Audiology Exam 2

up 5 down 10 procedure

to establish the pure tone threshold of a patient, when they can’t hear the sound increase by 5, if they can hear the sound decrease by 10. repeat this multiple times to establish a consistent threshold

pure tone threshold

the lowest intensity leevel the patient responds to at least 50% of a series of ascending (increasing intensity) presentations, with at least 2 responses out of at least 3 trials (up to 4) for single level

how to obtain a pure tone threshold

1. provide clear instructions

2. place the appropriate transducer on the patient

3. present tone by pressing and releasing the interrupter

4. how to vary frequency: start @ 1000 Hz go (1000,2000,4000,8000,500,250)

5. how to obtain the threshold at a given frequency: present tone at an easy level to hear (start at 30 or 40 dB), vary sound intensity up 5 down 10 method to find threshold

what is the dB level for normal hearing

<= 25 dB HL

what is the dB level for mild hearing loss

26-40 dB

what is the dB level for moderate hearing loss

41-55 dB

what is the dB level for moderately severe hearing loss

56-70 dB

what is the dB level for severe hearing loss

71-90 dB

what is the dB level for profound hearing loss

91+ dB

what is air bone gap

the difference between the air conduction results and bone conduction results

what is the pure tone average

the average of the hearing threshold levels at 500 Hz, 1000 Hz and 2000 Hz

what is masking?

the process of putting noise into the non test ear (NTE) while measuring responses in the test ear (TE)

why do we need masking

sounds may be heard by the non test ear that may contribute to performance due to cross hearing

what is cross hearing

reception of a sound signal by the non test ear during a hearing test (when testing AC or BC), this primarily happens via bone conduction

what is interaural attenuation

the difference in the level of a signal to the test ear (by AC or BC) compared to the level of the signal that occurs in the not test ear (by BC)

what is the difference between speech threshold and speech recognition tests?

speech threshold is the lowest level of speech that is detected or recognized, speech recognition is the ability to understand speech at a suprathreshold level

what is a spondee?

it is a word with two syllables, both pronounced with equal stress and effort

what is the relationship between SRT and PTA

SRT should be within 10 dB of PTA

speech recognition score

a percentage measure that quantifies how clearly speech is heard at a fixed suprathreshold level

speech banana

speech sounds are around 20-50 dB HL, vowels have a low frequency high intensity consonants have a higher frequency low intensity

SRT

speech recognition threshold

SDT

speech detection threshold

SRS/WRS

speech recognition score / word recognition score

admittance

the ease at which energy will flow through the vibrating system

impedance

the extent to which the system resists the flow of energy through it

how to tympanometry measure middle ear function

presenting probe tone, varying air pressure, measuring reflected sound

tympanogram

a graph produced during tympanometry that measures the flexibility (compliance) of the eardrum in response to air pressure changes

procedure for generating a tympanogram

a probe is sealed in the ear canal to play a continuous tone while an air pump sweeps the pressure from positive to negative. The device then measures how much sound reflects off the eardrum at each pressure level to plot its maximum flexibility on a graph.

factors affecting immittance in the middle ear system: mass and stiffness

Middle ear immittance is primarily governed by stiffness (controlling low frequencies) and mass (controlling high frequencies), with the system's resonant frequency occurring where these two forces balance

peak pressure

the air pressure where the eardrum is most flexible (TPP, where the peak lines up on the x axis)

what is addmittance of the middle ear (Ytm)

measures the maximum amount of energy flowing through the middle ear at that peak, peak on the graph

Vea

ear canal volume estimates the physical space between the probe tip and the eardrum

acoustic reflex

stapedius muscle (innervered by the facial nerve) contracts reflexively and bilaterally in response to an intense sound presented to either ear

acoustic reflex pathway

outer ear, middle ear, inner ear, ventral cochlear nucleus, superior olivary complex, facial nerve nucleus

what does OAE stand for

otoacoustic emissions

what are OAEs

a very low level acoustic energy (-10 to 20 dB SPL) produced by the cochlea with the primary sound coming from the active process of the outer hair cells

what does ABR stand for

auditory brainstem response

what is an ABR

a neuroelastic response from the eighth cranial nerve and brainstem pathways in response to brief sounds (ex. clicks) measured with electrodes on the surface of the head

what does DPOAEs stand for

distortion product otoacoustic emissions

what is DPOAEs

generated by the outer hair cells of the cochlea when the ear is stimulated simultaneously by two different pure tones (f1 and f2). The interaction of these tones creates a "distortion product"

what does presence of OAE indicate about the ear

present, normal outer hair cells and normal middle ear

absent: cochlear hearing loss or a conductive problem

what structures generate the ABR

generated by a sequence of neural structures beginning with the auditory nerve (Waves I and II) and continuing through the cochlear nucleus and superior olivary complex (Wave III). The signal then travels through the lateral lemniscus (Wave IV) to the inferior colliculus (Wave V), which is the most prominent and clinically useful peak in the waveform.

how does the auditory brainstem response change with intensity

As stimulus intensity decreases, the ABR waveform shows a significant increase in latency (the time it takes for peaks to appear) and a decrease in amplitude (the size of the peaks).

what is needed for Distrotion product otoacoustic emissions to be normal

at least 6 dB SNR, compare the result of ear to the floor noise must be at least 6 dB difference and the ear result amplitude must be at least -10