laryngeal dystonia introduction

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LARYNGEAL DYSTONIA Dr.Roohia

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about larynx anatomy, physiology,speech.pathology of laryngeal dystonia

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Page 1: Laryngeal dystonia introduction

LARYNGEAL DYSTONIA

Dr.Roohia

Page 2: Laryngeal dystonia introduction

DYSTONIA

Dystonias are a group of movement disorders

that are characterized by involuntary, action-

induced counterproductive muscle contraction.

Laryngeal dystonia(Spasmodic dysphonia (SD):

is a focal dystonia affecting the neural control of

the laryngeal musculature for speech production.

Spastic aphonia, spastic dysphonia, phonic

laryngeal spasm, coordinated laryngeal spasms,

mogiphonia, and laryngeal stuttering.

Page 3: Laryngeal dystonia introduction

REQUIREMENTS FOR SPEECH PRODUCTION

Respiration

Phonation

Articulation

Resonance

Page 4: Laryngeal dystonia introduction

WHAT IS REQUIRED FOR SOUND PRODUCTION?

Sound production requires two things:

Power/energy source

Vibrating element

When it comes to speech production, the

power source is air that comes from the

lungs and the vibration occurs in the vocal

cords

Page 5: Laryngeal dystonia introduction

RESPIRATION

Also known as breathing

Two phases:Inhalation

Also known as inspiration

Occurs when diaphragm lowers, which causes increased volume/space in thoracic cavity. This results in negative pressure in the lungs compared to the atmospheric pressure outside the lungs; therefore, air rushes from outside the body into the oral and nasal cavities, down the trachea, and into the lungs.

ExhalationAlso known as expiration

The decrease in the volume/space of thoracic cavity after inhalation results in positive pressure in the lungs. If the airway is open, air will rush out of the lungs (up the trachea and out the oral and nasal cavities) in order to equalize the outside and inside pressure.

Page 6: Laryngeal dystonia introduction

PHONATION

The act of phonation occurs in the larynx,

where the vocal cords are housed

The larynx is also called the “voice box”

Page 7: Laryngeal dystonia introduction

PHONATION

When air from the lungs is forced through closed vocal cords, the vocal cords vibrate and phonation occurs

The pitch of sounds produced in the larynx is dependent upon the tension of the vocal cords

Elongation and tension of the cords results in faster vibration = higher frequency/pitch

Shortening and relaxation of the cords results in slower vibration = lower frequency/pitch

Fundamental frequency of male voice=130 Hz

Fundamental frequency of female voice=220 Hz

The loudness of sounds produced in the larynx is dependent upon the speed of air flowing through the glottis (space between the cords).

The air speed is greatest when the pressure build-up below the vocal cords (subglottal pressure) is high

Page 8: Laryngeal dystonia introduction

ANATOMY: LARYNGEAL CARTILAGE

The Larynx is

composed of:

Cartilages (6)

Single cartilages:

Epiglottis, thyroid, cricoid

Paired cartilages:

Arytenoid, corniculate and

cuneiform

Muscles & Ligaments

Support and connect the

cartilages of the larynx

Form the vocal cords

Page 9: Laryngeal dystonia introduction

ANATOMY: LARYNGEAL MUSCLES

Page 10: Laryngeal dystonia introduction

ANATOMY: LARYNGEAL MUSCLES

Page 11: Laryngeal dystonia introduction

ANATOMY: LARYNGEAL MOTION

Abduction of vocal ligament

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ANATOMY: LARYNGEAL MOTION

Adduction of vocal ligament

Page 13: Laryngeal dystonia introduction

ANATOMY: LARYNGEAL MOTION

Tension of vocal ligament

Page 14: Laryngeal dystonia introduction

VOCAL CORDS

Also referred to as vocal folds

Housed within the larynx

Attached anteriorly to the thyroid cartilage and posteriorly to the arytenoid cartilages

Closed when we swallow to protect our airway

Open when we are breathing in order to allow air in/out of lungs

Vibrate open and closed during phonation

Page 15: Laryngeal dystonia introduction

LARYNGEAL INNERVATION

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THE PERIODS OF VOCAL FOLD CONTACT AND LACK OF

CONTACT IN ONE VIBRATORY CYCLE

Phase Description

Closing The vocal folds begin to close rapidly

from

their lower margin

Closed The medial edges of the vocal folds are

in

full contact

Opening The vocal folds begin to separate from

their

lower margin and gradually peel apart.

The superior margin remains in contact

until the end of this phase

Open The vocal folds are separated, the

longest

part of a normal vibratory cycle

Page 18: Laryngeal dystonia introduction
Page 19: Laryngeal dystonia introduction

VOCAL REGISTERS: CHARACTERISTICS OF VOCAL FOLD

ADDUCTION AND VIBRATION

Register may

include

Equivalent terms Vocal folds F0 range

Loft register

Highest vocal

frequancy

falsetto Thin,tense

lenghtened

Minimal vibration

275-1100

Modal register

Range of

fundamental

frequncies used in

speaking &singing

Chest,head,middle,

heavy voice

Complete

adduction

100-300

Pulse register

Lowest range of

vocal frequencies

laryngeal output is

percieved as

pulsatile

Vocal fry,glottal fry,

creaky voice

Long closed phase 20-60

Page 20: Laryngeal dystonia introduction

ARTICULATION

Tongue

Lips

Teeth

Alveolar ridge (gums behind upper teeth)

Soft Palate

Hard Palate

Velum/uvula

The variable action of the tongue on all of the structures listed above results in our ability to articulate different speech sounds

A PHONEME is the technical term for a specific sound of speechPhonemes are either vowels or consonants

Page 21: Laryngeal dystonia introduction

VOWELS

Vowel soundsThere are 5 vowels in the English language (a, e, i, o, u), but there are 12 different vowels sounds (i.e. the letter “i” makes different sounds in the words “miss” and “mice”)

The articulation of the different vowel sounds depends on:

The point of constriction

The degree of constriction

The degree of lip-rounding

The degree of muscle tension

Vowel sounds make up 38% of our speech

Page 22: Laryngeal dystonia introduction

CONSONANTS

Consonants of English are classified by:

Place of articulation

Manner of articulation

Degree of Voicing

Consonant sounds make up 62% of our speech

Page 23: Laryngeal dystonia introduction

CLASSIFICATION OF CONSONANTS BY PLACE OF

ARTICULATION

Bilabial: both lips come together (p, b, m, w)

Labiodental: lower lip and upper teeth make contact (f, v)

Dental: the tongue makes contact with the upper teeth (-th)

Alveolar: the tip of the tongue makes contact with the alveolar ridge (t, d, s, z, n, l)

Palatal: the tongue approaches the palate (j, r, -sh)

Velar: back of the tongue contacts the velum (k, g, -ng)

Glottal: this is really an unvoiced vowel (h)

Page 24: Laryngeal dystonia introduction

CLASSIFICATION OF CONSONANTS BY MANNER

OF ARTICULATION

Manner of articulation refers to the degree of constriction as the consonants begin or end a syllable

Stops are defined by complete closure of the lips and subsequent release (p, b)

Fricatives use an incomplete closure of the lips to create turbulent noise (f, s, sh)

Nasals resonate through the nasal cavity (m, n)Hint: try making these nasal sounds with your nostrils plugged

Glides and Liquids are produced when the tongue approaches a point of articulation within the mouth but does not come close enough to obstruct or constrict the flow of air enough to create turbulence (l, r, w)

Page 25: Laryngeal dystonia introduction

VOICED VS. VOICELESS CONSONANTS

Voiced consonants are produced with the

vocal cords vibrating

Voiceless consonants are produced with the

vocal cords open

Example

The sounds /f/ and /v/ are both labiodental fricatives;

however, /f/ is voiceless and /v/ is voiced

Page 26: Laryngeal dystonia introduction

RESONANCE

Dependent upon the size and shape of the:

Vocal Tract

Oral Cavity

Nasal Cavity

The resonant frequency of each of our voices will differ depending on the size and shape of the structures above, much like how the resonance of a cello or bass differs from a guitar, which differs from a ukelele.

Page 27: Laryngeal dystonia introduction

LARYNGEAL DYSTONIA

Spasmodic dysphonia (SD)

spasmodic dysphonia, a form of movement disorder that involves involuntary "spasms" of the muscles in the vocal folds causing breaks of speech and affecting voice quality.

Focal, adult-onset dystonia of laryngeal muscles

Intermittent phonatory breaks during speech secondary to spasms

Usually task specific - symptomatic when attempting voluntary speech

May be asymptomatic during reflexive phonation (coughing, laughing, crying, yawning)

Symptoms reduced/absent during singing or whisper

Page 28: Laryngeal dystonia introduction

ASSOCIATIONS

May be associated with:

Other focal dystonias

Blepharospasms, Torticollis, Writer’s Cramp

Underlying neurological

Parkinson’s, ALS

Environmental

Infection, trauma, meds

Psychogenic stimulus

Stress

Page 29: Laryngeal dystonia introduction

DEMOGRAPHICS

Affects approximately

1:10,000 Americans

Female to male ratio

3:1 up to 8:1

Peak age of onset 35-

45

Positive family history

in 12% of affected pt’s

Page 30: Laryngeal dystonia introduction

NEUROPATHOLOGY

two different neurologic pathways involved in

voice production one being voluntary and

the other involuntary.

Corticobulbar fibers from the cerebral cortex

descend through the internal capsule and

synapse on the motor neurons in the nucleus

ambiguus.

Page 31: Laryngeal dystonia introduction

alterations in anatomical connectivity of the corticobulbar tract (CBT) descending from the laryngeal/orofacial motor cortex to the brainstem phonatory nuclei.

The link between dystonia and basal ganglia dysfunction has been apparent Basal ganglia balance excitation and inhibition of the thalamo-cortical circuit involved in motor execution. This balance is thought to be altered in task-specific dystonias due to reduced GABAergic metabolism and dopaminergic receptor binding leading to excessive motor cortical excitation

Page 32: Laryngeal dystonia introduction

The cerebellum is involved in the motor

control via the ventrolateral thalamus and

has a modulatory role in coordination of

voice and speech production

Page 33: Laryngeal dystonia introduction

NEURAL PATHOLOGY NETWORK

. Direct projections from the laryngeal motor cortex (LM1) to the phonatorymotor nuclei(nucleus ambiguus, NA) descend via the corticobulbar/corticospinaltract (CBT/CST)

The putamen (Put) receives input from the LM1 and projects back to the LM1 via the globuspallidus&vth forming striato-pallido- thalamio cortical loop.

. Cerebellar motor input (Cbl) to the LM1 is via the VTh.

Page 34: Laryngeal dystonia introduction

Microstructural changes along the CBT/CST as well as in the regions directly or indirectly contributing to the CBT/CST found in this study (dashed areas) may affect voluntary laryngeal control in patients with SD.

Page 35: Laryngeal dystonia introduction

TYPES OF LARYNGEAL DYSTONIAS

Adductor – irregular hyperadduction of vocal

folds with excessive glottic closure

Abductor – incomplete, irregular vocal fold

approximation

Mixed – both elements are present

Adductor laryngeal breathing dystonia

(ALBD).

Page 36: Laryngeal dystonia introduction

CLINICAL FEATURES: ADDUCTOR TYPE

Most common ~85% of diagnosed cases

Choked, strained-strangled voice, with abrupt

breaks in phonation in the middle of vowels

Breaks are due to hyper-adduction of the

folds

Difficulty with “We eat eels every day” and

“We mow our lawn all year”

Page 37: Laryngeal dystonia introduction

CLINICAL FEATURES: ABDUCTOR TYPE

Rare ~15% of patients with SD

Breathy, effortful voice with abrupt breaks

resulting in whispered elements of their

speech.

Excessive and prolonged abduction during

voiceless consonants (/h/,/s/,/f/,/p/,/t/,/k/)

Difficulty with “The puppy bit the tape” and

“When he comes home we’ll feed him”

Page 38: Laryngeal dystonia introduction

MIXED TYPE

Extremely rare, with symptoms of both

adductor and abductor type

Page 39: Laryngeal dystonia introduction

ADDUCTOR LARYNGEAL

BREATHING DYSTONIA (ALBD).

persistent inspiratory stridor, usually normal

voice, and paroxysmal cough.

Some patients who have ALBD find it difficult

to breathe and swallow at the same time,

which results in dysphagia.

Page 40: Laryngeal dystonia introduction

CLINICAL CLASSIFICATION

Ludlow and Connor based on constant versus intermittent symptoms and the presence or absence of tremor.

ADDUCTOR TYPE

(1) constant harsh and tight voice,

(2) intermittent pitch and voice breaks in the middle of words,

(3) glottal stops with tremor at 4 Hz to 5 Hz in the middle of words

Page 41: Laryngeal dystonia introduction

ABDUCTOR TYPE

(1) constant whispering,

(2) intermittent breathiness with consonants

at the beginnings of words,

(3) voice tremor with breathy breaks at 4 Hz

to 5 Hz in the middle of words

Page 42: Laryngeal dystonia introduction

Koufman is based on independent visual

and acoustic evaluation using fiberoptic

laryngoscopy and extensive voice analysis.

Focal dystonias (LD) and

Nonfocal laryngeal dystonias

Page 43: Laryngeal dystonia introduction

Blitzer and colleagues used a variation of the Koufman and Morrison and RammageClassification systems.

Type 1 hyperadduction is forceful overcontraction at the glottic level only with tight compression of the vocal processes and arytenoids.

Type 2 is forceful contraction, including contraction of the false cords.

In types 3 and 4, there is supraglottic narrowing in the anteroposterior direction

Page 44: Laryngeal dystonia introduction

Patients with intelligible speech and normal

stroboscopic findings are classified as mild.

Barely intelligible or unintelligible speech

and normal stroboscopy are considered

moderate

Unintelligible speech who are unable to

trigger the strobe are considered severe.

Page 45: Laryngeal dystonia introduction

THANK YOU