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Pediatric Hearing Loss and Testing Techniques

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1 Pediatric Hearing Loss and Testing Techniques
Diego A Preciado MD PhD Pediatric Otolaryngology Children’s National Medical Center George Washington University Washington, DC

2 11 month child seems to ‘hear well’ at home, but daycare provider concerned with ability to respond to verbal stimuli at times

3 A) Child can only be tested asleep B) Child can be tested awake C) Child can only be screened for hearing loss at his age D) Child can only be tested by the old ‘rub/snap your fingers’ next to the ear trick

4 Childhood Hearing Loss
Moderate to profound congenital hearing impairment occurs in 4 per 1000 live births Recommendations specify that All children screened at birth All children diagnosed by 3 months of age All children treated by 6 months 43 states have mandated Universal Newborn Hearing Screening (UNHS) programs

5 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)

6 Here’s the clinical challenge we are faced with…..
Language behaviors UNHS Infants with HL ENT HA, Rehab, SLP Optimal Age for CI Target Age age in months 6 12 18

7 Electrophysiologic Testing
Use in neonates, uncooperative patients, brain injury Otoacoustic emissions (OAEs) Originates in cochlea, evoked with sound stimulation Absent suggests > 30 dB HL

8 Electrophysiologic Testing
Evoked auditory brainstem response (ABR or BAER) Auditory electrical responses Diagnoses presence, degree and type of HL

9 Hearing Loss Types Conductive Sensorineural Mixed
measured by “air” stimulation on audiogram Sensorineural measured by “bone” stimulation on audiogram Mixed

10 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”

11 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

12 Tympanometry Not a hearing test!
Objective measure of middle ear (ME) compliance Complements ear exam

13 COMPLIANCE/Admitance
Tympanograms Volume COMPLIANCE/Admitance

14 Tympanograms Type A- Normal

15 Tympanograms Type B- High Volume Type B- Low Volume
Perforation or PE tube Type B- Low Volume Fluid

16 Tympanograms Type C- Negative Pressure Retraction

17 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

18 Etiology of SNHL 70% recessive 25% dominant 5% X-linked

19 SNHL – Associated Conditions
Loop diuretics, aminoglycosides, aspirin Hyperbilirubinemia Severe depression at birth (asphyxia) Anomalies of external and middle ear Usually irreversible Family history – congenital, delayed onset childhood SNHL Congential infections – CMV, rubella Bacterial meningitis

20 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

21 Audiogram Listening to spoken language during early life is a critical prerequisite for the typical development of speech. Each of these terms is often accompanied by specific threshold levels of loss in the frequency region for speech. These terms are meant to convey the extent of hearing loss and are useful in explaining to parents how much of speech their child can expect to hear.

22 Behavioral Audiometry
Test Techniques: Behavioral Observation Audiometry (BOA) Visual reinforcement audiometry (VRA) Conditioned play audiometry (CPA) Conventional hand-raising procedures Gold Standard Achieve auditory thresholds at all test frequencies for both ears. Ongoing age-specific activity – the methodology and specific techniques are modified for the developmental age of the child. Utilize cross-check principle using available objective tests

23 Behavioral Observation Audiometry

24 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 Soundfield = air conduction/sometimes bone conduction *children are placed on parent’s/caregiver’s lap, or in a high chair, 450 azimuth to loudspeakers Warbled tones = modulated pure tone (frequency and amplitude) Narrowband noise = passing a broad band white noise signal through narrowband filters Observed responses: Early attending: Sucking, Eye widening, Eyebrow raise, ↑ or ↓ in motor activity Later attending: Searching behavior (without true localization), Listening posture, Localized head turn-4-7 mo: Side-to-side, 6-9 mo: Sides, above & below

25 Audiometry during infancy
Symbols Sound field S S S S Speech = 20 NBN or warbled tones = 20-50 S Speech does not occur at a single intensity or frequency. In general vowel sounds are low frequency in nature and more intense “carry more power”. Whereas consonants, particularly voiceless consonants /s/, /sh/, /t/ “fish” thin”, are composed of higher frequencies and are least intense. Each child’s capacities do vary as a consequence of listening circumstances. Descriptive terms only partially explain the listening experiences of a particular child. Age-appropriate responses for infants aged ~5 – 9 months

26 Visual reinforcement audiometry (VRA)
Employs lighted transparent-boxed toys to reinforce child’s localized response to onset of acoustic stimuli Conditioning phase; Testing phase


28 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 Transducers Sound field loudspeakers Insert or supra-aural earphones Bone conduction oscillator Stimuli Speech Narrowband noise (NBN) Warbled tones Parent’s voice

29 Conditioned Play Audiometry (CPA)
Child is taught a play task in response to the onset of an acoustic stimulus Children aged ~ years Older individuals with developmental involvements Transducers Insert or supra-aural earphones Bone conduction oscillator Sound field loudspeakers Stimuli Speech Warbled tones Pulsed tones Narrowband noise (NBN)


31 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

32 Pure Tone Audiograms ‘loudness’

33 Audiograms Bracket = Bone, Right Side Circle = Air, Right Side

34 Audiograms Bracket = Bone, Right Side Circle = Air, Right Side
CHL A-B gap

35 Audiograms Bracket = Bone, Right Side Circle = Air, Right Side

36 Audiograms Bracket = Bone, Right Side Circle = Air, Right Side

37 A 3 year old child presents with low volume, Type B tympanogram, and 20 dB Air Bone gap
Most likely diagnosis is A- Cholesteatoma B- TM perforation C- OM with effusion D- Sensorineural hearing loss

38 A 3 year old child presents with low volume, Type B tympanogram, and 20 dB Air Bone gap
Most likely diagnosis is A- Cholesteatoma B- TM perforation C- OM with effusion D- Sensorineural hearing loss

39 Hereditary Hearing Impairment
Dominant progressive, milder, late onset, penetrance/expressivity Recessive stable, severe, congenital, more symmetric



42 Waardenburg Syndrome Autosomal dominant
Variable expressivity Associated with pigmentary abnormalities White forelock (20-30%) Premature graying Vitiligo Heterochromia irdis

43 Treacher Collins Syndrome (Mandibulofacial Dystostosis)
Inheritance: Autosomal dominant with variable expressivity Molecular basis:Caused by mutations in Treacle gene (TCOF1)

44 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

45 Autosomal Recessive Syndromes

46 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

47 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


49 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

50 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

51 Clinical Genetics Sequence: multiple defects from a single defect
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

52 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

53 Connexin 26 GJB2 Connexin 26 is located on long arm of chromosome 13 and is a relatively simple gene, made up of only 2 exons, separated by an intron of 3148 bp. Exon 1 is UTR. Exon 2 contains the coding region of 681 bp (227 aa) and a 5’ UTR.

54 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

55 EVA Syndromic Non-syndromic Associated with SLC26A4 mutation (DFNB4)
Pendred’s More severe phenotype Non-syndromic More heterogenous hearing level

56 VA Size Boston M, et al. Oto-HNS, 2007

57 SLC26A4 mutations and hearing loss
Asaiez H, et al. Human Genetics, 2007


59 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

60 Clinical Evaluation Audiometric evaluation-Diagnosis Behavioral ABR

61 Results GJB2 and Imaging yield vs. SNHL
What are you going to say here?

62 Preciado D, et al. Otol Neurotol. 2005 Jul;26(4):610-5
History, Physical examination, Audiologic work-up Diagnosis apparent Diagnosis uncertain Appropriate treatment Bilateral Unilateral MRI, Preferential seating, Serial audiograms Sev-to-Prof Mod-Sev Mild-to-Mod GJB2 screen CT scan _ + _ + Genetic Counseling CT scan Appropriate treatment GJB2 screen Lab tests as indicated Lab tests as indicated ECG Preciado D, et al. Otol Neurotol Jul;26(4):610-5

63 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


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