Introduction:
Cochlear implantation is a standard intervention for children with severe to profound sensorineural hearing loss. However, the procedure may affect vestibular function due to its anatomical proximity to the cochlea. This study evaluated sacculo-collic pathway function using cervical vestibular evoked myogenic potentials (cVEMPs) in children undergoing unilateral cochlear implantation, comparing responses at three times: pre-operative (pre-op), immediate post-operative (post-op), and at a 3-month follow-up.

Material and methods:
This longitudinal study was conducted on 9 children (mean age 3.7 ± 1.4 years) with congenital bilateral severe-toprofound sensorineural hearing loss who all received a CI in the right ear. Assessments were done at 3 time points using cVEMPs. Parameters analysed comprised P1 and N1 latencies, P1–N1 amplitude, and interaural amplitude asymmetry ratio. Responses for 1 child could not be recorded at any time point, so reported data relate to the remaining 8 children.

Results:
At the pre-op stage, normal cVEMP responses were observed in 8 of the 9 children, with normal P1–N1 amplitudes and latencies. Post-operatively, 4 of the 8 exhibited absent or markedly reduced responses in the implanted (right) ear, with a significant decrease in amplitude (mean 15.1 ± 21.2 μV vs pre-op 101.5 ± 90.2 μV; p = 0.029). At the follow-up, partial recovery of amplitude was noted (mean 35.1 ± 30.3 μV). No statistically significant changes were found in latency across the different time points (p > 0.05), and responses in the non-implanted (left) ear remained relatively stable. However, 6 participants showed amplitude asymmetry > 33% post-operatively, with 4 exhibiting complete (100%) asymmetry; this difference was statistically significant p < 0.001).

Conclusions:
Findings suggest that cochlear implantation in children may induce temporary alterations in sacculo-collic function, mainly evidenced by a reduction in cVEMP amplitude post-operatively. The observed partial recovery at follow-up suggests reversible vestibular changes, possibly due to central compensation. This underscores the importance of ongoing vestibular assessment in pediatric CI recipients to monitor potential transient dysfunction and recovery patterns.