ENT for the PA-C, Apr 2012 Pediatric Hearing Loss and Testing Techniques Diego A Preciado MD PhD Pediatric Otolaryngology Childrens National Medical Center.

ENT for the PA-C, Apr 2012

Pediatric Hearing LossPediatric Hearing Lossand Testing Techniquesand Testing Techniques

Diego A Preciado MD PhDPediatric Otolaryngology

Children’s National Medical CenterGeorge Washington University

Washington, DC


• 11 month child seems to ‘hear well’ at home, but daycare provider concerned with ability to respond to verbal stimuli at times

A) Child can only be tested asleepB) Child can be tested awakeC) Child can only be screened for hearing loss

at his ageD) Child can only be tested by the old

‘rub/snap your fingers’ next to the ear trick


Childhood Hearing Loss

Moderate to profound congenital hearing impairment occurs in 4 per 1000 live births

Recommendations specify thatAll children screened at birthAll children diagnosed by 3 months of ageAll children treated by 6 months

43 states have mandated Universal Newborn Hearing Screening (UNHS) programs


Types of Hearing Tests

• Screening (PASS OR FAIL) (electrophysiological)– Otoacoustic Emissions (OAE)– Automated ABR

• Diagnostic (NOT PASS OR FAIL)– ABR (electrophysiological; all ages)– Pure Tone Audiometry (>4 yrs of age)– Infant Audiometry (>6 mo of age)

Here’s the clinical challenge we are faced with…..

UNHSInfantswith HL

0 6 12 18

OptimalAge for CI

TargetAge

Languagebehaviors

age inmonths

ENT

HA, Rehab, SLP

Electrophysiologic Testing

• Use in neonates, uncooperative patients, brain injury

• Otoacoustic emissions (OAEs)• Originates in cochlea, evoked with sound

stimulation• Absent suggests > 30 dB HL


Electrophysiologic Testing

• Evoked auditory brainstem response (ABR or BAER)

• Auditory electrical responses• Diagnoses presence, degree and type of

HL


Hearing Loss Types

•Conductive–measured by “air” stimulation on audiogram

•Sensorineural–measured by “bone” stimulation on audiogram

•Mixed


Conductive Loss

• Conductive loss (CHL) results from increase in impedance (resistance)

• Audiometric profile of conductive hearing loss is threshold for air conduction is worse than for bone conduction i.e. large “air-bone gap”


Conductive Hearing Loss• Generally reversible• Middle or External Ear Pathology• External auditory canal (EAC) obstruction

Cerumen impactions, foreign body, otitis externa, EAC atresia

• Abnormality of ear drum Perforation, retraction

• ME conditions AOM, OM with effusion, cholesteatoma, tumor

• Ossicular chain anomalies Disruption - associated with trauma Fixation – often congenital


Tympanometry

• Not a hearing test!• Objective measure of middle ear (ME)

compliance• Complements ear exam

TympanogramsCO

MPL

IAN

CE/A

dmita

nce

Volu

me


Tympanograms

Type A- Normal


Tympanograms

Type B- High VolumePerforation or PE tube

Type B- Low VolumeFluid


Tympanograms

Type C- Negative PressureRetraction


Sensorineural Loss

• Sensorineural hearing loss (SNHL) results because of lesions in the auditory nerves and/or cochlea

• Audiometric profile of sensorineural hearing loss demonstrates air conduction and bone conduction reduced without an air-bone gap


Etiology of SNHL

70% recessive25% dominant5% X-linked


SNHL – Associated Conditions

• Usually irreversible• Family history –

congenital, delayed onset childhood SNHL

• Congential infections – CMV, rubella

• Bacterial meningitis

• Loop diuretics, aminoglycosides, aspirin

• Hyperbilirubinemia• Severe depression at

birth (asphyxia)• Anomalies of

external and middle ear


Mixed Hearing Loss

• Mixed hearing loss results from BOTH a conductive and sensorineural hearing loss

• Audiometric profile shows a drop in air and bone conduction with an air-bone gap


Audiogram


Behavioral Audiometry

Test Techniques: • Behavioral Observation Audiometry (BOA)

• Visual reinforcement audiometry (VRA)

• Conditioned play audiometry (CPA)

• Conventional hand-raising procedures


Behavioral Observation Audiometry


Behavioral Observation Audiometry (BOA)

• Children aged ~5 months to 2 years– Individuals with

neurological/developmental involvements• Primarily sound field testing• Subjective observation by the clinician• Stimuli may include speech, warble tones,

narrowband noise (NBN), parent’s voice


Audiometry during infancy

SS

S S

Age-appropriate responses for infants aged ~5 – 9 months

Speech = 20

NBN or warbled tones = 20-50

SymbolsSound field

S


Visual reinforcement audiometry (VRA)

Employs lighted transparent-boxed toys to reinforce

child’s localized response to onset of acoustic stimuli



Visual reinforcement audiometry (VRA)

• Children aged 6 mo - ~ 3 years• Technique consists of conditioning & testing

phases• Responses may include localizations or BOA

responses• Disadvantages

– Dependent on conditioning child to task– Habituation to acoustic stimuli – Poor test reliability


Conditioned Play Audiometry (CPA)

Child is taught a play task in response to

the onset of an acoustic stimulus

Children aged ~ 2-2.5 - 5 years



Audiometry

• Conventional audiometry: ≥ 5 yrs• Zero-20 dB is normal range• Not absolute, but normalized scale• Hearing threshold measured for air

and bone conduction in decibels from 250 Hz – 8 KHz

Pure Tone Audiograms

‘loud

ness

’


AudiogramsBracket = Bone, Right Side Circle = Air, Right Side

NORMAL



CHL A-B gap



SNHL



MIXED HL

A 3 year old child presents with low volume, Type B tympanogram, and

20 dB Air Bone gap

Most likely diagnosis isA- CholesteatomaB- TM perforationC- OM with effusionD- Sensorineural hearing loss

A 3 year old child presents with low volume, Type B tympanogram, and

20 dB Air Bone gap

Most likely diagnosis isA- CholesteatomaB- TM perforationC- OM with effusionD- Sensorineural hearing loss


Hereditary Hearing Impairment

• Dominant– progressive, milder, late onset,

penetrance/expressivity• Recessive

– stable, severe, congenital, more symmetric

SYNDROMES


Waardenburg Syndrome• Autosomal dominant

– Variable expressivity• Associated with pigmentary abnormalities• White forelock (20-30%)• Premature graying• Vitiligo• Heterochromia irdis

Treacher Collins Syndrome (Mandibulofacial Dystostosis)

• Inheritance: Autosomal dominant with variable expressivity

• Molecular basis:Caused by mutations in Treacle gene (TCOF1)


Branchiootorenal Syndrome

• Autosomal dominant• Branchial cleft sinuses/fistulas• Renal anomalies

– These range from mild hypoplasia to bilateral renal agenesis

• External, middle and inner ear deformities• Estimated at about 2% of childhood deafness


Autosomal Recessive Syndromes


Pendred Syndrome

• Autosomal recessive • Abnormal incorporation of iodine• Perchlorate or thiocyanate tests are rarely

performed• Goiter and hypothyroidism usually present

by about 8 years of age


Pendred Syndrome

• Associated with enlarged vestibular aqueduct• Histologic evidence of hydrops and

degenerated changes of the stria vascularis have been described

• Treatment – – amplification– exogenous thyroid hormone



Usher’s Syndrome

• Usher’s Syndrome Type I (7 loci-MYO7A)– Autosomal recessive– Severe to profound hearing loss– Absence of vestibular response– Slow progression– Slowly progressive visual field deficits beginning

as early as age 9-10


Jervell and Lange-Nielson

• Autosomal recessive– Severe-to-profound Bilateral

• Cardiac conduction defects– Enlarged T-waves– Prolongation of the Q-T interval– Syncopal episodes– Sudden death


Clinical Genetics

• Not all that is genetic is a syndrome…

• Malformation: morphologic defect of an organ, part of organ resulting from an intrinsically abnormal developmental process

• Sequence: multiple defects from a single defect

• Syndrome: pattern of multiple anomalies pathogenetically related


Connexin 26

• Mutations in GJB2 (DFNB1) reported at ~30% (20%-70%) of severe to profound hearing loss

• Carrier rate-3.0% (Caucasian)• 35delG, M34T -Caucasian

167delT-Ashkenazi Jewish 235delC-Japanese


Connexin 26

GJB2


EVA

• Sensorineural Hearing Loss• Low Frequency Conductive Hearing Loss

Component• Usually stable hearing level• Occasionally Progressive• Although a congenital malformation of the

inner ear, frequently a later onset hearing loss


EVA

• Syndromic– Associated with SLC26A4 mutation (DFNB4) – Pendred’s– More severe phenotype

• Non-syndromic– More heterogenous hearing level


VA Size

Boston M, et al. Oto-HNS, 2007

SLC26A4 mutations and hearing loss

Asaiez H, et al. Human Genetics, 2007


Clinical Evaluation

• History and Physical• Syndromic findings

– Cutaneous, musculoskeletal, visceral (cardiac, thyroid, renal, visual/balance, cervical)

• Neonatal risk factors• Others-noise, head trauma, autoimmune,

Meniere’s, Lues• Extended family history

– pedigree


Clinical Evaluation

• Audiometric evaluation-Diagnosis– Behavioral– ABR


ResultsGJB2 and Imaging yield vs.

SNHL

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

bilateralsev-to-prof

bilateralmod-sev

bilateralmild-to-mod

unilateral

CT Scan

GJB2

GJB2 screen

+

CT scan

+_ _

Genetic Counseling

CT scan GJB2 screen

Lab tests as indicated

Lab tests as indicated

ECG

History, Physical examination, Audiologic work-up

Diagnosis uncertain

Bilateral Unilateral

MRI, Preferential seating,Serial audiograms

Appropriate treatment

Diagnosis apparent

Sev-to-Prof Mod-Sev Mild-to-Mod

Appropriate treatment

Preciado D, et al. Otol Neurotol. 2005 Jul;26(4):610-5


Conclusions

• You can screen or diagnose AT ANY AGE!• Screen for HL at birth, diagnose by 3 months• You can test awake starting at 6 months• Follow a logical sequential diagnostic work-up

paradigm based on history and physical• Laboratory investigation should be based on

these results and on clinical history

ENT for the PA-C, Apr 2012 Pediatric Hearing Loss and Testing Techniques Diego A Preciado MD PhD Pediatric Otolaryngology Childrens National Medical Center.

Documents

congenital slide

audiogram slide

slp slide

dc slide

procedures slide

normal slide

mo of age slide

middle ear slide