Systematic Review on Vestibular Symptoms in Patients With Enlarged Vestibular Aqueducts

Evaluation and diagnosis of pediatric patients with dizziness

PURPOSE OF REVIEW

Children experiencing dizziness frequently go unevaluated or experience delays in correct diagnosis due to systemic and inherent barriers. While most causes of pediatric dizziness do not involve the peripheral vestibular system, otolaryngologists are frequently consulted for expert opinion. This study offers a broad overview of the leading causes of pediatric dizziness and imbalance to assist otolaryngologists with evaluating and managing this challenging population.

RECENT FINDINGS

Evaluation of children with dizziness should exclude serious central nervous system conditions. Approximately 70% of nonhazardous cases of pediatric dizziness are caused by migraine-related conditions, concussion, or functional disorders. Etiologies for peripheral vestibular dysfunction include inner ear malformations and vestibular disorders more commonly seen in adults. Audiometric and vestibular testing can provide helpful information, although correct diagnosis depends on a detailed history.

SUMMARY

Otolaryngologists should be familiar with the conditions that cause dizziness in children. While most underlying causes are outside their scope of practice, understanding possible etiologies can facilitate correct diagnosis and appropriate management.

Enlarged vestibular aqueduct as a cause of postneonatal deafness

INTRODUCTION

The enlarged vestibular aqueduct (EVA) is the most frequent malformation of the inner ear associated with sensorineural hearing loss (5-15%). It exists when the diameter in imaging tests is greater than 1.5 mm at its midpoint. The association between hearing loss and EVA has been described in a syndromic and non-syndromic manner. It can appear as a familial or isolated form and the audiological profile is highly variable. The gene responsible for sensorineural hearing loss associated with EVA is located in the same region described for Pendred syndrome, where the SCL26A4 gene is located.

OBJECTIVE

To describe a series of children diagnosed with EVA in order to study their clinical and audiological characteristics, as well as the associated genetic and vestibular alterations.

METHOD

Retrospective study of data collection of children diagnosed with EVA, from April 2014 to February 2023.

RESULTS

Of the 17 cases, 12 were male and 5 were female. 5 of them were unilateral and 12 bilateral. In 5 cases, a cranial traumatism triggered the hearing loss. Genetic alterations were detected in 3 cases: 2 mutations in the SCL26A4 gene and 1 mutation in the MCT1 gene. 13 patients (76.5%) were rehabilitated with hearing aids and 9 of them required cochlear implantation.

DISCUSSION

The clinical importance of AVD lies in the fact that it is a frequent finding in the context of postneonatal hearing loss. It is convenient to have a high suspicion to diagnose it with imaging tests, to monitor its evolution, and to rehabilitate early.

Large Vestibular Aqueduct-Associated Symptoms: Endolymphatic Duct Blockage as a Surgical Treatment

OBJECTIVE

This study aimed to evaluate the effectiveness of endolymphatic duct blockage (EDB) on dizziness control in patients with a large vestibular aqueduct (LVA) and to evaluate its effect on hearing.

STUDY DESIGN

This is a prospective nonrandomized study.

SETTING

Five adults and one child with dizziness and five children with progressive hearing loss were referred to our tertiary centers.

METHODS

The dizziness handicap inventory (DHI) and DHI-PC (dizziness handicap inventory-patient caregiver) questionnaires were used before and after surgery. All patients underwent a preoperative temporal bone HRCT scan and pure tone audiometry one day before surgery, then four and twelve months after surgery and at the last follow-up. The mean follow-up time was 5.6 years. Student's t-test was used to compare DHI/-PC results.

RESULTS

The DHI scores were 44, 24, 84, 59 and 56 before surgery, respectively, for Patients 1 to 5. The DHI scores at four months was significantly different, i.e., 4, 6, 0, 7 and 18 (p = 0.001). No differences were found between 4 and 12 months. Patient 6 (child) had Trisomy 21; their DHI-PC score dropped from 38 (preoperative score) to 8 (postoperative score), showing no activity limitations; clinical evaluation showed the complete resolution of symptoms. We found no significant differences between hearing loss before the surgery and at 1 and 12 months post operation for four adult patients. Our fifth adult patient's hearing changed from severe to profound SNHL. For 5 out of 6 pediatric patients, preoperative PTA and mean ABG were 63 dB and 20 dB, respectively; postoperatively, they improved to 42 dB and 16 dB, respectively. The hearing loss level for the sixth pediatric patient dropped from moderate (PTA = 42 dB) to severe (PTA = 85 dB) due to an opening of the endolymphatic sac and a sudden leak of the endolymph.

CONCLUSIONS

EDB, using two titanium clips, seems to be helpful for controlling vestibular symptoms and for stabilizing hearing or even to improve hearing in 82% of cases. Nevertheless, there is a risk of hearing worsening.

Evidence of vestibular dysfunction in children with enlarged vestibular aqueduct

OBJECTIVE

To investigate the occurrence and characteristics of balance and vestibular deficits in pediatric patients with enlarged vestibular aqueduct (EVA).

MATERIALS AND METHODS

Retrospective review of 53 children with EVA who underwent a comprehensive vestibular evaluation in our pediatric balance and vestibular program. Laboratory testing included videonystagmography (VNG), rotary chair, video head impulse testing (vHIT), vestibular evoked myogenic potential (VEMP), subjective visual vertical (SVV) and Sensory Organization Test (SOT) in posturography.

RESULTS

The mean age of these children, 31 girls and 22 boys, was 7.1 years (SD = 4.8). Among these 53 children, 16 had unilateral EVA (7 on the left side and 9 on the right side) and 37 had bilateral EVA, in which genetic testing confirmed 5 cases of Pendred syndrome. Abnormal testing results were found in 58% (11/19) on SOT, 67% (32/48) on rotary chair, 55% (48/88 of ears) on VEMP, 30% (8/27) on vHIT, 39% (7/18) on SVV, and 8% (4/53) on VNG.

CONCLUSIONS

Vestibular dysfunction may be a common finding in children with EVA. Clinicians who provide medical care for children with EVA need to be familiar with signs of potential balance and vestibular impairments. Although performing vestibular evaluation on young children with EVA can be difficult, objective testing is important in order to identify any potential vestibular deficit in these pediatric patients so that proper vestibular rehabilitation and balance retraining can be provided.

Vestibular anomalies and dysfunctions in children with inner ear malformations: A narrative review

About 20% of children with congenital hearing loss present malformations of the inner ear. In the past few years much has been understood about the morphology and function of the anterior part of the labyrinth, since hearing loss may have a dramatic effect on the overall development of a child. Nowadays, for most of them, a chance for hearing rehabilitation is available, making hearing loss a treatable condition. The anomalies range from the lack of development of the whole inner ear to specific anomalies of isolated structures. Despite the frequent concomitant involvement of the posterior part of the labyrinth, this part of the inner ear is frequently neglected while discussing its morphology and dysfunction. Even though vestibular and balance function/dysfunction may have a significant impact on the global development of children, very little is known about these specific disorders in patients with inner ear malformations. The aim of this review is to summarize the available literature about vestibular anomalies and dysfunctions in children with inner ear malformations, discussing what is currently known about the topic.

Sudden bilateral hearing loss after vestibular-evoked myogenic potentials

This case report presents bilateral hearing loss after vestibular-evoked myogenic potential (VEMP) testing. The loud acoustic stimulus used in VEMP testing can cause noise-induced hearing loss in some cases with high sensitivity to noise exposure or by exceeding individual cochlear safety thresholds.