[Vestibular dysfunction after cochlear implant in adults]

According to the literature, clinical vertigo after cochlear implant (CI) occurs in 0.33-75%, a peripheral vestibular loss of function in 20-75%.

Between 2006 and 2009, 30 adults were implanted with a 22-channel Nucleus Freedom CI (41 operations). Cochleostomy was performed anterocaudal of the round window and the electrode inserted using the "off-stylet" technique into the scala tympani.

Clinical vertigo occurred after 10/41 (24.4%) operations: acutely in 5/41 (12.2%), continuous in 1/41 (2.4%), delayed for 6-18 months in 5/41 (12.2%). In the calorimetry, 3/27 (11.1%) vestibular organs displayed a loss of function (p = 0.16). Three of 8 patients (37.5%) with clinical vertigo after surgery showed a loss of vestibular function (p = 0.08).

Using the described techniques and materials, the risk of loss of vestibular function and the incidence of clinical vertigo can be minimized. Postoperative vertigo did not occur more often in patients with preoperative diminished vestibular function than in patients with normal findings. Therefore, preoperative vestibular function tests cannot be an indicator for the frequency of vertigo after CI. If one vestibular organ shows preoperative dysfunction, the non-affected normal vestibular organ should not be implanted.