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Flashcards in 7. Voice and Its Disorders Deck (72)
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1

Larynx (and VFs): Basic Principles

*Valve located at top of trachea
*Helps close entry into trachea so food, liquids, and particles do not enter lungs
*Houses VFs (opening bet. VFs is "glottis")
*VFs composed of layers: epithelium, the TA muscle, and lamina propria; Cover-body theory of phonation...
*Ventricular/false VFs lie above true VFs
*Aryepiglottic folds lie above ventricular folds; They separate the pharynx and laryngeal vestibule and help preserve airway
CN X: primary CN involved in laryngeal innervation (main branches: SLN and RLN)

2

Superior Laryngeal Nerve (SLN) and Recurrent Laryngeal Nerve (RLN)

SLN: internal branch: provides all sensory info to larynx; external branch: provides motor innervation to the cricothyroid muscle

RLN: supplies all motor innervation to interarytenoid, posterior cricoarytenoid, thyroarytenoid, and lateral cricoarytenoid muscles; Supplies all sensory info below VFs; If lesion to RLN, pt may experience diff. adducting VFs

3

Key Laryngeal Structures and Cartilages (9)

Hyoid bone
Epiglottis
Thyroid cartilage
Cricoid cartilage
Arytenoid cartilage
Corniculate cartilages
Cuneiform cartilages
Intrinsic laryngeal muscles
Extrinisic laryngeal muscles

4

Hyoid Bone

*Larynx suspended from hyoid
*Many extrinisic laryngeal muscles are attached to hyoid

5

Epiglottis

*Leaf-shaped cartilage
*Attached to hyoid
*Protects trachea by closing down inferiorly and posteriorly over laryngeal area, directing liquids and food into esophagus during swallowing

6

Thyroid Cartilage ("Adam's Apple")

*Largest laryngeal cartilage
*Shields other laryngeal structures from damage

7

Cricoid Cartilage

*Second largest laryngeal cartilage
*Completely surrounds trachea
*Linked with the paired arytenoid cartilages and the thyroid cartilage

8

Arytenoid Cartilages

*Positioned on the cricoid cartilage on either side of the midline
*Shaped like pyramids
*Vocal processes are the most anterior angle of the base of the arytenoids; True VFs attach at the vocal processes

9

Corniculate and Cuneiform Cartilages

Corniculate: Sit on apex of arytenoids; small, cone-shaped

Cuneiform: Tiny, cone-shaped cartilage pieces under mucous membrane that covers aryepiglottic folds

10

Intrinsic Laryngeal Muscles

*These pairs of muscles have both attachments to structures within larynx
*Primarily responsible for controlling vocalization
*With one exception (PCAs), all are adductors

11

Intrinsic Laryngeal Muscles (6)

Thyroarytenoids
Cricothyroids
Posterior cricoarytenoids (only abductors)
Lateral cricoarytenoids
Transverse arytenoids
Oblique arytenoids

12

Extrinsic Laryngeal Muscles

*One attachment to structure outside larynx and one within larynx
*All extrinisic laryngeal muscles attached to hyoid
*Elevate or lower position of larynx in neck; Give larynx fixed support
*Infrahyoids: "depressors"; depress laryx; impact pitch
*Suprahyoids: "elevators"; elevate larynx

13

Extrinisic Laryngeal Muscles: Infrahyoids (4) and Suprahyoids (6)

Infrahyoids: Thyrohyoids, Omohyoids, Sternothyroids, Sternohyoids

Suprahyoids: Digastrics, Geniohyoids, Mylohyoids, Stylohyoids

14

Age-Related Changes in the Larnx

*Hardening of laryngeal cartilages
*Degeneration and atrophy of intrinsic laryngeal muscles
*Degeneration of glands in laryngeal mucosa
*Degenerative changes in lamina propria
*Deterioation of cricoarytenoid joint
*Degenerative changes in conus elasticus

*These changes lead to "presbyphonia," an age-related voice disorder characterized by perceptual changes in quality, range, volume/loudness, and pitch

15

Pitch

*Perceptual correlate of frequency; Largely based on the frequency with which the VFs vibrate; This rate is often called the fundamental frequency(habitual pitch)
*Determined by mass, tension, and elasticity of VFs
*Higher pitch results when VFs are thinner, more tense, or both; Lower pitch results when the VFs are thicker, more relaxed, or both

16

Pitch: Frequency Perturbation/Jitter

*Are variations in vocal frequency that are often heard in dysphonic patients
*Measured instrumentally as a pt sustains vowel; useful in early detection of vocal pathology
*Pts w/ voice probs (e.g., tremor, hoarseness) might show a large amount of jitter
*People with no laryngeal pathology can sustain a vowel with less than 1% jitter

17

Volume

*Perceptual correlate of intensity; Determined by intensity of sound signal; Greater intensity means greater perceived loudness
*Sound is disturbance in air particles; it takes the form of waves that more forward and backward in mediums (e.g., air, water); "Amplitude" is extent of such movements; Greater the amplitude, the louder the voice

18

Volume: Amplitude Perturbation/Shimmer

*Cycle-to-cycle variation of vocal intensity
*Measured instrumentally as pt sustains vowel; useful in early detection of vocal pathology
*Speaker w/ no laryngeal pathology has very small amount of variation in intensity w/ each vibratory cycle
*Pts who have difficulty with regularity of VF vibration (e.g., roughness) may show large amounts of shimmer

19

Quality

Perceptual correlate of complexity; Refers to the physical complexity of the laryngeal tone, which is modified by resonating cavities; Determination of vocal quality is frequently subjective

20

Quality Types: Hoarseness and Harshness

*Hoarseness: combo of breathiness and harshness, which results from irregualr/aperiodic VF vibrations, which also lead to variation in F0
*Harshness: rough and "gravelly;" associated with excessive muscular tension and effort; VFs adducted too tightly and air is released too abruptly

21

Quality Types: Strain-Struggle and Breathiness

*Strain-struggle: phonation is effortful; sounds like "squeezing" voice at glottal level; initiating and sustaining phonation is difficult; talking fatigues; experience tension when speaking

*Breathiness: results from VFs being slightly open and air escapes through glottis and adds noise to the sound produced by VFs; Often feel like running out of air; Often soft, little variation in loudness, and restricted vocal range; May be due to organic (physical) or nonorganic (functional) causes

22

Quality Types: Glottal/Vocal Fry

*When VFs vibrate very slowly
*Low-pitch, "crackly"
*Usu. at end of utterance when air flow rate and subglottal air pressure are low and lung volume is less
*For some pts, glottal fry may help modify vocal quality problems such as stridency
*Other patients work to eliminate vocal fry by slightly increasing subglottal aur pressure and slightly elevating their pitch level

23

Quality Types: Diplophonia and Stridency

*Diplophonia: "Double voice;" Occurs when one can simultaneously perceive two distinct pitches during phonation; Usu. occurs when VFs vibrate at different frequencies due to different degrees of mass or tension; Ct with unilateral polyp, for example, may sound diplophonic

*Stridency: Shrill, somewhat high pitched, and "tinny;" Often caused by hypertonicity or tension of the pharyngeal constrictors and elevation of larynx; Tense pts may sound strident

24

Case History: The Clinician Needs To...

*Remember: a multidisciplinary, team-oritented approach is critical through evaluation

*Obtain info re: onset, duration, causes, variability of probs (ask pt and significant others)
*Obtain info re: any associated symptoms/probs (e.g., slurred speech, diff. swallowing, excessive coughing)
*ID factors (e.g., health, environ, fam hx) that may contribute to problem
*Gather info re: prev. tx, med. intervention, or other attempts to deal with voice prob
*Obtain descriptions of daily vocal use and possible abuse or misuse patterns (ask pt and sig. others)
**For culturally and linguisitically diverse cts: obtain specific perceptions of what constitutes "typical-sounding" voice in their culture

25

Instrumental Evaluation (9)

*Indirect Laryngoscopy (Mirror Laryngoscopy)
*Direct Laryngoscopy
*Flexible Fiber-Optic Laryngoscopy
*Endoscopy
*Acoustic Analysis
*Videostroboscopy
*Electroglottography (EGG)
*Electromyography (EMG)
*Aerodynamic Measurements

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Indirect Laryngoscopy
Direct Laryngoscopy
Flexible Fiber-Optic Laryngoscopy

Indirect Laryngoscopy: Mirror (+light) to view laryngeal structures during phonation (usu. "eee") and during quiet respiration

Direct Laryngoscopy: Performed by surgeon when pt under anesthesia in outpatient surgery; Laryngoscope introduced through mouth and into pharyx and positioned above VFs; Pt cannot phonate so VF function cannot be determined by surgeon can obtain a direct microscopic view of larynx; Valuable when biopsy is required due to suspicion of laryngeal cancer

Flexible Fiber-Optic Laryngoscopy: Tube inserted through nasal passage, passes over velum, and into position above larynx; Fibers transmit laryngeal image to specialist's eyepiece; Pt able to speak and sing; Specialist can obtain an excellent prolonged view of vocal mechanism and photograph rapid VF movement

27

Endoscopy

*Two types: flexible (inserted nasally) and rigid (inserted orally), using a 3.6mm tube
*(Fiber-optic) light at tip of scope and structures are illuminated by the light and viewed by specialist at other end of endoscope via window lens
*Endoscope can be attached to a video camera (videoendoscopy); A stroboscopic (flashing) light source can also be used
*W/ flexible endoscope, can view velopharyngeal (VP) mechanism, including VP valving; The endoscope (aka) nasopharyngoscope) can be lowered further to view laryngeal mechanism
*B/c pt can perform a variety of phonatory tasks, endoscopy may be used to study laryngeal anatomy and physiology in detail, incl. mucosal wave

28

Acoustic Analysis

*Acoustic measurements can be used to evaluate effectiveness of voice therapy/vocal surgery
*"Sound Spectography:" graphic representation of a sound wave's intensity and frequency as a function of time; "Spectogram:" resulting picture that reflects resonant characteristics of vocal tract and harmonic nature of glottal sound source

29

Videostroboscopy

*Helpful in differentiating bet. functional and organic voice probs and detecting laryngeal neoplasms (tumors)
*Can use flexible fiber-optic laryngoscope, a rigid endoscope, or both
*Strobe light permits optical illusion of slow-motion viewing of VFs during a variety of tasks; Observer perceives rapidly presented images as a complete picture of cycle-to-cycle vibration
*Microphone on pts neck to record voice, then introduces scope, switches on stroboscopic light, and asks pt to phonate
*Stroboscopic image on monitor yields info re: periodicity/regularity of VF vibrations, VF amplitude, glottal closure, presence and adequacy of mucosal wave, and possible presence of lesions or neoplasms

30

Electroglottography (EGG)

*Noninvasive procedure yields indirect measure of VF closure patterns
*Surface electrodes placed on both sides of thyroid cartilage, and a high-frequency electrical current is passed bet. electrodes while pt phonates
*Glottal wave form results and specialist is able to view VF vibration
*EGG can also detect breathy and abrupt glottal onset of phonation
*Disagreeance re: efficacy of EGG as a diagnostic technique; Best for cross-reference tool