Unlateral total deafness in children. Clinical problems with a special view to vestibular function

Vestibular Migraine of Childhood and Recurrent Vertigo of Childhood: Diagnostic criteria Consensus document of the Committee for the Classification of Vestibular Disorders of the Bárány Society and the International Headache Society

This paper describes the diagnostic criteria for “Vestibular Migraine of Childhood”, “probable Vestibular Migraine of Childhood” and “Recurrent Vertigo of Childhood” as put forth by the Committee for the Classification of Vestibular Disorders of the Bárány Society (ICVD) and the Migraine Classification subgroup of the International Headache Society. Migraine plays an important role in some subgroups of children with recurrent vertigo. In this classification paper a spectrum of three disorders is described in which the migraine component varies from definite to possibly absent. These three disorders are: Vestibular Migraine of Childhood, probable Vestibular Migraine of Childhood and Recurrent Vertigo of Childhood. The criteria for Vestibular Migraine of Childhood (VMC) include (A) at least five episodes with vestibular symptoms of moderate or severe intensity, lasting between five minutes and 72 hours, (B) a current or past history of migraine with or without aura, and (C) at least half of episodes are associated with at least one migraine feature. Probable Vestibular Migraine of Childhood (probable VMC) is considered when at least three episodes with vestibular symptoms of moderate or severe intensity, lasting between five minutes and 72 hours, are accompanied by at least criterion B or C from the VMC criteria. Recurrent Vertigo of Childhood (RVC) is diagnosed in case of at least three episodes with vestibular symptoms of moderate or severe intensity, lasting between 1 minute and 72 hours, and none of the criteria B and C for VMC are applicable. For all disorders, the age of the individual needs to be below 18 years old. It is recommended that future research should particularly focus on RVC, in order to investigate and identify possible subtypes and its links or its absence thereof with migraine.

Nonsyndromic Isolated Unilateral Cochlear Nerve Aplasia without Narrow Internal Auditory Meatus: A Previously Overlooked Cause of Unilateral Profound Deafness in Childhood

Objectives:

Juvenile or adolescent unilateral profound sensorineural deafness (worldwide prevalence, 0.1% to 0.2%) has been attributed to postnatal viral infection, sudden deafness, prenatal and perinatal problems including maternal rubella and viral infections, congenital inner ear anomalies, and other factors. Herein, 2 cases are reported and another potentially important cause of unilateral profound hearing loss is proposed.

Methods:

Two nonsyndromic cases of a presently “very rare” cause of pediatric unilateral deafness are presented as a retrospective case study.

Results:

The 2 patients showed isolated aplasia of the cochlear nerve; other branches of the eighth cranial nerve, the seventh nerve, and the inner ear were spared, and there was no anomaly of the internal auditory meatus. Both functional and imaging studies confirmed the isolated lesion (absence) of the cochlear nerve.

Conclusions:

Because of the absence of bony abnormalities, such cases may have been overlooked. The authors would like to advocate this isolated anomaly of the cochlear nerve as an important cause of juvenile or adolescent unilateral profound deafness.

Temporal bone high-resolution computed tomography in non-syndromic unilateral hearing loss in children

OBJECTIVE

The aim of this study was to disclose possible inner ear abnormalities/pathologies by means of high-resolution computed tomography (HRCT) of the temporal bone (TBHRCT) in children with unilateral hearing loss (UHL).

METHODS

Retrospective review of audiological evaluation and TBHRCT in 22 children with UHL.

RESULTS

Two thirds of the children showed profound hearing loss. Review of HRCT scans identified inner ear malformations/pathologies in 9 (41%) cases and a high jugular bulb (HJB), always dehiscent with the vestibular aqueduct, in another 5 (22%). Inner ear malformations included enlarged vestibular aqueduct, common cavity and cochleovestibular hypoplasia, while labyrinthine ossification was the detected pathology. In 1 child, the common cavity of the right ear was associated with congenital melanocytic naevus of the left eyelid and lipomeningocele. To the best of our knowledge, this condition has never been described.

CONCLUSIONS

The aetiology of UHL may be revealed in more than half of patients by means of TBHRCT. Besides common inner ear abnormalities, TBHRCT should be evaluated carefully to rule out HJB, dehiscences, diverticulum or erosion of inner ear structures.

A case of unilateral sensorineural hearing loss caused by a venous malformation of the internal auditory canal

Intracranial vascular malformations can be classified as telangiectasis, varices, cavernous malformations, venous malformations (VMs), or arteriovenous malformations. VMs are congenital vascular malformations of the brain thought to be anomalies of the normal venous drainage. VMs are the most common intracranial vascular malformations documented by brain imaging and by autopsy series. However, vascular lesions of the internal auditory canal (IAC) are extremely rare. We report here a case of a VM arising within the IAC and expanding to the brainstem, causing a unilateral profound sensorineural hearing loss (SNHL). To the best of our knowledge, this is the first documented case of a VM as a rare cause of a unilateral SNHL in a child.

Isolated cochlear nerve hypoplasia with various internal auditory meatus deformities in children

OBJECTIVES

We report neuro-otological findings in isolated congenital cochlear nerve hypoplasia with various bony deformities and evaluate relationships between functional impairment and the radiologic dimensions of the internal auditory meatus (IAM).

METHODS

We performed imaging and functional analyses on consecutive juvenile or adolescent patients between 2001 and 2005 with "isolated" unilateral hypoplasia of the cochlear nerve, without inner ear anomaly or other deformities.

RESULTS

Among 20 patients with unilateral profound deafness who underwent imaging studies, 10 (50%) passed the inclusion criteria. In all affected ears, auditory brain stem responses were absent and the speech discrimination score was very poor (0% to 5%). Distortion product otoacoustic emissions were good in 2 ears, fair in 1 ear, and poor in 7 ears. Caloric responses were absent in 2 ears, reduced in 3 ears, and normal in 5 ears. Inferior vestibular nerve function and facial nerve function were normal in all ears. Distortion product otoacoustic emissions and caloric responses tended to be better in ears with less severe narrowing of the IAM.

CONCLUSIONS

The risk of co-involvement of the inner ear and superior vestibular nerve functions is higher in the presence of a narrower bony IAM. Cochlear nerve hypoplasia is proposed as one of the most important causes of juvenile unilateral deafness because of its unexpectedly high incidence.

Assessment of vestibular function of infants and children with congenital and acquired deafness using the ice-water caloric test, rotational chair test and vestibular-evoked myogenic potential recording

CONCLUSIONS

The vestibular function can be assessed by ice-water caloric test, rotational chair test and VEMP recording in severely hearing impaired infants and young children, and 85% of these patients showed abnormal responses in these tests.

OBJECTIVES

To evaluate the vestibular function of infants and young children with congenital and acquired deafness, we examined the semicircular canal and otolith function in their early childhood.

MATERIALS AND METHODS

Our subjects were 20 children (11 boys, 9 girls; age range 31-97 months, mean age 54.2 months) with severe hearing impairment. Their vestibular functions were assessed by the ice-water caloric test, rotational chair test and vestibular-evoked myogenic potential (VEMP) recording.

RESULTS

Among these 20 severely hearing impaired children, only 3 (15%) showed normal responses in the caloric test, rotational chair test and VEMP recording bilaterally. Seven (35%) showed responses asymmetrically in the caloric test despite normal responses in the rotational chair test and VEMP recording bilaterally. Five (25%) showed hyporeflexia or areflexia in the caloric test bilaterally, but showed normal responses in the rotational chair test and normal reproducible or decreased VEMPs. Five (25%) showed no responses at all in the caloric test, rotational chair test and VEMP recording.

Function of semicircular canals, utricles and saccules in deaf children

OBJECTIVE

To study vestibular function in deaf children.

MATERIAL AND METHODS

In 36 deaf children the function of the semicircular canals, saccules and utricles was measured by means of caloric testing, recordings of vestibular-evoked myogenic potentials (VEMPs) and measurements of the subjective visual horizontal (SVH) at different body tilts, respectively.

RESULTS

In total, 30% of subjects had caloric hypo- or areflexia and 24% had a caloric asymmetry. VEMPs were weak or absent bilaterally in 22% of cases, and asymmetric in 19%. Regarding the utricle, 17% of subjects had a pathologically reduced perception of roll tilt to both sides and 25% had an asymmetry. In total, 30% of subjects were pathologic in all 3 tests and 30% were completely normal. Semicircular canal function correlated best with the function of the saccule. If hearing was better than 90 dB (pure-tone average of 0.5, 1.0 and 2.0 kHz) vestibular function was often normal. For hearing levels of 100-120 dB, otolith function declined significantly.

CONCLUSIONS

Vestibular function tends to be preserved up to a point where hearing is nearly extinct. Hearing level correlates more closely with otolith function, especially that of the utricle, than with semicircular canal function.

Prevalence of unilateral hearing loss in children: the National Health and Nutrition Examination Survey II and the Hispanic Health and Nutrition Examination Survey

We compared population-based prevalence rates of unilateral hearing loss among African-American, Cuban-American, Mexican-American, Puerto Rican, and non-Hispanic White children 6 to 19 yr of age. The prevalence (per thousand) of overall hearing loss (average decibel HTL >30) ranged from 6.4 in Mexican-Americans to 12.3 in Cuban-Americans. The prevalence of moderate to profound unilateral hearing loss (average decibel HTL >50) ranged from 0.0 in Cuban-Americans to 5.2 in Puerto Ricans. No statistically significant age or gender differences were found within any of the ethnic groups. Among these five ethnic groups, it is estimated that approximately 391,000 school-aged children in the United States have unilateral hearing loss.

Prevalence and etiology of unilateral sensorineural hearing impairment in a Finnish childhood population

A retrospective study was undertaken on the prevalence and etiology of unilateral sensorineural hearing impairment (> 25 dB at 0.5-4 kHz, including mixed hearing impairments with bone conduction thresholds > or = 25 dB) among children born between 1972 and 1986 in a province of eastern Finland. Only patients who had been diagnosed before the age of 10 years were included. A total of 84 children with such an unilateral hearing loss were identified, with prevalence of 1.7 per 1000 live births. A significant decline from the prevalence of 2.2 per 1000 in the 1970s to the prevalence of 1.2 per 1000 in the 1980s was observed, which was mainly due to the disappearance of hearing losses caused by mumps and measles in the 1980s and the decrease in cases attributed to otitis media. In agreement with some previous studies, a considerable male predominance was present. Thirty-five percent of the hearing losses were profound (> 95 dB) and 15% were severe (71-95 dB). Etiology of the hearing impairment was estimated as genetic in 2%, congenital non-genetic in 12%, delayed-onset non-genetic in 35% and remained unknown in 51%.

Electronystagmography findings in child unilateral sensorineural hearing loss of probable viral origin

We studied the labyrinthine function in a group of 72 children aged between 4 and 14 years affected by unilateral sensorineural hearing loss of probable viral origin. From the analysis of the results obtained we confirm the concomitance of cochlear and vestibular damage. However, there were no statistically significant differences between type of audiogram at onset of hearing loss and type of electronystagmography (ENG), while we found a direct correlation between the presence of vertigo or dizziness and type of ENG. Finally hearing recovery was influenced by the presence of vertigo or labyrinthine function alterations. The results of statistical analysis confirmed a significant statistical difference between patients with vertigo or dizziness (V(+)) and those without vertigo (V(-)) and also between patients with ENG 3 (subjects with spontaneous nystagmus or positional nystagmus and canal paresis ipsilateral to the cochlear lesion) and those with ENG 1 (subjects without spontaneous nystagmus or positional nystagmus and with normal vestibular reflex). In fact, hearing recovery was worse in V(+) group and in ENG 3 group.

A case of delayed endolymphatic hydrops

A 30-year-old male with delayed endolymphatic hydrops was given a sac operation. An intradural portion of the endolymphatic sac was resected and the epithelial surface was examined under a scanning electron microscope. The epithelium showed fibrous degeneration and disappearance of the epithelial cells. Pathogenesis of degeneration of the endolymphatic sac is discussed.

Endolymphatic hydrops induced by noise exposure

In animal with cochlear deafness induced by firecracker explosion, fibrous degeneration of the endolymphatic sac was observed 4 months after the disappearance of Preyer's reflex. Endolymphatic hydrops induced by noise exposure may develop as the results of degeneration of the endolymphatic sac due to cochlear deafness by acoustic trauma after the lapse of a long period of time.

Unilateral sensorineural hearing loss in children and auditory performance with respect to right/left ear differences

A group of children suffering from unilateral hearing loss (UHL) were evaluated. Serological tests were performed and vaccination against mumps was offered if negative. In 43.6% of the cases mumps was the plausible cause but a further 33.3% had positive serological tests for mumps without having had the clinical disease. Due to the long delay in the diagnosis of UHL, the question of mumps as major causative agent can be solved only when the results from prophylactic vaccination become apparent in the future. Thirty children aged 10-16 years underwent further audiological examination in order to detect any difference between right and left UHL. The results of word discrimination scores (PB lists) show the well known superiority of binaural v. monaural hearing but was too crude for a detailed analysis of ear difference. An interrupted speech test in background noise shows, however, that right ear impaired children perform significantly poorer than the left ear impaired and are at risk whenever reverberation conditions are poor.

Unilateral sensorineural hearing loss in children less than 15 years of age

1-10 years after the first examination, 56 children below 15 years of age with unilateral sensorineural hearing loss were re-examined with a test-battery consisting of puretone and speech audiometry, stapedius reflex tests, caloric tests, brainstem response audiometry and otoneurological tests. In no case was an acoustic tumour suspected on the basis of the test results. A small progression of the hearing loss occurred in only one ear. In no case did the healthy ears develop hearing loss during the observation period. Diagnostic procedures can in most of such cases be limited to pure-tone audiometry. Follow-up is indicated because some patients require advice considering education and evaluation regarding fitting of a hearing aid.

The abnormal temporal bone in the "normal" deaf

This study is concerned with the incidence and type of temporal bone anomalies that might be present in persons who, apart from their deafness, are normal. It also attempts to correlate demonstrated abnormalities with the etiology of deafness. Review of the results will permit a reassessment of the value of roentgenographic studies in the routine evaluation of deaf children. One hundred and four deaf students, 3 to 21 years of age, were studied by physical examination, audiometry, and temporal bone tomography. A pertinent history was requested, and appropriate medical records were obtained. Roentgenographically demonstrable abnormalities of the temporal bones were present in 19 students (18%) or 28 temporal bones (13%). Meningitis was the only entity to which a specific pathologic change could be ascribed. The number of abnormalities found in this population was significant and should re-emphasize the importance of temporal bone tomography in the total evaluation of deaf children.

Unilateral nerve deafness in childhood: a possible vascular etiology

Unilateral sensorineural hearing loss in an eight-year-old girl, with radiographic evidence suggesting occlusion of the anterior inferior cerebellar artery, is reported. Previous to the present report, a vascular etiology of this disorder has not been demonstrated.