Ramesh Parajuli MS (ORL-HNS)

Chitwan Medical College Teaching Hospital, Bharatpur-10, Chitwan, Nepal

DEAF CHILD

Definition Importance of early diagnosisMethods of screening Clinical evaluationDiagnostic methods Management

Contents

IDEA (Individuals with Disabilities Education Act) 2007 defines hearing loss:

- Deaf child is one who cannot understand spoken communication even with a hearing aid.

- A hard of hearing child is one who can hear spoken communication, but this does not necessarily mean that he understands it.

Definition

Permanent childhood hearing impairment (PCHI): confirmed permanent B/L hearing impairment exceeding 40 dBHL (average of pure tone thresholds at 0.5,1,2 & 4 kHz in better hearing ear).

Congenital or acquired

Prelingual deafness Vs postlingual deafness

-for the child’s education and management

Degree of hearing loss

0-15 dB Normal15-25 Minimal Hearing Loss26-40 Mild Hearing Loss41-55 Moderate Hearing Loss56-70 Moderately Severe Loss71-90 Severe Hearing Loss>90 dB Profound Hearing Loss

(Categories from the National Institutes of Health)

http://www.nih.gov/

Epidemiology One child in 1000 born - bilateral permanent childhood hearing impairment(PCHI)

-About 60% of these children= mod. Hearing loss (41-60 dBHL)

-Remainder have severe (61-80 dBHL) or profound (>81dBHL)(www.who.int/pbd/deafness/hearing_impairmencgrades/ en/index)

The prevalence of PCHI increases with age further 1 in 1000 develop acquired or progressive hearing impairment. (Fortnum et al., 2001)

PCHI – one of the most common abnormality present at birth

The prevalence of hearing loss- greater than that of most other diseases and syndromes (eg, phenylketonuria, sickle cell disease) screened at birth.

Two thirds of people with moderate to severe hearing impairment live in developing countries.

In developing countries-infection

congenital- rubella and CMV

acquired – mumps, measles, meningitis & COM

In developed countries- about half of PCHI—genetic cause

(www.who.int)

Terminology:

Bilateral Permanent childhood hearing loss (PCHL)

- Hearing loss >40 dB at (0.5k,1k,2k,4k ) – better ear

- 60 % children–mod CHL Acquired/Late onset permanent hearing loss

- Postnatal/after birthUnilateral permanent hearing loss

- Inability to hear from deaf side

- Difficulty – hearing – speech in noise

- Poor localization of sound

Auditory neuropathy/ Dyssynchrony (AN/AD)

- Damage to inner hair cells, synaptic junction, auditory

neurons in spiral ganglion

- Clinical test: normal OAE/ absent or abnormal ABR

- 10 % children - confirmed PCHL - Auditory neuropathy

- Found predominantly in NICU population Temporary childhood hearing loss

- OME – extremely common

- Major risk factors – season, passive smoking, bottle feed

URTI, NICU admission

- Speech and language delay

The High-Risk Register (HRR)Prior to implementation of universal newborn hearing screeningInfants identified at high risk for hearing loss – high risk register (HRR)screened

The risk factors for newborn:

(Joint Committee on Infant Hearing (JCIH) 2000 Position Statement)Family h/o permanent childhood sensorineural hearing loss In utero infection - cytomegalovirus, rubella, toxoplasmosis or herpesCraniofacial anomalies- morphological abnormalities of the pinna & EACNeonatal indicators - hyperbilirubinemia, persistent pulmonary hypertension of the newborn (PPHN), mechanical ventilationPostnatal infections - bacterial meningitis

Stigmata/ findings syndrome - SNHL or CHL or Eustachian tube dysfunction Parental or caregiver concern regarding hearing, speech, language, and/or developmental delay Head trauma Recurrent or persistent otitis media with effusion lasting for at least 3 monthsScreening by high risk register alone can only identify 15-20% of new born babies requiring help (NIH, 1993)

Prior to implementation of universal newborn screening - testing conducted only on infants meeting the criteria of the high-risk register (HRR).

HRR - as many as 50% of infants born with hearing loss have no known risk factors.

Reliable screening tests available- minimizes referral rates and maximize sensitivity and specificity.

Universal newborn hearing screening (UNHS)

National Institute for deafness and other communicative disorders (NIDCD) - consensus conference – on early identification of hearing loss – 1993 Recommended – UNHS

- Screening 1st three months of life

- Taken up by various agencies –

American academy of otolaryngology- HNS

American academy of speech and language

American academy of audiology •“Pass” or “Refer,” •“Refer” –

follow up testing confirmed referral to otolaryngologist

Initially – - In 1988 -hearing loss identified in children in the USA- 2.5 yrs - Severe to profound hearing loss or with multiple disabilities identified at or before age 2.5 yrs - Mild-to-moderate: not identified until school

Universal newborn hearing screening program 1997-2001 Mean age of diagnosis - 3.9 months Mean age of intervention - 6.1 months (Connolly et al., 2005)

Efficacy of Early Identification and Intervention

Definition of early identification and intervention - evolved over the years

Early identification -defined as intervention before the age of 18 months

The implementation of universal screening programs definition of early identification and intervention re-examined

Early identification - diagnosis as early as age 3 months

Early intervention - by age 6 months

Better language scores in severe- profound deaf children- hearing loss identified at an average age of 11.9 months, compared to 19.5 months (White SJ and White RE, 1987)Children identified and wore hearing aids by the age of 6 months acquired vocal communicative and linguistic skills better than children identified at a later age (Robinshaw HM, 1995)

Critical period of early identification & intervention- younger than 6 months (Yoshinago et al., 1998)

The ability to hear during the early years of life is critical for the development of speech, language & cognition Infants who are not identified before 6 monthsdelay in speech and language development

Intervention at or before 6 monthschild with impaired hearing to develop normal speech and language, alongside his or her hearing peers

Early identification-development of expressive, receptive language, cognition, behaviour, personality development

(Davis et al., 1992)

Delayed Diagnosis

Permanently impaired speech and language skills

Reduced intellectual ability

Lowered adult earnings

More limited social skill development

(Joint Committee on Infant Hearing (JCIH) 2007 Position Statement)

1. Definition of targeted hearing loss expanded to include neural hearing loss (eg. auditory neuropathy/dyssynchrony)

2. Separate protocols for neonatal intensive care units (NICUs) and well-baby nurseries. ABR screenings for all NICU babies, as well as babies admitted for >5 daysneural hearing loss will not be missed.

3. Referrals for all infants who do not pass ABR screening in the NICU.

4. Rescreening of all infants should include re-evaluation of both ears, even if the infant only failed one ear in the initial screening.

5. Audiologists with expertise in evaluating newborns should conduct diagnostic evaluations.

(Joint Committee on Infant Hearing (JCIH) 2007 Position Statement)

6. Children identified with hearing loss fit amplification within 1 month of diagnosis.

7. A genetics consultation to families of infants with hearing loss.

8. Children with hearing loss should evaluation by an otolaryngologist & ophthalmologist.

9. Children with any degree of bilateral or unilateral hearing loss consider early intervention services

10. Families all communication options and available hearing technologies

11. Early intervention services by professionals with expertise in hearing loss

Methods of Screening

Otoacoustic emission (OAE)

Principle:-Response of outer hair cells to acoustic stimuli

- Assess cochlear integrity

- Fast test for normal preneural cochlear function

Set up: - Probe assembly in EAC

- Tonal / click stimuli – delivered

- OAE - generated by cochlea

- Measured – microphone

If middle ear normal assesses cochlear function in frequency range 0.5-6kHz-Fast, efficient, frequency specific

Limitations:

- Efficacy reduced by contamination of low frequency

noise in busy nursery, wax/debris in EAC

- Middle ear pathology

- Auditory neuropathy-OAE may be normal ABR

- Stay in NICU >5 days ABR

Automated ABR (AABR):

- Auditory function from 8th nerve auditory brainstem

Set up–-Electrodes - forehead, mastoid, nape of neck -Click stimuli – in the canal earphone - 35 dB -Compare infant’s waveform - normative ABR infant data -Response – pass / fail -Screening tool - < 6 months

Advantages:•Can be done – with background noise•No interpretation required •Solely-screening technique identify infants, who require follow up testing

Disadvantages:•Lacks frequency specific information

•Can’t differentiate type/degree of hearing loss

•Requires increased preparation time prior to test

Diagnostic auditory brainstem reflex:-Not used in UNHS because of length of procedure, cost, audiologist -Unlike AABR-35 dB, Intensity of stimuli – varied – manual ABR -Allows to know – severity of hearing loss -Type of hearing loss -Not used for screening but for follow up

Follow – up testing Infants who do not “pass” F/U at 1 month interval F/U allowsmultiple testing sessions, medical intervention, parental counseling, appropriate amplification before age of 6 months If f/u delayed – need for sedation increases If infant fail 2nd screening session – diagnostic ABR/ OAE Auditory neuropathy/dyssynchrony- Normal OAE but abnormal ABR

What causes hearing loss ?

Syndromic hearing loss

Dominant Waardenburg BOR Stickler’s NF2 Treacher CollinsRecessive Usher Pendred Jervell/Lange-NielsenX-linked AlportMitochondrialChromosomal Down Syndrome

Non syndromic hearing loss

75% Recessive23% Dominant2% X-linked1% Mitochondrial

1/3 syndromic 2/3 nonsyndromic

Disabilities that occur with deafness (%)Deafness with No Other Disabilities

60.1

Learning Disability 10.7

Intellectual Disability 9.8

Attention Deficit Disorder (ADD/ADHD) 6.6

Blindness and Low Vision 3.9

Cerebral Palsy 3.4

Emotional Disturbance 1.7

Other conditions 12.1

(Gallaudet Research Institute, Jan 2003)

Syndromic hearing loss

• Pendred• Usher• Branchio-oto-renal• Waardenburg• Jervell and Lange-Nielsen• Alport• CHARGE association

Non syndromic hearing loss • Isolated genetic HL without

any other recognized abnormalities

• Two thirds of all congenital SNHL

• Over 50 genes; new ones discovered every year

• Testing available for only a small few

Connexin 26 (GJB2)

Most common hereditary SNHLCauses 50% of non-syndromic SNHL in the US and Europe.Recessive inheritance35delG – extremely common (2.5% carrier

rate)SNHL variable (severity, symmetry,

progression).Genetic testing widely available

Inner ear malformations 30- 35% of patients with SNHL - have malformations

Even higher % in unilateral SNHL

Malformations can occur in isolation, or as part of a

syndrome

Why is diagnosis important?Risk of meningitisRisk of progression of HLComplicates cochlear implantation

Michel aplasia: most severe, complete absence of bony & membranous labyrinth

Mondini’s aplasia: only basal coil present

Sheibe’s (cochleosaccular)dysplasia: most common, dysplasia in cochlea & saccule

Bing-Siebenman dysplasia: complete absence of membranous labyrinth but bony labyrinth present

Alexander’s dysplasia: Limited cochlear duct differentiation at the level of the basal coil

Enlarged vestibular aqueduct: early onset SNHL, progressive

Semicircular canal malformations

Evaluation

History:

Presentation depends on:

- Degree of hearing loss

- Patient’s age

- When hearing loss began ?

- Threshold of suspicion by parents

- Presence of identifiable risk factors

2/3 rd cases - parent’s 1st suspicion

10 % cases - Paediatrician

15 % cases - health caregivers

Meantime b/w 1st suspicion and diagnosis – 9 months

Evaluation of hearing loss:

Concern over child’s hearingBehavioural problems/personality defectsCongenital/postnatal - profound deafness - loss of cooing by age of 6–9 monthsMinor speech impediments, school failure Mental retardation, autism, attention deficits, adjustment disorders

History & Physical Examination

History:Characterize onset Identify risk factors and exposuresIdentify family history of SNHL

•Infections, other systemic diseases•Trauma, infections, diabetes, blood dyscrasias,

autoimmune, malignancy, meningitis, middle ear disease, noise exposure

•Balance problems, learning problems, speech delay•Any prior testing

-Changes, progression, fluctuation•Other symptoms- Visual, balance, tinnitus

Important ElementsPerinatal history

Family history

Neonatal history•Prematurity•NICU•Mechanical ventilation•Infections•Hyperbilirubinemia (transfused ?)•TORCHS/maternal infections

Physical Examination Usually normal

Detect syndromic features – Pigment anomalies (Waardenburg)– Ear pits, branchial anomalies (BOR)– Abnormal external ear (CHARGE, BOR)– Craniofacial abnormalities

– Pinna

- Microtia

- Canal atresia

•Rule out acquired conditions:-Pinna - EAC- Cerumen/ foreign body- Otoscopy/ Pneumatic otoscopy

• Current/ chronic infection • Perforation/ scarring TM

•Otoscopy/ EUM

- Cholesteatoma

- Abnormal TM/landmarks

- Fluid behind TM (OME )

•Head and neck evaluation

Aim of aetiological investigations Aim:

- Try answer parents – “why is my child deaf ? ”

- Identify and treat medical conditions

- Assist early decision making

Appropriate communication modes

Educational placement & counselling

- To inform genetic counselling

- Epidemiological research

Laboratory Studies

•Depending - patient's history & physical findings biochemical evidence •Diagnosis of SNHL -

•Testing thyroid function, measuring BUN and creatinine levels and urinalysis.•ECG - diagnosing – arrhythmia- Jervell Lange-Nielsen syndrome

• B/L hearing loss - (eg, ESR)

•Autoimmune inner ear disease

•Genetic screen

•Serology (suspected viral, autoimmune, syphilitic) •CBC

Risk of thalassemia or sickle cell diseaseMacro thrombocytopenia & leukocyte inclusions (a/w Alport syndrome)

•BiochemistryBUN & electrolyte abnormalities with renal dysfunction (e.g., Alport syndrome)Lipid profileGlucose

•Thyroid function testsCongenital or acquired hypothyroidismPendred syndrome

•Autoimmune work-upESRImmunoglobulinComplement

• Non-contrast CT of temporal bone Gold standard

Quick but may require sedation

Involves ionizing radiation

Excellent for almost all causes

• MRI

Detect abnormality of CNS

Certainly indicated in some unusual cases

(Russo et al., 2006)

Genetic evaluation: Why?

•Inheritance patterns

•Recognizing genetic syndromes

•To perform genetic testing

•To conduct genetic counselling(McCallum et al., 2006)

Arousal test:

Sound stimuli light sleep arousal

Auditory response cradle(ARC):

Baby in cradle-behaviour in response to sound stimulustrunk & limb movement, head jerk and respiration

Assessment of hearing

Audiometric Evaluation: when & what to do ?

Electrophysiological testing:

- Key developmental age: 0 – 6 months

- Mainly employed – Newborn screening

- Preschool screening /surveillance

- Diagnostic testing – 1st 6 months

(Sininger et al., 2003)

Also used -BOA fails to give reliable results

- Confirm hearing threshold – prior fitting hearing

aid /cochlear implant

Behavioural observation audiometry (BOA):Key developmental age: 0 – 6 months • Sound stimuli response change in behaviour e.g., alerting, widening of eyes or facial grimacing, arousal from sleep •Auropalpebral reflex•Moro reflex:•Cessation reflex: cessation of an activity•Use < 6 months – superseded by – OAE,ABR

Infant distraction test (IDT):

Key developmental age: 6–18 months

Normal response: Sound head turn to locate the source of sound

Visual Reinforcement audiometry (VRA):-Key development age – 6 to 36 months -Conditioning technique-Child trained to look for an auditory stimulus by turning head-reinforced by flashing light or toy

Performance testing:-Key developmental age: 2-5 yrs -Used till cooperation with PTA achieved-Child conditioned to wait for a sound respond play activity -Determine – minimal threshold response

Pure tone audiometry(PTA):-Key developmental age: > 3yrs-Instructed to raise the corresponding hand - sound is heard-CHL and SNHL can be differentiated-Quick and easy screening test - effective tool in schools-Disadvantages: formal evaluation takes time/ equipment

fully performed only -older, cooperative patients

Stepwise Workup (Preciado et al., 2005)

Algorithm1. Known or suspected aetiology (e.g. meningitis, trauma):

a. At diagnosis:•Ophthalmology

•Additional tests and/ or treatments only as clinically indicated by aetiology or clinical course

b. Serial Audiograms

2. Unilateral SNHL:

a. At diagnosis:•Imaging study•Ophthalmology

b. If imaging normalconsider Genetics referral

c. Serial Audiograms

3. Bilateral SNHL (unknown aetiology)a. At diagnosis:

•Imaging of temporal bone•Ophthalmology•Genetics referral (ideally, specialist in HL)•EKG•UA•Labs if clinically indicated (rarely)

b. Serial Audiograms, other referrals

Treatment Principles

- Identify, prevent, treat associated disorders

- Optimization of other sensory input

- Auditory Rehabilitation– Amplification (hearing aids)– Cochlear Implantation– Educational Interventions

• Preferential seating• In class amplifiers (FM systems)• Speech/ language/ auditory-verbal therapy

Management of associated disorders

• Cardiac (prolonged QT) – awareness, medication• Meningitis vaccinations:

– SNHL population, particularly those with malformations, at higher risk than general population

• Thyroid disease • Meningitis – steroids reduce the incidence of SNHL and

improve survival• Sudden SNHL – high dose steroids +/- antivirals may

improve recovery of hearing if begun promptly (controversy)

Management

Deafness heavy social & economic burden on individual, family, community & country

Multidisciplinary approach:

Parents’ reaction to the diagnosis:

-Shock, denial, anger, acceptance

-Dealt sympathetically

Subsequent management of the hearing impaired child:

1.Appropriate hearing aid selection

2.Promotion of the development of language & communication skills and if possible, speech development

Management Medical:

CHL: - Otitis media or its sequelae

- Otitis media with persistent effusion >3 months

- Obstruction of EAC 

- If hearing loss continues amplification

- hearing aid

- speech therapy

SNHL:

- Can’t be medically treated

- Amplification with hearing aids

- Speech therapy may be beneficial

Surgical management:-Some causes of CHL -Persistent chronic or recurrent otitis media -Cholesteatoma -Bone-anchored hearing aid (BAHA):

- Microtia

- Anotia - auricular reconstruction

- Persistent otorrhea

SNHL can not be treated with surgical means other than cochlear implantation

Hearing aids

• SNHLcan’t be corrected to normal by any form of medical or surgical Rx

• Some CHL- congenital abnormalities of the EAC & middle ear not suitable for surgical Rx

• Birth of totally deaf child-rarehigh powered hearing aids for residual hearing

• Types of hearing aids:

(I) Personal hearing aids: body worn aids, behind the ear aids, BAHA

(II) Aids not entirely worn by the listener: speech trainer, group hearing aids, Radio (FM) hearing aids, infrared hearing aid system, loop system

Cochlear Implantation

•Candidacy coordinated by audiologist•Requires specific expertise•Rapidly evolving field

•Much success in very young (< 18 months) children•Ongoing technological advances and opportunities

Communication methods in the education of deaf children

1.Auralism: use only speech and lipreading as a means of communication•Signing- strongly discouraged or prevented•Oralsits-ability to develop speech inhibited by allowing signing

2.Finger spelling:

3.Cued speech: •M,P,B or K,D,L – not distinguished by lipreading alone•Different hand shapes in different positions close to the speaker’s mouth to enable the child to discriminate the lip movement

4.Signing system (manualism):

British sign language, American sign language

5.Total communication:

Uses any and all modes of communication (combination of speech, gestures, signing, finger spelling, speech reading/lip reading, reading and writing)

Controversy:•Sensory inputs (auditory & visual)enhances language development•Total communicationimpair speech developement

The Deaf Community

Supportive, strong community

Does not view hearing loss as a disability

Rich history and language

(e.g., American Sign Language)

Children with cochlear implants may have limited access to the deaf community

Future Therapies

•Hair cell regeneration

•Auditory nerve regeneration

Assistive Devices

Obtain devices - doorbells, timers, alarm clocks and fire alarmsAlerting devices hearing dog alarm clock with flashing light devices producing strong vibration

Telecommunication devices Telephone amplifier Telephone coupler attached to hearing aid Telecommunication devices for deaf (TDD)

Teletypewriters (TTYs) machines - enable deaf people

to use the phone

Follow-up Deaf childFollow up Audiologist:

- Monitor progression

- Hearing loss

- Refit hearing aids - match changing losses/ growth of ears

Pediatricians:

Monitor linguistic/ social development

Children who are deaf or hard of hearing are at particular risk

for abuse

Thank YouKanyam, tea garden, Nepal