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Voice Disorders > Lecture 4 - 9/24 > Flashcards

Lecture 4 - 9/24 Flashcards

1
Q

Primary Function of the Larynx

A

To protect the airway -Mechanically blocks foreign objects & food -Forcefully expels aspirated material

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2
Q

Secondary Function of the Larynx

A

-To produce voice

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3
Q

Brief and unspecific anatomy of Larynx and surroundings…

A

Larynx is suspended from hyoid bone Supports the tongue root Attaches to strap muscles –The suprahyoid & infrahyoid muscles – Elevate & lower larynx

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4
Q

KNOW THIS ANATOMY: (11)

A

Pharynx Tongue Jaw Epiglottis Hyoid bone Thyroid cartilage Cricoid cartilage Cricothyroid joint (control pitch) Arytenoid cartilages Cricoarytenoid joint (adduct & abduct VFs) Trachea

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5
Q

Innervation of Instrinsic Laryngeal Musculature

A

Vagus Nerve – Recurrent Laryngeal Branch -Thyroarytenoid muscle -Lateral cricoarytenoid muscle -Posterior cricoarytenoid -Interarytenoid muscles Vagus Nerve – Superior Laryngeal Branch -Cricothyroid muscle

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6
Q

Actions of Laryngeal Muscles

A

Adduct VFs -Thyroarytenoid muscle – Rotates arytenoid cartilages inward -Lateral cricoarytenoid muscle – Rotates arytenoid cartilages medially -Interarytenoid muscles – Approximates arytenoid cartilages Abduct VFs -Posterior cricoarytenoid muscle – Rotates the arytenoid cartilages laterally Shorten & Soften VFs -Thyroarytenoid muscle – Draws arytenoid cartilages toward thyroid to shorten the VFs Lengthen & Stiffen VFs -Cricothyroid muscle – Pulls thyroid & cricoid cartilages together to stiffen & elongate VFs

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7
Q

Extrinsic Musculature and Innervation

A

Elevators:
Trigeminal Nerve, CN V
-Digastric muscle, anterior belly

Facial Nerve, CN VII

  • Digastric muscle, posterior belly
  • Stylohyoid muscle

Glossopharyngeal Nerve, CN IX
-Stylopharyngeaus

Hypoglossal Nerve CN, XII

  • Geniohyoid muscle
  • Thyrohyoid muscle

Depressors:
Hypoglossal Nerve, C-1, C-2, & C-3
-Sternohyoid muscle
-Omohyoid muscle
-Sternothyoid muscle
-Cricothyroid muscle

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8
Q

Newborn Larynx

A

Newborn
-Larynx rides high in throat
-VFs are 2.5 -3 mm long
-Laryngeal cartilage is pliable
-Arytenoid cartilage including vocal process makes up ½ of length of VF
-The membranous portion of VFs is thick & uniform
-No evidence of vocal ligament
*The layered structure of lamina propria is not
developed

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9
Q

Development of Larynx and VT

A

Age 1-2 years
Immature thin vocal ligament develops

Age 3
Myelination of laryngeal nerves is complete

Age 4
Vocal tract lengthens as larynx descends
-Posterior 1/3 of tongue descends into pharynx

By age 5
-Larynx has adult configuration

By age 13 -15
-Vocal ligament has developed
-The three layers of lamina propria have developed
-Mutation of larynx occurs & fundamental frequency drops
in both males & females
-Mean male F0 drops from 226 Hz to 120 Hz
-Mean female F0 drops from 230 to 220 Hz

20-21 years of age

  • Larynx reaches adult size
  • Male VFs are 17-21 mm
  • Female VFs are 11-15 mm

**Ossification of cartilage of larynx begins now & continues throughout entire life

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10
Q

Sex Specific Aging of Larynx

A

55+ Years Old

Males

  • Thickening of deep layer of lamina propria
  • Pitch elevates

Females

  • Thinning of lamina propria
  • Pitch lowers
  • Increased roughness
  • More vocal breakdowns
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11
Q

Aging of the Larynx (not sex specific)

A

80+ years old

Ossification of hyaline cartilage is almost complete
Heavier and less compliant

May have atrophy of the vocalis muscle

  • Bowing of membranous portion of VFs
  • Thinning of VF

May have stiffening of laryngeal joints

  • Difficulty positioning arytenoid cartilage of VFs
  • Glottal incompetency
  • Increase in jitter & shimmer
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12
Q

Small bumps in the aryepiglottic fold

A

Two corniculate cartilages

Two cuneiform/arytenoid cartilages

Vocal process

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13
Q

Vocal Folds

A

Move quickly – Close glottis (to protect airway)

Delicate – Should not be pressed tightly together for prolonged periods

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14
Q

Myoelastic Aerodynamic Theory of Voice Production

A

Muller, 1843; van den Berg 1958

  1. Air passes through a narrow glottis
  2. Membranous portions of VFs are sucked together by Bernoulli effect
  3. Cartilaginous portion remains in phonation neutral position
  4. Air pressure builds below closed glottis
  5. Subglottal pressure exceeds 3-4 cm of H2O
  6. Membranous portions are blown apart
  7. Lateral excursion of membranous tissue
  8. Elasticity of membranous tissue is sufficient to snap VFs together & close glottis to create first glottal pulse (producing quiet phonation)
  9. Frequency of vibration is determined by length in relation to stiffness & mass of VF
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15
Q

Manner of Onset of Phonation

A
  1. Abrupt onset
    - Full adduction of VFs (can lead to VF trauma)
  2. Delayed onset of phonation – Voiceless initiation /hu/
    - VFs partially abducted
  3. Simultaneous onset of phonation – Voiced /mhm/
    - VFs adducted to phonation neutral position
  4. Abrupt Onset – Effortful Phonation
    - Vocal folds hyperadducted
    - Large excursions of VFs & high impact stress
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16
Q

Abrupt Onset of Phonation

A
  • VFs fully adducted prior to onset of phonation
  • Hold breath momentarily before starting phonation
  • Feel strong burst at initiation
  • Unnecessarily large excursions of VFs
  • Possible phonotrauma
17
Q

Aphonic manner of phonation

A

Delayed onset of phonation – Exhalation initiated prior to adduction of VFs

  • Voiceless fricative
  • Whisper
  • Turbulent noise

Use in therapy – Decrease force of adduction of VFs & reduce effortful contact

18
Q

Simultaneous Onset of Phonation

A
  • Synchronized initiation of exhalation & adduction
  • Gentle vibration with full closure after several cycles
  • Effortless voicing
  • Goal of therapy
  • Synchronized adduction to phonation neutral position & initiation of exhalation
  • Maintain a small space (~ 3 mm) between arytenoid cartilages
  • Membranous portion vibrates in breath stream
19
Q

COORDINATION: INITIATION OF PHONATION

A

Produce a sustained /a/ & focus on the sensations in your upper airway – Link these sensations to physiology

Can you produce /a/ with a breathy onset, simultaneous onset (gentle), & an abrupt initiation of phonation?

20
Q

Multilayered Structure –
Cover, Transition, & Body

A

Cover – Flexible, medial edge of larynx – Generates mucosal wave

Squamous cell epithelium + gelatinous superficial layer of lamina propria

Transition – Intermediate + deep layer of lamina propria

Body – Stiffer thyroarytenoid muscle

21
Q

Epithelium

A

Ciliated columnar epithelium

Durable squamous cell epithelium

22
Q

Mucosal Wave

A

The cover is pliable, elastic, & not muscular, whereas body is stiffer & has active contractile properties that allow adjustment of stiffness

Primary striking zone midmembranous portion

Mucosal wave

  • Occurs in & travels through the loose cover
  • Generates harmonics & overtones in voice
  • Produces rich vocal quality

Changes in cover alter the mucosal wave

Changes in cover alter the voice

23
Q

Dynamic changes in prosody

A

Suprasegmental features

Modification of pitch, loudness, & timing

Mood

Intent of the message

24
Q

Pitch and F0

A

Pitch = Perceptual assessment

Fundamental frequency (Fo) = Rate of VF vibration

Fo ≠ Pitch

25
Q

Pitch Changes

A

Regulated by changes in VF length, stiffness, mass, & subglottal pressure

VF length is changed by contracting the cricothyroid muscles

VF is shortened and/or stiffened by contracting thyroarytenoid or vocalis muscle

Extrinsic muscles can raise or lower pitch

Intrinsic muscles can raise or lower pitch

(Does pitch match the patient’s age & gender?, Does the voice sound natural?, Focuses on resonance)

26
Q

pSub

A

Subglottal pressure is controlled by changing the pattern of respiratory muscle activation & VF resistance

-You automatically change your subglottal pressure when you change your loudness.

27
Q

The automatic coordination of subglottal pressure with sustained phonation depends on four things

A
  • Volume of air in lungs
  • Elastic recoil of chest wall
  • Activation of external intercostal & abdominal muscles
  • Coordination of respiration with medial compression (resistance) of VFs
28
Q

Vocal Intensity

A

Subglottal pressure (Ps ) pressure below VFs

Measured by how far a column of water would be moved

Ps of 2-3 cm of H2O = Quiet voice ~40 dB

Ps of 5-7 cm of H2O = Conversational loudness ~60 dB

Ps of 15-20 cm of H2O = Loud voice ~100 dB

Average range of intensity of a sentence ~ 30 dB

29
Q

Changes in Loudness

A

The duration of the closed phase of vibration increases with increased intensity

Sound pressure level increases when subglottic pressure increases

The medial compression of the VFs increases with loud sounds, and the larynx offers increased resistance to air flow

Result of excessive expiratory drive (subglottal pressure), medial compression, and stiffness of the VFs

Excessive loudness is a common risk factor/symptom

May lead to phonotrauma

30
Q

Quieter phonation – Confidential voice

A

Voice therapy focuses on reducing phonatory effort & decreasing the transglottal pressure differential

Exploit the effect of back pressure/inertance to maintain low effort during speech

31
Q

Quantifiable Measures: Fundamental frequency, Jitter, Shimmer, & Harmonics-to-noise Ratio

A

Fundamental frequency = Speed of vibration of VFs

Perturbation = Cycle-to-cycle variation in amplitude & frequency

Irregularity in VF vibration – Linked to laryngeal pathology, edema, stiffness, asynchrony, glottal closure

Noise in the signal = Ratio of harmonic sound to noise

Quantifiable Measures:

Pitch ≠ Fundamental Frequency

Mean fundamental frequency of infant distress cry

1-10 days = 384 Hz

4-6 weeks = 453 Hz

6-8 weeks = 495 Hz

6-9 months = 415 Hz

Mean fundamental frequency of sustained vowels

Mean male Fo = 130 Hz (range 85 & 155 Hz)

Mean female Fo = 220 Hz (165 to 255 Hz)

What does it mean if fundamental frequency is not within normal limits?

Pitch range

~ 35 semitones or 3 octaves

32
Q

Acoustic Analysis

A

Algorithms – Automatically calculate fundamental frequency, intensity, perturbation, voice range profiles

Threats to Reliability
-Variations in equipment
-Variations in protocol
-Environment (e.g., ambient noise)
-Internal variability (time since last meal, hydration levels,
caffeine intake, emotional state)
-Variation within & between sessions
-Automatic calculation of measures

Titze & Lang, 1993:

Unfortunately, algorithms used to automatically calculate fundamental frequency, shimmer, & jitter are unreliable when fundamental frequency variability exceeds 6% per cycle

If desired, can further analyze voice sample with hand measurements

33
Q

Objective Measures: Frequency Perturbation (Jitter)

A

Cycle-to-cycle variation in frequency

Collected on sustained vowels

Normative data supplied by instrument – Different instruments use slightly different formulas

34
Q

Quantifiable Measures: Amplitude Perturbation (Shimmer)

A

Amplitude perturbation (shimmer)

Cycle-to-cycle variation in amplitude

Data is collected on sustained vowels

Normative data supplied with instrument – Different instruments use slightly different formulas

35
Q

Quantifiable Measures: Harmonic-to-Noise Ratio

A

Sustained vowels

Compares harmonic energy to noise

Higher numbers = Greater periodic sound

Lower number = Greater aperiodic (noise) sound

Lower numbers = Greater roughness

Voice Disorders (8 decks)

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