Severe pediatric hearing loss often leads to vestibular dysfunction that affects balance and cognition. Hearing loss is associated with vestibular impairment in 40%-60% of cases. In Sweden, around 200 children are born annually with hearing loss, while the prevalence of severe cases is 0.2 to 0.3 per 1000 neonates. Vestibular impairment disrupts static acuity, leading to blurred vision, oscillopsia, and difficulties reading while the head is in motion. Cochlear implants are effectively used to treat severe hearing loss, but their long-term impact on the vestibular system has been understudied. This was well explained in a recent study published in the Audiology Research journal.
This study systematically evaluated all five vestibular components in youth who received cochlear implants during early childhood, including testing canal (anterior, lateral, posterior) and otolith (sacculus, utriculus) function separately from each other. This research highlights the importance of integrating vestibular assessments in cochlear implantation (CI) patient follow-ups for improved rehabilitation programs.
This study assessed vestibular function in the Teenager and Young Adults Cochlear Implant (TAYCI) group. This cross-sectional study examined 38 CI recipients aged between 11 and 20 years who underwent implantation during childhood. The age distribution was similar between the invited TAYACI (n = 108) and the participants who accepted participation in the group (n = 53).
Participants were tested at the audiology department of Karolinska University Hospital from March 2022 to June 2023. Two vestibular tests were employed, such as video head impulse test (vHIT) and cervical/ocular vestibular-evoked myogenic potentials (cVEMP/oVEMP) using air-conducted and bone-conducted stimulation. If gain values are 0.8-1.0 laterally and 0.7-1.0 vertically, without saccades, they are considered normal.
Patients gazed upwards at a 30-degree angle, staring at the ceiling, with 100 sweeps collected twice per side. Power analysis of vHIT results indicated the final cohort of 38 CI and 20 controls was sufficient for statistical inference. This study utilized an eclipse-evoked potential system for VEMP testing with specific EPx5 software v 4.6.1.
In vHIT Testing, all six canal gains were significantly lower in CI patients than normal hearing (NH) controls, with p-values ranging from 0.000 to 0.031. Dynamic visual acuity (DVA) testing gives 100% specificity (20/20) and 73.3% sensitivity (11/15) to identify bilateral lateral canal impairment (χ² = 24.6, p < 0.001). VEMP Wave Reproducibility (WR) was significantly lower in the CI group for all modules with p < 0.001. Pathological vHIT correlated with pathological bone conduction (BC) cVEMP (23/35 ears; 65.7%) and BC oVEMP (27/35 ears; 77.1%). Among 38 adolescents, 46.1% had abnormal lateral canal function, and 55% identified utricular issues.
This study’s limitation includes the absence of pre-operative vestibular function data due to a lack of testing at the beginning of the 2000s.
In conclusion, this research paper investigates vHIT and VEMP results in adolescents with early cochlear implants, focusing on their vestibular responses. The above-mentioned tests complemented each other in the overall vestibular assessment. DVA test helps in estimating the severity of oscillopsia due to severe bilateral canal impairment.
Reference: Karpeta N, Karltorp E, Verrecchia L, Duan M. Long-Term Follow-Up of Vestibular Function in Cochlear-Implanted Teenagers and Young Adults. Audiol Res. 2025;15(2):42. doi:10.3390/audiolres15020042
