Long-Term Effects on Vestibular Evoked Myogenic Potentials in Children With Cochlear Implantation

To analyze the long-term effects of cochlear implantation (CI) on vestibular evoked myogenic potentials (VEMPs) in children.

CI surgery was performed in a unilateral ear of 31 patients in the department of otolaryngology, Second Affiliated Hospital of Xi'an Jiaotong University from 2011 to 2015. The group comprised 15 boys and 16 girls, with a mean age of 10.68±7.60 years old. All operations were performed by the same surgeon, and the round window approach was used for all. Both ocular VEMPs (oVEMPs) and cervical VEMPs (cVEMPs) were detected on bilateral ears before operation. These were tested again from 1 to 5 years after operation (with device ON and OFF). The ears with CI were analyzed as the study group, and the non-operated ears were used as a control. The response rate, threshold, p13 (15) and n10 (23) latencies, and amplitudes of the VEMPs were analyzed and compared between groups.

Before CI, the response rates of the oVEMPs and cVEMPs in the implant ear were 58.06% and 61.29%, respectively. However, within 1 to 5 years after surgery, the oVEMP response rates decreased significantly to 16.13% (device ON, P <0.01) and 12.90% (device OFF, P <0.01). The response rates of the cVEMPs decreased to 22.58% (device ON, P <0.01) and 19.35% (device OFF, P <0.01). For those patients with elicited VEMPs, abnormal waveform parameters could be found in both the oVEMP and cVEMP, including elevated thresholds, decreased amplitudes, and changed p13 (15)/n10 (23) latencies.

Cochlear implant surgery can affect vestibular function of the implanted ear, which can be detected by the oVEMP and cVEMP tests. These effects can last for years.