The role of vestibular caloric tests in cochlear implantation

Vestibular function tests are often undertaken before cochlear implantation, in part to help select the side of surgery. The authors aim to determine whether implantation on the side of better vestibular function leads to greater perception of dizziness by patients than implantation on the side of worse or similar function.

Historical cohort study.

Tertiary cochlear implantation center.

The records of 177 adult recipients of a unilateral cochlear implant were reviewed retrospectively in 2 groups. Group A included patients with an implant in the ear with worse or similar caloric responses. Group B included patients with an implant in the ear with the stronger caloric response. All patients underwent preoperative bithermal caloric testing: a clinically significant difference was defined by a 20% lateral canal paresis. They were assessed postoperatively by the Dizziness Handicap Inventory and supplementary questions.

Fifty-seven percent of both groups reported dizziness in the first 7 days postoperatively. At 2 months, 20% of group A and 34% of group B experienced some dizziness. Fourteen percent of group A and 10% of group B felt that cochlear implantation had resulted in impaired balance. The Dizziness Handicap Inventory scores of 86% of group A (median score 0) and 76% of group B (median score 10) corresponded with low handicap. None of these results differed significantly between groups A and B.

Although cochlear implantation may result in dizziness, it is almost always short-lived and mild, even when the ear with the stronger caloric response is implanted.