Voice Disorders Quiz 1

trachea and the oropharynx.

airway during swallowing.

sound source for speech (phonation).

Hyoid bone

Thyroid cartilage

Cricoid cartilage

Arytenoid cartilages

The hyoid is embedded in the tongue base (the only “floating” bone in the body).

The larynx is suspended from the hyoid via the thyrohyoid membrane.

Elevation of the hyoid pulls the larynx up during swallowing.

The thyroid cartilage is a large structure consisting of two fused laminae (plates). Posterior thyroid is open.

Two pairs of thyroid horns connect to hyoid superiorly and cricoid cartilage inferiorly.

Vocal folds attach to the interior surface of the anterior thyroid cartilage by a fibrous bundle, the anterior commissure.

The cricoid is a complete ring of cartilage.

◦ Shaped like a signet ring with a large square plate (quadrate lamina) in the back.

The arytenoid cartilages sit on top of the quadrate lamina (forms the cricoarytenoid joints).

Arytenoids have a pyramid shape with a muscular process and a vocal process.

Laryngeal muscles attach to the muscular processes to move the arytenoids.

◦ Vocal folds attach to the vocal processes; moving the arytenoids will open and close the folds.

a fibrous bundle, the anterior commissure.

The epiglottis is a laryngeal cartilage

not involved in phonation.◦ Flips down to cover the larynx during

swallowing.◦ Bottom attached inside thyroid lamina

below thyroid notchAryepiglottic folds –joins sides of epiglottis to arytenoid cartilages

Pyriform sinuses - pockets between aryepiglottic folds & thyroid cartilage

◦ epiglottis projects upward above hyoid bone & attaches to root of tongue via glosso-epiglottic folds

Valleculae- pockets between anterior surface of epiglottis & root of tongue

The glottis is defined to include the vocal folds and the space between them.

◦ The anterior portion Is soft(membranous glottis).◦ The posterior portion is stiffer(cartilaginous glottis)

We can view the glottis from above using (trans)nasal endoscopy.

The arytenoid cartilages are visible only as bumps inside the aryepiglottic

folds( joins sides of epiglottis to arytenoid cartilages).

Pyriform sinuses: pockets between aryepiglottic folds & thyroid cartilage

Note orientation of image during endoscopy: Bottom of the image is anterior (front), top is posterior.

Abduction vs adduction◦ Phonation: Vocal folds are

adducted (median position)◦ Rest breathing: Vocal folds are

partly but not completely

abducted (paramedian position).

◦ Complete abduction (forced abduction) occurs during vigorous physical activity.

◦ Whisper: Membranous glottis (anterior) is closed and cartilaginous glottis (posterior) is open.

Suprahyoid◦ Digastric◦ Stylohyoid ◦ Mylohyoid ◦ Geniohyoid

Infrahyoid (Strap)◦ Sternohyoid and Sternothyroid ◦ Omohyoid and Thyrohyoid

One pair of muscles makes up the main body of the vocal folds

◦ Thyroarytenoid◦ Contraction influences

length/tension of vocal folds.

◦ Muscularis◦ Shortens and slackens

◦ Vocalis◦ Internaltension

Two pairs of vocal fold adductors (close the vocal folds)

LCA muscles originate on lateral cricoid and insert on muscular process of arytenoids.

Contraction rotates the arytenoids forward and toward midline, pulling vocal processes toward each other.

The IA runs between the posterior portions of the two arytenoids. Contraction pulls the arytenoids together, closing the posterior glottis.

Origin: lat. post. margin of 1 arytenoidCourse: horizontallyInsertion: lat. post. margin of opposite arytenoid Contraction: pulls arytenoids togetherCauses vocal folds to move togetherAlso a force in medial compression

Superficial to transverse interarytenoid Origin: from post. base of muscular

process of 1 arytenoid Course: obliquely upward Insertion: apex of other arytenoid CrisscrossedContraction: pulls apex medially

One pair of vocal fold abductors (open the vocal folds)

•The PCA muscles originate on the posterior cricoid and insert on the muscular process of the arytenoids.

•PCA contraction rotates the arytenoids in a posterior direction, pulling the vocal processes away from each other.

One muscle stretches/tenses the vocal folds (changes pitch)

Paired cricothyroid (CT)

muscles

CT is the only intrinsic laryngeal

muscle innervated by the superior laryngeal branch of CN X (Vagus).

Contraction of the CT muscle changes the angle between the thyroid and cricoid.

Increases the distance between the arytenoids and the anterior commissure.

This stretches the vocal folds. ◦ Increases tension◦ Raises vocal pitch

Has superior laryngeal and recurrent laryngeal branches.

Recurrent laryngeal: Loops under the aorta before returning to the larynx.

◦ Sends motor commands to all intrinsic laryngeal muscles except cricothyroid. ◦ Damagecancausedysphonia(abnormalvoice).

Superior laryngeal:◦ Sends motor commands to cricothyroid muscle of larynx, as well as inferior

pharyngeal constrictors◦ Damage may cause reduced ability to alter pitch

Aryepiglottic

Lateral border of epiglottis

Lateral border of arytenoid cartilage

Ventricular folds (False vocal folds)

Thyroid cartilage

Arytenoid cartilage

Superior to true folds

True Vocal Folds

Thyroid cartilage

Arytenoid cartilage

Inferior to ventricular folds

The "true" vocal folds - are made up of five layers:

epithelium - the surface "skin" of the the larynx, which is continuous with the lining of the mouth, pharynx and with the trachea below the larynx.

Lamina propria - three distinct layers, each with a different consistency ◦ superficial layer: a jelly-like

substance, close to the surface ◦ intermediate layer: an elastic,

fibrous substance, like rubber

bands◦ deep layer: a thread-like

collagenous fiber layer Vocalis muscle: the main body

of the vocal fold, and very stiff

Vocal folds are made up of layers that differ in density and stiffness. Layers of the vocal folds:

◦ The thyroarytenoid muscle◦ The lamina propria, three layers of mucous membrane

(stiff inner layers = vocal ligament; outer layer is elastic) ◦ A thin outer epithelial layer

Dividing the vocal fold layers:◦ Body = Thyroarytenoid muscle and

vocal ligament. Stiff and dense.

◦ Cover = superficial lamina propria and epithelium. Light and pliable.

Habitual Pitch/Modal Register – pattern of phonation used in daily conversation

◦ Vocal fundamental frequency –primary frequency of vibration.◦ We will discuss modal register /habitual pitch in more detail later in the semester.

NOTE: CONSIDERATION OF HABITUAL PITCH/MODAL REGISTER IS VITAL DURING A VOICE EVALUATION.

How does modal register relate to:

• Pitch◦ Tensionofvocalfolds ◦ Lengthofvocalfolds

• Loudness◦ Subglottalairpressure

*Sound is generated in the larynx by chopping up a steady flow of air into little puffs of sound waves.

The mechanism of vocal fold vibration has been described in the myoelastic-aerodynamic theory of phonation.

Holds that voice production results from a combination of:

◦ Muscle activity (myo)◦ Tissue elasticity (elastic)◦ Air pressure/airflow (aerodynamic)

First the vocal folds are adducted by muscular action (LCA and IA).

Then subglottal pressure builds up in the space beneath the vocal folds.

Eventually this pressure blows the vocal folds apart and air rushes through.

This burst of air sets the vocal tract into vibration, creating sound.

The vocal folds immediately begin to close:

Theelastictissuesnaturallyspringbackinto their original state.

By the Bernoulli principle, the flow of air creates negative pressure that sucks the vocal folds back together.

Then the cycle begins again.

The complete open-close cycle takes place hundreds of times per second during phonation.

Bernoulli principle: As the velocity of a moving liquid or gas increases, pressure within the substance decreases.

As a liquid or gas moves through a narrow channel, it increases in velocity.

Therefore, air passing through a narrow channel like the space between the vocal folds will increase in velocity and decrease in pressure.

The vocal folds must be closed.

The ratio of air pressure below the glottis (subglottal) to air pressure above the glottis (supraglottal) must exceed a certain positive value for phonation to occur.

In other words, subglottal pressure must exceed supraglottal pressure by a certain amount for phonation to occur.

Given a constant volume and flow of air at a point of constriction there will be:

• Decrease in air pressure and increase in velocity at point of constriction

Air speed increases as it passes through glottal opening, and pressure drops

Drop in pressure causes soft tissue of vocal folds to be sucked back in toward midline

Muscle

Vocal fold vibration

Vocal folds will be tightly adducted at midline by muscular action

LCA/IA

Tissue

Elasticity

• Elastic recoilforce is generated as vocal folds are displaced from adducted position

Airflow

Sub-glottal pressure builds up until it overcomes resistance of closed vocal folds

• Forces vocal folds apart from bottom to top = • Puff of air is released up through glottis

Air stream is flowing through an hourglass shaped constriction◦ Bernoulli effect causes air to flow faster and pressure

to drop at glottis

Drop in pressure causes vocal folds to be sucked inward

Elasticity also contributes to inward movement (back to

point of rest)

Vocal folds close; one cycle of vibration is completed

The rate of vocal fold vibration depends on the mass and tension of the folds.

Larger vocal folds vibrate more slowly.

Greater tension causes the vocal folds to vibrate faster.

The rate of vocal fold vibration determines the fundamental frequency (F0) of the speaker’s voice.

Fundamental frequency is perceived as the pitch of the voice.

Child F0 250-300 Hz

Adult Female F0 180-250 Hz

Adult Male F0 80-150 Hz

◦ The thyroarytenoid muscle◦ The lamina propria, three layers of mucous membrane

(stiff inner layers = vocal ligament; outer layer is elastic) ◦ A thin outer epithelial layer

◦ Body = Thyroarytenoid muscle and

vocal ligament. Stiff and dense.◦ Cover = superficial lamina propria and epithelium. Light and pliable.

Due to differences in stiffness, the body and cover tend to vibrate at different rates.

The flexible outer layers move in an “undulating, wave-like” fashion called the mucosal wave.

Complex vibratory pattern influences the sound produced by vocal fold vibration.

Normal voice quality depends on a freely flowing mucosal wave.

Vibratory cycle = glottal cycle = glottal period◦ Complete cycle of vibration◦ Measured with high speed photography using

stroboscopic light source ◦ 3 phases:

◦ Opening phase ◦ Closing phase ◦ Closed phase

◦ Flow of air through the glottis◦ Absent during closed phase◦ Increases slowly during open phase◦ Decreases rapidly during closing phase.

◦ The frequency of a sound is the rate at which the wave cycle repeats. ◦ A simple waveform has only one frequency. A complex waveform is

made up of two or more different frequencies.◦ A periodic waveform repeats itself over time. An aperiodic waveform

is random and non-repeating (e.g. “white noise”).

Pitch◦ Psychological phenomenon◦ Frequency = # cycles/second◦ Pitch = perceptual correlate of frequency;

measured in hertz (Hz)

Larynx rises in the neck (thyrohyoid

m.)

Length of vocal folds increases

(cricothyroid m.)

Tension of vocal folds increases in

vocal ligament

Mass of vocal folds decreases – they

get thinner

Air flow increases because it takes

less subglottal pressure to blow

thinner folds apart

Relation of pitch to vibratory cycle◦ As pitch increases, open phase increases

◦ vocal folds are easier to open◦ Although they close quickly, they don’t stay closed

as long◦ As pitch increases, vibratory cycle does not vary

systematically◦ Both opening & closing phases are affected by

increasing pitch, but exactly how this happens

varies from person to person

◦ Perceptual correlate of intensity◦ Intensity = physical property, measured in

decibels (dB)

• REMEMBER: Loudness

◦ Subglottal air pressure

Increased vocal intensity results from greater resistance by the vocal folds to the increased

airflow.

The vocal folds are blown further apart, releasing a

larger puff of air that sets up a sound pressure wave

of greater amplitude.

Latero-medial excursion of the vocal folds is

increased in each glottal cycle

◦ As loudness increases, relationship of open and

closed phases does not change◦ Increased latero-medial excursion.

Purpose:◦To obtain basic biographical information

◦ To obtain professional information ◦ To obtain health history

Patient with medical diagnosis: ◦ Evaluation by the SLP

Patient without medical diagnosis:

Evaluation by the SLP and ENT either together or in

close proximity

Cases reviewed with discussion of diagnosis and

treatment plan prior to presentation of information to patient.

Muscle Activity

Respiratory Activity

Laryngeal activity

Electromyography (EMG)◦ A technique used to investigate respiration, phonation and articulation◦ Provides information about the muscular forces involved in speech production

by recording muscle action potentials

Measures electrical activity of neural signals to muscles

Higher-amplitude signal: More motor units fire; stronger muscle contraction

Two types of electrodes:◦ Hooked-wire: Insert directly into muscles◦ Surface: Record all muscular activity below skin site

Useful for recording temporal aspects of muscle actions

Signal strength must be assessed in relative terms: More or less

activation for different speech tasks

• Respiration underlies speech production

Measures of respiratory function: ◦ Air volume◦ Air pressure◦ Air flow rate

◦ Analyzed together this data can provide possible causes of a number of speech disorders

Phonatory Aerodynamic System (PAS):The Phonatory Aerodynamic System (PAS) measures airflow, pressure, and other parameters related to speech and voice production to support evidence-based practice. The PAS utilizes easy-to use, protocol-driven software for consistent assessment to better understand a patient's condition.

• Pressure reflects respiratory and articulatory actions

Direct assessment of subglottal pressure is invasive: ◦ Tracheal puncture◦ Esophageal balloon

Indirect assessment is less invasive:

Pharyngeal pressure (pass a tube through nose)

Intraoral pressure (pass a sensor around the teeth)

Manometer - Water-glass manometer: Have patient create bubbles by

blowing through a straw into a glass of water with depth measurements

marked on the side.

◦ A patient who can sustain a stream of bubbles for 5 seconds through a straw at a depth of 5 cm is considered to have breath support adequate for speech (Duffy, 2005).

Perform a consistent set of tasks at when conducting a voice assessment.

- measure habitual pitch and loudness levels

- measure raised loudness levels

Spirometer measures airflow during nonspeech tasks

Flow during speech usually collected via Rothenberg face mask (pneumotachograph)

Divided masks may be used to assess oral versus nasal airflow

Measures of volume can be obtained as flow over time

A baffle between the nose and mouth separates nasal from oral airflows

Microphones placed on both sides of baffle

Ratio of nasal to oral signal strength = nasalance

Correlates with perceived nasality in speech

Electroglottograph – measures the degree of vocal fold contact

Measured by two small electrodes placed on either side of the larynx

Human tissue conducts electricity

more efficiently than air.

More current is transmitted when

vocal folds are closed.

Less current is transmitted when

folds are open.

Indicates amount of vocal fold

contact during each glottal cycles- not any info about glottal width or shape

• We need to look directly at the vocal folds – WHY?

Historically:

• Laryngoscope-laryngeal mirror-developed by Garcia (1854)

◦ Visualizes structure of vocal folds

Fiberoptic endoscope – flexible or rigid bundle of glass fibers used to convey an image of the glottis

◦ Halogen light source◦ Flexible scope usually passed

through the nasal cavity◦ Can view the glottis during speech ◦ Rigid scope usually passed orally

◦ Can view the glottis during sustained phonation

◦ Looks at laryngeal structure◦ Image can be viewed through an eyepiece or

recorded digitally/videotape/film

Stroboscope – light flashing at a fixed frequency (patient’s fundamental frequency - Fo)

GOLD STANDARD: Look at structure and function!

◦ Stroboscopic (Xenon) light source Uses rigid or flexible endoscope

visualizes vocal structure and function using stroboscopic light source

Image can be viewed through an eyepiece or recorded digitally/videotape/film

◦ Perception :

◦ Pitch - fundamental frequency (Hz)◦ Loudness - sound pressure level (dB)◦ Quality - -fundamental frequency perturbation (% jitter: <1%)-sound pressure level perturbation (dB value: <.5dB or % shimmer) -signal-to-noise ratio

- Acoustic analysis is a type of objective measure.

- Objective measures are used to support and validate clinical (subjective) judgments not to replace them.

- Fill the need for objective outcome measures to assess treatment efficacy. POTENTIAL BENEFITS OF ACOUSTIC ANALYSIS:

- More accurate and thorough diagnoses.- Better quantification of the impact of the disorder on vocal function.

- Objective documentation that can assist in subsequent evaluation of treatment effectiveness.

- Assist development of more comprehensive and better coordinated treatment plans.

- Increased efficacy (via data base).

ACOUSTIC ANALYSIS SHOULD BE INTEGRATED INTO A COMPREHENSIVE EVALUATION

Non-invasive

Low cost

Applicable to treatment as well as diagnosis

Supported by substantial body of literature

Repeatable

Reportable

Absence of Standards in Applying Acoustic Measurements

Tasks (instructions, controlling patient compliance and/or effort level,

etc);

Instrumentation (signal sampling rates, response characteristics);

Analysis methods (specific algorithims used, etc)

Quality of Normative Data

Sample sizes

Limitations in age representations

Non-standardized data collection and analysis

Use caution (wide margins for normal limits) in the application of currently available normative data.

Voice Disorders

◦ Voice disorders exist when a person’s vocal quality, pitch, or loudness differs from those of similar age, sex, cultural background, or geographic location.

Motor Speech disorders

Disorders of speech resulting from neurologic

impairment affecting the motor programming or

neuromuscular execution of speech.

Dysarthria

Apraxia

s/z ratio

The s/z ratio compares the individual’s ability to sustain the voiceless and

voiced fricatives.

Normal ratio is around 1.0–1.4,

Calculating the s/z ratio:

Ask the patient to take the deepest breath possible and sustain /s/ for as long as possible.

Use a stopwatch to time the /s/.

Now ask the patient to take the deepest breath possible and sustain /z/ for as long as

possible.

Use a stopwatch to time the /z/.

Divide the time recorded for /s/ by the time for /z/ to obtain the ratio.

Repeat the process at least 3 times

Longest duration of sustained phonation

Typical duration for adult ~20 seconds +5

Problems related to s/z ratio:

Ratios greater than 1.4 demonstrate that the patient is not able to sustain the voiced sound for as long as the voiceless sound, and this may indicate impaired glottal efficiency.

Evidence that there is considerable variability in the s/z ratios of healthy speakers with no voice problems, and there is overlap in the ratios of those with and without laryngeal pathology (Gelfer & Pazera, 2006).

NOTE: Clinicians should interpret results cautiously, if they choose to administer this task.

Relies on clinician’s ability to analyze speech (and related systems) by listening to it

Although susceptible to unreliability (as we shall see) and difficult to quantify, still most widely used method

Ultimate outcome is how well the speaker is able to be understood by a listener (if speaking is a realistic goal)

The Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) was developed as a tool for clinical auditory- perceptual assessment of voice.

◦ Its primary purpose is to describe the severity of auditory-perceptual attributes of a voice problem, in a way that can be communicated among clinicians.

◦ Its secondary purpose is to contribute to hypotheses regarding the anatomic and physiological bases of voice problems and to evaluate the need for additional testing.

CAPE-V is not intended for use as the only means of determining the nature of the voice disorder.

◦ Use instrumentation to analyze speech waveform◦ Generally used to explore speech impairment in greater

detail, with quantifiable, reliable measurements ◦ Use to confirm perceptual judgments◦ Useful for providing feedback in some forms of

treatment and in objectifying progress.

Research quality software for speech analysis

Dedicated hardware permits precise acoustic measurements

Microphone inputs directly to processor

Acquires, processes, displays, speaks, analyzes, edits, stores, prints data

◦ Processor feeds to computer for analysis and display

Most effective for research,clinical speech /voice analysis, singing

Analysis of Dysphonia in Speech and Voice (ADSV)

ADSV from KayPENTAX is the first commercial program of its kind.

It allows for voice quality assessment of sustained and continuous speech samples ranging from mildly to severely dysphonic voices.

Complements the perceptual evaluation and Multi-Dimensional Voice Program (MDVP) analysis (used for sustained phonation only).

ADSV also provides objective data which contributes to evidence-based clinical practice

Multi-Dimensional Voice Program (MDVP)

◦ Provides robust acoustic analysis of the voice quality of sustained phonation (plots multiple parameters from a single phonation)

Provides useful pitch information on running speech although designed for sustained vocalization

Most effective for pathological voice, may also be used for motor speech disorders

Client sustains an /ɑ/ vowel sound.

The MDVP automatically measures 30 parameters of the voice sample (including fundamental frequency, jitter, and shimmer) and compares them against built-in normative data.

Used for examination of voice behaviors

Provides a two dimensional profile of

an individual’s amplitude range as a function of total fundamental frequency range

Most effective for professional voice users, although may be used for vocal problems in the non-professional voice

◦ Provides real-time display of

fundamental frequency and

amplitude

Provides quantitative and objective

measures of speech/voice parameters via built in protocols for assessment and treatment tasks

Most effective for clinical speech and voice clients to address frequency, amplitude, voicing, timing, intonation and stress.

Provides objective tools of motor speech behaviors

Useful measurement of the extent of a speech problem and to

assess a patient’s progress

Most effective for patients with motor speech disorders.

Diadochokinetic rates measure performance in a maximum rate task (“Say puh-puh-puh as fast as you can”).

Can repeat a single syllable or a sequence of syllables (/pʌtʌkʌ/).

A standard part of the oral mechanism exam (evaluation of the structure and function of the articulators).

DDK rate or rhythm may be abnormal in patients with motor speech disorders.◦ CSL parameter DDKcvp (coefficient of variation of DDK period)

reflects how regularly spaced syllables are in their timing.

CSL automatically compares DDK rate (DDKavr) and rhythm (DDKcvp) against built-in normative data.

CSL norms are not ideal, but automatic measurement makes it easy to track progress.

◦ Provides real time biofeedback

of vowel and sibilant

characteristics

Can be expressed as spectral

display or vowel chart-defaults

for men, women, and children.

Clinical applications and singing

Effective for

articulation/phonological disorders and accent reduction.

Auditory feedback on CSL

Kay Facilitator-five modes of auditory feedback

◦ EASY TO USE/PORTABLE◦ Speech noise masking◦ Metronomic Pacing◦ Delayed auditory feedback ◦ Looping playback

◦ Speech-Voice Amplification

The Games Program for Multi-Speech and CSL provides a rich graphical environment for engaging biofeedback to help motivate and stimulate children in speech therapy.

These games provide biofeedback on specific tasks. for example, one game lets the client pilot an airplane by changing his, or her, pitch; another provides feedback for appropriate loudness.

Quiet environment (ideally, a sound-proof booth)

High quality microphone and recording systems (i.e., CSL

vs. Multi-Speech program)

Control microphone distance and placement

◦ You do not want to record ambient noise

Sound pressure level calibration◦ If all else fails- maintain as constant a set-up as possible as

comparison within and across patients are valid.

1. Supports evidence-based treatment

PAS provides key airflow and pressure measures of speech and voice production including graphical and quantitative data for monitoring and reporting patient performance. These data support evidence-based clinical practice.

2. Easy to use

PAS software utilizes a convenient set of protocols based on typical phonatory/aerodynamic tasks. These consistent and simple data collection methods minimize variability in application and help produce accurate results.

3. Improves clinical understanding

Measure of aerodynamic parameters improves clinicians’ understanding of phonatory behaviors and complements acoustic and imaging data.

•Regions that extend beyond green circle fall outside of normal range of variation (MDVP’s internal norms).

•Caveat: “At this time, the MDVP normative values should be regarded as preliminary and not as commonly recognized criteria by which abnormality is established” (Kent, Vorperian, & Duffy, 1999).

•Can use other (published) norms. •Can be used to track progress in

therapy - compare client against self.

•Used to obtain the individual’s perspective on degree of:

◦ pain◦ fatigue◦ perceptions about the disruption to communication

created by the voice problem• Measured using the quality of life instruments

• Voice Handicap Index (Jacobson et al., 1997)

Quality

Resonance

Pitch

Loudness

Prosody

• Breathy voice refers to voice produced with incomplete closure of the vocal folds.

◦ Vocal folds are close enough to vibrate, but a continuous stream of air can escape through opening in the folds during speech.

◦ Escaping air is audible as high-frequency aperiodic noise.◦ Phonation cannot be sustained as long as if air were valved

efficiently (complete seal).◦ Pitch range may also be reduced relative to normal

phonation.

Rough voice refers to voice produced with aperiodic vibration of the vocal folds.

This may be caused by an asymmetry in the vocal folds, e.g. a mass on one vocal fold.

Extraneous noise is created. Noise is at lower frequencies than the additive noise in breathy voice.

Hoarse voice can refer to a voice quality that is simultaneously rough and breathy.

Recall that these terms are not used in a universally consistent or standard fashion.

Voice Quality-

Evaluate during a sustained phonation and conversational speech sample

Subjective: Perceptually assess patient’s voice for hoarseness, breathiness, roughness, strained-strangled, harshness, etc

Objective: Assess using measures of jitter, shimmer, harmonics–noise ratio.

Suggested perturbation measures: Jitter: <1%Shimmer: <=3.81% or <.5dB Harmonics-to-noise ratio: >20

Acoustic Assessment:

Acoustics correlates of quality easily assessed during MDVP analysis.

A periodic waveform has a shape that repeats over time.

Recall that the human voice is nearly periodic, but no two cycles of vocal fold vibration produce identical waveforms.

There are small cycle-to-cycle variations in frequency (jitter) and also in loudness/amplitude (shimmer).

A small amount of jitter and shimmer is a normal property of the human voice.

What causes cycle-to-cycle changes in the waveform?

Vocal folds may be slightly asymmetrical; one fold may have more mucus on it

than the other, creating frequency irregularities.

Fluctuations in lung pressure may affect frequency or loudness.

Air may become turbulent as it passes through the glottis.

Abnormally high cycle-to-cycle variations may indicate pathology such as a mass on one vocal fold.

Harmonics-to-noise ratio (HNR):

A harmonic is a whole-number multiple of the

fundamental frequency.

Harmonics are the product of periodic vibration

of the vocal folds.

The human voice also features some aperiodic

noise (irregular vibration, noise of air escaping

if closure is not complete).

HNR compares the loudness of the

harmonics of the vocal source versus

extraneous noise. Higher = better.

NHR (noise-to-harmonics ratio) is the

inverse of HNR.

Multi-Dimensional Voice Program (MDVP)

Provides robust acoustic analysis of the voice quality of sustained phonation (plots multiple

parameters from a single phonation)

Provides useful pitch information on running

speech although designed for sustained

vocalization

Most effective for pathological voice, may also be

used for motor speech disorders

Task: Client sustains an /ɑ/ vowel sound.

The MDVP automatically measures 30 parameters of the voice sample (including fundamental frequency, jitter, and shimmer) and compares them against built- in normative data.

Measures of jitter, shimmer and HNR may be obtained by selecting the desired voice sample area while viewing a sound file – acoustic waveform and spectrogram and selecting Pulses.

Pitch-

Evaluate during sustained phonation and conversational sample

Subjective: Perceptually assess patient’s voice for pitch with regard to age, size, and gender.

Objective: Assess fundamental frequency (Hz), compare with normative data.

NOTE: No significant sex differences before puberty.

Average fundamental frequency:

~120 Hz for adult males

~220 Hz for adult females

Average adult male voice is approximately one octave lower than a female’s. Acoustic Assessment:

Evaluate during habitual pitch and pitch range tasks, although all tasks will provide frequency data.

Habitual pitch: Count from 1-10 in a natural voice

Pitch range: Start at a comfortable pitch and then go as high

as you can. Start at a comfortable pitch and then go as low as you can

Habitual pitch: Computer calculates average F0 across a conversational or reading sample.

Perceptual judgment of typical versus atypical

pitch may be misleading: A hoarse or breathy voice is typically perceived with an altered- pitch, although its F0 may not be abnormal.

We will also measure pitch variability (standard deviation of F0 in connected speech sample).

Pitch range (also called maximum phonational frequency range): Difference between speaker’s lowest and highest possible pitches.

◦ Reduced in patients who have trouble adducting the vocal folds due to weakness or mass(es) on the folds.

Task: Count to 10 in a normal voice

Following the recording, summary statistics are provided.

Mean habitual fundamental frequencies (F0 's) are typically observed between:

100-150 Hz for adult males

180- 230 Hz for adult females (Awan,

2001).

Example:

26 year old female

Mean fundamental frequency – 141.80

Hz

Measures total pitch range of the patientTask: Phonate at comfortable to highest /comfortable to lowest pitchTotal pitch range has been said to provide an important index of laryngeal health (Case, 1996) Often one of the first parameters of vocal capability affected in voice disorders.Normal range depends on age and gender of speaker

Loudness-

Evaluate during sustained phonation and conversational sample

Subjective: Perceptually assess patient’s voice for loudness during speech activities.

Objective: Assess intensity (dB), compare with normative data.

Suggested average intensity: ~60-70 dB SPL for everyone Intensity range:~50-110 dB SPL for everyone

Acoustic Assessment:

Evaluate during habitual pitch, phonatory respiratory control, and maximum phonation time; all tasks will provide intensity data.

• Phonatory/respiratory control◦ Influenced by breath support, efficiency of valving at vocal folds.

• Maximum phonation duration: Speaker sustains an ‘ah’ vowel for as long as possible.

◦ Influenced by breath support, efficiency of valving at vocal folds.

• Dynamic range: Difference between speaker’s softest non-whisper phonation versus loudest phonation.

Varies depending on the pitch being used.Tends to be decreased in Parkinson’s Disease and other conditions affecting muscles of respiration.