Management of a deaf child

1. MANAGEMENT OF
A DEAF CHILD

2.  Children with profound (>90dB loss) or total deafness fail to
develop speech and have often been termed as deaf-mute or
deaf dumb.
 the period of birth till 5 years of life is critical for the
development of speech, therefore, there is need for early
identification and assessment of hearing loss and early
rehabilitation in infants and children

3. AETIOLOGY
CONGENITAL
GENETIC
NON- GENETIC
ACQUIRED

4. GENETIC CAUSES
 Genetic disease results from abberations in coding function or processing of
human DNA.
 Congenital SNHL is accounted for by genetic factors in half of the cases.
 About 77% of cases of hereditary hearing loss are autosomal recessive and 22%
are autosomal dominant and 1% are X-linked.
 Approximately 30% of patients have syndromic hearing loss.
 Autosomal recessive non syndromic hearing loss is caused by mutations in GJB2
gene ( codes for protien connexin 26) and GJB6 gene (codes for connexin 30).

5. NON – GENETIC CAUSES
PRENATAL CAUSES PERINATAL CAUSES POSTNATAL CAUSES
Before Birth
Includes:
1) Infant factors
2) Maternal factors
During birth
Includes causes during birth
or early neonatal period.
After birth
Includes genetic and non
genetic factors

6. PRENATAL CAUSES
INFANT FACTORS
An infant may be born with inner ear anomalies due to genetic or
non genetic causes and these anomalies may be syndromic or non
syndromic.
The anomalies affecting inner ear may involve only membranous or
both membranous and bony labyrinth.
They include :

7. SCHEIBE’S DYSPLASIA :
1. It is the most common inner ear anomaly.
2. Bony labyrinth is normal and superior part of membranous labyrinth ( utricle and semicircular ducts ) is
also normal.
3. Dysplasia is seen in cochlea and saccule i.e. why called cochleosaccular dysplasia.
4. It is inherited as autosomal recessive nonsyndromic trait.
ALEXANDER DYSPLASIA :
1. Affects only the basal turn of membranous cochlea.
2. Only high frequencies are affected , residual hearing present in low frequencies
BING-SIEBERMANN DYSPLASIA :
Complete absence of membranous labyrinth.
MICHEL DYSPLASIA :
1. Complete absence of bony and membranous labyrinth.
2. Even the petrous apex is absent but middle and external ear may be completely normal.

8. MONDINI DYSPLASIA :
1. Only basal coil is present or cochlea is 1.5 turns.
2. There is incomplete partition between scalae due to absence of osseous spiral lamina.
3. Maybe unilateral or bilateral.
4. The deformity maybe seen in Pendred, Waaredenburg, branchio-oto-renal, Treacher- Collins
syndrome and wildervanck syndrome.
ENLARGED VESTIBULAR AQUEDUCT :
1. Vestibular aqueduct is enlarged >2mm, endolymphatic sac is also enlarged and can be seen on t2
MRI.
2. It causes early onset SNHL which is progressive and vertigo may be present and perilymphatic fistula
may occur .
SEMICIRCULAR CANAL MALFORMATIONS:
Both superior and lateral or only lateral semicircular canal malformations may be seen.

9. MATERNAL FACTORS
a) Infections during pregnancy :
Include toxoplasmosis, rubella, cytomegalovirus, herpes type1 and 2 and syphilis.
a) Drugs during pregnancy
Include streptomycin, gentamicin, amikacin, quinine or chloroquine. They cross the placental barrier
and damage fetal cochlea.
a) Radiation to mother in first trimester
a) Other factors :
Nutritional deficiencies, diabetes, toxemia, thyroid deficiency and maternal alcoholism.

10. PERINATAL FACTORS
 ANOXIA :
It damages cochlear nuclei and causes haemorrhage into the ear. Placenta praevia, prolonged labour,
cord arpund the neck amd prolapsed cord can acuse fetal anoxia.
 PREMATURITY AND LOW BIRTH WEIGHT
 BIRTH INJURIES :
Due to forceps delivery. May cause intracranial haemorrhage with extravasation of blood into inner
ear.
 NEONATAL JAUNDICE :
Bilirubin levels greater than 20% damages the cochlear nucleus.
 NEONATAL MENINGITIS
 SEPSIS
 OTOTOXIC DRUGS

11. a) Viral infections ( measles, mumps, varicella, influenza, meningitis,
encephalitis)
b) Secretory otitis media
c) Ototoxic drugs
d) Trauma eg. fractures of temporal bone, middle ear surgery, perilymph leak.
e) Noise induced deafness
ACQUIRED CAUSES

12.  MENINGITIS :
Most common cause of permanent childhood hearing impairment.
Risk of getting PCHI is 10% after bacterial meningitis
Early cochlear implantation is necessary as delay can cause cochlear ossification and makes implantation
difficult.
 MEASLES :
Highly infectious viral illness, reported as major aetiological agent for severe profound bilateral hearing
loss in children, mostly after 6 months of age.
Observed hearing loss can be conductive and is attributable to supprative otitis media, chronic
perforation and mastioiditis but mostly deafness is sensorineural.
 MUMPS :
Very rare but unilateral SNHL if present.

13. EVALUATION OF A DEAF CHILD
 FINDING THE CAUSE:
1. SUSPICION OF HEARING LOSS:
a) Hearing loss is to be suspected if :
i. The child sleeps through loud noises undisturbed or fails to startle to loud
sounds.
ii. Fails to develop speech at 1-2 years
iii. A partially hearing child may have a defective speech and perform poorly at
school.

14.  RISK FACTORS FOR HEARING LOSS IN CHILDREN:
a) Family history of hearing loss
b) Prenatal infections
c) Craniofacial abnormalities including those of pinna and ear canal
d) Birth weight less than 1500g
e) Hyperbilirubinemia requiring exchange transfusion
f) Ototoxic medications included but not limited to aminoglycosides used in multiple courses or in
combination with loop diuretics.
g) Bacterial meningitis
h) APGAR score 0-4 in 1 min or 0-6 in 5 min.
i) Mechanical ventilation for 5 days or more
j) Syndromic findings associated with hearing loss

15. ASSESMENT OF HEARING IN
INFANTS AND CHILDREN

17. SCREENING TESTS
 They are employed to test hearing in high risk infants and are based on infants
behavioral response to sound signal.
 Right now we have a universal neonatal screening programme for early detection.
 Tests used are : otoacoustic emmisions (OAE) and auditory brainstem response
(ABR).
1. OAEs are generated at the outer hair cells and can be picked up from the external
ear as the energy produced by them travels in reverse direction from outer hair cells
to ossicles, then TM and to the ear canal, from where it is picked up. OAEs are
absent if outer hair cells are not functional or there is middle ear effusion or canal
debris due to meconium.

18.  ABRs are generated in response to sound stimulus presented to the ear and
picked up from the scalp. With a response of 30-35 dB normal HL, the infant who
passes the test and the hearing is considered normal. Infants who fail these tests
are followed up with repeat tests
 AROUSAL TEST : a high frequency narrow band noise is presented for 2 seconds
to the infant when he is in light sleep. A normal hearing infant can be aroused
twice when three such stimuli are presented to him.
 AUDITORY RESPONSE CRADLE: it is a screening device for newborns where the
baby is kept in a cradle and his behavior ( trunk and limb movements, head jerk
and respiration) in response to auditory stimulation.

19. BEHAVIOUR OBSERVATION
AUDIOMETRY
MORO’S REFLEX CESSATION REFLEX COCHLEOPALPEBRAL
REFLEX
Sudden movement of limbs
and extension of head in
response to sound of 80-90
dB
An infant stops activity or
starts crying in response to
sound of 90dB
Child responds by a blink
to a loud sound.

20. DISTRATCTION TECHNIQUES
 Used in children 6-7 months old. The child at this age turns head to locate
source of sound.
 In this test, the child is seated in mother’s lap, an assistant distracts the
child’s attention while the examiner produces a sound from behind or
from one side to see if child tries to locate it.
 Sounds used are high frequency rattle (8kHz), low frequency hums,
whispered sounds, xylophone, warbled notes or narrow band noise (500-
4000Hz)

21. CONDITIONING TECHNIQUES
VISUAL REINFORCEMENT
AUDIOMETRY
PLAY AUDIOMETRY SPEECH AUDIOMETRY
• It is a conditioning
technique in which the
child is trained to look
for auditory stimulus by
turning his head.
• This test helps to
determine the hearing
threshold.
• Child is conditioned to
perform an act such as
placing a marble in a
box, putting a ring on a
post or putting a plastic
block in a bucket each
time he hears a sound
signal.
• each correct
performance is
reinforced by praise,
encouragement or
reward.
• Child is asked to repeat
names of certain objects
or to point them out on
pictures. The voice can
be gradually lowered.
• In this speech
discrimination and
hearing level can be
tested and also child’s
expressive ability can be
examined.

22. OBJECTIVE TESTS
 EVOKED RESPONSE AUDIOMETRY:
ELECTROCOCHLEOGRAPHY
• It can measure auditory sensations upto 20dB. But it is an invasive procedure requiring
placement of electrodes on TM.
AUDITORY BRAIN STEM RESPONSE
• It is not a direct test of hearing. Identifiable waveforms are present 10-20dB above behavioural
threshold. ABR provides ear specific information and can be done under sedation.

23.  OTOACOUSTIC EMISSIONS :
Transient evoked emissions are absent in ears where the hearing loss
exceeds 30dB. Distortion product emissions are absent when hearing
loss exceeds 50dB.
 IMPEDANCE AUDIOMETRY :
Normally, stapedius muscle contracts reflexly in response to sound of
70-100dB. And this reflex can be recorded. Absence indicates middle ear
disorder, retrocochlear hearing loss or severe SNHL.

24. SINGLE SIDED DEAFNESS:
 Screening helps in early detection of unilateral sensorinueral hearing loss.
 Previously, unilateral hearing loss was considered of little significance as speech
and language developed appropriately
 unilateral hearing loss results in an inability to hear from the direction of deaf
side, difficulty in hearing speech in noise and poor localization of sound.
 children with unilateral hearing loss appear to have increased rates of grade
failures, need educational assistance and may show behavioral issues in
classroom.

25. INVESTIGATIONS
 CLINICAL EXAMINATION :
All children with hearing loss of unknown cause should be evaluated for features associated
with syndromic deafness. Important features include branchial cleft pits, cysts or fistulae,
preauricular pits, telecanthus, heterochromia iridis, white forelock, pigmentary anomalies, high
myopia, pigmentary retinopathy, goitre, craniofacial abnormalities.
 AUDIOLOGY:
Skilled audiological testing is performed to assess the severity of hearing loss.

26.  IMAGING :
Imaging can detect treatable pathologies such as perilymph fistula, inner ear
malformations with an associated risk of meningitis and the enlarged vestibular
aqueduct. Both CT and MRI can be useful.
On CT scans,a large vestibular aqueduct is most common finding , while cochlear
dysplasia is most common abnormality in scans showing multiple abnormalities.
Other abnormal findings include lateral SCC dysplasia, otic capsular lucency, small
internal auditory canals and hypolastic cochlea.
MRI scans are more likely to detect abnormalities with increasing severity of
hearing loss and a significantly higher imaging yield with unilateral SNHL than with
bilateral.

28. MANAGEMENT
 PARENTAL GUIDANCE
 HEARING AIDS
 COCHLEAR IMPLANTS
 SPEECH AND LANGUAGE THERAPY
 EDUCATION OF THE DEAF
 VOCATIONAL GUIDANCE