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XXXSpeechSciDrMT2
XXXSpeechScience Dr. Milner Test 2
| Question | Answer |
|---|---|
| The nerve fibers from the Cochlear Nucleus decussate between what 2 things | The nerve fibers from the cochlear nucleus decussate between the cochlear nucleus and and superior olivary complex |
| The neural tract that crosses the brainstem is the | Trapezoid Body |
| 1/3 of the nerve fibers reach the superior olivary complex on the | ipsilateral side |
| 2/3 of the nerve fibers decussate going contralateral and 1/3 remain | ipsilateral |
| The 2nd major nucleus in the pons region is the | lateral lemniscus |
| the third major nucleus at the level of the midbrain is the | inferior colliculus |
| Connected fibers allow crossover between the two | inferior colliculi |
| A nerve tract that crosses the brainstem that is a neural tract is the | Trapezoid Body |
| Some fibers bypass the inferior colliculus and go directly from the | lateral lemniscus |
| The fibers that bypass the inferior colliculus and go directly to the lateral lemniscus go to the | medial geniculate body |
| The medial geniculate body is located in the | thalamus |
| The tract that runs to the medial geniculate body fans into | auditory radiations |
| The auditory radiations fan out from the medial geniculate body to the | auditory cortex via auditory radiations |
| The auditory cortex is in which lobe of the brain | temporal lobe |
| Know lecture 4 slide 6 | lecture 4 slide 6 |
| Where is the auditory reception area of the brain located | in the temporal lobe |
| Where does the understanding of speech and processing of other complex acoustic signals happen? | In the Auditory Reception Area in the Temporal Lobe |
| Where does the perception of pitch and loudness take place | at the level of the brainstem |
| You can use a single neuron reponse to a variety of stimuli to obtain | the response pattern of a neuron |
| Damage along the pathways or at level of auditory cortex produces difficulties | understanding speech |
| Difficulty understanding what is 'coming in' and then difficulty producing something appropriate in response | damage along pathways or at level of auditory corex |
| The firing of a neuron is recorded at three points | before |
| The three points of recording the firing of a neuron (before | during and after stimulus presentation) are then |
| Averaging the three points of recording the firing of a neuron can show the | response pattern for a particular neuron |
| Post-stimulus time histograms show | the neural response pattern as well as the spontaneous discharge rate |
| Spontaneous discharge rate | rate at which a neuron fires in the absence of stimulation |
| Spontaneous discharge rate and neuron response pattern are both shown in a | post-stimulus time histrogram |
| In a post-stimulus time histogram you will see a | baseline and a return to baseline, if you look at firing rate and average it you get spontaneous discharge rate |
| Spontaneous discharge is when the neuron isn't really firing as much as reacting to | natural electrical activity |
| Neurons are 'tuned' to be responsive to different stimuli or | sounds |
| Auditory stimuli can be different sounds and different sounds are used as | stimuli |
| If we only want to activate a small number of neurons we use a | pure tone as stimuli |
| If we use speech as a stimuli we get | way more neural activity |
| We can actually activate neurons in | certain places |
| Pitch and loudness are processed at the level of the | brainstem |
| Pitch Pattern Perception | hear three tones and determine pitches |
| If person has a problem with a Pitch Pattern Perception test they could have problems at the level of the | brainstem as pitch and loudness are processed at the level of the brainstem |
| The cochlear nucleus divides into two portions | dorsal and ventral portions |
| Dorsal and Ventral portions are division of the | cochlear nucleus |
| Dorsal and Ventral portions of the cochlear nucleus have | second order neurons |
| Second order neurons synapse with | CN VIII |
| The response pattern of second order neurons is | complex |
| Second order neurons may respond to specific stimuli events such as | onset of sound or frequency changes |
| Some second order neurons have variable... | firing rates |
| Synapse | point of information transmission |
| Chart B of lec 4 slide 9 is reacting to | sound onset |
| Another type of neuron in the cochlear nuclei are the | internuncial neurons |
| Internuncial neurons are innervated by and also innervate other neurons in the | cochlear nucleus |
| Internuncial neurons can do two things to other neurons | inhibit or excite |
| Internuncial neurons innervate and are innervated by other neurons in the | cochlear nucleus |
| Internuncial neurons can be stimulated but can also inhibit a response | from other neurons |
| Internuncial neurons can inhibit or | excite |
| What is the SOC | Superior Olivary Complex |
| The SOC is the most peripheral point in the | CANS Central Auditory Nervous System |
| The SOC is where in relation to the CANS | most peripheral point |
| The superior olivary complex is the most peripheral point in the CANS to recieve | input from BOTH COCHLEAS |
| The SOC controls the reflex activity of which two muscles? | the Stapedius and Tensor Tympani muscles |
| How do neurological impulses from sounds arrive at the SOC? | via CN VIII |
| After neurological impulses from sounds arrive at the SOC via CN VIII this happens | Messages are sent down to the Stapedius Muscle via CN VII and the muscle contracts |
| After CN VII sends a message to the stapedius muscle causing it to contract we know that | a neurological impulse from sounds arrived at the SOC via CN VIII |
| SOC is important for what? | Sound Localization!!! |
| SOC is able to be used for sound localization because it is sensitive to difference cues in | Time and Intensity |
| CN VIII to Superior Olivary Complex then to | CN VII and then to Stapedius |
| Auditory testing from one tone can tell us about which cranial nerves? | CN VIII and CN VII |
| Auditory testing from one tone can tell us about CN VIII and CN VII and two other things what are they: | Stapedius and SOC |
| start on slide 13 lecture 4 | here |
| After a message goes CN VIII to SOC to CN VII to the Stapedius it goes to the Lateral Lemniscus and the Inferior Colliculus but SOMETIMES | it SKIPS the Lateral Lemniscus and just goes directly to the Inferior Colliculus |
| Message can SKIP the | Lateral Lemniscus |
| After the message SKIPS the Lateral Lemniscus | it goes directly to the Inferior Colliculus |
| The MAJORITY of the information from the SOC is received at the | Inferior Colliculus |
| What is the IC | Inferior Colliculus - the place where the majority of information from the SOC arrives |
| What happens to information at the level of the IC | it is synthesized with visual |
| Neural impulse information combines with these at the level of the IC | visual |
| Where does the Startle Reflex originate | at the Inferior Colliculus |
| When a newborn hears a sound and startles we know that auditory information is traveling up system all the way to the | inferior colliculus |
| After the Inferior Colliculus information goes to the MEDIAL geniculate bodies of the | thalamus |
| The Thalamus routes information from the sensory systems to the appropriate areas of the | midbrain and cortex |
| What parts of the brain help coordinate the sensory and motor systems | the medial geniculate body |
| Most auditory information is directed to | Heschl's Gyrus |
| Heschl's Gyrus is made up of | auditory radiations that are part of the Temporal Superior Gyrus of the Temporal Lobe |
| Wernicke's Area | contains information necessary for speech comprehension |
| Where is Wernicke's Area located | in the Cerebral Cortex |
| Sound is | a physical event |
| 3 necessary components for sound production | energy source, body capable of vibration, and a medium |
| Sounds are | tiny fluctuations in air pressure that radiate from a source |
| Pressure changes from sound waves are | localized disturbances from ambient air pressure |
| Ambient pressure in room | = Patm |
| The most common medium for sound is | air |
| Billions of particles that make up air are called | molecules |
| Molecules are spaced consistently with regard to | distance from each other |
| Air and other propogating mediums have these properties | Mass Elasticity |
| Mass is | any form of matter (solid |
| Air particles consist of | mass |
| Elasticity is the | ability to resist permanent distortion to its original shape |
| The ability to resist permanent distortion to original shape is | Elasticity |
| Springiness | the propensity of the particles of a medium to return to their original position once they are no longer being displaced. |
| The propensity of particles in a medium to return to original position after no longer being displaced is | Springiness |
| If Elasticity results in Springiness together they form | Stiffness |
| Stiffness | = elasticity resulting in Springiness |
| Small weight to rubber band and bouncing of mass versus weight | springiness |
| Elasticity | will resist being distorted |
| Springiness | wants to go back to original position |
| Inertia | common to all matter 'an object in motion remains in motion / an object at rest remains at rest until it is acted upon by an external force |
| Resistance | why a vibrating body will not remain in motion indefinitely |
| Why does energy dissipate in a system by converting energy into thermal energy (heat) | Resistance |
| Impedance | = mass stiffness and resistance |
| An overall opposition to energy transfer in a mechanical system is | impedance |
| What are some things that can cause impedance | mass |
| The dissipation of vibratory energy is called | damping |
| An example of dissipating is | a pendulum slowing down gradually |
| Pressure | force distributed over a particular area |
| Pressure is measured in | dyne/cm2 or Pa (pascals) |
| 0.0002 dyne/cm2 = | 20 micropascals |
| When there are pressure variations from Patm | sound occurs |
| Variations that occur with a frequency of occurence are detectable by | the auditory system |
| The law that describes the relationship between volume of air and pressure is | Boyles's Law |
| Boyle's Law | at constant temperature as volume decreases air pressure in a container increases proportionately. |
| As air molecules become more densely packed with volume decreasing | the density and air pressure increase |
| As volume increases | pressure and density decrease |
| Cycle of increased pressure (tuning forks) = | compression or condensation phase |
| Cycle of decreased pressure (tuning forks) = | rarefaction phase |
| Small increases and decreases in ambient pressure that propogate through space are phases called | compression/condensation and rarefaction |
| Sound waves radiate from a point source in a | spherical wave |
| In a spherical wave of radiation from a point source there are areas of | condensation and rarefaction alternately |
| Wave motion in a sound wave is | longitudinal |
| Longitudinal wave motion is when molecules move parallel to the direction that the | wave is traveling. |
| The movement that occurs when an object is set into motion by a force is, | Vibratory Motion |
| The simplest pattern of vibratory motion is the | Sinusoidal or sine wave |
| The sinusoidal wave (sine wave) is the | simplest pattern of vibratory motion |
| Sine wave = | continuous |
| The continuous | regular |
| Displacement occurs when an object is | acted upon by a force |
| The displacement pattern of a sine wave is called | simple harmonic motion |
| Simple Harmonic Motion is the term we use to describe | the displacement pattern of a sine wave |
| disturbance in a medium such as activation of tuning forks or a clockk pendulum | vibratory motion |
| Lecture 5 slide 10 | view this slide |
| Sine Wave: 0 90 180 270 360 | 0 180 and 360 cross zero amplitude |
| On a sine wave the wave is halfway finished at | 180 degrees |
| On a sine wave compression is finished at | 90 degrees |
| On a sine wave rarefaction is finished at | 270 degrees |
| At 360 degrees on a sine wave the wave has begun its next | cycle of movement |
| On a sine wave the amount of displacement around rest has to be | symmetrica |
| Whatever the amplitude is at 90 degrees on a sine wave | it is the same but negative at |
| If the amplitude at 90 on a sine wave is 3 | then the amplitude at 270 is |
| Characteristics of a Sine Wave are | displacement around rest is symmetric and the vibratory pattern of a given wave repeats itself into infinity |
| The vibratory pattern of a sine wave | repeats itself into infinity |
| What is symmetric in a sine wave | the displacement around rest |
| One Cycle in a sine wave is | one complete transition of sinusoidal motion from 0 to 360 degrees |
| What are the 5 criterion for describing SHM | Frequency Period Amplitude Phase and Wavelength |
| Which of the criterion for describing Simple Harmonic Motion is missing | Frequency Period Phase Wavelength |
| Which of the criterion for describing SHM is missing | Wavelength Frequency Phase Amplitude |
| Frequency is | the number of cycles completed in |
| Frequency is described using what unit of measure | Hz (hertz) |
| What is the psychological correlate for frequency | PITCH |
| Pitch = | frequency |
| 8 | 000 Hz = 8 |
| 250 Hz = sounds like a fog horn | really low pitch |
| Hz = frequency | number of cycles completed in one second |
| Period = | amount of time it takes a sinusoid to complete one cycle |
| Units = | Time (T) usually measured in seconds or milliseconds |
| Time is the reciprocal of | frequency |
| T = | 1/f |
| F = | 1/T |
| If have period | can compute frequency |
| If have frequency | can compute period |
| 1 Hz = | 1 cycle is complete in one second |
| Period should be represented in what unit of measure | seconds or milliseconds |
| If four sine waves in one second | t = 1/f t = 1 / 4 = .25 seconds |
| The strength of vibration of molecules | amplitude |
| Amplitude | the strength of vibration of molecules |
| Amount of vibratory displacement | the distance molecules are displaced from object at rest. |
| The psychological correlate of amplitude | loudness |
| There are four ways to measure amplitude | IA PA P2PA RMS A |
| Of the ways to measure amplitude how do they vary | 1 varies with time and the other three are time independent |
| The one way to measure amplitude that varies with time is | instantaneous amplitude |
| Amplitude is determined by | how much force is exerted |
| Increased force | increased amplitude because of increased displacement of molecules |
| Psychological correlate of amplitude | LOUDNESS |
| Instantaneous amplitude | varies with time displacement at any given moment in time |
| Peak amplitude | a point of positive or negative maximum displacement |
| Peak to peak amplitude | total distance from point of positive maximum displacement to negative maximum displacement |
| RMS amplitude | square numbers add them divide by how many or you can multiply by .707 |
| To find the average amplitude of a sine wave | calculate RMS |
| No displacement | Zero Amplitude |
| RMS = | square root of the mean of the squared deviations of the IA |
| Average 1A of a sine wave = | 0 |
| Squared IAs become | positive |
| To use the .707 | multiply .707 by peak amplitude |
| Squared = | multiplied by itself (negative x negative = a positive) |
| Phase | the point in a cycle when an object BEGINS to vibrate |
| Phase is measured in | degrees |
| Starting Phase | the point in the cycle when an object begins to vibrate |
| Instantaneous Phase | measurement of phase at ANY point along the waveform |
| Starting phase | zero degrees |
| Instantaneous phase | any point along the wave form |
| Wavelength | distance between 2 consecutive positive peaks (points of condensation) in a wave or between 2 consecutive negative peaks (points of rarefaction) in a wave |
| Wavelength is directly affected by | Hz and the speed of sound |
| Wavelength is directly affected by | Frequency in Hz and the speed of sound |
| Measure of sound in air = | c (constants) |
| C = | 344m/sec or 1100 ft/sec |
| To measure wavelength = | l = c/f where c = 344 m/sec or 1100 ft/sec |
| Quick calculations of wavelength | use 1000 ft/sec in l = c/f |
| Speed of sound in air | tend to use meters as measurement |
| Wavelength is | frequency divided by constant c/f |
| Wavelength gets | SHORTER as frequency gets higher |
| As frequency gets higher | WAVELENGTH gets SHORTER |
| It is harder for a high frequency wave to travel so wavelength is | shorter |
| Low frequencies travel farther so wavelength is | longer |
| When waves travel completely freely in space | completely free boundary |
| When a wave hits an object | completely fixed boundary |
| A boundary can be neither completely free nor completely fixed if a change in | medium |
| If part of the wave is reflected and part is transmitted | the boundary is neither completely free nor completely fixed – like in ear |
| A wave may be reflected off an object | this is called Reverberation |
| Reverberations | multiple sounds which are reflected continuously in a confined space creating a prolongation of the sounds existence. |
| A wave can be reflected or transmitted or | absorbed by the object it has struck. |
| Think of sound in a room | it can be absorbed by soft things or reflected by hard smooth things or transmitted through |
| When waves combine it is called | interference |
| Interference is not a negative thing it is just the word we use to describe two waves | traveling together in space. |
| Interference can be one of two things | constructive or destructive. |
| Superposition does NOT mean waves combine | it means they OVERLAP. |
| Interfering is the word for | the combination of two waves. |
| Destructive interference could result in waves being | reduced or cancelled out. |
| If the 2nd wave is 180 degrees out of phase when it meets up with the 1st wave | you have a positive peak meeting up with a negative peak = cancel. |
| If the two waves meet and they directly overlap you get superposition but also when they both peak at their positive peak they AMPLIFY but imperceptibly. | |
| Two waves that meet and directly overlap are | moving in phase with each other. |
| Reverberation is the | enemy. |
| Reverberation is the enemy as it results in a | degraded signal that is hard to decipher and hear especially with background noise. |
| Periodicity | when a wave shape repeats itself over time as a function of time |
| An example of periodicity would be | a pure tone |
| Aperiodicity | when the wave shape does NOT repeat itself as a function of time (ie: noise |
| Fundamental frequency | the lowest frequency in a wave also known as the first harmonic |
| Complex periodic waves have whole number multiples of the | fundamental frequency known as harmonics |
| Complex aperiodic sounds do NOT have what? | Complex aperiodic sounds do NOT have fundmental frequencies nor harmonics since there is no repetition in the wave. |
| Since there is no repetition in a complex aperiodic wave there are no | fundamental frequency nor harmonics. |
| In a complex aperiodic sound energy is distributed throughout the sound spectrum | at a particular instant in time. |
| The more a sound bounces around the more | degraded it becomes. |
| Periodicity is when a wave repeats itself over and over in time and every wave looks like the cycle before it | a sine wave. |
| A sine wave is one frequency that repeats itself into | infinity. |
| Aperiodic does not repeat itself as a function in | time. |
| Complex periodic waves | multiple frequencies in a repeatable pattern. |
| An example of a complex periodic sound would be /a/ | there is more than one frequency (formant frequencies) |
| Complex periodic waves have more than one | frequency |
| Frequencies in complex periodic waves are | whole number multiples of the fundamental frequency. |
| The fundamental frequency is also the | first harmonic |
| The fundamental frequency is also the | lowest frequency in that sound |
| Whole number multiples of the fundamental frequency of 100 Hz | 200 Hz |
| Whole number multiples of the fundamental frequency of 150 Hz | 300 Hz |
| Fundamental frequencies together form the | complex periodic wave |
| The waves in a complex periodic wave are not | random |
| Complex APERIODIC wave | more than one frequency but does not repeat itself in a periodic fashion and the frequencies are random and not mathematically related to each other. |
| An example of a complex aperiodic wave is | /sh/ /f/ |
| Low frequency | high amplitude |
| High frequency | low amplitude |
| Amplitude is related to | intensity |
| Low frequency soundshave greater energy and therefore | more amplitude or intensity |
| In a Wave Periodicity spectrum the peaks are | high peaks are peaks of energy in the sound called Formants F1 F2 F3 |
| Low frequency = high amplitude | |
| Why are certain frequencies amplified (in the vocal tract or a guitar)? | because their frequencies are close to the natural resonant frequency of that container |
| The three harmonics that are amplified have | the highest amplitudes they are called formants |
| Low frequency sounds have greater energy and therefore | more amplitude or intensity - easier to hear |
| High frequency sounds have less energy and therefore less intensity | harder to hear for those with hearing loss |
| Does the resonance of the vocal tract change? | YES when you go to produce different speech sounds via things like lip rounding etc. |
| Steam hissing | complex aperiodic whole bunch of frequencies energy is diluted |
| /s/ | energy aross board but a concentration in the high freuqency range |
| complex aperiod sound contains | all the frequencies that there are |
| with /s/ a speech sound | you still have all the frequencies but some are enhanced because they are close to the natural resonance of the vocal tract because it is in position to produce /s/ |
| The amplitude of the high frequencies in the complex aperiodic sound /s/ are higher than | the low frequency aperiodic sounds in /s/ |
| When the vocal tract is in position to produce /s/ | you get more natural resonance in the high frequency sounds |
| Impedance | opposition to the flow of energy |
| What are three components of impedence | Mass Stiffness and Resistance |
| Mass | energy storing component |
| Stiffness | energy storing component |
| Resistance | energy dissipating component |
| What are two energy storing components that relate to impedence | mass and stiffness |
| What is the energy dissipating component of impedance | resistance |
| Resistance | roll a heavy ball up a hill let the ball go and it rolls down the hill expending the stored energy |
| Resistance changes | the form of energy |
| The process by which resistance changes the form of energy is known as | transduction |
| When you rub your hands together to create friction and heat this is | transduction because you turn mechanical energy into thermal energy |
| Mass and stiffness determine the rate of what | the rate at which a system vibrates when set into vibration |
| Vibration rate is determined by | mass and stiffness |
| Increased stiffness with constant mass | = higher rate of vibration or frequency of vibration |
| Resistance determines | how long a system will vibrate |
| Frequency of vibration increases | when stiffness is greater than mass |
| Frequency of vibration decreases | when mass becomes greater than stiffness |
| Resonant frequency = | natural frequency |
| Resonant frequency is the frequency with which | a system vibrates when set into motion |
| Resonant frequency is determined by | the relative magnitude of the mass and stiffness components of its impedance |
| If mass and stiffness are equal | the opposition to the flow of energy is from resistance alone |
| All systems respond best when stimulated at their | resonant frequency |
| If you strike a set of tuning forks | one will vibrate louder when put on a table as it is being stimulated at its resonant frequency |
| Resonant frequency occurs at the midpoint of | stiffness decreasing and mass increasing |
| The tone at the resonant frequency becomes | louder |
| When a tone at the resonant frequency becomes louder it contrarily | vibrates for a shorter time |
| When tuning fork tines are placed upon a table where does the energy go | into the tabletop |
| When tuning forks impart energy into a table top what happens to the energy | it gets used up quickly and goes into the table |
| Why does energy get used up quickly by tuning forks placed on a tabletop | the tabletop is larger and uses it up rapidly |
| The rate at which the magnitude of vibration and loudness of a sound decreases is called | damping |
| Damping is the rate at which | magnitiude of vibration and loudness decrease |
| Heavy damping | when sound diminishes rapidly |
| Light damping | when sound diminishes slowly |
| When sound diminishes slowly | Light Damping |
| When sound diminishes rapidly | Heavy Damping |
| Little damping occurs at or near the | resonant frequency |
| Why does little damping occur at the resonant frequency | because there is very little opposition to the flow of energy known as very little impedance |
| If there is very little impedance | there is very little damping and the sound must be at or near the resonant frequency |
| If the tuning fork frequency is close to that of the tabletop | there is very little damping |
| If the tuning fork frequency is far from that of the tabletop | there is more damping due to the increased impedance |
| Impedance | opposition to the flow of energy |
| If you put four tuning forks on a table one may vibrate louder because | its frequency is closer to the natural resonant frequency of the table |
| Some speech sounds will get enhanced because | their frequencies are closer to the natural resonant frequency of the vocal tract |
| Nearer the resonant frequency there is not a lot of | impedance |
| Reduction in intensity no enhancement of intensity | damping |
| Quarter Wave Resonator | a cavity closed at one end and open at the other |
| The tube length needed for resonance to occur with the test tube tuning fork experiment is | equal to the wavelength of the frequency of the stimulating sound divided by 4. |
| The wavelength of the frequency of the stimulating sound divided by 4 | is the tube length needed for resonance to occur if it is open at one end and closed at the other |
| Wavelength = c/f | |
| c/f = | wavelength |
| .68m = | 68cm |
| 68 cm = | .68m |
| For 500 Hz compute wavelength | 350/500 = .68m = 68cm |
| Once you know the wavelength you can calculate | the length of the tube / quarter wave resonator |
| To compute tube length needed for resonance to occur | wavelength divided by 4 if a quarter wave resonator |
| Compute tube length needed for resonance to occur in a quarter wave resonator if the wavelength is 68 cm | 68 cm divided by 4 = 17cm |
| Compute tube length needed for resonance to occur in a quarter wave resonator if the frequency of the stimulating sound is 1000Hz | 340/1000 = .34m = 34cm 34cm/4 = 8.5 cm tube length |
| As the tube length decreases natural resonant frequencies of the vibration of the tube become | higher |
| As the tube length increases | natural resonant frequencies of the vibration of the tube become |
| Length of tube and the natural resonant frequency of the tube are | inverse |
| Shorter vocal tract | higher resonant frequencies as with a child |
| Frequency Response Curve | the graph of frequencies to which a resonator will respond |
| Two Types of Frequency Response Curves | Undamped Resonators and Damped Resonators |
| Cavities and tubes can act as resonators because they are | columns of air vibrating at certain frequencies |
| Undamped Resonators | resonate to a NARROW range of frequencies and generate a SHARP peaked response curve |
| UNDAMPED | NARROW AND SHARP |
| Damped Resonators | resonate to a broad range of frequencies and generate a flat |
| DAMPED | broad range flat broad response |
| The range of frequencies to which a resonator responds | bandwidth |
| Bandwidth | the range of frequencies to which a resonator responds |
| Bandwidth is measured across the frequency response curve where | at the half power point |
| The half power point | where bandwidth is measured across the frequency response curve |
| What is the value of the bandwidth from the peak value of the spectrum | 3 dB lower than the peak value |
| Vocal tract responds to schwa at what frequencies | 500 1500 2500 |
| Undamped resonator is vocal tract | in a neutral position relatively unimpeded. |
| Vocal tract can be damped or undamped depending on multiple variables including | articulators. |
| The range of frequency to which a resonator responds is called | bandwidth. |
| Vocal tract in position for schwa = | 500 1500 2500 etc. |
| The bandwidth of the vocal tract when it is in position for schwa is | 500 Hz to whatever frequency the vocal tract is responsive to – we only care up the highest frequency for speech sounds which only goes up to 5000 or 6000 Hz. |
| The length of the vocal tract in the average male for the production of schwa | 17 cm |
| 17 cm = | length of vocal tract in average male for production of schwa |
| Resonant frequency of this tube is 500 Hz | male human vocal tract |
| Resonant frequencies are the | ODD NUMBER multiples of that lowest frequency (not 500 1000 1500) but rather 500 1500 2500 |
| We don’t take all the harmonics because | the brain recognizes certain intervals. |
| The brain recognizes the fundamental frequency and then the odd number harmonics for example | 500 is first harmonic |
| As length of tube or vocal tract gets shorter | the resonant frequency goes up |
| As the length of the tube or vocal tract gets shorter the resonant frequency goes up and so | do the whole number multiples. |
| Adult male has longest vocal tract | female shorter and child is shortest smallest vocal tract. |
| The odd numbers are resonant frequencies if the cavity is | open at one end and closed at the other. |
| Two quarter wave resonators in the human body are | the human vocal tract and the ear. |
| If not a resonant frequency | they still EXIST but they don’t get amplified. |
| With regard to resonant frequency and odd number multiples the odd numbers determine | the odd numbers determine the formants. |
| To find length of vocal tract in a quarter wave resonator | find wavelength then divide by four . |
| The decimal goes away when go from | meters to cm |
| Half Power Point | 3 dB down from the peak draw a line across look at point that corresponds in frequency |
| dB is a | RATIO not an actual value |
| Decibel = | unit of measurement of amplitude of a signal |
| Unit of measurement of the amplitude of a signal | dB = decibel = a ratio |
| When amplitude is being measured in terms of pressure or power use | dB |
| There is no such thing as | absence of sound |
| There is no such thing as zero sound pressure because some reference pressure is used to represent | zero |
| The reference pressure is | the smallest pressure variation from Patm produced by a 1kHz tone detected by young adults the smallest amount of pressure that can be detected |
| 0 db | = a really soft sound (because it is a ratio) |
| The pressure variation is represented by: | 0.0002 dyne/cm2 |
| A measure of force in square centimeters | dyne |
| Why are dynes measured in square cm | that is the size of the area over which the force is distributed |
| The reference pressure is also noted as | 0.0002 µbar (microbar) and more commonly 20 µpascals (microPascals) |
| Decibel = | think loudness |
| Pitch = | frequency |
| The normal hearing young adult is btw 19 and 26 years of age = no hearing damage. What is the smallest pressure variation they can hear | = .0002 dyne/cm2. |
| Sound is | a disturbance that causes a change in atmospheric pressure (change in pressure from atmospheric) |
| 10 million:1 = | smallest pressure detectable by humans. We can perceive very very very small changes in pressure because ear is a finely tuned instrument. |
| Logarithms are scientific shorthand | 10 to the 3 is 1000. 10 to the 2nd power is 100. Log of 100 = 2. (count the zeros) |
| The equation for computing decibels in sound pressure level is: | 20 [log10 (x/0.0002)] where x is measured pressure |
| 20 [log10 (x/0.0002)] | This equation yields the decibels in dBSPL |
| Sound pressure = | sound power squared (double the exponent) |
| 20 [log10 (x/0.0002)] X = | measured pressure |
| 20 [log10 (x/0.0002)] Ie: | x = .0002 dyne/cm2) .0002 divided by .0002 = 1 Log 10 of 1 is 0 20 x 0 = 0 dBSPL |
| 0 means | measured pressure is equal to the reference pressure. Still could be a sound. |
| Log10 | just use log function on a calculator |
| In clinical audiology we use dBHL decibels hearing level. dBHL is an arbitrary system made up by someone but not a physical measurement… it is | arbitrary |
| In THIS CLASS we use | dBSPL… |
| Use HL scale to test hearing (this is normal hearing this is not) | detects a loss in hearing need to know what normal is … developed a scale this number to this number is normal hearing. . . |
| 1000 Hz (= 1kHz) it is 0 dBHL it is 7.5 dBSPL | Meaning that at that frequency the average normal listener would begin to hear a tone at 7.5 dBSPL. |
| 20 [log10 (x/0.0002)] | This equation yields the decibels in dBSPL |
| See Lecture 7 Slide 11 | dBHL to dBSPL 125 Hz - 8K Hz all are 0 dBHL and sound pressure level is higher then lower than higher again 45 to 9 to 15.5 |
| Sound amplitudes are determined by | sound pressure |
| Sound pressure level measured in | dynes/cm2 or Pascals |
| Referent point for SPL | = .0002 dyne/cm2 or 20uPa |
| The weakest amplitude sound humans can hear at 1000 Hz = | .0002 dyne/cm2 or 20uPa |
| Which scale is used when testing hearing | HL scale |
| Why on the HL scale is the zero point different at different frequencies | human hearing is not the same for each frequency. |
| With low frequency sounds and high frequency sounds in order to hear it you need | more pressure |
| The ear hears 1000 Hz the best threshold of 0 dBHL means | excellent hearing. |
| If the person’s dBHL threshold is 50 | they cant hear it if the sound is below 50 dBHL |
| Low frequency sounds have a long | wavelength |
| We start testing hearing at what frequency? | 250 Hz it sounds like a foghorn or a heartbeat |
| Zero is the lowest limit of normal hearing and is referred to as | audiometric zero |
| Best hearing range for humans is between | 500 Hz and 4000 Hz |
| 500 Hz to 4000 Hz | ideal hearing range for humans |
| dBHL | a scale made up to show what is normal hearing for a species |
| Know the markers for 1000 Hz | and know the trend and know the range |
| A tone at what frequency is easiest for humans to hear | 1000 Hz |
| The study of the human perception of sounds and psychological correlates of the physical properties of sounds | psychoacoustics |
| The study of the relationship between perception of sensory information and the physical properties of sensory stimuli | |
| Auditory sensitivity relies on variables. List 4 of them: | characteristics of the stimulus |
| Give two examples of a characteristic of the stimulus: | frequency |
| When you use a tone of 1000Hz on a hearing test who will hear it best | the normal hearing young adult |
| Give an example of a method of assessment: | hear the beep & raise your hand |
| Give two examples of listener variables: clearer instructions to listener can yield better results and fatigue can result in inaccurate ones. Also attention span or ability to attend can be listener variables. | |
| Give an example of methods of stimulus presentation: | pulse tone versus continuous tone |
| Why is a pulse tone possibly preferable when giving a hearing test? | you get slightly lower thresholds and people with tinitis often find it easier to pick out a pulse tone than a continuous tone |
| Auditory sensitivity relies on sensitivity of the ear but is subject to a lot of other | variables |
| With regard to stimulus characteristics the human ear can detect sounds in what frequency range | 20-20 |
| Human hearing is most sensitive to sounds in what range | 500 – 5000 Hz range |
| Most of the frequencies contained in speech are in the range where hearing is most sensitive | 500 Hz – 5000 Hz |
| There are many sounds that exist in the atmosphere that are outside our ability to detect | ie: fluorescent light hum |
| The Human Audibility Curve represents | auditory sensitivity across frequencies |
| What is the main reason people seek audiologic help | because they want to talk to people |
| With really high or really low frequencies you need more dB to hear them as you get | older |
| On the Human Audibility Curve what two variables are represented | X = Hz and Y = dB |
| With regard to stimulus duration the auditory system integrates energy over time - meaning a longer stimulus is | easier to detect - to a point (then neurons stop firing.) |
| What is the shortest duration that produces a sensation of tonality | 10 ms for many pure tones |
| The ear’s sensitivity to a tone will improve until the sound is up to | 300 ms long |
| Temporal integration is also known as | summation |
| The improvement in detection with a longer stimulus duration is called | temporal integration or summation |
| Temporal integration function for individuals with normal auditory function is | relatively constant over a wide range of frequencies |
| The magnitude of the temporal integration function is reduced for individuals with | cochlear hearing loss |
| • 10 ms long is great for a hearing test pure tone | – it is one frequency. If a pure tone is shorter than 10 ms |
| • The ear’s sensitivity improves up to a point | – at 300ms you no longer get that improvement in sensitivity… |
| • The improvement in detection of a longer stiumulus duration | = temporal integration or summation |
| • 10 ms to 300 ms duration is across multiple frequencies | – don’t need more or less for diff frequencies – is a constant. |
| • A tone has to be within a certain duration to be detectable | temporal integration or summation |
| • 10 ms to 300 ms duration for a sound to be detected | is for normal hearing |
| • Many times cochlear damage involves the cells that are responsive to this particular function | called temporal integration |
| • On a Human Audibility Curve Better is | Low number on Y (dB) |
| • Which is the ear is more sensitive to 1000 Hz or 125Hz | 1000 Hz |
| • Good is LOW in audiology. In hearing you want LOW threshold. You want threshold to be as low as possible. If it is zero | you have REALLY good hearing! |
| • In order to hear a 125 Hz sound it needs to be about | 50dB which is a very loud sound. |
| As threshold gets lower you have better sensitivity; low threshold can detect a really soft sound. If their threshold was 90dB | can’t detect anything softer in sound than 90dB. |
| • As the duration of the stimulus increases | the change in sensitivity for pure tones is about |
| • As the duration of the stimulus increases threshold goes down! As the duration of the tone increases | threshold goes down |
| • Longer duration = | lower threshold |
| • Longer tone | better hearing |
| • From 10 ms to 300 ms the change in sensitivity is about | 10dB |
| • Four pulse tones in 300 ms the actual signal PRESENTATION | is 300 ms long |
| • 3 Parameters of a Sound | There are frequencies of the stimulus the intensity of the stimulus and the duration off the stimulus |
| • . Can talk about a sound with regard | to frequency intensity and its duration. |
| • For each listener there is a range of intensities that person can hear | from the softest sound the ear can detect to the level of discomfort or tactile sensation of sound usually from 0-140 dBSPL |
| • Threshold of feeling is called threshold of feeling | because the sound is so intense it creates a bone conducted response; low frequency sounds can create vibrotactile response too. |
| • Dynamic range = range of intensities a person can hear from threshold of | hearing to threshold of feeling 0 dBHL to 140 dBHL |
| Lower than 250 Hz and higher than 8 | 000 = |
| Bottom curve is the | human audibility curve |
| Top Line | threshold of feeling |
| On the threshold of feeling not much difference as a function of frequency when you get to that level of 130 dB to 140 dB | |
| The auditory response area is the | middle also known as the dynamic range |
| Dynamic range | = auditory response area |
| Minimum Audibility to Threshold of Feeling | = auditory response area = dynamic range |
| Hearing loss would be called reduced | dynamic range |
| In many people with sensorineural loss the threshold of feeling or discomfort is way before | 140 dB |
| Recruitment | the term for sound becoming unusually loud in people with sensorineural loss and lowering their threshold of feeling and discomfort |
| Hearing aids go to 100dB | we can set them within a person’s dynamic range from their minimum audibility curve to their threshold of feeling; we set them to auditory response area. |
| Sensorineural loss: sounds are soft but also | distorted; cranking up the sound doesn’t fully fix sensorineural loss can make it louder but can’t fix distortion. |
| • Threshold of feeling threshold of discomfort | followed by threshold of pain |
| • Human Audibility curve is on the exam | it is the bottom line. |
| • Stimulus Presentation Methods | There are two ways which sound is presented to a listener: via earphones or in the sound field |
| • Earphones: | allow for ear-specific information as well as more accurate control of the acoustic signal |
| • Use of phones obliterates the | natural resonance of the outer ear |
| • With use of headphones there is no natural resonance of the outer ear and | There is no benefit of bilateral summation |
| • With the use of headphones | Ambient noise is reduced |
| • If using headphones for a hearing test | Application of information obtained under headphones to real-world listening must be cautious |
| • Sound field: | sound is presented through speakers |
| • With sound field stimulus presentation | Must be wary of reverberation: reflected sound. When incident and reflected sound meet each other there are variations in sound pressure levels |
| • Head shadow | reduces sound level at the ear on the far side from the sound source |
| • Body baffle | means that the presence of the body in the field causes both reflection and absorption of the sound |
| • Sit in the booth and the sound comes to you over speakers = | sound field |
| • Two ways to present sound – have to do one or the other | not both. |
| • No headphones | with little kids or if people have hearing aids in. |
| • When possible use earphones/headphones because it helps block out ambient noise | also you can present a stimulus to only ONE ear with headphones. |
| • Drawbacks: when you put earphones over pinna | called supraaural (over the ear) or pinnay |
| • In a sound field you get binaural summation. With headphones you can’t benefit from | binaural summation and don’t get natural resonance. |
| With a hearing test you always test one ear or the other… and then both. So you get left ear | right ear |
| We never use a pure tone in the sound field because | pure tones are more apt to be subject to reverberation and cancelation. |
| Know what head shadow is. | Sounds arrive at one ear before they arrive at the other and by the time they get to far side they get reduced. |
| • Thresholds measured with earphones = | Minimum Auditory Pressure (MAP) |
| • Thresholds measured in the sound field = | Minimum Auditory Field (MAF) |
| • MAP | Minimum Auditory Pressure |
| • MAF | Minimum Auditory Field |
| • MAF yielded lower thresholds. Average normal hearing young adult has better hearing in sound field because of the | 3 dB boost. Ends up being 6 – 10 dB increase in sensitivity! |
| • In audiology clinic the first thing you do everyday | is calibrate equipment… |
| • When MAF and MAP curves are compared | it can be seen that MAF is more sensitive than MAP by 6-10 dB |
| • Why would the sound field results yield more sensitive hearing than hearing under headphones? | 3 reasons:, • Lack of ear canal resonance under headphones • Lack of binaural summation • Factors due to earphone calibration |
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