Basic Acoustics and Psychoacoustics Flashcards
______ is the study of the physics of sound
acoustics
_______ is the study of the experience of sound
psychoacoustics
Describe vibration:
Molecules are pushed together (condensation) and pulled apart (rarefaction).
Describe how sound waves occur:
Molecules are pushed together and pulled apart this movement is passed to adjacent molecules. This succession of movement forms waves.
What two properties can characterize sound:
Frequency
Intensity
T or F: Frequency is a physical measure while pitch is the psychoacoustic correlate
True
Define Frequency:
The number of complete oscillations of a vibrating body per one second. Measured in Hz
T or F: Pitch is the same with or without human perception.
False - Frequency is the same but pitch requires perception
__________Hz is the human frequency range.
20-20000 Hz
What animal has the frequency range closest to humans?
Chinchilla
_________ frequency is the lowest frequency in a complex sound
fundemental frequency
________ are whole number multiples of the fundamental frequency.
harmonics
Complex sounds consist of __________
2 or more tones of different frequencies occuring at the same time
_______= power / area
Intensity
_______ is measured in W/msquared and is the amount of sound per unit of area
Intensity
Intensity is a _______ measure while _______ is the psychoacoustic measure
physical
loudness
What unit is loudness measured in?
phon (a subjective measure) - often how we perceive loudness depends on our experiences
Intensity is the same with or without human perception and is measured in _____
decibels
The range of the auditory system is ______ dB
0 - 140dB
Decibels are expressed as a ratio of a measured sound pressure to a _______
reference point
SPL stands for _______
Sound Pressure Level
What is the reference level for dB SPL?
0.0002 dynes/cm squared
HL stands for ______
Hearing level
What is hearing level and how was it calculated?
HL is the average hearing performance. A large group of uni students determined the softest level of sound they could detect. This sound was 0 dB HL
What is the reference for dB HL?
Lowest SPL the average adult can detect
To convert from dB HL to dB SPL you _____ the conversion
add
To convert from dB SPL to DB HL you _____ the conversion
subtract
What does SL stand for?
Sensation Level
What is the reference for dB SL?
The auditory threshold of a specific individual.
________ is the number of dB of a sound above the level where the person can just barely hear.
dB SL
T or F: Normal conversation occurs at 40 to 45 dB SPL
False - Normal converstion occurs at 40 to 45 dB HL or 60 to 65 dB SPL
The tuning for test, tests____________
tests air and bone conduction
The tuning fork can quantify ______ but not ______
frequency but not intensity
List three disadvantages of the tuning fork:
1) Cannot control the test ear
2) Many people won’t hear it
3) Cannot control intensity
Review textbook on 4 types of tuning fork tests. . .
I know :(
What are 5 possible purposes of a hearing screening:
1) identify people with potential hearing problems
2) identify people in need of referral
3) collect data
4) provide education opportunity
5) Promote good hearing health
List three thing Hearing screening don’t do:
1) Identify type of hearing loss
2) Identify degree of hearing loss
3) Provide accurate individual ear information
T or F: At a hearing screening we should screen the hearing of someone who uses a hearing aid
False - hearing screening only identify if there is hearing loss, someone using a hearing aid already knows they have hearing loss.
__________ is perhaps more important than the hearing screening itself
Ensuring follow up services
A false positive hit rate is when the screening indicates ______________________
a potential problem and there isn’t one
A false negative hit rate is when the screening indicates _____________________
no potential problem and the person has hearing loss
Too many false positives ___________ while too many false negatives _____________.
fatigue the referral system
make the program useless
Ideally we want a screening protocol that has a _____ hit rate.
high
T or F: After a hearing screening you should say that their hearing is normal.
false - never say hearing is normal based on a screening tell them to get it checked if they are concerned.
What terms do we use instead of pass or fail in a hearing screening?
Pass or refer
List the two phases of a pure tone hearing screeing:
Training Phase and Test Phase
What is the point of the training phase?
To make sure the person understands the instructions
At what frequency and intensity is the training phase done at?
1000Hz
60 dB HL
Describe the test phase:
- Limited # of freq. selected
- Specific intensity level identified
- ears are screened separately
- 3 presentation of each frequency
What frequencies and intensity is the test phase done at?
1000, 2000, 4000 Hz
25 DB HL (occasionally 40 dB HL for Geriatric and 20 dB HL for paediatric)
If the person responds to 2/3 of each freq. screened the person passes if they don’t respond to 2/3 of each frequency they are _______
referred
Why don’t we test 250 and 500HZ in a hearing screening?
Hearing screenings take place in an uncontrolled test situation and these frequencies are hard to hear in that environment.
Why don’t we screen higher frequencies (6000, 8000 etc.)?
They are more difficult to keep in calibration
They are lost more easily with inaccurate headphone placement.
Why might someone not respond during a hearing screening? (lots of reasons)
- machine not turned on / no sound being produced
- client didn’t understand or forgot the instruction
- client is faking
- client is non-compliant
- headphones aren’t positioned correctly
- too much background noise
- client distracted
- OR Client didn’t hear
Why might someone respond during a hearing screening?
- Randomly responding
- Watching non-verbals or button pushing of tester
- Long periods of silence makes them nervous/ think they heard a sound
- OR Client heard the sound
In a false positive response pattern . . .
The client indicates they heard a tone when they didn’t
In a false negative response pattern. . .
The client doesn’t indicate they heard a tone but they did
When conducting a hearing screening it is important to become familiar with the equipment. The attenuator dial could also be called the ______ dial.
dB
What are important considerations when determining the chair placement during a screening?
- make sure they can’t see you pushing the button or read the facial cues
- face away from distractions, in a quiet place
When placing the headphones during a hearing screening make sure to _________, _________, _______ and orient with the red on the ________ .
approach from the front
remove obstructions
tighten after the headphone is in place
right ear of the client
During a hearing screening instructions should be _____, _______ and _______. Make sure to check back with the client and allow time for _______.
short, simple and clear
questions
T or F: Getting a case history is just as important as the actual hearing test if not more so.
True
_________ provide enormous amounts of information in a minimal amount of time and can be compared with test results for consistency.
case histories
What are two main things a case history provides?
1) Information about the client (What they say, don’t say, how they act, how they answer)
2) Chance to establish a Rapport (gain trust, gauge support system)
What are two formats for obtaining a case history?
1) Interview (done by audiologist or support staff)
2) Form (client fills it out)
The type of appointment influences the type of information needed. In a diagnostic appointment ________ info is more important but in a rehabilitative appointment ________ info is more useful
medical
situational (communication, family perspective)
Who should you interview?
- the client (even children)
- Parents, caregiver, significant other
Describe a casual or informal interview style:
Rarely ask direct or specific questions, take few notes during the interview, notes are made later
Describe an authoritarian or formal interview style:
Ask simple, direct, highly specific questions. Write as you go.
Basic components of an interview should include:
hearing info, health, screening results noise exposure listening issues, situations amplification history For children: developmental info, language milestones, caregivers and family history
