Balance Control during Stance and Gait after Cochlear Implant Surgery

Abstract

Background: After cochlear implant (CI) surgery, some patients experience vertigo, dizziness and/or deficits in vestibulo-ocular reflexes. However, little is known about the effect of CI surgery on balance control. Therefore, we examined differences in stance and gait balance control before versus after CI surgery. Methods: Balance control of 30 CI patients (mean age 59, SD 15.4 years), receiving a first unilateral CI surgery, was measured preoperatively and postoperatively 1 month after the initial implant stimulation (2 months after surgery). Trunk sway was measured during 14 stance and gait tests using an angular-velocity system mounted at lumbar vertebrae 1–3. Results: For pre- versus postoperative comparisons across all 30 patients, a nonsignificant worsening in balance control was observed. Significant changes were, however, found within subgroups. Patients younger than 60 years of age had a significant worsening of an overall balance control index (BCI) after CI surgery (p = 0.008), as did patients with a normal BCI preoperatively (p = 0.005). Gait task measures comprising the BCI followed a similar pattern, but stance control was unchanged. In contrast, patients over 60 years or with a pathological BCI preoperatively showed improved tandem walking postoperatively (p = 0.0235). Conclusion: Across all CI patients, CI surgery has a minor effect on balance control 2 months postoperatively. However, for patients younger than 60 years and those with normal balance control preoperatively, balance control worsened for gait indicating the need for preoperative counseling.

The effect of cochlear implant surgery on vestibular function in adults: A meta-analysis study

“…Among all the 38 articles, after judgment based on the risk of bias analysis (JBI), analytic cross-sectional studies, and according to each study type, 25 studies showed a low risk of bias ( 9 , 14 , 16 , 24 , 27 , 31 , 33 , 35 , 36 , 38 , 39 , 42 – 44 , 46 , 48 – 55 ), 10 articles ( 15 , 23 , 25 , 26 , 28 – 30 , 32 , 34 , 47 ) showed a moderate risk of bias, and 3 articles ( 21 , 40 , 45 ) had a high risk of bias.…”

“…Regarding reports of pre-existing symptoms, the majority of articles did not mention them, however, about post symptoms, 17 cited vertigo as the main symptom ( 9 , 14 – 16 , 21 , 25 , 26 , 28 , 30 , 33 , 39 , 40 , 44 , 48 , 50 – 52 ), and in 5 of these ( 25 , 26 , 28 , 30 , 39 , 51 ), the round window was the surgical intervention, 5 ( 16 , 21 , 33 , 40 , 44 ) had cochleostomy, in 1 ( 25 ) both interventions were present, and the others did not mention the surgery, despite having reported the symptoms. Of all the articles eligible for this review, 44.7% ( 9 , 14 – 16 , 21 , 25 , 26 , 28 , 30 , 33 , 39 , 40 , 44 , 48 , 50 – 52 ) reported vertigo as a post-implantation symptom, followed by dizziness and imbalance ( 16 , 29 , 32 , 35 , 36 , 38 , 39 , 44 , 45 , 48 , 50 , 51 , 53 ); however, in 7.8% ( 34 , 54 , 55 ) of the studies, there were no reports or citations of any referred symptom ( Supplementary Table 1 ).…”

“…Overall, the performance of postural stability did not appear to be affected by CI surgery ( 15 ). Stieger's analysis ( 55 ) indicated that 5 of 15 (33%) patients who had normal balance preoperatively had pathological balance control postoperatively. Furthermore, 3 of the 12 (58%) patients who were <60 years of age had pathological balance postoperatively.…”