An audio-vestibular study of 128 children presenting to a specializedpaediatric audio-vestibular clinic: Should every child withhearing impairment have vestibular function assessed?

EWA RAGLAN1,2, PAUL RADOMSKIJ1, JOHN VENESS2 & KAUKAB RAJPUT2

1Department of Audiological Medicine, St. George’s Healthcare NHS Trust, London, and 2Department of Audiological

Medicine, Great Ormond Street Hospital for Sick Children, London, UK

AbstractThis is a study of the vestibular function of 128 children with a varying degree/type and cause of hearing impairmentpresenting to a specialized paediatric vestibular service. It shows that there are some syndromic and non-syndromicconditions that may be associated with vestibular dysfunction. Due to the relatively small cohort of children tested with alesser degree of hearing impairment, the study is unable to confirm the proportional dependence of the presence ofvestibular dysfunction with the degree of hearing impairment but it confirms such a trend. However, it supports earlierfindings that profound hearing loss due to autosomal recessive inheritance associated with mutation in the Connexin 26gene is not associated with vestibular dysfunction of the lateral semicircular canal. It further shows that children withprofound hearing loss and lack of vestibular function present with a history of gross motor developmental delay. It arguesthat the referral of a child for vestibular assessment should be based on the knowledge of syndromic/non-syndromicconditions associated frequently with inner ear anomalies as well as the knowledge of the noxious factors that may lead tovestibular dysfunction and also hearing impairment such as meningitis, rubella, birth risk factors and ototoxicity.

Key words: children, hearing impairment, vestibular dysfunction, Connexin 26

Introduction

Several factors such as anatomical proximity, com-

mon developmental processes, possible susceptibility

to the effects of the same developmental or other

noxious factors all lead to the understanding that

there is a high probability of hearing disorders being

associated with vestibular disorders.

Indeed, this correlation has been documented by a

number of authors (1�3). With the increasing pre-

valence of permanent hearing impairment associated

with increasing age in children (4,5), it is reasonable

to conclude that prevalence of vestibular disorders

should also increase. The prevalence of vestibular

disorders in children in the community is not well

known, although some studies (6) indicate that there

may be an increased prevalence with age. Moreover,

the prevalence of vestibular disorders in children

with hearing impairment ranges between 30% and

40% in different studies, with an increased preva-

lence in children with profound hearing loss (7). It

has been reported that about 30% of children with

congenital autosomal dominant deafness would have

either a unilateral or bilateral vestibular disorder

(8,9). Children with autosomal recessive conditions

(10) and those with progressive mixed hearing loss

were also found to have vestibular abnormalities

(11,12).

Methods

Subjects

One hundred and twenty-eight children of both

sexes with hearing impairment, ranging from 11

months to 18 years of age (mean age, 8�10 years)

were referred to the specialized (third level of care)

paediatric vestibular clinic and studied.

The children with hearing impairments were

referred to the clinic because of symptoms of

dizziness, imbalance or as part of assessment for

pre-cochlear implantation.

Each child had a detailed clinical history taken

(inclusive of motor development status (13)), eye

movement examination, gait and stance tests

on hard floor and on thick padded foam as well as

Correspondence: Ewa Raglan, Great Ormond Street Hospital for Sick Children, Great Ormond Street, London WC1, UK. Tel: �44 207 813 8430.

Fax: �0207 829 7877. E-mail: RaglaE@gosh.nhs.uk

Audiological Medicine. 2009; 7: 143�147

ISSN 1651-386X print/ISSN 1651-3835 online # 2009 Informa UK Ltd. (Informa Healthcare, Taylor & Francis As)

DOI: 10.1080/16513860903205683

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the head thrust test (14) performed. The audio-

vestibular assessment was followed by aetiological

studies in accordance with the established BAAP

protocol (15) for patients presenting with hearing

impairment. The diagnosis of a child’s medical

condition was made on the basis of the clinical

history, examination and results of the aetiological

tests.

Audiometric assessment

We performed audiometric assessment inclusive of

age appropriate behavioural hearing tests (16),

which was supported by auditory electrophysiologi-

cal results (ABR) where appropriate, and further

complemented by standard measures of middle ear

function and tympanometry (17). From this we were

able to establish not only the presence or absence of

hearing impairment but also its type � conductive,

sensorineural or mixed � as well as the degree of loss,

being mild, moderate, severe or profound, as pre-

sented in Table I (4).

Vestibular assessment

All children had objective vestibular assessments

carried out with eye movements measured using

electro-nystagmography (ENG); in older children

video-nystagmography (VNG) and caloric testing

was also preformed.

The computerized vestibular laboratory (Neuro-

kinetics, Inc.) was able to run a full range of tests,

but the final choice of tests was dependent upon the

child’s maturational age. However, all children were

tested using the rotational techniques, using impul-

sive stimuli at a velocity of 60 s�1 and if possible also

at 90 s�1 and 120 s�1, as well as the sinusoidal

stimuli at a frequency of 0.04, 0.08 and 0.16 Hz with

a peak velocity of 60 s�1.

Depending upon the child’s cooperation, further

tests were carried out such as pursuit, saccades, full-

field optokinetic response as well as subjective visual

vertical and visual horizontal. Where appropriate,

caloric testing was carried out using the Fitzgerald-

Hallpike (18) method of binaural stimulation; re-

sultant data were analysed according to Jongkee’s

(19) formula.

It is important to note that these data relate only

to the function of the lateral semicircular canal,

which is the subject of testing using this battery

approach. Saccular or utricular function was not

tested in this study. The objective test results were

considered to be complementary to the clinical

vestibular assessment.

The obtained results were compared with norma-

tive data for our laboratory (for older children, aged

8�10 years), where abnormal rotational impulsive

response at velocity stimulation of 60o/s is more than

17% and the results of caloric testing are abnormal

when canal paresis is more than 20% and the

directional preponderance is also worse than 20%.

Considering jointly the results of the ENG/VNG

recording and the caloric testing, the vestibular

function was classified as:

. normal;

. hypo-function, where there was a presence of a

spontaneous nystagmus without optic fixation

on gaze testing, a significant directional pre-

ponderance on rotational tests and partial canal

paresis found on caloric testing;

. absent, where there was no response on rota-

tional as well as caloric testing with supporting

clinical history and tests. The diagnosis of

absence of vestibular function bilaterally in

profound hearing impairment was also made

on the basis of combined information from the

positive history of unbalance, especially in

certain situations such as darkness, history of

delayed motor development and the results

of clinical and neurootological assessment

inclusive of a positive Halmagyi response,

abnormalities of gait testing (veering off on

the straight-line walk, widening of the gait

base with eyes closed or blindfolded when

walking or standing, falling on the foam pad

with eyes closed as well as no response on the

rotational and caloric tests described above).

Results

In the studied group there were four children with

various degrees of conductive hearing loss: a child

with dysmorphic features had absent vestibular

function, a child who had vestibular hypofunction

had Down’s syndrome and two children had

CHARGE association (Table II) (20).

There were seven children with a mild degree of

sensorineural hearing loss and totally normal vestib-

ular function and those children had the following

conditions: epilepsy, Arnold-Chiari malformation,

labyrinthine concussion after a head injury, Meniere’s

Table I. Classification of hearing impairment. The level of the

thresholds measured in the better hearing ear at: 0.5, 1, 2, 4

kHz�average hearing level (4).

Mild 20�39dB HL

Moderate 40�69dB HL

Severe 70�94dB HL

Profound ��95dB HL

144 E. Raglan et al.

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disease and three children where diagnosis of the

condition was unknown (see Table III).

There were 20 children with moderate/severe

hearing impairment. In this group thirteen children

had normal vestibular function, inclusive of 10

children with migraine, one with X-linked deafness,

one with global developmental delay and birth

asphyxia. Six children presented with vestibular

hypofunction: three with a large vestibular aqueduct,

one with branchio-oto-renal syndrome, one with

CHARGE association, one with Gaucher’s syn-

drome, and child with CMV had an absent vestib-

ular function (see Table IV).

The largest group studied was that with bilateral

profound hearing impairment. The majority of those

children were assessed pre-cochlear implantation. In

our unit those children undergo a lengthy assessment

process comprising not only audiovestibular and

radiological testing but also a thorough aetiological

evaluation looking for the possible cause of the

hearing impairment. The protocol embraces genetic

testing that consists not only of later genetic coun-

selling but above all routine genetic blood sample

testing for the Connexin 26 mutation (21). In this

large group of 97 children with profound hearing

loss, 40 had normal vestibular function, 36 suffered

with hypo-function and 21 had absent vestibular

function (Table V, Table VI and Figure 1).

Table VI shows the vestibular status of children

with profound hearing impairment due to a variety

of medical conditions (hereditary with different

modes of inheritance, acquired, syndromic). The

striking observation is the result of normal vestibular

function in all children (16) who were shown to be

Connexin 26 positive. All children with absent

vestibular function presented with gross motor

developmental delay.

Of the five children with CHARGE association,

none had normal vestibular function, 3 had absent

vertibular function and 2 presented with a hypo-

function not correlating with the degree or type of

hearing impairment. Seventeen cases were studied

with meningitis with profound hearing loss. Among

those only three had normal vestibular function,

three had hypo-function and 11 had absent vestib-

ular function with a clinical presentation of delayed

gross motor skills.

Conclusions

There are several observations that could be drawn

from this study. Children with profound hearing

impairment and absent vestibular function present

with gross motor developmental delay. Patients who

show profound hearing loss due to the Connexin 26

mutation generally have normal vestibular function

(on testing lateral semicircular canal function).

However, the rate and degree of vestibular dysfunc-

tion in severe/profound hearing loss is generally

higher than in a milder degree of hearing impairment

with the exception of Connexin 26 pathology.

However, some patients have vestibular hypo-

function or absent vestibular function and yet pre-

sent with a varying degree and type of hearing

impairment like CHARGE association and congeni-

tal CMV. The presence or absence of vestibular

dysfunction in patients with hearing impairment

Table II. Conductive hearing loss versus vestibular status (n�4).

Condition Vestibular status

Dysmorphic 1 Absent

CHARGE assoc. �2 Hypo-function

Down’s syndrome �1 Hypo-function

Table III. Degree of SNHL versus vestibular status (n�7) (mild

hearing impairment).

Epilepsy 1 Normal

Arnold-Chiari 1 Normal

Lab Concuss. Post head 1 Normal

Meniere’s disease 1 Normal

Unknown 3 Normal

Table IV. Moderate/severe hearing loss and status of vestibular

system.

Category

Number

(total�20)

Status of

vestibular system

Migraine 10 Normal

CMV 1 Absent

LVA 3 Hypo-function

BOR 1 Hypo-function

X-linked deaf. 1 Normal

CHARGE

assoc.

1 Hypo-function

Gaucher’s

syndrome

1 Hypo-function

Birth asphyxia 1 Normal

Global dev.

delay

1 Normal

Table V. Profound SNHL and vestibular function (n�97).

Normal 40 (41%)

Hypo-function 36 (37%)

Absent 21 (22%)

Audio-vestibular study of children: need for vestibular function assessment 145

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depends upon the nature of the medical condition.

There are some syndromic conditions presenting

with anatomical anomalies of the inner ear where,

regardless of the degree and type of hearing impair-

ment, the vestibular function will be affected such as

in CHARGE association. There will be other

syndromic and non-syndromic conditions that are

not associated with congenital anatomical anomalies

of the inner ear and which will have the vestibular

dysfunction, such as the Usher syndromes or con-

genital cytomegalovirus infection.

Therefore, the decision regarding whether or not

the child should be referred for vestibular assessment

should be based on knowledge of the syndromic and

non-syndromic conditions that may present with or

without inner ear anomalies associated with the

vestibular dysfunction, as well as the knowledge of

the noxious factors that may lead to vestibular

dysfunction such as meningitis, rubella, birth risk

factors and ototoxicity.

A clinical presentation including a history of

dizziness, imbalance or delayed motor development

and profound hearing loss is also an indication for

vestibular assessment.

Discussion

There are a number of reasons why most children

with permanent sensorineural hearing impairment

should have vestibular assessment performed. Not

only does assessment help to confirm the syndromic

diagnosis (Usher syndrome) and provide a more

comprehensive phenotypic picture for the genetic

diagnosis to be made, but also in some cases of

profound hearing loss it may explain the reasons for

the gross motor developmental delay.

Delayed gross motor development observed in

small children with absent vestibular function in-

dicates the importance of these structures in the

normal development of equilibrium. Such children

who have a normal functioning central nervous

system (CNS) will compensate for their loss well

and eventually, by the time they become adolescents,

will have normal balancing function but will need to

be aware of the need to recognize dangerous

environmental situations, such as being in total

darkness (22). Such a situation may lead to disor-

ientation of the vestibular, visual and proprioceptive

input with grave consequences for their well-being.

This study presents a large group of patients with

profound prelingual hearing loss and normal vestib-

ular function (vestibular ocular reflex of the lateral

semicircular canal) who suffer with autosomal

recessive deafness due to a Connexin 26 mutation.

This study corresponds to the results of work of Todt

et al. (23), who reported a normal lateral canal as

well as utricular function in patients with Connexin

26 mutations but abnormal function of the saccule

as tested using VEMPs. Unfortunately this test was

not available for our study at the time.

Table VI. Profound SNHL and vestibular data.

Vestibular function

Category No. Normal

Hypo-

function Absent

Connexin 26 16 16

Auto-dominant 5 3 2

Auto-recessive 10 6 4

Waardenburg

syndrome

6 4 2

Prematurity 2 2

Craniosynostosis 1 1

Maternal rubella 1 1

Pearson’s syndrome 1 1

Head injury 1 1

Auditory neuropathy 1 1

Large vestibular

aqueduct

4 1 3

Mondini defect 1 1

Secondary

endolymphatic

hydrops

1 1

Meningitis 17 3 3 11

Congenital CMV 4 1 0 3

Pendred syndrome 2 2

Usher syndrome 3 2 1

CHARGE

association

5 2 3 1

Moebius syndrome 1 1

Embro

rhabdomysarcoma

1 1

Gentomicin

ototoxicity

1 1

Unknown 13 5 4 4

0

2

4

6

8

10

12

14

16

Connexin26

Auto Rec Auto Dom LVA Meningitis CMV cong Waarden Charge

No

of P

atie

nts

normal

hypo

absent

Figure 1. Profound Hearing Loss versus Vestibular Status.

146 E. Raglan et al.

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The relatively small number of children presenting

with lesser degrees of hearing impairment where

vestibular function was studied does not confirm the

assumption that the increased degree of hearing

impairment is accompanied by an increased rate of

vestibular dysfunction. However, this study shows a

trend between degree of hearing impairment and

presence of vestibular dysfunction. This notion has

been supported by a number of authors (8,9).

At present the needs of this population of patients

are not met adequately and there is unknown

demand for a service. The results of this study

indicate the implication for development of paedia-

tric services inclusive of networked care, need for

development of the vestibular screening battery and

further refinement of qualitative and quantitative

vestibular assessment in children.

Early diagnosis of vestibular dysfunction in

those children and their subsequent management

through appropriate physiotherapy programmes

should lead to potentially better clinical outcomes.

Vestibular assessment should be an integral part of

the evaluation of children with sensorineural hearing

impairment and this view is supported by other

authors (22,24�26).

References

1. Brookhouser PE, Cyr DG, Beauchaine KA. Vestibular find-

ings in the deaf and hard of hearing. Otolaryngol Head Neck

Surg. 1982;/90:/773�7.

2. Arnvig J. Vestibular function in deafness and severe hardness

of hearing. Acta Otolaryngol. 1955;/45:/283�8.

3. Selz PA, Girardi M, Konrad HR, Hughes LF. Vestibular

deficits in deaf children. Otolaryngol Head Neck Surg. 1996;/

115:/70�7.

4. Davis A, Davis K, Mencher G. Epidemiology of permanent

childhood hearing impairement. In: Newton VE, editor.

Paediatric Audiological Medicine. London: Whurr; 2009.

p. 1�28.

5. Parving A, Christensen B. Epidemiology of permanent hear-

ing impairment in children in relation to costs of a hearing

health surveillance programme. Int J Otorhinolaryngol. 1996;/

34:/9�23.

6. Niemensivu R, Pyykko I, Wiener-Vacher SR, Kentala E.

Vertigo and balance problems in children: an epidemiological

study in Finland. Int J Pediatr Otorhinolaryngol. 2006;/70:/

259�65.

7. Moller C. Balance Disorders. In: Newton VE, editor.

Paediatric Audiological Medicine. London: Whurr; 2002.

p. 379�96.

8. Huygen PL, van Rijn PM, Cremers CW, Theunissen EJ. The

vestibulo-ocular reflex in pupils at a Dutch school for the

hearing impaired: findings relating to acquired causes. Int J

Pediatr Otorhinolaryngol. 1993;/25:/39�47.

9. Huygen PL, Verhagen WI. Peripheral vestibular and

vestibulo-cochlear dysfunction in hereditary disorders. J

Vestib Res. 1994;/4:/81�104.

10. McLeod AC, Sweeney A, McConnell FE, Kemker FJ, Nance

WE, Webb WW. Autosomal recessive sensorineural deafness:

a comparison of two kindreds. South Med J. 1973;/66:/141�52.

11. Cremers CW. Audiological features of the X-linked progres-

sive mixed deafness syndrome with perilymphatic gusher

during stapes gusher. Am J Otol. 1985;/6:/243�6.

12. Cremers CW, Huygen PL. Clinical features of female hetero-

zygotes in the X-linked mixed deafness syndrome (with

perilymphatic gusher during stapes surgery). Int J Pediatr

Otorhinolaryngol. 1983;/6:/179�85.

13. Moller C. Vestibular testing in children. In: Newton VE,

editor. Paediatric Audiological Medicine. London: Whurr;

2009. p. 412�7.

14. Halmaguyi M. Diagnosis and management of vertigo. Clin

Med. 2005;/5:/159�65.

15. Aetiological investigation into severe to profound permanent

hearing loss in children. (2008), http://www.baap.org.uk/doc

s/BAAP-BACDA%20Aetiological%20Guidelines%202008%

20Octct.pdf

16. Tweedy F, Booth R. Behavioural tests of hearing. In: Newton

VE, editor. Paediatric Audiological Medicine. London:

Whurr; 2009. p. 52�71.

17. Jerger J. Clinical experience with impedance audiometry.

Arch Otolaryngol. 1970;/92:/311�24.

18. Fitzgerald D, Hallpike C. Studies in human vestibular

function, observation on the directional preponderance of

caloric nystagmus resulting from cerebral lesions. Brain.

1942;/65:/115�22.

19. Jongkees LB. The caloric test and its value in evaluation of the

patient with vertigo. Otolaryngol Clin North Am. 1973;/6:/

73�93.

20. Blake KD, Davenport SL, Hall BD, Hefner MA, Pagon RA,

Williams MS. CHARGE association: an update and review

for the primary paediatrician. Clin Pediatrics. 1998;/37:/

159�73.

21. Bitner-Glindzicz M. Hereditary deafness and phenotyping in

humans. Br Med Bull. 2002;/63:/73�94.

22. Rine RM, Cornwall G, Gan K, LoCascio C, O’Hare T,

Robinson E. Evidence of progressive delay of motor develop-

ment in children with sensorineural hearing loss and con-

current vestibular dysfunction. Percept Motor Skill. 2000;/90:/

1101�12.

23. Todt I, Hennies HC, Kuster W, Smolle J, Redemacher G,

Mutze S. Neurootological and neuroanatomical changes

in the Connexin 26 related HID/KID syndrome. Audiol

Neurootol. 2006;11:242�8, Epub 2006 May 4.

24. Angeli S. Value of vestibular testing in young children with

sensorineural hearing loss. Arch Otorhinolaryngol Head &

Neck Surg. 2003;/129:/478�82.

25. Phillips JO, Backous DD. Evaluation of vestibular function in

young children. Otolaryngol Clin N Am. 2002;/35:/765�90.

26. Fife TD, Tusa RJ, Furman JM, Zee DS, Frohman E, Baloh

RW, et al. Assessment: vestibular testing techniques in adults

and children. Report of the Therapeutics and Technology

Assessment Subcommittee of the American Academy of

Neurology. Neurology. 2000;/55:/1431�41.

Audio-vestibular study of children: need for vestibular function assessment 147

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of

Wat

erlo

o on

10/

27/1

4Fo

r pe

rson

al u

se o

nly.