Voice Test 1 (Intro & Anatomy)

A voice disorder exists when:

1. A persons quality, pitch, & loudness differ from those of similar age, gender, cultural background, & geographic location (ie., not representative of the speaker)

2. When the perceptual properties of voice are so deviant that they draw negative attention to the speaker

3. When the structure &/or function of the laryngeal mechanism no longer meet the voice requirements of the speaker- ex. If they are a teacher and their voice fatigues by noon. A voice should last throughout the day without effort or pain.

3 goals in the assessment & management of voice disorders:

1. Evaluation of laryngeal function using auditory and visual-perceptual tasks watching and listening, acoustic analysis, and aerodynamic measures 

2. Identification and modification or elimination of functional causes that lead to the development of the voice disorder functional is from abuse or misuse of the voice, organic is from structural changes/deficits

3. Develop a plan that will remediate the voice disorder and return the voice to improved function- Requires patient buy-in

In order to meet voice tx goals and SLP must:

1. Understand anatomy & physiology

2. be familiar w. common VF pathologies

3. understand etiologic factors

4. know appropriate diagnostic techniques

5. develop a bank of clinical management techniques

Early foundations of voice rehab evolved into several general voice management orientations:

1. Hygienic voice therapy

2. Symptomatic voice therapy

3. Psychogenic voice therapy

4. Physiologic voice therapy

5. Eclectic approach

Hygienic voice therapy:

(vocal hygiene) concentrates on functional behavioral causes, “what is the patient doing to cause it,” vocal misuse/abuse. Identify behaviors and work to modify/eliminate/educate

Symptomatic voice therapy:

Modify deviant vocal symptom, negative qualities: hypernasal, strained, breathy, etc. Use facilitating techniques once deviant vocal symptom(s) have been identified. Try with patients (stimulability)

Psychogenic voice therapy:

Focuses on emotional and psychological status of the patient and how that might be contributing to the voice problem. The problem is there is no research proving that psychogenic therapy remediates voice disorders.

Physiologic voice therapy:

“If there is a voice disorder, there has to be an imbalance between the subsystems of voice” subsystems: respiration, phonation, and resonance. Also looks at laryngeal structures.

Eclectic approach:

Using a combination of all types of voice therapies. Highly recommended.

3 Levels of folds:

1. Aeryepiglottic folds

2. Ventricular folds (false vocal folds)

3. True vocal folds

Aeryepiglottic folds

• Connect the epiglottis to the arytenoids and form the upper rim of the larynx structure.

• When the epiglottis retroverts, these help to seal off the vestibule for airway protection.

• Creates the opening to the airway

Ventricular folds (false vocal folds)

• Just superior to the true folds (above the ventricles). Above and out to the side with the ventricle in middle. In healthy voice productions, these should not move/approximate towards each other

• They compress tightly during coughing, sneezing, & physical activities requiring a build up of subglottic pressure (thoracic fixation).

• They assist with airway protection during swallowing.

• They may close during hyperfunctional phonation. Too much effort

True vocal folds

• Lighter color and more medial

• Open for breathing, closed for airway protection, and vibrate to produce sound. We don’t want them to fully close or be tight during phonation

• Close tightly for vegetative acts such as cough, throat clear, swallow, or activities requiring thoracic fixation

Active inspiration

Works to make thoracic cavity bigger

Passive inspiration

You are not engaging in much activity and everything goes back to baseline

5 restoring forces of respiration:

1. Relaxation of inspiratory muscles

2. Natural elasticity of the lungs

3. Gravity

4. Visceral pressure (viscera= abdominal muscles)

5. Torque of the ribs

Muscles of inspiration

• Diaphragm

• Costal elevators

• External intercostal muscles

• Scalene muscles

• Sternocleidomastoid

• Pectoralis major & minor muscles

• All located in the thoracic cavity except the diaphragm

Muscles of expiration

• Internal and external oblique muscles

• Rectus abdominus

• Internal intercostal muscles

• Transverse abdominus

• All located in the abdomen except the internal intercostals

Checking action

The ability to sustain and control airflow on the way out in order to phonate

Laryngeal structures: Framework

1. Hyoid bone

2. Epiglottis

3. Thyroid cartilage

4. Cricoid cartilage

5. Arytenoid cartilages

6. Cuneiform cartilages

7. Corniculate cartilage

Hyoid bone

• Only bone that doesn’t attach to any other bone or cartilage

• (floating bone) horse shoe shaped bone that creates the top of the larynx.

• Horns are called cornu.

• Connects extrinsic muscles laryngeal muscles

Epiglottis

• Single cartilage

• looks like a tongue

Thyroid cartilage

• Largest of the laryngeal cartilage, looks like an ‘h’.

• Has 2 cornu on the bottom “inferior cornu of the thyroid cartilage” and 2 on the top “superior cornu of the thyroid cartilage”, has a thyroid notch, right below is a thick part that is commonly known as the adams apple called the thyroid prominence.

• Made of 2 large flat plates that are called the thyroid lamina.

• Vocal folds are attached to the thyroid prominence

  
  

Parts of the thyroid cartilage

• Inferior cornu of the thyroid cartilage

• Superior cornu of the thyroid cartilage

• Thyroid notch

• Thyroid prominence (Adam’s apple)

• Thyroid lamina

Cricoid cartilage

• Single cartilage that forms the base of the larynx.

• It looks like a signet ring.

• Skinny part is called the arch and the large flat part is called the cricoid lamina

Parts of the cricoid cartilage

• Arch

• Cricoid lamina

Arytenoids cartilages

• Paired cartilage.

• They look like pyramids.

• Have 2 processes

2 processes of arytenoid cartilages

• Vocal process

• Muscular process

Anterior commisure

where the vocal folds attach to thyroid cartilage

Cuneiform cartilages

• Paired cartilage.

• Edge of the aryepiglottic folds over and the cuneiform cartilage is inside the fold to provide stability and structure to the epiglottis

Corniculate cartilage

• Paired cartilage.

• Small on top of the arytenoids.

• Have no real function

Laryngeal structures: Joints

• Cricoarytenoid joint

• Cricothyroid joint

Cricoarytenoid joint

• On top of the cricoid that allows the arytenoids to move.

• Rotational movement.

• Main job is to open and close the vocal folds

Cricothyroid joint

• Where the inferior cornus of the thyroid cartilage has a joint with the cricoid cartilage.

• Allows the thyroid cartilage to rock back and forth to lengthen and tense the vocal folds to change the rate of vibrations and makes the pitch get higher and then to shorten and relax the vocal folds to make pitch lower.

• Main job is pitch adjustment

Extrinsic laryngeal muscles

• One muscle is found in the laryngeal structure and the other is outside.

• Usually larger muscles involved in gross motor movements.

• Tend to move the larynx as a whole unit

• Suprahyoid muscles

• Infrahyoid muscles

Suprahyoid muscles

• generally pull the larynx up = elevators

• From the hyoid bone up

  • Stylohyoid

  • Mylohyoid

  • Digastric

    • Anterior

    • Posterior

  • Geniohyoid

Stylohyoid

• Temporal bone (styloid process) to hyoid bone

• Raises hyoid bone posteriorly

Mylohyoid

• Mandible to hyoid

• Raises hyoid bone anteriorly

Digastric- Anterior

• Mandible to hyoid

• Raises hyoid bone anteriorly

Digastric- Posterior

• Temporal bone to hyoid process

• Raises hyoid bone posteriorly

Geniohyoid

• Mandible to hyoid

• Raises hyoid bone anteriorly

Infrahyoid muscles

• generally pull the larynx down = depressors

• From the hyoid bone down

  • Thyrohyoid

  • Sternothyroid

  • Sternohyoid

  • Omohyoid

Cricothyroid

• Goes in the front from the cricoid to the thyroid.

• When they contract it pulls the thyroid down and elevates pitch.

• Adductor muscle

Thyroarytenoid

• These are the vocal folds

• Adductor muscle

Lateral Cricoarytenoid

• From the side of the cricoid cartilage to the arytenoids

• Closes the arytenoids to close the vocal folds

• Adductor muscle

Interarytenoids

• Between the two arytenoids

• Oblique Arytenoids

• Transverse Arytenoids

Oblique Arytenoids

• Attached across at an angle

• Adductor muscles

Transverse Arytenoids

• Goes straight across from one to the other to adduct the vocal folds

• Adductor muscles

Posterior Cricoarytenoid

• From the back of the cricoid cartilage to the arytenoids

• Pulls the arytenoids to open the vocal folds

• Abductor muscle

5 layers of adult vocal folds

1. Epithelium

2. Superficial layer of the lamina propria

3. Intermediate layer of the lamina propria

4. Deep layer of the lamina propria

5. Vocalis muscle

Epithelium

• Outermost layer

• Mucosal layer made up of stratified squamous cells

• Very thin and “compliant” moves easily

  
  

Basement Membrane Zone (BMZ)

• A well-defined microcellular transition region between the epithelium and the superficial lamina propria.

• It is made up of collagen anchoring fibers that allow tissue in the VF mucosa to shift & glide.

• Where the Lamina Propria and epithelium come together.

• Stays connected, but still moves around

  
  

Superficial Layer of the Lamina Propria

• Made up of fewer elastin and collagen fibers, not as dense.

• Very loose and flexible.

• A lot of vibration occurs in this layer.

• If a pathology invades into this space it will impact vibration of folds and therefore the voice

• Reinkes Space is located her

Intermediate Layer of the Lamina Propria

• Made up of mostly elastin fibers and not as many collagen fibers

• More dense but still vibrates

Deep Layer of the Lamina Propria

• Made up of mostly collagen fibers with few elastin fibers

• Even more dense

Vocal ligament

intermediate layer + deep layer of the lamina propria

Vocalis Muscle

• This is the actual muscle tissue that can contract and relax

• Main body of the vocal folds

• Provides the tonicity

• Is has muscle tone, mass and stability, most dense, only active layer

Afferent (sensory)

• Incoming from the larynx up to the brain

• Sensory messages from sensory receptors in the laryngeal mucosa and respiratory passages send afferent messages to the CNS via the internal branch of the Superior Laryngeal Nerve (branch of the Vagus Nerve X) and terminate in the medulla at the nucleus tractus solitaries (NTS)

Efferent (motor)

• From the brain to the larynx

• Motor messages go through both the superior and recurrent branches of the vagus nerve

• Motor commands for voice production originate in the pre-central gyrus of the cortex

• Both pyramidal and extrapyramidal motor pathways are involved in laryngeal control

• The nucleus ambiguous contains central origins of the laryngeal motoneurons for all intrinsic laryngeal muscles – motoneurons for esophageal and respiratory control are also located here.

• The nucleus ambiguous is located in the reticular formation

• The only intrinsic laryngeal muscle innervated by the superior laryngeal nerve is the cricothyroid muscle. Damage will impact pitch

2 branches of the Vagus nerve (X)

• Superior laryngeal nerve

• Recurrent laryngeal nerve

Superior laryngeal nerve

• Internal branch

• External branch

Superior laryngeal nerve: Internal branch

Provides sensory information from the larynx

Superior laryngeal nerve: External branch

• Motor innervations to the Cricothyroid muscle

• The only intrinsic laryngeal muscle innervated by the superior laryngeal nerve is the cricothyroid muscle.

• Damage will impact pitch

Recurrent laryngeal nerve

• Courses down near the heart then back up – more so on the left than on the right. Therefore, they are more susceptible to injury.

• Supplies all sensory information below the vocal folds- ex. If something gets into our trachea or lungs we get the sensation to cough it out

• Supplies all motor innervations to the posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid, and oblique/transverse interarytenoids (all intrinsic except the cricothyroid m.)- damage will impact vocal fold movement and cause vocal fold paresis or paralysis

Other impacted nerves in voice

• CN IX

• CN XI

• CN XII

CN IX

• Glossopharyngeal

• Carries sensory info from tongue and faucialar arches and motor info to the pharynx and soft palate- damage can impact resonance

CN XI

• Accessory nerve

• Provides motor info to the neck muscles and the levator veli palatini- damage can impact resonance

CN XII

• Hypoglossal nerve

• Provides motor innervation to tongue muscles and strat muscles in neck which are extrinsic laryngeal muscles which raise and lowers the hyoid muscles- may impact professional voice users

Laryngeal reflexes

• Laryngeal adductor response

• Laryngospasm

Laryngeal adductor response

tight sphincteric closure to protect the airway by closing off the trachea and lungs (via sensory receptors in the mucosal tissue, joints, and muscles)

Laryngospasm

extreme glottis closure in response to stimulants that irritate the VF mucosa- Common irritants are cleaning supplies, perfume/cologne, chemicals, air pollutants. When this happens frequently it can be referred to as “Irritable larynx syndrome” and can lead to larynx abuse or phono trauma

Dyspnea

Difficulty breathing

Stridor

Noisy breathing/inhalation

Voice quality affected by:

• Integrity of the VF

  • Symmetry

  • Regularity/periodicity

• Glottal configuration/shape

• Degree of glottal constriction

Developmental changes in babies

• Larynx sits very high in the neck at C3/C4 level

• As the baby grows the larynx descends lower

Developmental changes in childhood

• Vocal folds for boys and girls are often very similar until about 10 years of age

Developmental changes in puberty

• At age 10 we start to see very different voice patterns.

• By puberty the larynx has descended to the C6/C7 level.

• Facial changes for boys and girls.

• Testosterone levels increase in males which stimulates the growth the adams apple which is the thyroid prominence.

• 5 layers of the vocal folds are fully formed during puberty.

Developmental changes in adulthood

• By adulthood the female focal fold length is about 11-15mm and males 17-21mm

Developmental changes in old age

• Presbylaryngeous or presbyphonia is how the focal folds are impacted by age.

• As we get older the vocal folds get thinner and create bowing.

• The vocal quality tends to deteriorate, pitch and loudness decreases, and vocal endurance decreases

Myoelastic Aerodynamic Theory (Vandenberg)

• Phonation is cyclical 

• Prephonation phase: 

  • Exhalation is occurring: vocal folds are open

  • Vocal folds begin to approximate or adduct due to contraction of the adductor muscles

  • The glottis is getting smaller and subglottic pressure is building

• Phonation phase: (can also be called the attack phase)

  • Subglottic pressure builds until it overcomes the resistance of the folds and they are blown apart

  • Instantaneous sudden release of high velocity airflow through the glottis

  • Due to the Bernoulli principle: (airflow pressure and velocity are inversely related. As one goes up, the other goes down,) the high velocity airflow through the glottis causes a sudden drop of pressure in the glottis (between the vocal folds)

  • This negative pressure (suction) sucks the folds back together

  • In addition to the suction, the natural elasticity of the folds also helps bring them back together

  • Once back together, pressure begins to build again

• New cycle begins back at the subglottic pressure

• The only way that phonation can occur is with the principles of the bernoulli effect

• Abductors kick in when you take a new breath

Bernoulli principle

airflow pressure and velocity are inversely related. As one goes up, the other goes down

Hirano’s Body-Cover Theory

• Looks at the importance of the layers in terms of the vibratory patterns

• Hirano re-groups the 5 layers (epithelium, 3 layers of lamina propria, muscle tissue-vocalis) into 3 distinct vibratory divisions, based on their unique vibratory properties:

  • Cover

  • Transition

  • Body

Hirano’s: Cover

• epithelium + superficial layer of LP

• Very compliant. Moves the most, oscillating

Hirano’s: Transition

• intermediate + deep layers of LP

• Couples the two other layers and allows them to move separately

Hirano’s: Body

• vocalis muscle

• Most stiff, has most mass, provides stability, little vibrations, only layer with tonicity

Mucosal wave

• The flexible and compliant layers of the LP and epithelium oscillate over the mass and stability of the vocalis muscle and deeper layers of the LP to create an undulating or oscillating motion – a ripple effect or complex waveform that moves across the vocal folds.

• Horizontal, vertical, and longitudinal movements are present.

• Layers of mucus are creating a wave over the top of the stable muscle.

• Good indicator of whether you have good vibration of the folds.

• Can help identify cysts or tumors under the surface.

• Anything under the surface disrupts the wave and effects the voice.

Pitch is determined by:

• Rate of vocal fold vibration

• Measured in Hz

To increase pitch:

• Increasing the tension in the folds, elongated and thinner, the folds vibrate faster.

• Cricothyroid muscle contracts which lengthens and tenses the folds

To decrease/lower pitch:

• Decrease tension, vibrate more slowly, vocal folds get short and fat.

• Thyroarytenoid muscle relaxes

Changes in subglottic pressure:

If we build up more pressure we can help increase our pitch by controlling the airflow

Changes in vibratory amplitude:

If you change the loudness of your voice that will change the pitch

Loudness determined by:

• The amplitude (how far apart from the midline the vocal folds go) of the vibratory cycle.

• Measured in dB.

• Build more subglottic pressure to blow them farther apart.

• To create a louder voice we can take a deeper breath, have a longer closed phase.

• Resonation can also influence loudness

Vocal quality control affected by:

• Integrity of VF vibration

  • Symmetry: the two folds should be moving in mirror to one another, can be impacted by pathologies or paralysis and paresis

  • regularity, and periodicity: cycle to cycle variation. Cycles should look identical without quick changes

• Glottal configuration/shape

• Degree of glottal constriction

Deviations or cycle-to-cycle variations:

• Aperiodicity

• shimmer

• jitter

Shimmer

cycle to cycle variations in loudness

Jitter

cycle to cycle variations in pitch

Registers:

• A register is a characteristic pattern of vocal fold vibration

• Falsetto (loft)

• Modal (chest)

• Glottal fry (pulse)

• Vibrato

Falsetto (loft)

• The upper limits of the pitch range (“eeeee”)

• Cricothyroid is contracted very tightly.

• VF are pulled so tightly that only a limited portion of the VF are vibrating.

• Lots of subglottic pressure and airflow

Modal (chest)

• Normal speaking voice.

• Should have good glottic closure, range of amplitude, and mucosal wave

Glottal fry (pulse)

• A therapeutic technique.

• At the low end of the pitch range.

• Very little subglottic pressure.

• VF have to be relaxed.

• If they have hyperfunction they won’t be able to do it.