity

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • When MRI shows small or absent CN
  • Before considering cochlear implantation
  • For poor cochlear implant outcomes
  • For ABI candidacy evaluation
  • For genetic and syndromic workup

Treatment Methods

01
High-resolution MRI internal auditory canal
02
EABR for nerve function assessment
03
Cochlear implant trial in hypoplasia
04
Auditory brainstem implant for aplasia
05
Auditory-verbal therapy
06
Multidisciplinary team counseling

Which Department to Visit?

You can visit our KBB (Kulak Burun Boğaz) department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

Learn About KBB (Kulak Burun Boğaz) Department

Let us help you

You can make an appointment with our specialists or contact us for your concerns.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.