Evoked Potential

Adult Case History Questionnaire

What brings you in today/How can I help you?
  • How long has this been happening?
  • Gradual or Sudden Profound or Diminished​
  • Significant event around loss?
  • One ear L or R or both ears?
  • Constant or fluctuation?
  • Difficulty in certain/specific situations?
  • Quiet places?
  • Background Noise?
  • Speech?
  • Aural pressure, fullness, pain (otalgia), drainage/fluid (otorrhea)?
  • Falls
  • Facial numbness?
  • Numbness around your ear?
  • Head trauma?
  • Numbness around your ear after trauma?
  • Hear voice while talking or chewing?
  • Work Related?

Do you have any noises/tinnitus in your ears?
  • One ear L or R or both ears
  • What does it sound like? Roaring?
  • Constant or intermittent
  • Anything that triggers it? Weather?
  • How bothersome is it on a scale from 1 to 10

Do you have any dizziness or balance issues?
  • When did it start?
  • Constant or intermittent
  • Have you ever had a middle ear infection?
  • Infections as a child?
  • Was it treated?
  • When was your last infection?

Have you ever been or are you currently exposed to loud noises?
• Occupational
• loud machinery, factory, military
• Recreational
• Do you fire guns?
  • If yes, which hand
  • Be on the lookout for noise induced hearing loss
  • Concerts, motorcycles
• Do you wear hearing protection?

Family History of Hearing loss
• Pregnancy
Previous surgeries?
• Cause?

Previous hearing test?
  • Results

Medications?
  • Ototoxic?
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Anything else that you’d like to add before we begin testing?
  • ​?

Results Flowchart

Comprehensive audiometry threshold evaluation and speech recognition
  • Pure Tone Audiometry/Air Conduction Thresholds (AC)
  • Bone Conduction Thresholds/Pure Tone (BC)
  • Speech Audiometry Thresholds (WRS) with Speech Recognition Thresholds (SRT)

Otoscopy
  • Clear external canals unilaterally/bilaterally?
    • Potentially conductive or SNHL
  • Occluded canals unilaterally/bilaterally?
  • Potentially conductive or SNHL​

Immitance
  • Tympanometry
    • A - Normal
      • indication of SNHL
    • As - Flat/Shallow
      • indication of Conductive
    • Ad - Hypercompliant
      • Key is to see if ear canal volume is normal
      • Static admittance
      • Indication of perforation or disarticulation of ossicular chain
    • B
    • C
  • Acoustic Reflex Thresholds - the neural integrity of the auditory eighth cranial nerve
    • Elevated or Absent
    • Ipsi or Contra
    • When ARTs are absent with sound present to one ear (ex, R/Ipsi, R/Contra) are consistent with right afferent portion of reflex arc missing and one ear is okay ipsilaterally (ex: L/Ipsi is okay, but L/Contra is not) 
Speech Reception Thresholds
  • ​Normal levels
    • 15 Normal ability to receive speech
    • 35 Mild loss ability to receive speech
  • In agreement with pure tone thresholds?
    • average 500Hz, 1000Hz and 2000Hz

Pure Tone Thresholds
  • Limits of hearing

Word Recognition Thresholds
  • Be sure to include masking
  • Test for rollover P/I (performance intensity function)
  • Pb Max Calculation of Pb Max - Min/Max
    • ​dividing the amount of rollover by the maximum score
    • max score 96%, minimum score 56% this is a rollover index of 0.42
    • 96-56/96 = 0.42; lower limit is 0.25-0.45
    • regardless, the difference between 96% and 56% in conjunction with these other signs is clearly indicative of rollover
  • ​Therefore, start at a high level of 80dB HL
    • if the patients score is greater than 80% then significant rollover is ruled out 

Otoacoustic Emissions - Test the functional integrity of the cochlear outer hair cells
  • Present and Robust?
    • Indication of intact outer hair cells
  • Absent?
    • Is there a conductive component?
  • The presence of symmetric OAEs in ears with asymmetric hearing is suggestive of retrocochlear disorder on a specific side

ABR - Functional diagnostic of the integrity of the brainstem; DAN, PAN, CN, SOC, IC; SUGGESTS AUDITORY NERVE OR BRAINSTEM PATHOLOGY
  • Neurodiagnostic
    • ​Standard stimulus rate
      • Normal peak and interpeak latencies?
      • Delayed peak and interpeak latencies?
    • Use condensation, rarefaction and alternating click polarities and AVERAGE them
    • Look for repeatable response
    • Look for cochlear microphonic reversal
    • Look for the disappearance of the cochlear microphonic with tube clamping to rule out stimulus artifact
    • Look for grossly abnormal waves at a non-typical stimulus rate, say 11.1 clicks per second
    • replicable peaks?
    • Wave I to III interwave intervals
    • Wave III to V interwave interval
    • Wave I to V interwave interval
      • deviations from the norm?

Recommendations

Conductive Pathology
  • Significant Air-Bone Gap can be ruled out by switching Headphones for Inserts

Retrocochlear Pathology
  • Retrocochlear pathology should be suspected when a patient presents with asymmetrical hearing loss, unilateral tinnitus and unilateral aural fullness
  • Word recognition scores may not be affected when an auditory lesion is present
  • Acoustic Reflex decay is an important diagnostic tool in identifying retrocochlear lesions
  • asymmetric symptomatology, asymmetric hearing sensitivity, absent ARTs with contralateral and ipsilateral signals presented to one side, rollover of the word recognition function and preservation of OAEs
  • Look for an overall pattern of normal function in one ear and symptomatic in one ear (ex: Right Ear: asymmetric symptomatology, asymmetric hearing sensitivity hearing sensitivity, ARTs, WRSs and OAEs)
  • 20% rule for rollover
    • over 20% is retrocochlear
    • less than 20% is cochlear
  • Fun Fact: bilateral tumors are associated with Neurofibramatosis2

Auditory Neuropathy
  • Pattern of findings (absent ARTs with the presence of DPOAEs) is commonly manifested in patients with auditory neuropathy spectrum disorder
    • DPOAEs should be absent with a given magnitude of hearing loss
    • Absence of ARTs to contralateral and ipsilateral stimulation with present DPOAEs are an important indicator for ABR testing
  • ABR testing could confirm or deny the presence of nonorganic hearing loss versus ANSD
  • Cochlear implant or BAHA? hearing aids may not help because it's not just an amplification thing! for kids it can work!
  • ARTs absent, OAEs present, ABR waveforms being significantly degraded or absent, with CM activity
  • hearing thresholds can range from within normal limits to a profound hearing loss that can fluctuate
  • POOR SPEECH RECOGNITION, PARTICULARLY WHEN IN NOISY ENVIRONMENTS
  • Most always have ANSD
  • can be the inner hair cells, the inner hair cell/cochlear nerve fiber junctions and/or cochlear nerve fibers
  • may want to refer to a neurologist
  • auditory communication strategies

Vestibular Problems
  • Comprehensive vestibular function testing would be indicated

Hearing Protection
  • Include hearing protection in everything that you do

Types of Amplification
  • Unilateral can use a bicross
  • BAHA for bone stimulation
  • Dexterity issues may need something to just insert in the ear without fine manipulation
Evoked Potential
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San Francisco, California 94133
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