Voice Midterm

Systems of Voice Production

Articulatory system, Laryngeal system, Respiratory system

Articulatory system

resonance

Laryngeal system

vocal fold vibration

Respiratory system

outgoing air stream; relatively constant Psg

Laryngeal system location

suspended (below) from the hyoid bone; sitting on top of the trachea

Laryngeal system primary/biological function

controls airflow into and out of lungs; prevents food and liquid from entering airway

Laryngeal system secondary function

voice production

Voice tells us about…

• Laryngeal pathology: functional, organic, neurogenic

• Whole person: emotions

Functional

caused by something we do to our own voice

Organic

a structural change in the vocal folds that we did not cause

Neurogenic

a neurological issue that causes a voice disorder

Larynx is built of…

bone, cartilages, and muscles

Laryngeal bone

Hyoid bone: horseshoe shaped, not attached to any other bone or cartilage, supportive structure for tongue root, inferior attachment for tongue muscles, superior attachment for extrinsic laryngeal muscles

Laryngeal individual cartilages

• Cricoid: most inferior laryngeal cartilage, full ring which is wide posteriorly and narrow anteriorly

• Thyroid: largest laryngeal cartilage, shield-like shape, closed anteriorly and open posteriorly

• Epiglottis: attached to thyroid and arytenoids, prevents food/liquid from entering larynx

Laryngeal paired cartilages

• Arytenoids: positioned posteriorly on top of the cricoid, 3 processes: muscular, vocal, apex

• Corniculates: on top of arytenoids

• Cuneiforms: within aryepiglottic folds, provide structural support

Arytenoids determine…

adduction or abduction

Ventricular folds (false vocal folds)

• Cover the true vocal folds

• On the outer edges; we see the white tissue of the true vocal folds

Glottis

horizontal space between the vocal folds

Intrinsic Laryngeal Muscles

• Adductors

• Abductor

• Tensors

Intrinsic Laryngeal Muscles ADDUCTORS

• Lateral cricoarytenoids

• Interarytenoids (transverse and obliques)

Intrinsic Laryngeal Muscle ABDUCTOR

Posterior cricoarytenoid (rotates away)

Intrinsic Laryngeal Muscles TENSORS:

• Cricothyroid (pars recta and pars oblique) (rotate downward)

• Thyroarytenoids (inside vocal folds)

Every muscle has…

…an origin (start) and an insertion (end)

When a muscle contracts/shortens…

… the insertion moves towards the origin

Extrinsic Laryngeal Muscles

• Elevators

• Depressors

Extrinsic Laryngeal Muscles ELEVATORS

• Digastric

• Geniohyoid

• Mylohyoid

• Stylohyoid

• Genioglossus

• Hyoglossus

Extrinsic Laryngeal Muscles DEPRESSORS

• Sternohyoid

• Omohyoid

• Sternothyroid

Other extrinsic laryngeal muscles

• Thyrohyoid/Hyothyroid: elevator and depressor; when it contracts it simply reduces space between the two structures

• Cricopharyngeus: not an elevator or a depressor; source of vibration in esophageal speech production

Digastric

• Extrinsic elevator

• Anterior: inner front surface of mandible to hyoid

• Posterior: Hyoid to mastoid

Geniohyoid

• Extrinsic elevator

• Mandible to hyoid

Mylohyoid

• Extrinsic elevator

• Floor of mouth

Stylohyoid

• Extrinsic elevator

• Styloid process of the skull to hyoid

Genioglossus

• Extrinsic elevator

• Mandible to tongue

Hyoglossus

• Extrinsic elevator

• Hyoid to tongue

Sternohyoid

• Extrinsic depressor

• Sternum to hyoid

Omohyoid

• Extrinsic depressor

• Shoulder blade to hyoid

Sternothyroid

• Extrinsic depressor

• Sternum to thyroid

What part of the vocal folds does vibration

• Anterior two thirds are muscular; vibrates

• Posterior third is cartilaginous; does not vibrate

• The muscle or cartilage is what is under the actual vocal fold tissue

Vocal fold anatomy

• Cover: epithelium (encases the entire vocal fold), superficial lamina propria, Reinke’s space is between these two layers

• Transition: intermediate lamina propria, deep lamina propria

• Body: thyroarytenoid muscle

How the vocal fold anatomy is categorized

• Outer layer is most moveable, inner layer is least moveable

• Grouped based on how much they move during vibration

Vocal fold physiology

Two types:

• Abduction and adduction

• Vibration

Paramedian

Anywhere between adduction and abduction

Myo

Muscle contraction (adductors and abductors)

Elastic

Vocal fold elasticity

Aerodynamic

Air pressure and airflow

Myoelastic-aerodynamic theory of phonation

1. Adduction: adduction muscles contract, vibration begins

2. Vibration: Psg increases and blows vocal folds apart, air flow is released into the articulatory system, vocal fold elasticity and Bernoulli effect return vocal folds to midline

3. Abduction: abduction muscles contract, vibration ends

Vertical phase difference

• How the vocal folds vibrate

• Vocal folds open from bottom to top and close from bottom to top

Bernoulli effect

Fast moving air passing through the vocal folds creates a drop in pressure that pulls tissue inward

Vagus nerve (X)

• Wanderer: distribution through neck, throax, abdomen

• Many branches: e.g., pharyngeal nerve, superior laryngeal nerve, recurrent nerve

Innervation

Motor command is brought to a muscle

Recurrent nerve

Goes past the larynx, into thorax, then loops back up to larynx

Afferent

Sensory

Efferent

Motor

Pharyngeal nerve

• Afferent component: tongue base, upper pharynx

• Efferent component: innervates almost all velopharyngeal muscles (causes velum to elevate)

Pharyngeal nerve damage symptoms

• Hyper nasality

• Nasal regurgitation

• Swallowing difficulty (when afferent component is damaged)

Superior Laryngeal Nerve

• Afferent component: internal branch, upper (supraglottal) larynx

• Efferent component: external branch, cricothyroid muscle (main muscle of V.F. tension)

Superior laryngeal nerve damage symptoms

• Loss of sensation in upper larynx

• Monopitch (cannot lengthen or shorten vocal folds)

Recurrent nerve

• Efferent component: all intrinsic muscles except cricothyroid

Recurrent nerve damage symptoms

• Unilateral damage: breathiness

• Bilateral damage: aspiration, laryngeal stridor (phonation on inhalation), limited pitch range

Infant larynx

• High in neck; cricoid at C1-3 level

• Cartilages more elastic

• Shorter VF (3mm)

• Higher F0 (500 Hz for cry at birth)

Adult larynx

• Lower in neck; cricoid at C4-6 level

• Cartilages more osseous

• Longer VF (15-20 F, 20-25 M)

• Lower F0 (200Hz F, 100Hz M)

Objective measures

• Frequency (Hz)

• Jitter (%)

• Intensity (dB)

• Shimmer (dB)

Subjective descriptors

• Pitch

• Loudness

• Quality (breathiness, hoarsness, harshness, tremor, etc)

Pitch

• Perceptual (subjective) correlate of frequency

• F0 (fundamental frequency)= frequency of V.F. vibration

Thinner and tense vocal folds…

… higher pitch

Thicker and relaxed vocal folds…

… lower pitch

Voice registers

• Modal register (chest register): comfortably produced frequencies

• Pulse register (glottal/voice fry): below comfortable register

• Loft register (falsetto): increased voice pitch above comfortable registers

Frequency Perturbation

Jitter:

• objective: measured by % difference (1% is normal range)

• Amount of variation in the duration of a glottal cycle

• Not healthy if used at all times

Loudness

• Perceptual (subjective) correlate of intensity

Higher Psg…

… increased loudness

Lower Psg…

… decreased loudness

Intensity perturbation

Shimmer:

• Cycle to cycle variation of amplitude/voice intensity

• Expressed in dB

Quality

• Distinctive characteristics of voice, exclusive of pitch and loudness

Effects of resonance on voice quality

• Hyponasality (too much nasality)

• Hypernasality (cannot fully elevate velum)

Effects of vocal folds on voice quality

• breathiness

• hoarseness

• harshness

• strain-strangle

• tremor

Voice disorder

a condition in which voice functioning is unacceptable to the user in social, professional, or other contexts, and for which the SLP or other practitioner generally finds some corroborative evidence

Incidence

Within a certain time frame

Prevalence

In this specific moment in time

Incidence of voice disorders

• Children: 6-9%

• Adults: 3-9%

• Elderly: 47%

• Professional voice users: 30%

Pitch disorder

• monopitch

• reduced pitch range

• inappropriate pitch

• pitch breaks

Loudness disorder

• monoloudness (cannot increase loudness)

• reduced loudness range (can increase volume, but not as much as usual)

Perceptual signs of voice problems

• Pitch

• Loudness

• Quality

Causes of voice disorders

3 types of voice disorders:

1. functional: how we use our voice

2. organic: pathological problem

3. neurogenic: neurological

Cannot treat a voice disorder without knowing…

… the cause

• determining the cause is essential for treatment

• two people can have the exact same symptoms with two completely different causes (voice overuse vs. laryngeal cancer)

Functional voice disorder types

1. Muscle tension dysphonia (MTD)

2. Psychogenic voice disorders (PVD)

Phonotrauma

Expressive talking/shouting/cheering. prolonged loudness, speaking in noisy environment, inappropriate pitch level, excessive coughing/throat clearing

Functional voice disorder series of events

Phonotrauma→ Structural changes→ Voice disorder→ Social, emotional, occupational problems

Muscle tension dysphonia example

• Vocal nodules

• Vocal polyps

• Contact ulcers

Psychogenic voice disorder examples

• Puberphonia

• Functional aphonia

Vocal nodules

• most common benign growths in children and adults

• caused by continuous phonotrauma

• typically bilateral, at anterior middle 3rd

• initially soft, later hard

• glottal hourglass figure during phonation

Vocal nodule symptoms

• Breathy and hoarse voice

• Sensation of something on vocal folds; need to clear throat

• Could lead to lowering of pitch or reduced pitch range

Vocal polyps

• masses on vocal folds

• single traumatic vocal event→ hemorrhage→ polyp

• typically unilateral, at anterior-middle third junction

• softer than nodules; may be filled with fluid

2 types of vocal polyps

1. Sessile

2. Pedunculated

Sessile

Broad based

Pedunculated

Narrow based

Vocal polyp symptoms

• Breathy and hoarse voice; possible diplophonia (2 pitches at once)

• Could affect pitch

• Severe cases: barely any pitch, monoloudness, aphonia

Contact ulcers/granuloma

• ulcerations along posterior third of glottis

• chronic inflammatory disease of the larynx

Three most common causes of contact ulcers/granuloma

1. Slamming together of arytenoids (functional disorder)

2. Reflux (organic disorder)

3. Intubation (organic disorder)

Contact ulcers/granuloma symptoms

• Hoarse voice

• Vocal fatigue

• Pain in laryngeal area

• Pitch breaks

• Trouble manipulating loudness

Build up from ulcers

Granulomas