Audiology term 1 test

Cross hearing can cause a shadow curve that follows the shape of the other ear’s …

Bone conduction thresholds

Sound is a … wave

Longitudinal

In terms of sound, condensation is ?

When the molecules are closer together (higher pressure)

The frequency of a wave is measured by

Hertz (Hz)

If 10² is 100, what is log10 of 100?

2

How to convert factors of x10 to decibels

Count zeros and multiply by 20

What is x100 in decibel terms

40dB

What is x1/1000 in decibel terms

-60dB

When doubling by decibel scale

+6dB

When halving by decibel scale

-6dB

The period of a 1kHz wave is

1 millisecond

The period of a 500 hz wave is

2 milliseconds

Period =

1 / frequency

What is the speed of sound in air

340 metres per second

Frequency is the

Number of wave cycles per second

What is the wavelength of a 340 Hz sound

1 metre

What is the wavelength of 3400Hz wave

10cm

dB A =

The A-weighted scale

What is the dB A scale best used for

Measuring quiet sounds

dB SPL measures

The physical amplitude of any sound

dB C is best used for

Human loud sounds

dB SPL =

Decibel sound pressure level

What is the reference sound pressure level for dB SPL …μPa RMS

20

dB HL =

Decibel hearing level

The dB HL scale allows the average human threshold to be what on the audiogram?

0dB

What is this?

A Low-pass filter

What is this?

A high-pass filter filter

What is this?

A band-pass filter

Doubling your distance from a 50dB SPL sound source

Reduces its level by 6 dB

Transmission loss is the

Difference in SPL on either side of the barrier

Reverberation time is given by the

RT60

Head shadows are larger at

High frequencies

Sound waves are

Minute fluctuations in atmospheric pressure

What is the range of human hearing

20Hz to 20kHz

What do sound level meters do?

Give an overall measure of frequency

Why do you use spectral analysis

To see every frequency of every part of the wave

What does filter mean

To take the energy of a signal and remove some of it

An audiogram has … at the top and … at the bottom

Quiet sounds, loud sounds

On an audiogram different …

Frequencies of speech lie on different parts

What type of frequencies can wrap around objects?

Low frequencies

What type of frequencies will be blocked?

High frequencies

Reverberation refers to the fact that

Sound takes time to die away

How can you measure reverberation?

RT60

Transmission loss is the

Difference in SPL on either side of a barrier

If you double the density of a wall

The transmission loss increases by 6dB (you loose 6dB)

If you double the thickness of a wall

Transmission loss increases by 6dB

To get a large transmission loss we want

High mass, low stiffness, high damping, and a large impedance mismatch

To improve the acoustics of a classroom we

Reduce reverberation time, and increase sound absorption

The opposite of medial

Lateral

What is this part of the pinnacle called

Helix

What is the red shaded part of the pinna called

Cavum concha

The ear canal consists of the … portion and the … portion

bony, cartilaginous

What are 3 functions of the cerumen (ear wax)

Cleaning, lubrication, antibacterial/antifungal

What are 3 layers of the tympanic membrane

Epidermal layer, mucosal layer, and lamina propria

Which part of the tympanic membrane has the lamina propria?

Pars tense (tense part)

A Marginal perforation is

One which lies close to the annulus and touches the edge. These do not heal as easily

The annulus is the

Thickened fibourous ring around the edge of the tympanic membrane

What are the 3 ossicles

Incus, malleus, stapes

Which is the promontory

D

Which is the manubrium of the malleus

A

Which is the umbo

C

What middle-ear impedance matching process contributes the most?

The area ratio of the TM to the oval window

In humans how much bigger is the TM than the oval window?

17 times as large

The long crus/process of the incus is 1.3 times shorter than the

Manubrium of the malleus, thus causing a corresponding increase in force

The structure responsible for the aeration of the middle ear is the

Eustachian tube

Which wall of the tympanic cavity contains the entrance to the Eustachian tube

Anterior

Which middle ear muscled is innervated by the trigenimal nerve

Tensor tympani

What does the tensor tympani attach to

The malleus

Which middle ear muscle contracts in response to sound

Stapedius tendon

Which middle ear muscle contracts in anticipation to sound

Tensor tympani

Sound waves are

minute fluctuations in atmospheric pressure

Humans can detect frequencies between

20Hz and 20kHz

What does the cavum concha form

The vestibule at the entrance to the ear canal

Where is the cymba concha

In between the Crura of the anti-helix and helix

Rarefaction is when

Molecules are pulled further apart

What innervates the posterior, superior and anterior auricular muscles

The post auricular branch of the facial nerve

The main function of the pinna is to

Collect and direct the sound waves to the tympanic membrane

The pinna is important for directional hearing particularly when distinguishing between

Up/down and front/back

The medial 2/3s of the external auditory meatus (ear canal) is the …

Bony portion

The lateral 1/3 of the external auditory meatus (ear canal) is the …

Cartilaginous portion

What is responsible for the production of ear wax

The cartilaginous portion of the ear canal

How is cerumen (earwax) produced

A mixture of viscous secretions from sebaceous glands and less-viscous ones from modified apocrine sweat glands

Otoscopy means

Looking down the ear canal

What happens if you shine a light in a normal ear drum

The ear drum should be pearly, translucent and reflect light

The interaural inntenuation for air conduction with supra-aural is

40dB HL

What is the interaural attenuation for air conduction with inserts?

50-60dB HL

masking is the process whereby the …

Detection threshold for one sound (the probe) is increased by the presence of another sound (the masker)

What is the upwards spread of masking mean?

Low frequencies can mask higher frequencies, but higher frequencies can’t mask lower ones

How can you best mask a probe?

By presenting a masker centred at the same frequency

Narrow band noise is noise …

23-35% Around the frequency we’re interested in

Under masking occurs when …

Less than the minimum masking level is used, resulting in the non-test ear detecting the stimulus

Overmasking occurs when …

The level of masking is higher than the maximum point of plateau resulting in test ear hearing the masking noise

Masking plateau is

The range between the min and max levels, after 20dB of plateau we can accept the threshold as from the test ear

The lamina propria is a

Fibrous layer called the pars tensa

The epidermal layer is

Skin that lines the outside of the ear drum

The mucosal layer

Lines the middle ear cavity with mucosa

The malleus is the … the incus is the … the stapes is the …

Hammer bone, anvil, stirrup

Order of the ossicles is

Ear drum, malleus, incus, stapes, oval window

The ossicles pass …

Sound vibrations from the ear drum, through each bone, to the oval window of the cochlea