Long-term analysis of vestibular function in cochlear implant recipients with enlarged vestibular aqueduct.

OBJECTIVE

To compare long-term vestibular function in cochlear implant recipients with enlarged vestibular aqueduct and those without inner-ear malformations.

METHODS

A comparative analysis was conducted on 53 cochlear implant recipients (27 with enlarged vestibular aqueduct, 26 with no inner-ear malformations). Vestibular function was assessed using caloric testing, vestibular-evoked myogenic potential, the video head impulse test and age-appropriate symptom questionnaires.

RESULTS

Enlarged vestibular aqueduct patients demonstrated significantly better preservation of otolithic function post-implantation, with higher cervical vestibular-evoked myogenic potential response rates (56 vs 12 per cent, p = 0.001). Caloric testing showed similar vestibular dysfunction across both groups. Both cohorts exhibited significant asymmetry between implanted and non-implanted ears.

CONCLUSION

Cochlear implantation impairs vestibular function regardless of cochlear morphology, affecting both otolithic and low-frequency semicircular canal function. However, better saccular function preservation in enlarged vestibular aqueduct patients suggests unique vestibular adaptation, with implications for counselling and rehabilitation.