Section 2 Flashcards
What is the dynamic range of hearing?
The range of intensity of which the fiber will increase its intensity rate as the sound increases. Only about 50dB
Name the two efferent pathways into the cochlea
1.) Crossed Olivocochlear Bundles
2.) Uncrossed Olivocochlear Bundles
What do we mean when we characterize the classic phsycophysical methods described by Fechner as “inefficient?” Who modified one of these methods to be more efficient and what is his method called?
Bekesy Tracking: Von Bekesy thought that the classic methods were inefficient and wasted everyone’s time because you would spend a significant amount of time presenting too loud/soft sounds that was nowhere near a person’s threshold. He cleans up the Method of Limits and starts with a loud sound, goes down until they can’t hear it, then goes back up until they can, back down, etc and then takes the average of the reversal points
What are the 3 psychophysical methods described by Fechner?
1.) Method of Constant Stimuli
2.) Method of Limits
3.) Method of Adjustment
In SDT, what is a hit?
A signal is presented and you say “yes”
In SDT, what is a miss?
A signal is presented and you say “no”
In SDT, what is a false alarm?
A signal is not presented and you say “yes”
In SDT, what is a correct rejection?
A signal is not presented and you say “no”
How does hearing sensitivity as plotted on an audiogram show thresholds differently from when plotted on a threshold function? Why are audiograms plotted this way?
Audiograms use a 0dB HL scale because we are comparing the subject’s hearing with the average person’s hearing. A threshold function uses the dB SPL scale. We are also asking different questions. The threshold function asks “What is the smallest sound a person can hear?” and the audiogram is asking “What can I hear compared to everyone else?”
What is 0db SPL?
0dB SPL is a method of measuring hearing level using an onjective level of sound. It is about 20 micropascals
What is 0dB HL?
0dB HL is the average of a large set of human hearing to define a normal hearing range. It is used to compare to the average person’s hearing level. A score of 0dB HL at different frequencies would mean you have no hearing loss
What does the smallest sound a person can hear depend on?
1.) Question you’re asking
2.) How you measure it
3.) Frequencies
4.) Continuous vs intermittent sounds
5.) Duration of sound
How would you use the concepts of Signal Detection Theory to create a test to differentiate between 2 different diagnoses?
You should use SDT to create a test with a high hit rate and a low false alarm rate. A high hit rate means the test has good sensitivity, which means that it will actually detect a disorder when it is actually present. A low false alarm rate means the test has good specificity, which means if a disorder is not present then the test will not detect anything
What is a high-pass and low-pass filter?
High pass: only frequencies above a certain frequency can pass through
Low pass: only frequencies below a certain point can pass through
Why do we care about the cubic difference tone?
-It’s why beating occurs
-Product of OAE, which we use to assess the function of OHC and identify potential HL related to cochlear damage
What is the cubic difference tone?
Difference tone that generates the biggest response on the BM
2f(1)-f(2)
What is the goal of Critical Band Theory?
To find the narrowest band of noise possible that will still effectively mask a target
What is Critical Band Theory?
The range of frequencies that activates the same part of the BM. When multiple tones are close in frequency, they can share hair cells on the BM and fall within the same critical band
What does Critical Band Theory help to explain?
When the target sound and masker fall into the same critical band, they get “mixed” together and are perceived as one sound
What is afferent innervation density?
The distribution of afferent fibers is not equal across the entire BM. They are more dense/concentrated toward middle frequency ranges (1000-4000Hz). This is where we are more behaviorally sensitive and this is where the afferent fibers are more multivesicular
What is the Upward Spread of Masking?
The phenomenon in which a lower frequency masker masks a signal more effectively than a masker at the signal frequency
**If a lower frequency sound is too intense, they can mask over the high frequency regions of the BM
What is Signal Detection Theory?
A framework that allows you to separate a person’s hearing sensitivity from their response bias. There is always some sound present because of physiological activity. People also have biases and make internal decisions about their criterion and where to set it
What do we mean by sensitivity in SDT?
Sensitivity is how far apart the means of the distributions are