Air and Bone‐Conducted Vestibular Evoked Myogenic Potentials in Cochlear Implants

Aniket Saoji, PhD, CCC-A Director, Cochlear Implants at Mayo Clinic Rochester MN

13 years of employment with Advanced Bionics (AB). Consultant for AB.

Research support from AB, Cochlear, Med-EL, and Envoy Medical.

Causes of vestibular dysfunction from cochlear implant surgery

1) Electrode insertion trauma 2) Acute serous labyrinthitis from cochleostomy 3) Foreign body reaction with labyrinthitis 4) Endolymphatic hydrops 5) Electrical stimulation from the implant Ibrahim et al., 2017

1) Video head impulse test (vHIT) 2) Caloric tests 3) Vestibular evoked myogenic potentials (VEMPs) 1) Cervical VEMPs 2) Ocular VEMPs 4) Dizziness Handicap Investory (DHI) 5) Computerized dynamic posturography (CDP)

Saccule

Inferior vestibular nerve

Lateral vestibular nucleus

11th cranial nerve

Sternocleidomastoid muscle

Saccule

Inferior vestibular nerve

Lateral vestibular nucleus

11th cranial nerve P1 – N1 ~ 20 to 30 ms latency Sternocleidomastoid muscle

Pre-op C-VEMP N = 344 N = 227 N = 117

Post-op C-VEMP N = 341 N = 130 N = 211

Ibrahim et al., 2017

Wideband absorbance patterns in CI (shapiro et al 2019)

Implanted ear Unimplanted ear

Impairment of middle ear conduction (≥ 5 dB) can lead to absence of air-conduction VEMPs.

Duration Patients Age (Yrs) Gender Ear of use Etiology (months) CI 3 69 F Right 52 SNHL CI 7 59 M Right 12 SNHL CI 10 38 F Left 1 SNHL CI 13 53 M Right 61 SNHL CI 14 44 M Right 13 SNHL

Acoustic pure tone stimulus presented via insert ear phones and bone vibrator (B-81).

Stimulus: 500 Hz Duration: 4 ms (± 1 ms) Presentation level: 95 dB for air-conduction VEMPs and 75 dB for bone-conduction VEMPs.

Unimplanted ear Implanted ear

AC-VEMP

BC-VEMP

Changes in middle ear mechanics following cochlear implant surgery can lead to absence of air-conduction C-VEMPs in the implanted ear.

Bone-conduction C-VEMPs can be used to ascertain vestibular trauma from cochlear implant surgery.