Changes in Vestibular Function Following Pediatric Cochlear Implantation: a Prospective Study

A Clinical Framework for Video Head Impulse Testing and Vestibular Evoked Myogenic Potential Assessments in Primary School-Aged Children

OBJECTIVES

This study aimed to offer normative data and age trends of an age-appropriate vestibular test protocol in a large group (n = 140) of school-aged children (6 to 13 years old) as well as to provide a practical and clinical framework for accurate performance and interpretation of vestibular test results in this specific age group.

DESIGN

The typically developing participants (mean age of 9.51 ± 2.04 years) were recruited to provide a representative group of 20 children for each of the seven age groups that were composed of children aged from 6 to 13 years in 1-year intervals. Each age group consisted of 10 boys and 10 girls. The protocol comprises the video head impulse test, and cervical and ocular vestibular evoked myogenic potential assessments to provide a child-friendly, noninvasive, short, and portable test battery, which is equally applicable in the hospital and office-practice, and which provides information on the integrity of all five parts of the peripheral vestibular system.

RESULTS

The study demonstrates that all included tests and methods, with an overall test duration of 25 min 12 sec ± 5 min 10 sec, were feasible to perform in primary school-aged children, taking into account some practical adaptations. Concerning the video head impulse test, no clinically relevant sex and age effects were noted. However, t tests revealed significant differences for the mean gain of the horizontal (right > left; t[139] = 14.563; p < 0.001) and posterior semicircular canals (left > right; t[139] = -4.823; p < 0.001) between both sides. For the cVEMP assessment, no laterality differences were observed for any of the parameters, but a significantly shorter N1 latencies in the youngest age categories (<8 years), compared with the oldest groups were observed [F(6,118) = 8.336; p < 0.001; partial ƞ² = 0.298]. For all oVEMP parameters, no laterality, sex, or age differences were seen. On the basis of the presented normative data, cutoff criteria were proposed with accompanying clinical recommendations to perform vestibular function testing in this target population.

CONCLUSIONS

This is the first study in a large group of school-aged children offering normative data and age trends of an age-appropriate vestibular test protocol that evaluates the integrity of all parts of the peripheral vestibular organ. The reported normative values and clinical cutoff values will enable appropriate and age-specific interpretation of clinical and scientific results. Moreover, in combination with extensive history taking, and additional vestibular testing (e.g., rotatory chair test, caloric testing) when needed, the results of this study may support clinicians in the diagnosis of side-specific and location-specific vestibular deficits, which is required for accurate counseling and referral for further follow-up and/or intervention.

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.

Pediatric Vestibular Assessment: Clinical Framework

OBJECTIVES

Although vestibular deficits can have severe repercussions on the early motor development in children, vestibular assessment in young children has not yet been routinely integrated in clinical practice and clear diagnostic criteria to detect early vestibular deficits are lacking. In young children, specific adjustments of the test protocol are needed, and normative data are age-dependent as the vestibular pathways mature through childhood. Therefore, this study aims to demonstrate the feasibility of an extensive age-dependent vestibular test battery, to provide pediatric normative data with the concurrent age trends, and to offer a clinical framework for pediatric vestibular testing.

DESIGN

This normative study included 133 healthy children below the age of 4 years (mean: 22 mo, standard deviation: 12.3 mo, range: 5-47 mo) without history of hearing loss or vestibular symptoms. Children were divided into four age categories: 38 children younger than 1 year old, 37 one-year olds, 33 two-year olds, and 25 three-year olds. Children younger than 3 years of age were examined with the video Head Impulse Test (vHIT) of the horizontal semicircular canals, cervical vestibular evoked myogenic potentials (cVEMP) with bone conduction stimuli, and the rotatory test at 0.16, 0.04, and 0.01 Hz. In 3-year old children, the vHIT of the vertical semicircular canals and ocular vestibular evoked myogenic potentials (oVEMP) using a minishaker were added to the protocol.

RESULTS

The horizontal vHIT appeared to be the most feasible test across age categories, except for children younger than 1-year old in which the success rate was the highest for the cVEMP. Success rates of the rotatory test varied the most across age categories. Age trends were found for the vHIT as the mean vestibulo-ocular reflex (VOR) gain increased significantly with age (r = 0.446, p < 0.001). Concerning the cVEMP, a significant increase with age was found for latency P1 (r = 0.420, p < 0.001), rectified interpeak amplitude P1-N1 (r = 0.574, p < 0.001), and averaged electromyographic (EMG) activity (r = 0.430, p < 0.001), whereas age trends for the latency N1 were less pronounced (r = 0.264, p = 0.004). Overall, the response parameters of the rotatory test did not show significant age effects ( p > 0.01), except for the phase at 0.01 Hz (r = 0.578, p < 0.001). Based on the reported success rates and age-dependent normative vestibular data, straightforward cutoff criteria were proposed (vHIT VOR gain < 0.7, cVEMP rectified interpeak amplitude < 1.3, oVEMP interpeak amplitude < 10 µV) with accompanying clinical recommendations to diagnose early vestibular impairment.

CONCLUSIONS

In this large cohort of typically developing children below the age of 4 years, the vHIT and cVEMP were the most feasible vestibular tests. Moreover, the age-dependent normative vestibular data could specify age trends in this group of young children. Finally, based on the current results and clinical experience of more than ten years at the Ghent University Hospital (Belgium), a clinical framework to diagnose early vestibular deficits in young patients is proposed.

A longitudinal study of cortical auditory maturation and implications of the short inter-implant delay in children with bilateral sequential cochlear implants

OBJECTIVE

This longitudinal study aimed to investigate the maturational development of P1 latency and the effects of a short inter-implant delay in children who received bilateral sequential cochlear implants.

MATERIALS AND METHODS

Fourteen children (first CI mean age: 1.4 ± 0.4 years and Second CI mean age: 3.3 ± 0.5 years) who had received sequential bilateral cochlear implants during the sensitive period for auditory maturation participated in our study. The speech-evoked cortical P1 response was recorded after the activation of the second CI at four intervals (implant activation, 3 months, 6 months, 12 months) under three listening conditions (first CI, second CI, binaural).

RESULTS

Our results showed that the P1 latencies of the second CI reached normative values within 3 months, but did not reach the P1 latency of the first CI until 12 months. We found a strong negative correlation between the inter-implant delay and the P1 latencies of the second CI when the second CI was activated.

CONCLUSION

Changes in cortical auditory responses over time resulted in normal auditory maturation in children with sequential bilateral cochlear implants during the sensitive period. The results also provide evidence that the timing of auditory experience in the first ear during the sensitive period may influence the speed of compensation in children receiving sequential cochlear implants.

Vestibular Infant Screening-Flanders: What is the Most Appropriate Vestibular Screening Tool in Hearing-Impaired Children?

OBJECTIVES

As children with sensorineural hearing loss have an increased risk for vestibular impairment, the Vestibular Infant Screening-Flanders project implemented a vestibular screening by means of cervical vestibular evoked myogenic potentials (cVEMP) at the age of 6 months for each child with hearing loss in Flanders (Belgium). Given that vestibular deficits can affect the child's development, this vestibular screening should allow early detection and intervention. However, less is currently known about which screening tool would be the most ideal and how vestibular impairment can evolve. Therefore, this study aimed to determine the most appropriate tool to screen for vestibular deficits, to assess the necessity of vestibular follow-up, and to set clinical guidelines for vestibular screening in children with hearing loss.

DESIGN

In total, 71 children with congenital or early-onset sensorineural hearing loss were enrolled (mean age at first appointment = 6.7 months). Follow-up was provided at 6 months, 1, 2, and 3 years of age. Below three years of age, the video Head Impulse Test (vHIT) of the horizontal semicircular canals (SCC), the cVEMP, and the rotatory test at 0.16, 0.04, and 0.01 Hz were applied. At 3 years of age, the vHIT of the vertical SCC and ocular vestibular evoked myogenic potentials (oVEMP) were added. To evaluate early motor development, the Alberta Infant Motor Scale (AIMS) results at 6 months and 1-year old were included.

RESULTS

At 6 months of age, the highest success rate was obtained with the cVEMP (90.0%) compared to the vHIT (70.0%) and the rotatory test (34.3-72.9%). Overall, vestibular deficits were found in 20.0% of the children, consisting of 13.9% with both SCC and otolith deficits (bilateral: 9.3%, unilateral: 4.6%), and 6.1% with unilateral isolated SCC (4.6%) or otolith (1.5%) deficits. Thus, vestibular deficits would not have been detected in 4.6% of the children by only using the cVEMP, whereas 1.5% would have been missed when only using the vHIT. Although vestibular deficits were more frequently found in severe to profound hearing loss (28.6%), characteristics of vestibular function were highly dependent on the underlying etiology. The AIMS results showed significantly weaker early motor development in children with bilateral vestibular deficits ( p = 0.001), but could not differentiate children with bilateral normal vestibular function from those with unilateral vestibular deficits ( p > 0.05). Progressive or delayed-onset vestibular dysfunction was only found in a few cases (age range: 12-36 months), in which the hearing loss was mainly caused by congenital cytomegalovirus (cCMV).

CONCLUSIONS

The cVEMP is the most feasible screening tool to assess vestibular function in 6-months-old children with hearing loss. Although the majority of children with vestibular deficits are detected with the cVEMP, the vHIT seems even more sensitive as isolated SCC deficits are associated with specific etiologies of hearing loss. As a result, the cVEMP is an appropriate vestibular screening tool, which is advised at least in severe to profound hearing loss, but certain etiologies require the addition of the vHIT (i.e., cCMV, meningitis, cochleovestibular anomalies with or without syndromic hearing loss).

Mild therapeutic hypothermia protects against inflammatory and proapoptotic processes in the rat model of cochlear implant trauma

OBJECTIVE

Mild therapeutic hypothermia (MTH) has been demonstrated to prevent residual hearing loss from surgical trauma associated with cochlear implant (CI) insertion. Here, we aimed to characterize the mechanisms of MTH-induced hearing preservation in CI in a well-established preclinical rodent model.

APPROACH

Rats were divided into four experimental conditions: MTH-treated and implanted cochleae, cochleae implanted under normothermic conditions, MTH only cochleae and un-operated cochleae (controls). Auditory brainstem responses (ABRs) were recorded at different time points (up to 84 days) to confirm long-term protection and safety of MTH locally applied to the cochlea for 20 min before and after implantation. Transcriptome sequencing profiling was performed on cochleae harvested 24 h post CI and MTH treatment to investigate the potential beneficial effects and underlying active gene expression pathways targeted by the temperature management.

RESULTS

MTH treatment preserved residual hearing up to 3 months following CI when compared to the normothermic CI group. In addition, MTH applied locally to the cochleae using our surgical approach was safe and did not affect hearing in the long-term. Results of RNA sequencing analysis highlight positive modulation of signaling pathways and gene expression associated with an activation of cellular inflammatory and immune responses against the mechanical damage caused by electrode insertion.

SIGNIFICANCE

These data suggest that multiple and possibly independent molecular pathways play a role in the protection of residual hearing provided by MTH against the trauma of cochlear implantation.

Evaluation and management of paediatric vertigo

PURPOSE OF REVIEW

This review summarizes the most current information on cause, evaluation and treatment of dizziness in children.

RECENT FINDINGS

There has been an increased understanding of the multifactorial cause of dizziness in the paediatric population. Quantitative vestibular testing is increasingly used and valuable as a diagnostic adjunct. Vestibular rehabilitation, migraine hygiene, psychological therapies, pharmaceuticals and/or surgery can be used as well tolerated and effective treatments for vertigo in children and adolescents when tailored to cause.

SUMMARY

Paediatric vertigo can be effectively evaluated through careful history taking and physical examination along with adjunctive tests, such as vestibular testing and audiometry, when appropriate. Options for treatment of vestibular disorders in children and adolescents have greatly expanded in recent years allowing for the effective management of nearly all cases of paediatric vertigo, though a multimodal and/or multidisciplinary approach is often needed.

Task force Guideline of Brazilian Society of Otology ‒ hearing loss in children - Part I ‒ Evaluation

OBJECTIVES

To provide an overview of the main evidence-based recommendations for the diagnosis of hearing loss in children and adolescents aged 0 to 18 years.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on childhood hearing loss were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The evaluation and diagnosis of hearing loss: universal newborn hearing screening, laboratory testing, congenital infections (especially cytomegalovirus), genetic testing and main syndromes, radiologic imaging studies, vestibular assessment of children with hearing loss, auditory neuropathy spectrum disorder, autism spectrum disorder, and noise-induced hearing loss.

CONCLUSIONS

Every child with suspected hearing loss has the right to diagnosis and appropriate treatment if necessary. This task force considers 5 essential rights: (1) Otolaryngologist consultation; (2) Speech assessment and therapy; (3) Diagnostic tests; (4) Treatment; (5) Ophthalmologist consultation.

Predicting Early Vestibular and Motor Function in Congenital Cytomegalovirus Infection

OBJECTIVES

Congenital cytomegalovirus (cCMV) can affect vestibular function, which is an important cornerstone for early motor development. This study aims to identify risk factors for early vestibular dysfunction with severe repercussions on the motor outcome.

METHODS

This prospective cohort study included 169 cCMV-patients with complete vestibular assessment (lateral video Head Impulse Test and cervical Vestibular Evoked Myogenic Potentials) before the age of 18 months (mean 8.9, standard deviation 3.27 months). Motor results using the Alberta Infant Motor Scale were collected in 152 of these patients. Logistic and linear regression models were applied to identify risk factors for the vestibular and motor outcomes, respectively.

RESULTS

The odds of developing early vestibular dysfunction were 6 times higher in patients presenting with hearing loss at birth compared to those born with normal hearing (p = .002). Within the latter group, significant predictors for vestibular dysfunction were (delayed-onset) hearing impairment at the time of vestibular testing (p = .003) and the presence of periventricular cysts on magnetic resonance imaging (p = .005). Remarkably, none of the patients infected during the third trimester of pregnancy (n = 14) developed early vestibular dysfunction. On average, vestibular-impaired patients had a z-score on the Alberta Infant Motor Scale that was 1.17 points lower than patients without vestibular deficit (p < .001).

CONCLUSION

Early vestibular loss can have a significant adverse effect on motor development. Hearing and cranial imaging findings could facilitate the widespread implementation of a (targeted) vestibular assessment approach in the cCMV-population.

LEVEL OF EVIDENCE

3 Laryngoscope, 2022.

Vestibular function in children with cochlear implant: Impact and evaluation

Over the last 30 years, cochlear implant (CI) has been dedicated to improving the rehabilitation of hearing impairments. However, CI has shown potential detrimental effects on vestibular function. For children, due to atypical symptoms and difficulty in cooperating with vestibular function tests, systematic and objective assessments of vestibular function with CI have been conducted sparsely. This review focuses on the impact of vestibular function in children with CI and summarized the evaluation of vestibular function in children. In addition, some recommended strategies are summarized and proposed.