1 - Basics of Sound Processing Flashcards
What happens to an auditory nerve if it continues to be stimulated?
The firing rate drops until the energy output is balanced by the energy input
What happens when an auditory nerve is first stimulated?
It responds vigorously
What do we call it when a drop in sensitivity causes a drop in threshold?
Temporary Threshold Shift
TTS
Temporary Threshold Shift (TTS) is an example of _______.
Neural Adaption
When does fatigue occur?
When sensitivity is reduced and absolute threshold increases
How does fatigue differ in low exposure and high exposure situations?
Low Exposure - Transient
High Exposure - Can be permanent and/or pathological
What is the abnormal growth of perceived loudness that occurs in response to sensation levels?
Loudness Recruitment
When does loudness recruitment usually occur?
In impaired ears but it can occur with normal hearing
What is loudness recruitment associated with?
It is connected to Outer Hair Cell damage
In what conditions is loudness recruitment absent?
Conductive or retroconductive deafness
What happens when there are increases in sound intensity?
Larger areas of the basilar membrane are stimulated
Neurons with high threshold have _____ & _____.
Low spontaneous firing rates
Less sensitive synapses
Neuron saturation = ____________
Fatigue
The dynamic range for neurons with high spontaneous firing rates is __________.
Small
15-30 dB
What is the firing frequency usually?
A logarithmic function of stimulus intensity
Where does loudness grow more rapidly?
At low frequencies rather than in middle frequencies
What do equal loudness contours show?
How loud a 1,000 Hz tone must be to sound equally loud to another tone
What is a phon used to measure?
Equal loudness contours
What is the Power Law?
The size of the exponent depends on the perception of a stimulus’ intensity
Sone
The loudness of a 1,000 Hz tone at 40 dB
What happens to the perceived pitch when a fundamental is greater than 50 Hz?
It is perceived to be the same whether or not the fundamental frequency is present
How does the basilar membrane behave?
Like a narrowly tuned bank of filters or critical bands
What happens when any given pitch stimulates the basilar membrane?
It stimulates the part of the basilar membrane that is tuned to that frequency
What is the ability to detect changes over time due to auditory gaps or amplitude modulation?
Temporal Resolution
Temporal Acuity
Do age related deficits in temporal resolution correspond with hearing loss?
No. They are probably due to central auditory disfunction
Do older listeners need more time to process sound information?
Yes
Monoaural
Sound in one ear
Binaural
Sound in both ears
Diotic
Same stimulus in both ears
Dichotic
Stimulus is different in each ear
What is the duplex theory?
That sound localization uses both ITD (Interaural Time Difference) and ILD (Interaural Level Difference)
What is the smallest spatial separation between sequential sounds?
The minimal audible angle
