What evaluations and preparations are necessary before undergoing a cochlear implant?

Pre-Cochlear Implant Requirements

All cochlear implant candidates require comprehensive audiometric testing, temporal bone CT imaging, MRI of the internal auditory canal, medical evaluation by an otolaryngologist, speech-language pathology assessment, and psychological evaluation before proceeding with surgery. 1

Audiological Assessment

• Complete audiometric testing must document severe to profound sensorineural hearing loss, typically using the "60/60" guideline (which has 96% sensitivity for identifying candidates) 1
• Verify proper hearing aid fitting through real-ear measurements to confirm hearing aids are meeting prescriptive targets before considering cochlear implantation 1
• Perform speech recognition testing in both quiet and noise conditions to document limited benefit from conventional amplification 1
• Assess residual hearing in both ears to determine the optimal implantation strategy (unilateral versus bilateral) 1

Imaging Studies

CT Temporal Bone (Required)

• High-resolution CT of the temporal bone without IV contrast is the first-line imaging modality for surgical planning 2
• CT provides critical preoperative information including:
  • Detection of cochlear malformations (Mondini deformity, common cavity, large vestibular aqueduct syndrome) 2, 3
  • Identification of otosclerosis changes 2
  • Assessment for round window occlusion 2
  • Detection of labyrinthitis ossificans 2
  • Evaluation of ossicular chain abnormalities 2
  • Identification of variant facial nerve anatomy 2
  • Measurement of cochlear and vestibular aqueduct size (alerts surgeon to potential CSF gusher risk) 2
  • Assessment of mastoid pneumatization and tegmen position 4

MRI Head and Internal Auditory Canal (Required)

• MRI with high-resolution T2-weighted sequences provides complementary anatomical information that directly impacts surgical approach 2
• MRI is essential for detecting:
  • Cochlear nerve deficiency or absence 2
  • Cochlear malformations not visible on CT 2
  • Central causes of hearing loss 2
  • Inner ear structural abnormalities 5

Both CT and MRI are necessary for complete presurgical evaluation 2, 5

Medical Evaluation

• Comprehensive otologic examination by an otolaryngologist to identify any contraindications to surgery 1
• Evaluation for underlying etiology of hearing loss that may impact outcomes 1
• Assessment for general anesthesia readiness 2

Multidisciplinary Team Assessment

Speech-Language Pathology Evaluation

• Conduct speech-language pathology evaluation to assess current communication abilities and establish baseline speech and language skills 1, 6

Psychological Assessment

• Perform psychological evaluation to assess cognitive function, realistic expectations, and readiness for the implantation process 1
• Expectation management is critical - patients must understand the device provides a new type of auditory sensation rather than restoration of previous hearing 2
• Include family members in counseling sessions as family support throughout the process correlates with better outcomes 2

Pediatric-Specific Requirements

• Use age-appropriate audiological testing with consideration for early intervention, as delays impact speech and language development 1
• Assess developmental milestones and language acquisition 1

Pre-Operative Counseling and Preparation

• Review consent forms and introduce post-operative rehabilitation services 2
• Arrange meetings with previous cochlear implant recipients when possible to help manage expectations 2
• Ensure family support is in place - greatest success occurs when outcomes match or exceed pre-operative expectations of well-counseled families 2

Common Pitfalls to Avoid

• Do not delay referral for cochlear implant evaluation in patients with progressive hearing loss - only 5-12.7% of potential candidates currently receive devices due to inadequate clinician knowledge of when to refer 1
• Do not proceed without adequate verification of hearing aid fitting - this is a common error that leads to inappropriate candidacy determination 1
• Do not rely on CT head alone - it provides insufficient temporal bone detail for surgical planning 2
• Do not skip imaging studies - 14.3% of candidates have middle or inner ear malformations that critically impact surgical approach 3