Speech Science-Phonatory/laryngeal System

Front 1

What are the Vocal Folds?

Back 1

-valve in the airway at the level of the larynx
-pair of structures made of epithelial tissue, mucous membrane and muscle
-primary role is to vibrate and generate voice signal
-also play a role in protecting airway during swallowing, coughing and strenuous lifting
-continuously altering between pulling together and pushing apart

Front 2

What are the False Folds for?

Back 2

The false folds and epiglottis are located above the true vocal folds and are primarily there to protect airway during swallowing

Front 3

What is phonation?

Back 3

The vibration pattern of the vocal folds, which can be modulated in many ways: breathy, hoarse, harsh, whisper, soft, loud...

Front 4

What are the main cartilages in the larynx?

Back 4

Thyroid:
-largest cartilage of the larynx
-the anterior end of the vocal folds attach to the inside of the thyroid cartilage

Arytenoid:
-a pair of small pyramid shaped cartilages that sit at the posterior edge or the thyroid cartilage and sit on the top of cricoid cartilage
-the posterior end of the vocal folds attach to the arytenoid cartilages, thus the vocal folds stretch between the thyroid and arytenoids cartilages

Cricoid:
-a complete ring of cartilage that is just below the thyroid and arytenoids cartilages
-the thyroid and arytenoids cartilages attach and form joints on the back of the cricoid

Front 5

What is the Posterior cricoarytenoid muscle (PCA)?

Back 5

-originates on the posterior part of the cricoid cartilage and inserts on the muscular process of the arytenoid cartilage
-muscle contraction causes the arytenoids to rotate outwards and open the vocal folds (abduction)

Front 6

What is the Lateral cricoarytenoid muscle (LCA)?

Back 6

-arises from the lateral border of the cricoid cartilage and inserts into the muscular process of the arytenoid cartilage
-muscle contraction causes the arytenoids to rotate inwards and close the vocal folds (adduction)

Front 7

What do the interarytenoid muscles do?

Back 7

-oblique and transverse
-attaches between the two arytenoids cartilages and pulls them together when contracted – thus pulls the vocal folds together

Front 8

What is the cricothyroid muscle?

Back 8

- originates on the lateral surface of the cricoid cartilage and inserts on to the lower edge of the thyroid cartilage
- pulls the thyroid cartilage forward and downward
- tenses and lengthens the vocal folds; raises pitch

Front 9

What are the thyroarytenoids (thyrovocalis)?

Back 9

-forms the main mass of the true vocal folds
-originates on the vocal process of the arytenoid cartilage and inserts on to the angle of the thyroid
-can stiffen and tense the vocal folds (can change vocal pitch and quality)

Front 10

What is Myoelastic-Aerodynamic Theory of Phonation?

Back 10

Describes voice production as a combination of muscle forces (myo), tissue elasticity (elastic), and air pressures and flows (aerodynamic)

1.To initiate phonation the vocal folds are brought together (adducted) by continuously contracting the closing muscles (LCA and IA), a process referred to as medial compression
2. Once the vocal folds close, the subglottal pressure begins to build up quickly
3. Once the subglottal pressure becomes high enough (3-5 cmH20) it forces the vocal folds apart
4. This rapid opening of the vocal folds causes a rapid flow of air through the opening in the vocal folds.
5. The rapid flow produces a negative air pressure to develop between the vocal folds and this causes the vocal folds to be pulled back together (Bernoulli effect)
6. The vocal folds are also pulled back together by the elastic recoil of the vocal fold tissues and the continuous closing muscle contractions
7. Once the vocal folds are back together (closed), the cycle repeats itself again and again

Front 11

What are the 5 layers of the vocal folds?

Back 11

Cover:
1) epithelium
2) superficial layer of lamina propria

Transition:
3) intermediate layer of lamina propria
4) deep layer of lamina propria

Body:
5) thyrovocalis muscle

Front 12

What's the Cover Body Model?

Back 12

The stiffness of the cover and body layers of the VFs can be adjusted by contracting different muscles and this allows for a complex variety of voice qualities to be produced.

Front 13

What kinds of vibration phases are there in VF vibration? Describe each.

Back 13

1) vertical: these vibrations are reflected by a time lag between the opening and closing of the inferior and superior portions of the vocal folds.
2) longitudinal: this is reflected by a time lag between the opening of the anterior and posterior portions of the folds.

-during opening the folds open from posterior to anterior
-during closing the folds close from front to back

Front 14

What is a Glottogram?

Back 14

Glottogram: Measurement of vocal fold opening and closing.

Front 15

How are Glottograms measured?

Back 15

1. High Speed Cinematography: using a laryngoscope to film back of throat, taking 20-40 pics per vibration.

2. Video Stroboscopy: takes pictures in sync with a flashing light where only one picture is taken per vibration and the flashing gives the illusion of a slow motion movie of the vibration cycle.

3. Electroglottography (EGG): Using two electrodes on the thyroid plates, electrical resistance is measured at the level of the glottis.

Front 16

What is Vocal Frequency?

Back 16

-opening and closing of the vocal folds during phonation results in the generation of a complex periodic sound with a certain fundamental frequency (F0)
-fundamental frequency can be measured directly from the speech waveform
-the period (or frequency) of this waveform can be determined by measuring the duration of a single cycle of vibration (i.e. peak to peak measurement)
-the period is inversely related to frequency; a cycle of vibration that is 10 milliseconds in length reflects a vibration frequency of 100 Hz (cycles/sec)
-F0 is not usually calculated by hand because you typically want to calculate over many seconds of speech

Front 17

What is Visipitch?

Back 17

A computer program to measure pitch using algorithms.

Front 18

What is the average F0 for...
Infants?
Children?
Young men?
Young women?
Older males?
Older females?

Back 18

Infants: 350-500hz
Children: 270-300hz
YAM: 120hz
YAF: 220hz
OAM: 140hz
OAF: 180hz

Front 19

What is the F0SD?

Back 19

For normal conversation, about 20-35hz

Front 20

How much range do we see with F0? What affects this?

Back 20

-there are age and sex difference when it comes to how large a range people have in their F0.

Infants: 1200hz range (largest)
YAM: 65hz
YAF: 95hz
OAM: 78hz
OAF: 100hz

-too large a range can indicate problems with pitch control.

Front 21

What is the Maximum Phonation Frequency Range (MPFR)?

Back 21

-obtained while producing stepping or gliding tones
-range from the lowest to the highest tone that a person can sustain (includes the falsetto mode of phonation)
Adult males : 80 to 700 Hz ; (about a 600 Hz range)
Adult females: 135 to 1000 Hz; (about a 850 Hz range)
-singers=wider range; disordered=much more narrow range

Front 22

What is vocal amplitude/intensity?

Back 22

-speech amplitude is determined by the amplitude of sound that is created by phonation
-speech/vocal amplitude is measured in decibels and must be referenced and calibrated (i.e. 6 or 12 inches mouth to microphone distance)

Front 23

What is the average amplitude level during normal conversation?

Back 23

Around 70dB at 12'' calibration.
-age and sex have small effects, but the order goes from: men>women>children&older

Front 24

What is dynamic range?

Back 24

Dynamic range: Softest phonation to maximum loudness of phonation (about 50dB-115dB)

Front 25

What are cycle-to-cycle variations in F0 and amplitude?

Back 25

An estimate of the average variation in each adjacent cycle of vocal fold vibration.

Front 26

What is Jitter?

Back 26

The average cycle-to-cycle variation in the time (period) of vibration
-normal=less than 1%

Front 27

What is Shimmer?

Back 27

The average cycle-to-cycle variation in the amplitude of vibration
-normal=0.5dB

Front 28

What is the Signal-to-Noise Ratio (aka Harmonics to noise ratio)?

Back 28

The amplitude of the speech signal at the specific frequency of F0 is determined and it is divided by the amplitude of other non F0 frequencies (excluding the harmonics)
-the non F0 frequencies are considered to be noise (i.e. like the frequencies produced during a whispered /a/ instead of a voiced /a/)
-a normal voice will have a relatively small amplitude of these noise frequencies relative to the high amplitude of the F0 (signal) frequency
-higher signal/noise (S/N) is associated with a normal voice
-lower S/N is associated with a poor voice
-normal S/N values=15-20 dB
-below 15 dB may indicate a voice problem

Front 29

What is vocal frequency and amplitude like in people with Parkinson's disease?
-F0?
-intensity/amplitude?
-phonational range?
-dynamic range?

Back 29

-higher F0
-lower amplitude/intensity
-lower phonational range
-lower dynamic range

Front 30

What is cycle-to-cycle variation like in Parkinson's disease?

Back 30

-higher Jitter and Shimmer (breathy/harsh voice)

Front 31

What kind of treatments are out there to help Parkinson's patients with their voice? How are the outcomes measured?

Back 31

1) Voice Intensity Treatment Programs (e.g. Lee Silverman Voice Therapy)
2) Levodopa medication (dopamine replacement)

-outcomes measured include increased vocal amplitude/intensity and reduction in jitter/shimmer.

Front 32

What is Unilateral Vocal Fold Paralysis?

Back 32

-complete or partial paralysis of the vocal fold on one side (unilateral)
-often the result of damage to the recurrent laryngeal nerve during chest or neck surgery
-the voice is perceived to be breathy, harsh, diplophonic and reduced in loudness

Front 33

What is vocal frequency and amplitude like in people with vocal fold paralysis?

Back 33

-Lower F0
-diplophonia (double pitch)
-lower amplitude/intensity
-decreased phonational and dynamic range

Front 34

What is cycle-to-cycle variation like for people with vocal fold paralysis?

Back 34

-higher than normal Jitter and Shimmer (breathy voice)

Front 35

What kind of treatments are out there for vocal fold paralysis? What are the outcomes?

Back 35

Thyroplasty : surgical procedure that involves the insertion of a small piece of material into the lateral side of the paralyzed vocal fold.
-acts to push the vocal fold towards the midline and bring the folds together for phonation

Outcomes:
-increased vocal amplitude (intensity)
-reduced dipliphonia
-reduced shimmer and jitter

Front 36

What is Spasmodic Dysphonia (Laryngeal Dystonia)?

Back 36

-irregular involuntary contractions of the laryngeal adductor muscles
-believed to be a dystonic type of movement disorder involving damage to the basal ganglia
-the voice is perceived as strained and contains frequent irregular vocal spasms and voice arrests

Front 37

What is vocal frequency and amplitude like for people with Spasmodic Dysphonia?

Back 37

-higher F0
-fluctuations in amplitude/intensity
-voice breaks

Front 38

What is cycle-to-cycle variation like in people with Spasmodic Dysphonia?

Back 38

-higher Jitter and Shimmer (strained voice)

Front 39

What kind of treatments are out there for Spasmodic Dysphonia? What are the outcomes?

Back 39

Botulinum toxin (Botox) injection – either unilateral or bilateral injection of Botox into the thyrovocalis muscle – causes a mild partial paralysis of the vocal fold which significantly reduces the vocal spasms – a temporary reversible paralysis lasting about 4-6 months

Outcome measures:
-reduced SDF0 (variability)
-reduced voice breaks (reduced spasms)
-reduced shimmer and jitter
-reduced laryngeal resistance