Pediatric Assessment

Otoscopy

Verify clean external auditory canals and note any abnormalities either inside or outside the ear

Tympanometry

Purpose: To assess middle ear (ME) function and identify need for medical management
Purpose: To assess impact of middle ear (ME) status on threshold information
  • Infants under 6 months - 226Hz for volume and 1000Hz for mobility of tympanic membrane
  • Infants over 6 months - 226Hz

Acoustic Reflexes

  • 90 dB screen at 1000 Hz is acceptable to confirm presence or absence of acoustic reflexes – use caution if tympanometry is abnormal
  • Use the same probe tone as the tympanogram

DPOAEs

  • Screening is appropriate if child is moving or uncooperative
  • Select a diagnostic DPOAE protocol. A screening protocol is
    appropriate if time is limited or child is
    moving.
  • Use the Boystown Extended norms (95th percentile criterion) to determine presence of the emission.

ABR 

Purpose: To assess neural synchrony along the ascending auditory pathways through the level of the brainstem
Priority: Baby may wake at any time, Rule out ANSD, Obtain adequate information to proceed with amplification, Replicate
  • This is not a true measure of hearing sensitivity but a best estimation of hearing threshold levels in infants
  • Objective measure (not influenced by behavior)
  • Frequency specific
  • Ear specific
  • Natural sleep is preferred
  • 2 channel recording
    • High forehead (FPz)/Top of scalp (Cz)*preferred
    • Lower forehead (GND)
    • M1
    • M2
  • Neurodiagnostic ABR
    • Use a click stimulus at 80 dBnHL – 13.1 cps for >1000 averages using
      a rarefaction polarity (to compare against Gorga norms)
    • Switch to condensation polarity and record.
    • If a response is not present at 80 dBnHL, increase stimulus intensity
      and record. Also consider slowing the click rate to improve waveform
      morphology.
    • Mark waveforms
      (including cochlear microphonic, if applicable) and comment on morphology.
    • Analyze latencies
    • Absolute wave latencies – I, III, V
    • Interpeak wave latencies – I-III, III-V, I-V
    • Repeat for opposite ear
  • Test for ANSD
    • If the rare / con click response is abnormal, change polarity to alternating and record
    • If a cochlear microphonic is present using rarefaction / condensation
      polarities and primary waveforms are absent, record rarefaction and
      condensation runs again with the insert tubing pulled out of the
      transducer box.
    • This
      will help distinguish the cochlear microphonic from stimulus ring.
    • Note “Stimulus on, but insert out of ear
      ” on the waveform printout.
    • It is helpful to overlay the rarefaction and condensation runs on the
      waveform printout to highlight the cochlear microphonic reversal
  • Threshold ABR Testing
    • Threshold ABR testing
    • Begin with 2000 Hz toneburst at 80 dBnHL
    • If present, mark wave V and decrease by 40 dBnHL. Begin threshold
      estimation.
    • Use bracketing method
    • Mark wave V for each present response
    • Replicate, replicate, replicate
    • 10 dBeHL (using correction factors) is considered normal for peds and 20
      dBeHL for adults. Do not test lower
    • Repeat for other ear
    • After 2000 Hz has been completed, proceed to 500 Hz, 4000 Hz, and
      finally 1000 Hz. Consider additional frequencies.
    • Record ABR thresholds and estimated hearing thresholds on the ABR
      worksheet
    • Print latency-intensity functions with report
  • Latency Intensity Function
    • As intensity decreases, the latency of wave V increases
  • Bone Conduction ABR
    • Bone conduction ABR
    • If air conduction thresholds are elevated, bone conduction testing is
      indicated to aid in determining type of hearing loss.
    • Use a click stimulus (alternating polarity at 11.1 cps), unless 500 Hz is
      indicated
    • Be certain to start your stimulus presentation at a softer level (ie. 55
      dBnHL), to avoid waking the baby (as a result of stimulus volume or
      oscillator vibration).
    • Complete threshold
      search.
    • Record threshold and estimated threshold on the ABR worksheet
  • Typical Follow Up is 2 - 6 weeks

ASSR

  • Auditory Steady State Response
  • ​If a hearing loss is suspected, specifically in a severe to profound hearing loss range, complete frequency specific threshold search using ASSR due to ABR intensity limitations

Case Study

  • Dx
    • No Response ABR
    • Absent DPOAE
    • Flat HF Tympanometry
  • Tx
    • Refer to ENT for evaluation of ME function
    • Re-evaluate at 6 months
  • Follow up
    • Normal Tympanometry
    • Present DPOAE
    • No Response ABR
    • Large Cochlear Microphonic Present
  • Dx
    • ANSD