Voice and Craniofacial Disorders By: Grace Castillo & Christine Truong
What is a Voice Disorder? A voice disorder is differences in quality, loudness, and pitch compared to ● “normal”. “Normal” being different than people with similar: ○ Age, gender, geographic location, cultural background ● Perceptual features (what we hear vs. what we expect to hear) ○ deviate from norms such that they draw attention of those listening
Terms to Know Pitch : The perceptual correlate of frequency that is largely based on the frequency with which ● the vocal folds vibrate Volume : The perceptual correlate of intensity which is determined by the intensity of the ● sound signal Intensity : Sound pressure ● Jitter (Frequency Perturbation): Variations in vocal frequency that are often heard in dysphonic ● patients Shimmer (Amplitude Perturbation): Cycle-to-cycle variation of vocal intensity ● Hoarseness : A combination of breathiness and harshness which results from irregular vocal ● fold vibrations Harshness : Rough, unpleasant, and “gravelly” sounding that is associated with excessive ● muscular tension and effort Strain : Phonation is effortful and the patient sounds as if he/she is squeezing the voice at the ● glottal level
Terms to Know Glottal fry (Vocal Fry): Heard when the vocal folds vibrate very slowly with the resulting sound ● occurring in slow but discrete bursts and extremely low pitch Glottal stop / Ɂ /: A stop consonant produced in place of other glottal consonants ● Diplophonia : “Double voice”; occurs when a listener can simultaneously perceive two distinct ● pitches during phonation Stridency : Voice sounds shrill, unpleasant, somewhat high pitched and tiny ● Breathiness : Results from the vocal folds being slightly open or not firmly approximated ● during phonation Hypernasality : Excessive nasality; sounds like the patient is speaking through their nose ● Hyponasality : Patients speak with decreased or insufficient intraoral breath pressure, ● affecting the production of fricatives, affricates, and plosives
Risk Factors of a Voice Disorder Vocal abuse Personality Related ● ● Phonotrauma Environmental stress ○ ○ Repetitive throat clearing Identity conflict ■ ○ Coughing Gender dysphoria ■ ■ Talking over background Psychological and psychiatric ■ ○ noise problems Medically related ● Direct and indirect surgeries ○ Medical/health conditions ○ Medications ○
Associated Cranial Nerves and Their Function CN X (Vagus) ● The primary CN involved in laryngeal innervation ○ Functions: ● Motor: controls most muscles of the larynx, ○ pharynx, and palate for phonation, swallowing, and resonance; controls the gag reflex with CN IX Sensory: sensation from posterior tongue and ○ larynx; regulates oxygen intake and lung Inflation
CN X Branches SLN ● Internal branch provides all of the sensory information to the larynx ○ External branch supplies motor innervation solely to the cricothyroid muscle ○ RLN ● Supplies all motor innervation to the interarytenoid, ○ posterior cricoarytenoid, thyroarytenoid, and lateral cricoarytenoid muscles Supplies all sensory information below the vocal folds ○
Associated Cranial Nerves and Their Function CN VII (Facial) ● Innervates the posterior ○ belly of the digastric muscle of the vocal folds
Respiratory System Respiratory system ● One of the suppliers for the power of the voice ○ Ventilation ● Air movement (transfers air in/out of the lungs) ○ Respiration ● Gas movement across membranes ○ Exchanging: ○ Atmospheric gas with that of blood gases ■ Blood gases with that or organ-producing gases ■ Take oxygen in and release carbon dioxide ■
Clavicular Breathing Most shallow type of breathing ● Breathing into the top third of the lungs ● and no deeper How it works: ● Raising the clavicle & shoulders during ○ Inhalation Keep the rest of the torso motionless ○
Clavicular Breathing Example
Diaphragmatic-Abdominal Breathing Helps strengthen your diaphragm ● One of the biggest benefits is reducing stress ● How it works: ● The diaphragm is a dome-shaped respiratory muscle ○ found near the bottom of your ribcage. When you inhale and exhale air, the diaphragm & other respiratory muscles around your lungs contract. During inhalation, your diaphragm contracts so that your lungs can expand ○ into the extra space and let in as much air as is necessary. Muscles in between your ribs, known as intercostal muscles, raise your rib ○ cage in order to help your diaphragm let enough air into your lungs.
Diaphragmatic-Abdominal Breathing Example
Thoracic Breathing How it works: ● Start by inhaling (this expands the thorax) ○ This causes the intercostal muscles to elevate ○ the ribs (as compared to abdominal breathing using the diaphragm)
Thoracic Breathing Example
How Vocal Folds Vibrate
Myoelastic-Aerodynamic Theory Myo = Muscle Elastic = Stretchy Aerodynamic = Airflow & pressure Starting point: VFs are in the closed position ● Build up of air pressure from lungs increases → causes VFs to abduct ● Air flows through the glottis ● Natural tissue elasticity takes over to bring VFs to adducted position ● This is one vibration cycle ● This theory assumes air pressure below and airflow between the VFs ● interact with VF tissues to set them in motion for a time Problem: VF vibration will dampen over time ●
Hirano’s Body-Cover Theory Takes into account role of the layers and how ● they contribute to VF movement VFs can move in 3 ways: ● Horizontally: closed at midline to opening out (clap hands) ○ Vertically: down to up (zipper) ○ Longitudinally: front to back ○ Speed and extent of VF movement increases or decreases based on these ● types of movements This theory focuses on VF movement ●
Titze’s Self-Oscillation Theories One-mass or uniform block model ● Air from lungs moves in one direction ○ Air pressure builds up below the VFs, pulls them apart, and then the VFs are pulled back ○ together As the VFs move closer together, airflow between them is reduced (less space for air to ○ pass) Air above closing VFs continues to move up at the same speed (inertia) ○ Speed of air pressure is maintained except for just above the VFs ○
Titze’s Self-Oscillation Theories cont. Three mass model ● Added 2 other masses: VF cover & thyroarytenoid ○ Masses move independently yet are linked ○ At different points in the vibration cycle ○ Bottom portion of the VFs are farther apart than the upper portion and vice versa ■ There is greater air pressure when bottom parts are further apart ○ Uneven air pressure maintains VF vibration ■ This model is better than the first one ●
Vocal Tract Sound/voice (starts out as acoustic energy) is generated by a subglottic air ● pressure It is powered by the respiratory system ● Source: laryngeal complex - VF vibration ● Filtered by: size and shape of vocal tract ● resonating cavities 3 subsystems ● Oral cavity ○ Nasal cavity ○ Pharynx ○
Vocal Fold Microstructure 5 Layers ● (1) Epithelium ○ Lamina Propria ○ (2) Superficial layer ■ (Reinke’s Space) (3) Intermediate layer + ■ (4) Deep layer = Vocal Ligament (5) Vocalis Muscle ○ [Thyroarytenoid muscle]
Key Voice Characteristics Pitch ● Fundamental frequency (FF) - rate of vibrations of the VFs ○ Measured in Hz ○ Phonatory modes or registers ○ Falsetto ■ Modal ■ Glottal fry ■ Factors affecting FF ○ VF length ■ VF tension ■ Subglottic pressure ■ Amplitude of vibration ■
Key Voice Characteristics Quality ● Perceptual judgments of quality are often subjective, though ○ standard measures make this somewhat more objective Factors that influence phonatory quality: ○ Integrity of vibration: regular, symmetry, phase shape/closure ■ and slope of glottal flow waveform Integrity of the respiratory system ■ Supraglottic vocal tract ■
Key Voice Characteristics Loudness ● Vocal intensity - SPL of acoustic signal we hear ○ Measured in dB ○ Factors affecting intensity: ○ Subglottic air pressure ■ Transglottic air flow ■ VF vibration phase closure ■ Supraglottic vocal tract resonating cavities ■
Vocal Pathologies 8 Categories ● Structural ○ Inflammatory ○ Trauma/injury ○ Systemic ○ Nonlaryngeal Aerodigestive ○ Psychiatric/Psychological ○ Neurologic ○ Other Disorders ○ Separate Category: Gender Dysphonia & Gender Reassignment ■
Structural Pathologies: Benign VF Lesions Etiology Characteristics Treatment Vocal Nodules -Phonotrauma -Rough, breathy, tense, -Voice therapy to ensure -Vocal misuse difficulty breathing proper voice use -Vocal abuse -Surgery Vocal Polyps -Dysphonia -Surgery -Vocal rehab therapy Vocal Cysts -Dysphonia/aphonia Does not respond to therapy!!! -Surgery Reactive VF Lesions -Caused from a contralateral -Hoarseness -Voice therapy VF cyst; it’s a reaction to a -Conservative management unilateral VF lesion
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