Anatomy, Physiology, and Assessments Flashcards
√What are the embryological precursors of the larynx? What is their blood supply? How do these precursors predict the patterns of laryngeal lymphatic drainage?
Supraglottic Larynx:
- Buccopharyngeal primordium, developed from the 3rd and 4th branchial arches
Glottic and Subglottic larynx:
- Formed by a union of lateral furrows that develop on each side of the tracheobronchial primordium, developed from 6th branchial arch
Blood Supply (dual) & Lymphatic drainage:
Supraglottis:
- Blood supply: Superior laryngeal arteries (from the superior thyroid artery > external carotid)
- Lymphatics follows the arteries down to the carotid sheath to drain into deep cervical chain nodes in level II & III
- Lymphatics drain bilaterally (b/c supraglottis forms as a whole with no fusion in the midline, unlike glottis/subglottis)
Glottis & Subglottis:
- Blood supply: Inferior laryngeal arteries (originating from the inferior thyroid artery > thyrocervical trunk > subclavian artery)
- Lymphatics follows the arteries to drain into the prelaryngeal and pretracheal nodes (level VI) before reaching the deep cervical chain nodes in level IV
- Glottis is formed by paired structures (union on each side of primordium) that fuse in midline. Lymphatics thus drain unilaterally and vocal folds have sparse lymphatics
- Glottic cancers must invade deeply before accessing lymphatics. Hence - Low incidence of LN mets and propensity for unilateral mets
√Outline the Embryology of the Larynx
- 4 weeks: Formation of the laryngotracheal groove in the ventral wall of the primitive pharynx
- 5-7 weeks: Elongation of the laryngotracheal diverticulum, separated from the dorsal foregut by the tracheoesophageal septum
- 8-9 weeks: Epithelial proliferation obliterates the laryngeal lumen
- 10 weeks: Recanalization of the laryngeal lumen is complete
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√Name the boundaries and subsites of the supraglottis, glottis, and subglottis.
What are the 5 subsites of the supraglottis?
Supraglottis Boundaries:
- Superior: Superior surface of epiglottis, hyoepiglottic ligament, AE folds
- Inferior: two definitions: (1) Midpoint of laryngeal ventricle, or (2) Superior most limit of the true vocal fold
- Anterior: Thyrohyoid membrane, thyroid cartilage
Supraglottis Subsites:
- Aryepiglottic folds
- False vocal folds
- Suprahyoid epiglottis
- Infrahyoid epiglottis
- Arytenoids
Glottis Boundaries:
- Superior: same as inferior supraglottis
- Inferior: 1cm below superior limit
- Anterior: Thyroid cartilage
Subglottis:
- Superior: 1cm below imaginary line described above
- Inferior: Inferior border of cricoid
- Anterior: Cricothyroid membrane, cricoid cartilage
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√Describe the Epithelial linings of the larynx.
What are the areas that are rich in glands? 4
Supraglottis:
- Epiglotiss, lingual surface: Non-keratinizing, stratified squamous cell epithelium (SSCE)
- Epiglottis, laryngeal surface - upper half and lateral borders SSCE, lower half respiratory (ciliated pseudostratified columnar epithelium with globlet cells)
- False fold: Respiratory epithelium (Pseudostratified columnar epithelium)
- Edges of the AE folds = stratified squamous epithelium
Glottis:
- Floor to ventricle to subglottis: Non-keratinizing Stratified squamous epithelium
- Anterior and posterior commissure: respiraotry epithelium
Subglottis:
- Respiratory epithelium - Pseudostratified columnar epithelium
Areas that are rich in glands:
- Ventricle
- Saccule
- Anterior and posterior commissure
- Subglottis in kids
√Describe the lymphatic drainage patterns of the larynx
Supraglottis: Bilateral II, III, IV
Glottis: Sparse lymphatics, metastasis rare unless deep invasion. (VI first if reached)
Subglottis: Commonly unilateral, can involve VI (III, IV, VII possible)
What are two paired joints of the cricoid?
- Cricoarytenoid
- Cricothyroid
Describe the cricoarytenoid unit. What is its importance?
Cricoarytenoid unit
= the functional unit of the larynx
= at least 1 arytenoid + its attachment to the cricoid
Significance: At least one cricoarytenoid unit is needed to maintain speech and swallowing without a tracheostomy
What are the cricoarytenoid joint stabilizers?
- Posterior cricoarytenoid ligament
- Fibrous articular capsule
- Vocal ligament
Describe the borders of the Quadrangular Membrane. What is its significance?
Quadrangular Membrane
= Ligament that forms the AE folds and the false vocal folds
= Forms the superior border of the paraglottic space
Borders:
- Superior (free margin): AE fold
- Inferior: Vestibular ligament (of false vocal folds)
- Posterior: Arytenoid, corniculate, cuneiform
- Anterior-Superior: Lateral margin of epiglottis
- Anterior-inferior: Thyroid alae
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Describe the Conus Elasticus. What is its significance?
Conus Elasticus
= Ligament that forms the vocal ligament
= Forms the inferior border of the paraglottic space
= Connects the cricoid cartilage with the thyroid and artyenoid cartilages, composed of dense fibroconnective tissue with abundant elastic fibers
Borders:
- Inferior: Attaches to cricoid cartilage
- Supero-Anterior: Attaches to anterior commissure at thyroid
- Supero-Posterior: Vocal process
- Superior free edge: Becomes the vocal ligament
- Anterior: continuous with cricothyroid membrane
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What is Broyle’s Ligament? What is its significance
Broyle’s Ligament
= Ligament connecting the anterior commissure to the thyroid cartilage
= Lacks perichondrium, so provides a point of invasion into the thyroid cartilage and pre-epiglottic space
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What is the petiole?
Triangular point at the base of the epiglottis where the thyroepiglottic ligament attaches to the thyroid cartilage
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What is the angulation of the thyroid prominence?
Male - 120 degrees
Female - 90 degrees
√What are the attachments of the superior, middle, and inferior constrictor muscles?
SUPERIOR:
1. Skull base
2. Pterygomandibular raphe
3. Medial pterygoid plate
4. Mylohyoid line
5. Base of tongue
“Sue Me Punch My Base of tongue”
MIDDLE:
1. Stylohyoid ligament
2. Hyoid bone
INFERIOR:
1. Thyroid cartilage
2. Cricoid cartilage
Describe the boundaries, lymphatic drainage, and contents of the pre-epiglottic space. What is its significance? What is another term for the space?
Aka. Boyer’s space
Superior: Hyoid bone, Hyoepiglottic ligament, and valleculae mucosa
Anterior: Thyrohyroid membrane and thyroid cartilage
Posterior: (Infra-hyoid) Epiglottal cartilage and the thyroepiglottic ligament (posterior-inferior interface between pre-epiglottic space and paraglottic spaces)
Inferior: Lower portion of the hyoid bone until mid-portion of thyroid cartilage; thyroepiglottic ligament
Lateral: Open - continuous with the paraglottic spaces
Lymphatic Drainage: through thyrohyoid membrane and spread bilaterally to LN in Level II & III
Contents: Fat and areolar tissue
Significance:
- Involvement of the PES allows for spread into the paraglottic space (involvement of either entity upstages to T3)
- Easily invaded by an infrahyoid epiglottis mass due to fenestrations in the epiglottic cartilage
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Describe the boundaries of the para-glottic space. What is its significance? What is another term for the space?
Aka. Tucker’s space
Space that is lateral to the true&false cords and extends laterally to the thyroid cartilage (space between the thyroarytenoid muscle and cartilage)
Borders:
- Medial (from superior to inferior): Quadrangular membrane, Laryngeal ventricle, Conus Elasticus (lateral portion of the cricothyroid membrane, that comes up and forms the vocalis muscle)
- Lateral: Thyroid cartilage (anterior), Mucosa of medial wall of the piriform sinus (posterior)
- Inferolateral: Cricothyroid membrane
- Superior/anterior: Continuous with PES
- Posterior: Pyriform sinus
Significance: Extension into the PGS allows for spread into any of the 3 subsites of the larynx
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What are the borders of the pyriform sinus?
- Medial: aryepiglottic cords
- Lateral: thyroid cartilage
- Posterior: low pharyngeal wall
Discuss the normal length of the vocal folds in infants, adult males and females
Infant = 7-8mm
Male = 17-23mm
Female = 12-17mm
What are the layers of the vocal fold from superficial to deep?
- Epithelium (stratified squamous)
- Superficial lamina propria
- Intermediate lamina propria
- Deep lamina propria
- Vocalis muscle
*ILP + DLP = Vocal ligament
What are the cell types of each of the layers of the vocal folds?
- Epithelium (stratified squamous)
- Mucosal layer
- Stratified non-keratinizing squamous epithelium - Superficial lamina propria
- Few fibroblasts
- Scant elastic and collagen fibers - Intermediate lamina propria
- Mainly elastic fibers, few fibroblasts - Deep lamina propria
- Collagenous fibers, fibroblasts - Vocalis muscle
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Describe Reinke’s space and list two points of significance for this space
Reinke’s space = Space between the vocal ligament and the epithelium of the vocal fold (ie. the SLP).
Clinical Significance:
1. Fluid can accumulate here causing Reinke’s edema
2. Gelatinous matrix within Reinke’s space allows for vocal folds to vibrate freely
Differentiate the laryngeal vestibule from the laryngeal ventricle
Vestibule = The laryngeal inlet to the superior or surface of the false vocal cords
Ventricle = The pouch between the true and false vocal cords
√List the 6 different extrinsic laryngeal elevators and their innervations
Suprahyoid musculature (5):
1. Anterior belly of digastric (V3)
2. Posterior belly of digastric (VII)
3. Mylohyoid (V3)
4. Geniohyoid (C1 carried by hypoglossal nerve)
5. Stylohyoid (VII)
Sylopharyngeal (IX)
√List the 4 different extrinsic laryngeal depressors and their innervations
Strap muscles (4)
1. Omohyoid (Ansa, C1-3)
2. Sternohyoid (Ansa, C1-3)
3. Sternothyroid (Ansa, C1-3)
4. Thyrohyoid (Ansa, C1 only)
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What are the 4 “airway dilator” muscles?
- Genioglossus/Geniohyoid
- Anterior digastric
- Dilator naris
- Posterior cricoarytenoid
“Dilate a GAP”
√List the intrinsic laryngeal muscles, their innervations, and their functions.
Which muscles are located within the conus elasticus? Which for quadrangular membrane?
p4 paired muscles, 1 unpaired muscle
Abductor (only 1):
1. Posterior Cricoarytenoid (x2 paired)
- Innervation: RLN
- Function: only vocal fold abductor
Adductor (4)
1. Cricothyroid (x2)
- Innervation: External branch of SLN
- Function: Adducts, Lengths and tautens vocal folds to increase pitch
- Lateral Cricoarytenoid (x2)
- Innervation: RLN
- Function: Adducts vocal folds - Interarytenoid (x1 unpaired)
- Sometimes referred to as transverse and oblique arytenoids
- Innervation: RLN (bilateral innervation as it’s an unpaired muscle)
- Function: Adducts vocal folds - Thyroarytenoid (x2)
- aka. vocalis
- Innervation: RLN
- Function: Adducts, Shortens and relaxes vocal folds to lower pitch
WITHIN THE CONUS ELASTICUS:
1. Thyroaytenoid (vocalis)
2. Interarytenoid
3. Lateral cricoarytenoid
4. Posterior cricoarytenoid
WITHIN THE QUADRANGULAR MEMBRANE:
1. Thyroepiglottic (widen laryngeal inlet)
2. Aryepiglottic (close laryngeal inlet)
3. Thyroarytenoid
4. Cricothyroid
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Laryngology anatomy
List 2 functions of the superior laryngeal nerve
- Innervation to the cricothyroid
- Sensory mucosal innervation superior to the true vocal folds
Where do the recurrent laryngeal nerve and internal branch of the superior laryngeal nerve enter the larynx?
RLN - Cricothyroid joint
Internal branch of SLN - Pierces the thyrohyoid membrane along within the superior laryngeal artery
√List the laryngeal cartilages
Three paired cartilages:
1. Arytenoid
2. Corniculate (sits like a “crown” on the arytenoids)
3. Cuneiform (floats in AE folds to add structural support)
Three unpaired cartilages:
1. Thyroid cartilage
2. Cricoid cartilage
3. Epiglottis
Variable presence:
1. Triticeal cartilage: small cartilage located within the lateral aspect of the thyrohyoid membrane, that may be bilateral, unilateral or absent. It is considered a lateral anatomical variant
Describe the motor and sensory innervation to the larynx
Superior Laryngeal Nerve:
1. External Branch: Motor to cricothyroid muscle
2. Internal Branch: Sensation to supraglottis and glottis. Pierces through thyrohyoid membrane
Recurrent Laryngeal nerve:
a. Motor to all other intrinsic muscles of the larynx except the cricothyroid muscle
b. Sensation to the subglottis and glottis
c. Goes through the cricothyroid joint.
Nerve of Galen:
- Anastomosis between SLN and RLN at glottis
Describe the pathway and innervation of the superior laryngeal nerve
Branches from CNX at lower aspect of the nodose ganglion (sensory) ~36mm from jugular foramen/nucleus ambiguous (motor), divides ICA and IJV with CNXII
Internal branch:
- Sensory, enters larynx with superior laryngeal artery off of superior thyroid artery through thyrohyoid membrane, supplies false fold, epiglottis, pyriform sinus, Glottis and partly subglottis
External branch:
- Motor, supplies cricothyroid
- Runs on the posterior surface of the sternohyoid
What is Artenia Lusoria? 3
Right non-recurrent laryngeal nerve
Aberrant right subclavian (retroesophageal)
Absent innominate
What is the incidence of right and left NON-recurrent RLNs? What are they associated with?
Right: 0.5% (1/200) associated with aberrant subclavian artery (artenia lusoria)
Left: 0.004% (1/250000) associated with situs inversus and dextrocardia
What are the layers of the vocal folds? Describe 3 different anatomical schemes to describe this.
5 layer scheme:
1. Squamous epithelium
2. Superficial lamina propria
3. Intermediate lamina propria
4. Deep lamina propria
5. Vocalis (thyroarytenoid)
Vocal ligament = ILP + DLP
3 layer scheme:
1. Mucosa = epithelium
– separated by Reinke’s space = SLP
2. Vocal ligament = ILP + DLP
3. Muscle = Vocalis
2 layer scheme (cover + body):
1. Cover = Epithelium + SLP + ILP
2. Body = DLP + Vocalis
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Describe the Hirano’s Cover-Body theory of the larynx
Cover = Epithelium + SLP
Transition zone = ILP + DLP
Body = Vocalis
The contrasting masses and physical properties of the cover and body causes them to move at different rates which create vibration and sound at the level of the vocal folds.
Vocal adjustments are regulated by changing the mechanical and vibratory properties of both.
Describe the Myoelastic Aerodynamic Theory of phonation. What was the old theory of phonation?
Previous theory “Neurochronaxic Hypothesis” where vocal fold movement was caused by thyrhmic impulses in the nerves of the larynx. However, this was not reasonable given the frequency of vibration that was needed.
Myoelastic Aerodynamic Theory:
1. Inhalation = air enters lungs
2. Glottic closure = Voluntary adduction of the cords by the intrinsic laryngeal musculature
3. Expiratory force = Diaphragm contracts for expiration
4. Increased subglottic pressure builds below the glottis with expiration
5. Pressure opens the glottis from inferior and moves superiorly
6. Vocal folds spring back to midline (which involves 2 components)
i/ Aerodynamic component: Due to negative pressure from Bernouilli’s principle, as air rushes through a narrowed glottis, the vocal folds pull together
ii/ Myoelastic component: Elastic recoil occurs from the vocal folds
7. Cycle repeats, and this forms the mucosal wave
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What is the travelling wave theory in voice production?
- Vocal fold vibration occurs in lateral & vertical planes
- Sequence: lower margin separates, elliptical volume of air formed in subglottal vault, glottal puff is released as upper margin separates, lower margin returns to midline, then upper margin does also
- This occurs anterior then posterior
- Phase delay (vertical phase difference) - the time delay between closure of upper and lower vocal fold margins - should normally be 1/3-1/2 of the vibratory cycle
What two forces are responsible for bringing the vocal folds back to midline during phonation?
According to myoelastic aerodynamic theory of phonation:
1. Bernouilli effect
2. Elastic recoil
What are the functions of the larynx? List 4
- Phonation
- Airway protection
- Respiration (breathing)
- Valsalva (generating intrathoracic pressure)
Describe the 5 fundamental components of speech production
- Respiration/Generator = Lungs produce airflow
- Phonation = generation of sound by vocal fold vibration
- Articulation = shaping of the voice into words
- Resonance = induction of vibration of the rest of the vocal tract (chest, pharynx, head) to modulate laryngeal output with selective amplification of certain component frequencies
- Prosody = Intonation
What are the 5 requirements for normal phonation?
- Adequate breath support /expiratory force
- Regular approximation of the vocal folds
- Favourable vibratory properties
- Favourable vocal fold shape
- Control of length and tension of the vocal folds
What are the 3 essential parameters of normal vocal fold vibration and voice production?
A. Posterior commissure closure & glottal gap
- Interarytenoid & lateral cricoarytenoid muscles both close and oppose the vocal folds
B. Symmetric thyroarytenoid stiffness
- Increase pitch and resistance
- Cricothyroid antagonizes the thyroarytenoid while also thinning and lengthening the vocal fold
- This increases tension and pitch while decreasing the area of contact
C. Equal vertical height position of the vocal folds
What are formants?
Formants are specific harmonic frequencies that are amplified by resonance through the vocal tract.
In phonetics, formants are the prominent frequency bands that are used to determine the phonetic quality of a vowel (typically the first 2 formants are enough to identify a vowel).
Each vowel sound production usually has 4-5 formants:
1. First 2 are responsible for vowel recognition
2. 3-5 color the sound and provide timbre
3. Voice professionals can bring formants 3-5 closer together to form a “ring”, termed the singer’s formant
Define Dysphonia. How does it differentiate with hoarseness?
Dysphonia = Altered vocal quality, pitch, loudness, or vocal effort that impairs communication as assessed by a clinician and/or affects quality of life
Hoarseness is a symptom of altered voice quality reported by patients
What are 10 key questions to ask when taking a vocal history?
- OPQRST - onset, provoking and resolution factors, quality, severity, timing/duration
- Dysphagia, odynophagia, globus
- Dyspnea, stridor
- Dysphonia (GRBAS - grade, roughness, breathiness, aesthenia, straining)
- Constitutional symptoms
- History of voice abuse
- History of professional voice use - for singers, their level of training, amplification, practice schedule, style, amount of time practice/performing, changes in vocal range, environmental changes, air travel (dry air)
- Voice use demands (occupation, social voice use, kids/pets/large friend groups)
- Smoking and alcohol consumption, caffeine water intake in day
- Symptoms of GERD
- Psychosomatic stressors
- Recent surgery or intubation
- Past laryngeal procedures
- Autoimmune conditions
- Medications
List 3 subjective patient voice evaluation scales that can be used for vocal assessment? List 4 additional voice quality assessment scales?
- Voice handicap index (VHI)
- Voice related QOL (V-RQOL)
- Voice symptom scale (VSS)
- Reflux symptom index (RSI)
- Speech Handicap index (used in patients with H/N cancer)
- Cough severity index
- Dyspnea index
List 2 rating scales for auditory perceptual assessment of voice quality.
- GRBAS: Grade, Roughness, Breathiness, Asthenia, Strain
- CAPE-V: Consensus Auditory Perceptual Evaluation of Voice
Describe the GRBAS scale, and how it is scored?
Grade (overall)
Roughness
Breathiness
Asthenia (weakness)
Strain
Each is graded from a score of 0-3 for a total score of 15
Describe the CAPE-V assessment. What does it stand for, how does it work, and what are the 6 standard sentences?
CAPE-V = Consensus Auditory Perceptual Evaluation for Vocal assessment
- Rating tool based on 6 core parameters: overall severity, roughness, breathiness, strain, pitch, loudness. This is marked on a 10cm line
- Scored based on 2 sustained vowels, 6 standard sentences, and at least 20 seconds of natural running speech
6 Standard Sentences “All WHEMP”
1. “The blue spot is on the key again” – contains all the english vowel sounds
2. “We were away a year ago” – All voiced (W) (Adductor SD)
3. “How hard did he hit him?” – Soft onsets (H) (Abductor SD)
4. “We eat eggs every easter” – Hard glottal onsets (E) (Adductor SD)
5. “My mamma makes lemon muffins” – Nasal sounds (M)
6. “Peter will keep at the peak” – Voiceless plosives (P) (Abductor SD)
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What are the 7 different types of phonemes in the English langued? How many total phonemes are there in the english language?
FAV People are on SNL
Total of 44 phonemes in the English language, grouped in 7 different types.
- Fricatives (aka. Sibilants)
- Sounds produced by frication (air turbulence)
- Eg. “S” “Sh” - Affricates
- Stop sound + fricative
- Eg. Ch = t+sh - Vowels
- Speech sound without any stricture in the vocal tract (a, e, i, o, u, sometimes y) - Semivowels
- Phonetically similar to a vowel but forms the boundary of a syllable rather than the nucleus
- Eg. W in “west”, Y in “Yes” - Stops (aka. Plosives)
- Sounds that stop and then release oral airflow
- Eg. “P”, “B” - Liquids
- Voiced continuant sounds made when the tongue partially closes the mouth, producing vowel like sounds
- Eg. “L”, “R” - Nasals
- Sounds produced by occluding mouth and directing airflow through the nose
- Eg. “M” “N” “Ng” are the only nasal consonants
What is the Rainbow passage and how is it used?
Phonetically balanced standardized text. Used to facilitate objective voice analysis.
What are the 4 types of resonance in speech?
Hypernasal, Hyponasal, Cul-de-sac, Mixed
Hypernasal = Too much sound energy in nasal cavity during phonation
Hyponasal = Too little sound energy in nasal cavity during phonation
Cul-de-sac = Sound resonates in a cavity but is “trapped” and cannot exit due to obstruction
Mixed = Combination of the above
Describe the elements of physical examination for evaluation of a voice complaint. Group them into 3 categories of examination. List 10 different examination points
A. Auditory Perceptual Assessment
1. GRBAS
2. CAPE-V
3. Resonance (hypernasal, hyponasal, cul-de-sac)
4. Prosody (speech rate, intonation, stress patterns)
B. VIsual Perceptual Assessment
1. General Appearance
2. Posture, MSK tension
3. Neurologic signs (e.g. tremor, wasting, slowness, dyscoordination, focal dystonias, etc.)
4. Syndromic Features
C. Tactile Perceptual Assessment
1. Palpation of laryngeal neck muscles
2. Mobility of larynx and cartilages
Describe the 6 elements of aerodynamic analysis of voice (ie. airflow). Explain each elements’ definition, how its measured, and what is considered normal. What do their abnormal values tend to indicate?
Components:
1. Intraoral air pressure (aka. Subglottic air pressure)
2. Phonation threshold pressure
3. Airflow
4. Laryngeal airway resistance
5. Maximal phonation time
6. Velopharyngeal function
Intraoral pressure:
- Measured during a stop (aka. plosives), usually “p”
- Estimate for subglottal air pressure, which requires a direct tracheal puncture to actually measure
- Abnormal values may indicate lack of driving pressure, VPI, increased vocal fold mass or stiffness
- Normal = ~7cm H2O
Phonation Threshold Pressure (PTP):
- Defined as the minimum subglottal pressure necessary to initiate vocal fold vibration
- May correspond to symptoms of increased vocal effort
- Can change with dehydration, vocal fatigue, voice warm-ups
- Normal ~3cm H2O, 8cmH2O for high pitches (range 6-8)
Airflow:
- Airflow through glottis and subglottic pressure measured, which determines the glottic resistance (Ohm’s law)
- Vocal efficiency = acoustic power/subglottic power (pressure)
- Airflow voice measures include MPT and phonation threshold pressure; measurements can be obtained with a phonatory aerodynamic system (PAS) sold by pentax.
- Measured in volume (mL or L) per unit of time
- Increased with poor glottal closure (e.g. VFI or paresis) and can be decreased with vocal fold hyperfunction
- Normal = ~100ml/sec
Laryngeal Airway Resistance:
- Defined as ratio of translaryngeal air pressure to airflow
- High pressure + low airflow = high resistance
- Higher laryngeal resistance can indicate increased vocal intensity, longer closed phase, or higher force of glottal closure
- Normal ~27-51cm H2O/L/s (lower for men, higher for women)
Maximal Phonation Time:
- Normal values: Women = 15-25s, Men = 25-35s
- MPT of ≤ 7 seconds indicates poor glottic efficiency
Velopharyngeal Function:
- Nasometry can measure nasalance (ratio of nasal sound energy to total sound energy)
- Hypernasal = Nasalance > 25-33% for non-nasal passages
- Hyponasal = Nasalance < 50% for nasal passages
In Speech Aerodynamic (Airflow) studies, give the normal values for transglottal airflow rate, glottal resistance, and subglottal pressure
- Transglottal airflow rate = 100cc/sec
- Glottal resistance = 30-50 cm H2O
- Subglottal pressure = 6-8 cm H2O
Describe the 5 elements of acoustic analysis. What are the normal values?
Elements:
1. Fundamental Frequency
2. Intensity
3. Range
4. Perturbation Measures
5. Spectral/Cepstral Assessment
Fundamental Frequency:
- Men 100-125Hz, Women 190-225Hz (approx 100Hz more)
- Voice is a complex group of waves. Any frequencies above the Fundamental Frequency (F0) are multiples of F0 called harmonics.
- Maximum frequency range = 2.5-3 octaves
Intensity:
- Measured in dB SPL (Sound Pressure Level)
- Average = 70dB SPL (60-110)
- Acoustic correlate to loudness
- Implications of abnormal values: Parkinson’s, VF motion impairments, Difficulty speaking quietly in scarring of VF lesions.
Range:
- Minimum and maximum frequencies an individual can produce
- Normal 80-1100Hz
Perturbation Measures:
- Measures of variability in the sound wave / noise
- Jitter = Cycle to cycle variation in frequency. Normal ≤0.4%
- Shimmer = Cycle to cycle variation in amplitude. Normal ≤0.5dB
- Harmonic-to-Noise Ratio = 10xlog10(harmonic%/noise%) - quantifies the degree of hoarseness, normal > 7dB. Increasing jitter and shimmer results in increased hoarseness
- Perturbation analysis cannot be done if they are markedly dysphonic and cannot set a fundamental frequency
Spectral/Cepstral Assessment:
- Spectrum = Displays frequency vs. amplitude
- Spectral tilt = indicates whether low or high frequencies dominate the spectrum
- Increased spectral tilt (ie. less high frequency information) is associated with a breathy voice
- Cepstrum = Spectrum of a spectrum
- Cepstral Peak Prominence (CPP) = Measure of signal periodicity that corresponds to regularity of harmonic peaks
- Higher CPP = better voice quality and vice versa
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Define phonation quotient
Maximum phonation time divided by patient’s vital capacity
What are the 4 vocal registers, from lowest to highest?
- Vocal fry
- Modal
- Falsetto
- Whistle
What is the human vocal fundamental frequency?
- Men ~125Hz (increases with age)
- Women ~225Hz (decreases with age)
- Children ~250-300Hz
- Vocal range = 80-1100Hz
What are four objective voice measurement tools?
- Glottography
- Video stroboscopy
- Air flow measures
- Acoustic measures
What is Glottography, and what are the types? What are the elements for measurement?
What is Electroglottography? How do you measure it and how do you interpret the results?
Method to measure / monitor vibrations of the vocal folds
Glottography types:
1. Photoglottography (PGG): Measures degree of light passage through vocal folds (change in light transillumination)
2. Electroglottography (EGG): Measures degree of electrical conduction across vocal cords during closure (change in electrical conduction)
Measurements:
1. Speed Quotient = Ratio of time vocal folds are opening to time vocal folds are closing
2. Shift Quotient = Ratio of (time to peak VF opening) to (Duration of VF opening)
3. Open Quotient = Proportion of time VFs are opwn during cycle (normal is 2/3)
4. Closed Quotient = Proportion of time VFs are closed during cycle (normal is 1/3)
Electroglottography (EGG) = Transcutaneous measurement of the contact time of the vocal folds. Measured using ‘conductance’ of the electric signal from the vocal folds to the electrodes.
- Conductance INCREASES when Vocal folds contacts = positive EGG slope tracing
- Conductance DECREASES when Vocal folds separate = negative EGG slope tracing
Results show the opening and closing rates of the vocal folds. The results are relative (not absolute) and do not measure glottal area or closure. The waveform shape just describes the pattern of VF vibration.
Purpose of the results is to allow isolated measurement of vocal fold fundamental frequency and vibration without the influence of surrounding resonant structures or shaping (ie. formants).
Kevan page 11
What are the 9 elements measured on stroboscopy?
MRS FAAC VP
F-CAMPS
- Mucosal wave (moves in a vertical and horizontal direction - cover over body - starting inferior to superior)
- Regularity/Periodicity
- Degree to which the time it takes to complete one phonatory cycle is similar to the time it takes to complete the next cycle
- Best assessed in the locked phase. Regular = image appears static. Irregular = image quivers
- Causes of irregularity: VF paresis, lesion, flaccidity, unsteady tonus (SD, neuromuscular disease), inconsistent force (e.g. functional pulmonary disease)
- Aperiodicity also increases with age - Symmetry: extent to which VF mirrors each other during vibration
- Fundamental Frequency
- Amplitude: horizontal excursion from midline during vibration, which is a measure of pliability/stiffness
- Normal = one-third to half of the width of the vocal fold
- Amplitude = 1/frequency - Adynamic Segments
- Glottic Closure patterns: indicates the degree and pattern of VF contact at the most closed instant of the vibratory cycle (using the most comfortable pitch and loudness)
- Vertical Closure level
- Normal = VF meet at the same vertical plane
- Off-plane closure = neuromuscular differences between folds (paralysis, paresis), laryngeal trauma, or surgery - Phase Closure: Open phase vs. Closed phase dominant
What is phase closure and how is it defined? What is considered normal phase closure? How does it change with increasing frequency?
Phase closure = The amount of time the true vocal folds spend open vs closed during phonation.
Normal phase closure
- Open = 2/3 of vibratory cycle
- Closed = 1/3 of vibratory cycle
More time is spent closed at higher frequencies.
If more time is spent in open phase = open phase dominant
If more time is spent in closed phase = closed phase dominant
What are 10 assessment tasks using stroboscopy?
- Sustained “ee” at normal pitch, normal loudness
- Quiet “ee”
- Loud “ee”
- Pitch glide from mid-range to high (CT muscle)
- Sustaining the high note (CT muscle)
- PItch glide from mid-range to low
- Sustaining the low note
- Phonation on inhalation
- “Ee” at NPNL with locked phase
- Physical manipulation of the larynx or trial therapy (unloading) also possible
- Monitor the patient’s voice so that all of the necessary information is recorded
- Most vibratory parameters are rated from “ee” at normal pitch, normal loudness
What are 7 types of glottic closure patterns on stroboscopy? When are they typically seen?
- Complete
- Posterior gap (can be normal in some women, seen in MTD)
- Anterior gap (can be normal in some men and older women, seen in MTD)
- Spindle (presbylarynx)
- Hourglass (bilateral lesions; e.g. vocal fold nodules; unilateral lesion with contralateral reactive lesion; glottic lesions)
- Asymmetric/irregular
- Incomplete (gap extends along entire length of VF, usually due to impairment, scar, MTD/aphonia)
Kevan Page 20
Vancouver Pg 172
Describe Narrow Band Imaging. How does it work? What 2 scenarios are they useful to be used in?
Uses blue light (415nm, green 540nm), which has a shorter wavelength and better absorbed by hemoglobin, to assess for mucosal and vascular irregularities (high Hgb structures become more apparent and well visualized)
Clinical implications:
1. Highlights submucosal vascular patterns under leukoplakia, improving identification of suspicious areas that may need biopsy
2. Aids with RRP diagnosis
What is the Edrophonium Test?
AKA Tensilon test
AKA Acetylcholinesterase inhibitor test
Assess for vocal fatigue recovery after administration of an Achase inhibitor (prevents ACh breakdown)
Patients with Myasthenia Gravis and vocal manifestations will show transient vocal improvement
What are the muscles that are targeted/sampled for laryngeal EMG?
- Thyroarytenoid/vocalis = adduction
- Posterior cricoarytenoid = abduction
- Cricothyroid = SLN activity
List 7 indications for using Laryngeal EMG
- Assess RLN recovery post vocal fold paralysis
- Decision for early thyroplasty in unilateral VFP
- Decision for lateralizing/destructive procedures in bilateral VFP - Differentiate between vagal (RLN+SLN) injury vs. isolated RLN injury
- Distinguish paralysis vs. fixation
- Guide/landmark botox injections
- Intraoperative monitoring
- Distinguish synkinesis
- Diagnose neurologic disorders (e.g. decreased laryngeal recruitment over time with myasthenia gravis)
When is the optimal timing for laryngeal EMG?
Abnormal laryngeal EMG findings develop 2-3 weeks after injury, as it takes time for denervation to occur.
If reinnervation occurs, polyphasic reinnervation potentials start 6-12 weeks after injury.
Therefore initial EMG at 6-12 weeks after neural injury is most helpful time for prognostication (but must be at least 3 weeks)
What 3 types of activity can be recorded with laryngeal EMG? What is considered good vs. bad prognosis? How does laryngeal EMG help predict recovery?
Types of activity recorded:
1. On insertion
2. Spontaneous activity at rest
3. Volitional (with speaking
GOOD Prognosis:
- Polyphasic action potentials
BAD Prognosis:
- Sharp waves
- Fibrillation potentials
- Synkinesis (e.g. activation of TA with sniff, which would suggest adduction with nasal inhlaation)
Laryngeal EMG is GOOD at predicting BAD recovery, but BAD at predicting GOOD recovery
- Presence of fibrillation potentials or sharp waves at 3 weeks out makes it unlikely that there will be recovery
- However, the presence of polyphasic action potentials doesn’t predict good recovery
- Patients may develop synkinesis (e.g. aberrange regrowth of PCA fibers to the thyroarytenoid –> causing antagonistic activity)
Kevan Page 11/12
What is laryngeal synkinesis?
Aberrant reinnervation of the laryngeal musculature.
For example, where fibers to the PCA instead innervate the TA, resulting in no movement of the vocal folds due to simultaneous antagonistic action
What mechanisms alter vocal pitch? List 5 different ways.
Changes in:
- Vocal fold length
- VF tension
- VF mass
- Subglottic air pressure
- Vibratory speed
What are 3 elements/contributors that can increase fundamental frequency of phonation?
- Cricothyroid muscle contraction
- Increase in subglottic pressure (minor factor)
- Can be increased by shortening the vibratory surface, increasing tension of decreasing the mass of the VF
What are 3 factors that affect the amplitude of vocal fold vibration?
- Pliability of the vocal fold tissues
- Subglottic pressure (decreased pressure = decreased amplitude)
- Force of medial compression (has to increase along with subglottic pressure to increase amplitude)
Most important physiologic mechanism affecting vocal amplitude is subglottic pressure!
See Alex’s Questions from May 12
What can cause increased or decreased mucosal wave?
See Alex’s Questions from May 12
List 6 examples of pathologies that lower fundamental frequencies. What do they have in common?
Anything that does the following can lower fundamental frequency:
1. Increase vocal fold mass
2. Lengths or relaxes the vocal folds
Pathologies:
1. VF polyp
2. Reinke’s edema
3. Tumor
4. Aging in women
5. Puberty
6. Nodules
7. Hypothyroidism
NPP HART
List 4 examples of pathologies that raise fundamental frequency. What do they have in common?
Anything that shortens or tenses the vocal folds can raise fundamental frequency.
Pathologies;
1. Anterior glottic web (shorter cord overall but over the same amount of tension across the vocal cord, therefore gives you a net increase in tension)
2. Muscle tension dysphonia
3. Parkinson’s disease
4. Aging in men
5. Tension-producing VF masses (e.g. Sulcus)
6. Puberphonia
MS PAPA
Define Diplophonia
The production of 2 simulatneous fundamental frequencies, caused by asymmetric stiffness of the vocal folds (divergent travelling wave velocities)
Plica ventricularis = False VF phonation
List 4 advantages and 2 disadvantages of rigid endoscopy.
List 5 advantages and 4 disadvantages of flexible endoscopy.
Advantages of RIGID:
1. Superior optics (higher resolution and contrast)
2. Superior light (brighter, clearer pictures)
3. Superior resolution and magnification
4. Avoids wide angle distortion compared to flexible endoscopy
5. Can perform interventions through scope
6. Simple exam, does not usually require topical anesthetic
Disadvantages of RIGID:
1. Active phonation limited to sustained vowels
2. Requires extended neck, protruded tongue (non-anatomical positioning)
3. Size of glottic gap may appear exaggerated
4. Mobility of arytenoids may not be accurately assessed
5. Disorders more evident in connected speech rather than sustained vowels are not well documented (e.g. MTD, SD)
Note: 90 degree endoscope to reduce neck extension may help improve some of these factors
Advantages of FLEXIBLE:
1. Patient tolerance
2. Patient anatomy may preclude endoscopic visualization
3. Allows for superior functional examination (e.g. advanced speech sets, singing)
4. Can also assess nasopharynx and velopharynx
5. Can assess multiple angles
6. Can do esophagoscopy and tracheoscopy as well
7. Glottic gap more accurately assessed
-Preferred if there is a question of movement rather than structure - e.g. SD, VFI
Disadvantages of FLEXIBLE:
1. Can’t manipulate airway/perform procedures
2. Wide angle distortion (fish-eye lens)
3. Honey comb effect of fiberoptic fibers (trade-off between adequate focus and light fiber mismatch)
4. Worse optics, light transport, and magnification
5. Feels more uncomfortable and “invasive” to patient than the rigid
6. Risk of nosebleed, adverse reactions to anesthetic, vasovagal reactions
- a lot of optics issues can be resolved with newer “chip-tip/distal chip” scopes
List the evaluated features and tasks assessed during continuous light endoscopy.
VC SPASM:
V - Vascularity (or risk of hemorrhage)
C - Cords edges
S - Structure (overall)
P - Change in Position (height)
A - Arytenoids movement and position
S - Supraglottis/subglottis activity
M - Mucosa/mucous color and quantity
Tasks:
1. Deep breathing
2. Easy breathing (rest)
3. Sniff
4. Cough (easy cough and throat clear)
5. Long “EEE” at a comfortable pitch and volume
6. Short “EEE’s”
7. Laryngeal diadochokinesis: consists of rapid repetitions of “ee” or “hee” with glottal stops between each
8. Repetitions of short “ee” followed by a quick sniff through the nose
What is a stroboscope?
An instrument for determining the speed of cyclic motion (vibration) that causes the motion to appear slowed or stopped
- Assessed the status of the cover (tethering)
- Determines open-closed and phase ratios
Describe the phases of stroboscopy
Strobe light can be emitted in 2 ways: synchronized or unsynchronized
- Synchronized (locked)
- Strobe light is at the same frequency as phonation (light flashes at same rate equal to frequency, giving illusion of immobility)
- Ideally the vocal folds will appear to stand completely still as the light will illuminate at the same portion of the cycle
- Movement of the vocal folds suggest aperiodicity - Desynchronized (running)
- When the light flashes slightly faster or slower than the frequency of the VF vibration, creating the illusion of motion
- Strobe light is offset by ±1 to 2Hz to the phonatory pitch, so each flash will illuminate a dfiferent phase
- Will give the appearance of slow motion
- More commonly used clinically
What are the limitations of stroboscopy? List 2.
- Cannot effectively perform stroboscopy with a markedly dysphonic voice without any periodicity - waveform must be relatively periodic to track fundamental frequency and trigger strobe
- Shows sampling of vocal fold movements, but not every glottic cycle
What is Talbot’s Law?
Talbot’s Law: The retina is only able to resolve around 5 images per second (0.2 seconds per exposure). Thus, sequential images produced at an interval of < 0.2seconds per exposure produce the illusion of a continuous appearance.
- Theory behind why stroboscopy gives the appearance of continuous motion
- Some studies disprove this theory and state this is not actually how stroboscopy works
Discuss the Lombard effect
The involuntary tendency of speakers to increase their vocal effort when speaking in loud noise to enhance the audibility of their own voice
What are 7 objective tests that can be ordered or done to further evaluate the larynx?
- Glottography - Photo or Electroglottography
- Modified Barium Swallow/Video Fluoroscopic Swallowing study (MBS/VFSS) - assess phases of swallowing across different consistencies
- Flexible Endoscopic Evaluation of Swallowing (FEES)
- Laryngeal EMG
- Flexible Nasolaryngoscopy
- Video Stroboscopy
- Narrow Band Imaging
- Edrophonium (Acetylcholinesterase inhibitor test)
What are the boundaries of Joll’s space?
Lateral: Upper lobe of thyroid and superior thyroid artery
Medial: Midline
Superior: Attachment of sternothyroid to thyroid cartilage
What are the AAO Dysphonia Guidelines strong recommendations?
- Do not prescribe PPI/steroid/antibiotics prior to laryngoscopy
- All patients should be offered SLP referral
- All dysphonia > 4 weeks require laryngoscopy
What are high risk features of dysphonia? 6
- Recent H/N or chest surgery
- Increasing WOB or SOB
- Associated neck masses
- Recent intubation
- Smoking/tobacco use
- Professional voice user
Define glottal puff
The release of air as the upper margins of the vocal folds separate
Name 16 perceptual voice abnormalities
- Abnormally high fundamental frequency
- Abnormally low fundamental frequency
- Abnormally loud voice
- Abnormally soft voice
- Decreased smoothness
- Decreased intelligibility
- Hypernasality
- Hyponasality
- Hoarseness
- Harshness
- Diplophonia
- Tremorous
- Stridulous
- Breathy
- Arrest of phonation (vocal breaks)
- Aphonia
When is phonation on inhalation useful? 2 situations
- Unloading supraglottis in cases of supraglottic squeeze/MTD to better visualize glottis
- Better visualization of lesions on inferior glottis edge
