Audiovestibular Consequences of Congenital Cytomegalovirus Infection: Greater Vulnerability of the Vestibular Part of the Inner Ear

Abstract

Objectives: To investigate the impact of congenital cytomegalovirus infection on cochlear and vestibular function.Design: This retrospective study conducted between March 2014 and March 2020 included children with confirmed congenital cytomegalovirus infection who underwent a complete audio-vestibular evaluation. It included a bithermal caloric test, a video head impulse test and a cervical vestibular evoked myogenic potential associated with a complete hearing assessment. Results:The cohort of 130 children included in the study had a median age of 21 months (interquartile range: 12 to 37 months). Eighty-three children (64%) showed an inner ear impairment (both cochlear and vestibular). The vestibular part of the inner ear was significantly more frequently impaired than the cochlear part (ρ = 0.003). Sixty-two children (48%) showed confirmed hearing impairment. The severity of hearing loss was variable, with a high proportion of profound hearing loss (30/62, 48%), which was often bilateral (47/62, 76%). The vestibular assessment showed a canal function disorder in 67 children (88%) and an otolith function disorder in 63 children (83%; ρ = 0.36). The video head impulse test was significantly less altered (64%) compared with the bithermal caloric test (80%; ρ = 0.02) and the cervical vestibular evoked myogenic potential (83%; ρ = 0.009). Only seven out of 83 children (8%) showed hearing loss without vestibular dysfunction, of which only one had a normal hearing screening test at birth. For the children who passed the hearing screening test at birth and presented an inner ear impairment [n = 36, median age: 16 (11 to 34) months], vestibular disorders were later found in 35 children (97%) and 17 of them (47%) developed hearing loss secondarily. This underlines the importance of assessing both vestibular and auditory parts of the inner ear. When comparing the agreement of cochlear and vestibular impairment, the severity and the laterality of the impairment were low [Cohen's kappa 0.31 (0.22 to 0.40) and 0.43 (0.32 to 0.55), respectively]. Conclusion:In our study, we demonstrated that although both cochlear and vestibular parts of the inner ear can be impaired by congenital cytomegalovirus infection, the vestibular part seems more often impaired compared with the cochlear part. This underlines the importance of vestibular evaluation in the follow-up of cytomegalovirus-infected children associated with hearing assessment.

Predicting Early Vestibular and Motor Function in Congenital Cytomegalovirus Infection

“…Identifying predictive factors for vestibular dysfunction to enable a targeted approach could therefore markedly increase the feasibility of vestibular evaluation in the large cCMV‐population. Various studies have previously shown that vestibular dysfunctions more commonly occur in patients with SNHL compared to normal‐hearing patients 12,13,17,19 . This was also confirmed by our results, the odds for vestibular impairment in children with SNHL at birth being 6 times higher compared to normal‐hearing children.…”

“…This approach is also in line with the ideal of the Vestibular Infant Screening—Flanders project (VIS‐Flanders), a recent initiative in our country in which vestibular screening is provided for children with confirmed permanent hearing loss after refer on the neonatal hearing screening 42–44 . Unfortunately, this approach seems insufficient for the cCMV‐population, as vestibular function is not necessarily safeguarded in normal‐hearing cCMV‐children 8,12,13,16,19 . Although the risk is considerably lower, the number of normal‐hearing cCMV‐patients is much higher than the number of hearing‐impaired cCMV‐patients.…”

“…Sensorineural hearing loss (SNHL), the most common sequela in cCMV, is reported to be caused by viral labyrinthitis potentially combined with detrimental host immune responses 5–7 . Although it has long remained in obscurity, growing evidence shows that not only auditory but also vestibular function can be affected 8–19 . As vestibular input is an important cornerstone for adequate early motor development, timely detection of vestibular loss could be important to reach a child's full potential 20–24 .…”

“…As vestibular input is an important cornerstone for adequate early motor development, timely detection of vestibular loss could be important to reach a child's full potential 20–24 . Research suggests that cCMV‐related vestibular dysfunction primarily occurs in children with SNHL, but also normal‐hearing asymptomatic children can be affected 8,10,12,13,16,19 . Moreover, similar to cCMV‐related SNHL, 25–28 cCMV‐related vestibular loss appears to be unpredictable in onset and severity 10,13,19 .…”

Congenital cytomegalovirus infection diagnostics and management

“…Overall, compared to children with symptomatic cCMV, neurodevelopmental and other sequelae are uncommon in children with asymptomatic cCMV, particularly in children with no evidence of SNHL prior to 2 years of age [37]. Increasingly, vestibular dysfunction with visual and balance disorders are being reported in children with symptomatic and asymptomatic cCMV with and without hearing loss [38,39 ▪ ,40 ▪ ].…”