Intro to Audiology and Properties of Sound

echale ganas!

What is Inverse Distance Law?

+6dB doubles the intensity of the sound, 2x the distance = ½ the intensity of the sound

Real life example of Inverse Distance Law?

Sitting closer to the front of a classroom you will be able to hear better than if you sit further away

What is Constructive Interference?

Combining sine waves can amplify sound (compression + compression = amplify sound)

Real life example of Constructive Interference?

Two speakers at a music concert would make the music louder and more audible

What is Destructive Interference/Cancellation?

2 sounds of identical frequency, but 180 degrees out of phase, will cancel each other out (compression + rarefaction = cancellation)

Real life example of Destructive Interference/Cancellation?

Two instruments playing at the same time and they will cancel out; noise cancellation headphones, the headphones are the object tha tis interfering with the sound and not being able to hear sound; hearing aids and not being able to hear microwave “beep” since hearing aid cancelled the “beep”

What is Masking?

If 2 sounds hear simultaneously, the intensity of one sound may be sufficient to cause the other to be inaudible

Real life example of Masking?

If airplane passes by, you won’t be able to hear your friend on phone since the airplane is so loud; blow drying your hair and someone is trying to talk to you and you cannot hear their voice

What is Resistance/Impedance?

A surface/body that retards (does not permit) the progression of sound - Generally, > density of object > the impedance (wall vs sheet)

Real life example of Resistance/Impedance?

Being inside a car and you are trying to talk to someone outside the car with window rolled all the way up, the object (window) sound will be diminished making it difficult to understand what is being said, once the window is rolled down then you can hear clearly; trying to talk to someone in your room with the door closed, you wont be able to hear them as well

What is Resonance?

Mass, elasticity, frictional characteristics of surface/body determine its frequencies of most efficient and least efficient vibration (music through a wall); characteristics of a surface vibrate or resonate well with certain frequencies

Real life example of Resonance?

Feeling vibrations of music/bass from your next door neighbor; sopranos being high pitched will break the glass

What is Reverberation?

Reflections of sound as it travels through space and encounters surfaces/bodies causing an echo

Real life example of Reverberation?

You are in a empty room or cave and the echo is very loud due to no objects such as furniture or people to absorb sound

What is Precedence effect?

Fusion by the brain of incident waves and reflected waves (bouncing wave forms) into single perception

Real life example of Precedence effect?

The teacher is talking and the children in the classroom just perceive one sound coming out of his mouth and do not perceive multiple reflected signals

How is masking used in audiological testing?

Refers to introduction of noise to the non-test ear during a pure-tone audiogram, this aims to ensure that the tested ears hears the presented tone and is not “cross-head” by the non-test ear

How prevalent is HL in children?

34 million

How prevalent is HL in adults?

432 million

How is the prevalence different between developed and developing countries?

Developed countries have more medical opportunities but developing countries do not have medical to cover expenses but it can also be because of religous beliefs

Worldwide, is the prevalence increasing or decreasing? Why?

Increasing because of th epoulation is aging and hearing loss is more common as humans get older

What is Hearing Conversation? Why is it important?

The practive of protecting hearing and implementing ways to prevent hearing loss, it is effective bc workers need to be able to have knowledge to protect themselves from HL and be provided with toold to protect their hearing

What is OSHA’s permissible noise exposure?

Limit 90 dB with 5dB exchange for an 8-hour workday

What is NIOSH standards for noise exposure?

Limit 85dB with 3dB exchange for an 8-hour workday

What is within the scope of practice for an audiologist?

In the field of audiology, their scope:

• of practice involves testing hearing, testing balance function,

• fitting hearing aids,

• programming or mapping cochlear implants,

• assessing the integrity of spinal nerves and providing therapy for aural rehabilitation.

  Their practice also includes:

• providing intraoperative monitoring, assessing noise levels to protect hearing,

• representing hearing aids and cochlear implant manufacturers.

• They are educators who can also provide expert testimony and consultation and participate in research.

Where does this scope of practice overlap with an SLP?

SLPs and audiologists overlap in that to develop language, you need to be able to hear it. hear it. SLPs can refer a child to an audiologist to have their hearing tested. They also work closely after cochlear implants have been put in to aid the child in developing their language.

What is frequency?

Measures the number of cycles per second of a sound wave

How is frequency measured?

Measured in Hertz (Hz)

What is subjective correlate for frequency?

Is pitch

What is intensity?

Measures the amplitude and vibration of a sound

How is intensity measured?

Measured in decibels (dB)

What is the subjective correlate for intensity?

Is loudness