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
NORMAL

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

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

36. Audiograms Bracket = Bone, Right Side Circle = Air, Right Side
MIXED HL

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

40. SYNDROMES

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