Effect of cochlear implantation on vestibular function in children: A scoping review

Long-Term Follow-Up of Vestibular Function in Cochlear-Implanted Teenagers and Young Adults

BACKGROUND

Vestibular function implements head position regulation and body spatial navigation. It matures during childhood and adolescence and integrates with the completion of an individual's motor development. Nevertheless, vestibular impairment is associated with profound paediatric hearing loss and has a negative impact on the child's motor proficiency. Cochlear implantation (CI) is the treatment of choice for severe hearing loss, where conservative treatment plans are not appropriate or fail. The Teenager and Young Adults Cochlear Implant (TAYACI) study investigates the long-term outcomes of early implantation with respect to the hearing, speech, psychological, and balance development among CI users.

METHODS

This study focuses on the vestibular function and the appropriate methods for vestibular assessment. The results of two established vestibular test methods are explored: the video head impulse test (vHIT) and cervical/ocular vestibular-evoked myogenic potentials (cVEMP, oVEMP) with air and bone conduction vibration stimulation. The results of vHIT, cVEMP, and oVEMP, per implanted ear and the relation to the aetiology of hearing loss are reported. An additional dynamic visual acuity (DVA) test was included to assess clinical oscillopsia.

RESULTS

Overall abnormal lateral canal testing was detected in 35/76 (46.1%) of the implanted ears. Bone-conducted cVEMP (BC cVEMP) was pathological in 33/76 (43.3%) and BC oVEMP in 42/76 (55.3%). Lateral canal impairment was associated with the background diagnosis of the hearing loss. Oscillopsia was related to bilateral canal impairment (sensitivity 73% specificity 100%).

CONCLUSIONS

Lateral canal testing together with BC VEMPs were the most reproducible modules for vestibular testing The above tests were related to each other and complemented the overall vestibular assessment. DVA is a helpful tool to screen dynamic oscillopsia in patients with bilateral vestibular impairment.

Cochlear Implant (CI) procedure. Italian Clinical Practice Guidelines of the Italian Society of Otorhinolaryngology (SIOeChCF) and Italian Society of Audiology and Phoniatrics (SIAF). Part 2: cochlear implants in children

Objective

Cochlear implant (CI) is a well-established treatment for children with sensorineural hearing loss without benefit from hearing aids. The Italian guidelines date back 15 years; given the expansion of indications for CI (including single side deafness and asymmetrical hearing loss) it became necessary to establish updated guidelines.

Methods

Thirteen experts and 2 patient representatives selected the key questions and drew up recommendations. The document was developed following the GRADE methodology. The methodological team of the Mario Negri Pharmacological Research Institute performed systematic reviews for each question and supported the overall process.

Results

Four key questions were identified and recommendation formulated, with subgroups and implementation considerations.

Conclusions

Though the systematic research of scientific literature found a scarcity of randomised trials and an overall poor conduct and reporting quality of primary studies and systematic reviews, conditional recommendations in favour of CI have been formulated for different subgroups of children. Further studies should enrol a larger number of participants and use consistent instruments to evaluate hearing outcomes, in order to increase comparability of results and data pooling through meta-analysis.

Subconscious vibrotactile stimulation improves mobility and balance in patients with bilateral vestibulopathy: adherence over 2 years

Objective

To investigate the effect of daily use of subconscious vibrotactile stimulation in bilateral vestibulopathy (BVP) patients, who judged the effect of vestibular rehabilitation as insufficient.

Methods

BVP patients were asked to wear a subconscious vibrotactile stimulation belt for 2 h. Patients who reported benefit after 2 h of use, were instructed to wear a subconscious vibrotactile stimulation belt in daily life, for up to more than 2 years. Follow-up consultations (mostly by telephone calls) were scheduled after 2 weeks, 2 months, 1 year, and 2 years of use. During these consultations, adherence and the self-reported overall Balance and Mobility Score (BMS) were evaluated.

Results

One hundred twenty-one BVP patients were included. Regarding adherence, 74% of patients (n = 89) wanted to proceed with daily use at home after 2 h of try out. Of these patients, 90% (n = 80) was still wearing the belt daily after 2 months, and at least 81% (n = 72) after 1 year and 73% (n = 65) after 2 years. It should be noted that lack of adherence after 1 and 2 years resulted from a loss to follow-up. All patients responding to telephone consultations in the 2 years follow up were wearing a subconscious vibrotactile stimulation belt daily. The median BMS score significantly improved within 2 h of use, from 4 to 6 points (p < 0.0001). Compared to baseline, the median BMS score significantly improved with >=3 points after 2 weeks, 2 months, 1 year, and 2 years of daily use (p < 0.0001). Long-term adherence was high in patients who experienced an increase of two or more points on the BMS, after 2 weeks of daily use.

Conclusion

The Subconscious vibrotactile stimulation improves self-reported balance and mobility in a subgroup of motivated BVP patients in which vestibular rehabilitation is insufficient.

Audiological and Vestibular Follow-Up for Children with Congenital Cytomegalovirus Infection: From Current Limitations to Future Directions

Currently, the guidelines for audiological and vestibular follow-up in children with congenital cytomegalovirus (CMV) are not well-defined. The general recommendation is to evaluate hearing in all children with congenital CMV at the same intervals: once every 3-6 months up to 1 year of age, once every 6 months from 1 to 3 years of age, and once a year from 3 to 6 years of age. Additionally, there are no universally accepted protocols for the vestibular follow-up of children with congenital CMV, although video head impulse test (v-HIT) and cervical vestibular-evoked myogenic potentials (cVEMPs) are sometimes used. This narrative review critically evaluates existing audiological and vestibular follow-up approaches for children with congenital CMV, highlighting the need for personalized protocols. Tailoring follow-up schedules with different timing and methods based on risk factors, such as the trimester of maternal infection, CMV PCR results in amniotic fluid, and valganciclovir use, would indeed allow for more precise evaluations, timely interventions, and optimized resource allocation. This strategy would also alleviate the logistical and emotional burdens on families by ensuring that high-risk children receive more frequent and appropriate assessments and early interventions, while lower-risk children avoid unnecessary testing.

Vestibular Preservation in Pediatric Cochlear Implantation

OBJECTIVES

Evaluate the rate of preserved vestibular function in pediatric cochlear implant surgery.

STUDY DESIGN

Retrospective case review.

METHODS

Pre- and post-operative vestibular tests were compared in children who underwent cochlear implantation at a tertiary level pediatric hospital over a 4-year period.

RESULTS

Data from 59 implanted ears in 44 children was included. Median age was 2.8 years at initial testing (range 7 months - 21 years) with 1:1 male/female ratio. Implant surgeries were 26 unilateral, 13 bilateral simultaneous, and 5 bilateral sequential. The majority were implanted with slim, non-styletted electrodes (86.4%) via a round window approach (91.5%). Normal pre-operative results were preserved post-operatively on rotary chair testing in 75% (21/28) of patients, cervical vestibular evoked myogenic potential testing in (75%) 30/40 of ears tested, ocular vestibular evoked myogenic potential testing in 85.7% (6/7) of ears tested, video head impulse testing in 100% (9/9) of ears tested, and computerized dynamic posturography in 100% (5/5) of patients tested. Overall, 62.5% of patients had no new deficits on any vestibular test performed post-operatively.

CONCLUSIONS

Preservation rates of vestibular function following cochlear implant surgery were higher in this cohort than what has been reported in many earlier studies. Contemporary, less traumatic electrodes and insertion techniques may be a significant factor. The risk of causing a new, severe bilateral vestibular loss with long-term functional impacts appears to be low. Further study is warranted on the impacts of different cochlear implant electrode designs and insertion approaches on post-operative vestibular preservation.

LEVEL OF EVIDENCE

4, Case Series Laryngoscope, 134:1913-1918, 2024.

Balancing Act: A Comprehensive Review of Vestibular Evaluation in Cochlear Implants

Cochlear implantation, a transformative intervention for individuals with profound hearing loss, has evolved significantly over the years. However, its impact on the vestibular system, responsible for balance and spatial orientation, remains a subject of ongoing research and clinical consideration. This narrative review highlights key aspects of vestibular evaluation in patients undergoing cochlear implantation. Preoperative vestibular assessment is crucial to establish baseline vestibular function and identify any pre-existing balance issues. Various tests, including caloric, rotational chair, vestibular-evoked myogenic potential, and video head impulse tests, play a vital role in evaluating vestibular function. The goal is to assess the risk of vestibular disturbances arising from the surgery, guide surgical planning, and detect pre-existing alterations that could be totally or partially compensated. While some patients experience minimal vestibular disruptions, others may encounter transient or persistent balance issues following cochlear implant surgery. Postoperative vestibular testing allows for the early detection of such disturbances, enabling timely interventions like vestibular rehabilitation and evaluating changes produced due to surgical complications or changes in the patient's prior conditions. Challenges in vestibular evaluation include individual variability in patient responses, the proximity of the cochlea to the vestibular system, and the need to tailor testing protocols to individual needs. Further research is essential to refine testing protocols, minimize vestibular disturbances, and improve outcomes for cochlear implant candidates. A multidisciplinary approach involving otolaryngologists, audiologists, and physical therapists is integral to comprehensive patient care in this context. In conclusion, vestibular evaluation in patients undergoing cochlear implantation is critical for optimizing surgical planning, managing postoperative issues, and enhancing the overall quality of life for individuals embarking on the journey of restored hearing.