Pure Tone & Speech Audiometry Flashcards

What is a bone conduction audiogram used to determine?

Answer: The cochlear and neural reserve of the auditory system, bypassing the outer and middle ear

Bone conduction testing delivers sound vibrations directly to the cochlea via a bone oscillator placed on the mastoid or forehead, bypassing the outer and middle ear to assess sensorineural reserve.

A patient's audiogram shows air conduction thresholds of 50 dB HL and bone conduction thresholds of 15 dB HL at 2000 Hz. What type of hearing loss does this indicate?

Answer: Conductive hearing loss

An air-bone gap of 35 dB (50 dB AC minus 15 dB BC) with normal bone conduction indicates a conductive hearing loss, meaning the outer or middle ear is impeding sound transmission to an otherwise functional cochlea.

What does the Speech Recognition Threshold (SRT) measure and how does it relate to the pure tone average (PTA)?

Answer: The lowest level at which the patient can correctly repeat 50% of spondee words; it should agree within 10 dB of the PTA

SRT is the hearing level at which a patient correctly identifies 50% of spondee (two-syllable, equal stress) words. It should agree within 10 dB of the PTA (average of 500, 1000, 2000 Hz thresholds) as a validity check.

What is the purpose of masking in audiometry?

Answer: To prevent the non-test ear from responding to sounds presented to the test ear, ensuring thresholds reflect only the test ear

Masking introduces a noise (usually narrowband noise) into the non-test ear to prevent it from detecting cross-heard sounds intended for the test ear, ensuring that thresholds reflect only the ear being tested.

What pure tone average (PTA) threshold range defines a moderate hearing loss?

Answer: 41-55 dB HL

According to standard audiometric classification, moderate hearing loss falls in the 41-55 dB HL range. Patients in this range typically have significant difficulty understanding speech without amplification.

Which test is used to assess the acoustic reflex and can help identify middle ear pathology or auditory nerve dysfunction?

Answer: Acoustic immittance testing (tympanometry and acoustic reflex testing)

Acoustic immittance testing includes tympanometry (middle ear pressure and compliance) and acoustic reflex testing (stapedius muscle contraction in response to loud sounds), helping identify middle ear pathologies and retrocochlear disorders.