module 6 - phonatory physiology

is the Bernoulli effect an argument that Neurochronaxis Theory is incorrect?

NO

recurrent nerve length

neuron firing rate

chest thump

vocal fold muscle fiber orientation

^all argue that what theory is incorrect?

Neurochronaxic Theory

what does the bernoulli effect state?

as velocity of air through tube increases = pressure decreases

what is the issue with the recurrent nerve length for the Neurochronaxic theory?

the left and right nerves are a different length

the maximum firing rate for neurons is about __ Hz

400

Bernoulli Effect is a restatement of the conservation of ____

energy

Bernoulli effect comes into play for myoelastic aerodynamic theory when the vocal folds are coming together/going apart

coming together

the shortfall of myoelastic aerodynamic theory is that it does NOT account for what?

does not account for energy loss

functional definition of phonation

any type of laryngeal sound production in speech - sound that results from the vibration of the vocal folds

phonation

energy transition definition

conversion of potential energy of compressed air into kinetic energy of acoustic vibration

what are the two movement theories?

neurochronaxic theory

myoelastic-aerodynamic theory

what does neurochronaxic movement theory claim?

frequency of vocal fold vibration dependent on rate of neural impulses delivered to laryngeal musculature

what are the 5 issues with neurochronaxic movement theory?

action potential firing rate

vocal fold muscle fiber orientation

recurrent laryngeal nerve length

chest thump

airflow

movement theory: neurochronaxic

problems with neurochronaxic: action potential firing rate

up to 400Hz in humans, but phonation can occur at higher frequencies

movement theory: neurochronaxic

problems with neurochronaxic: vocal fold muscle fiber orientation

TA fibers are mostly A-P direction. abduction would require M-L direction

movement theory: neurochronaxic

problems with neurochronaxic: reccurent laryngeal nerve length

recurrent nerve on left side is different length than right side

• left is longer

movement theory: neurochronaxic

problems with neurochronaxic: chest thump

sudden push to the chest (or abdomen) can alter the pitch

movement theory: neurochronaxic

problems with neurochronaxic: airflow

experiments have shown that phonation is impossible w/o pressurized airflow

what are the 2 important conservation laws?

conservation of mass

conservation of energy

conservation of mass law claims what?

speed must increase through smaller cross-section (such as going through a tube)

conservation of energy law claims what?

energy can be exchanged freely between KE and PE… BUT must add up to same total

conservation of energy law equation

TE = KE + PE

total energy

constant throughout system

kinetic energy

energy of motion

potential energy

STORED energy that can create motion → pressure

Bernoulli Effect in larynx

vocal folds provide a constriction in vocal tract

• reduction in area in glottis → increase in velocity

• increase in velocity → reduction in pressure

Bernoulli Effect in larynx:

pressure ______ as air flows through glottis, and ____ again beyond it

pressure decreases as air flows through glottis, and increases again beyond it

Bernoulli Effect in larynx:

decrease in pressure results in vocal folds being…

sucked toward each other

what is required for self-sustained oscillation? (3)

stable equilibrium point

inertia in the system

no net energy loss in system

finite element models can account for variation in vocal fold opening and closing behavior in what dimensions? (3)

horizontal

vertical

time

what does a spring represent in models

elastic force

mass provides ___ in a model

inertia

the two mass model adds _____ relative to the one mass model

vertical phase difference

the three mass model adds ____ relative to the two mass model

variation in effective mass

the tweak to the myoelastic aerodynamic theory was the addition of…

inertance

what 2 muscles are involved in pitch control?

thyroarytenoid TA

cricothyroid CT

what are 2 primary adjustments for intensity?

subglottal pressure

glottal adduction

what has the strongest impact of F0?

change in stress/tension

an increase in effective mass is a result of _____ activation

thyroarytenoid TA

the primary adjustment for intensity control is…

subglottal pressure

when adjusting intensity, what changes in the glottal waveform?

velocity of vocal fold closing

what is the primary adjustment for spectrum control?

thyroarytenoid TA activation

what are the biomechanical components represented within the vocal fold system? (3)

spring

mass/inertia

dashpot

what is required for self-sustained oscillation? (3)

stable equilibrium point

inertia

no net loss of energy OR added energy to compensate for any loss

what does the 2 mass model NOT account for?

variation in effective mass

with a CONVERGENT glottis, the lower portion is ___ open than the upper portion

more

intertance is the measure of…

resistance to change in airflow of gas

what are the 3 major categories of phonatory adjustments?

frequency

intensity

spectrum

the effective mass is the portion of the vocal fold that is…

vibrating

what happens to F0 between men and women in the senior years?

F0 converges

is the superficial lamina propria a part of the BODY in the body-cover theory?

no

is there vertical phase difference in the loft register?

no

myoelastic-aerodynamic theory

5 steps of myoelastic aerodynamic theory

1. subglottic pressure builds up and pushes folds apart (start of vertical phrase difference)

2. as vocal folds move apart, folds stretch, creating elastic restoring recoil force

3. as they move further apart, the elastic force increases until it is greater than the pressure

4. the elastic force starts to pull folds together

5. bernoulli effect lowers pressure between folds, helping to bring folds together

myoelastic-aerodynamic theory

when pressure increases, vocal folds ___

abduct

solution to myoelastic-aerodynamic theory issue of not accounting for energy loss

inertance

do the top and bottom edge of the vocal folds move at the same time during vibration?

no, there is a phase difference

what 3 types of phase differences are there in vocal fold vibration?

superior-inferior

anterior-posterior

closing-opening

which edge of the vocal folds closes first in vocal fold vibration?

bottom/inferior closes first

which phase difference is normal in vocal fold vibration?

superior-inferior is normal

anterior-posterior is ABnormal and might mean pathology

in closing-opening phase differences:

which phase is longer?

opening phase much longer than closing phase (slams shut)

in closing-opening phase differences: explain the 3 steps of the cycle

1. opening: slowly increases

2. slams shut

3. stays closed for a while

vibration models: biomechanics

what does the spring represent in the larynx

elastic recoil force of the tissue of the vocal folds

vibration models: biomechanics

dashpot represents what in the larynx

represents energy that is lost and opposition to motion

in larynx: used to decrease velocity of mass due to elasticity

vibration models: biomechanics

what does mass represent, and what does it account for?

mass represents mass

accounts for inertia

vibration models: biomechanics

what is the general biomechanical system law?

TE = KE + PE - energy loss

vibration models

3 requirements for self-sustaining oscillation

1. stable equilibrium position

2. must be inertia in system to overshoot equilibrium

3. net energy loss in system = 0 (no loss of energy)

vibration models

one mass model

simplest model

consists of mass, spring, and dashpot

vibration models

2 issues with one mass model

no vertical phase difference

no variation in effective mass possible

vibration models

two mass model allows for…

vertical phase difference

vibration models

issue with two mass model

no variation in effective mass possible

vibration models

three mass model allows the ability to vary…

effective (vibrating) mass

the two and three mass models allow for what to move independently from each other?

body and cover can move independently from each other

vibration models

convergent glottis is the opening/closing phase

opening

vibration models

divergent glottis is the opening/closing phase

closing

vibration models

convergent vs. divergent glottis

convergent: lower glottis is more open than upper glottis

divergent: lower glottis is less open than upper glottis

vibration models: inertance

inertance of the ____ volume is much bigger than the ___ volume

supraglottic > glottic

vibration models: inertance

supraglottic volume responds much ____ to changes in pressure than the glottic volume (because of inertance)

slower

vibration models: inertance

____ pressure above glottis (supraglottic) in closing phase provides bulk of suction that pulls vocal folds together

reduced

vibration models: myoelastic aerodynamic theory tweaked (current)

currently, we understand:

energy transfer from airflow to vocal folds is a result of the ___ of the air above glottis

inertance

vibration models: myoelastic aerodynamic theory tweaked (current)

currently, we understand:

the _____ pressure pushes folds open from below and ____ of the air above the glottis pulls them closed from above

subglottal

inertance

vibration models: myoelastic aerodynamic theory tweaked (current)

currently, we understand:

folds are pushed open from above/below

below

vibration models: myoelastic aerodynamic theory tweaked (current)

currently, we understand:

folds are pulled closed from above/below

above

phonatory adjustments

what are the 3 phonetic characteristics you might want to vary

F0 (pitch)

intensity (loudness)

spectrum (sound quality)

phonatory adjustments

phonatory adjustments can be made by changing 1 of what 5 control variables?

vocal fold length

vocal fold tension

vocal fold effective mass

vocal fold adduction

subglottal pressure

phonatory adjustments: frequency

what is fundamental frequency

rate of vocal fold vibration

phonatory adjustments: frequency

control of fundamental frequency:

• what are the 2 primary adjustments?

• what is the 1 secondary adjustment?

2 primary: fold tension*, fold length

1 secondary: effective mass

phonatory adjustments: frequency

what has the biggest impact on F0 control?

fold tension

phonatory adjustments: biomechanics

stiffness depends on ___ and ___ of folds

length

tension

phonatory adjustments: biomechanics

kinetic energy is mass/stiffness/damping

mass

phonatory adjustments: biomechanics

potential energy is mass/stiffness/damping

stiffenss

phonatory adjustments: biomechanics

energy loss when vocal folds collide is mass/stiffness/damping

damping

phonatory adjustments

what two muscles are responsible for setting phonation PITCH

cricothyroid CT

thyroarytenoid TA

phonatory adjustments

are CT and TA an antagonist pair of muscles

yes, work in opposition to set length and stress

phonatory adjustments

CT moves thyroid ___ + ____ to lengthen folds

forward and down

phonatory adjustments

TA moves thyroid ___ closer to arytenoids to shorten the vocal folds

back

phonatory adjustments

are intrinsic or extrinsic muscles primarily adjusting fold stress and tension

intrinsic, extrinsic only supplemental

phonatory adjustments

when extrinsic supplement for adjustment:

elevating larynx ____ tension

increases

phonatory adjustments

when extrinsic supplement for adjustment:

lowering larynx ____ tension

reduces

phonatory adjustments

extrinsic muscles may also __ larynx to provide support for CT and TA

stabilize

phonatory adjustments: frequency

what is effective mass?

portion of fold that is vibrating