SLHS Unit 2

Developmental disorders

 become evident as a baby or child develops, often without na clear cause

Congenital disorders

present at birth (e.g., down syndrome)

Acquired disorders

emerge in a person who previously had typical communication, often due to an illness or neurological event (e.g., stroke)

Functional

no known cause

Articulation

motor aspects

Phonology

linguistic aspects

Organic

developmental or acquired

Motor/neurological

Execution (dysarthria), Planning (apraxia)

Structural

Cleft palate/other orofacial anomalies, Structural deficits due to trauma or surgery

Sensory/perceptual

hearing impairment

Structural causes of speech sound disorders

Imprecise articulation due to structural damage or abnormality of the articulators

Cleft palate

Failure of the lip and/or the palate to fuse during fetal development, A congenital condition, Makes it difficult or impossible to speak typically, Can be repaired surgically, but speech sound disorder may persist

Cleft lip

problems with labial sounds

Cleft palate

hypernasality, incomplete constriction of oral cavity

Neuromotor causes of speech sound disorders

Imprecises articulation due to impaired nervous system control of the muscles (dysarthria, apraxia of speech

Dysarthria

muscles are weak or paralyzed, lack coordination, or a combination of the above

Apraxia of speech

problems with planning how to move the muscles

features of dysarthria

Imprecise articulation, Speech is slow and effortful, Disorders of voice and/or respiration are common

causes of dysarthria

congenital, acquired neurological conditions (stroke, parkinsons disease, amyotrophic lateral sclerosis (ALS)

Apraxia of speech

No muscular weakness or paralysis

features of apraxia of speech

Imprecise articulation, Speech is slow and effortful, May struggle with the articulators (“articulatory groping”), Disorders of voice or respiration are not common

causes of apraxia of speech

Developmental disorder in children, Acquired disorder in adults, often resulting from stroke 

Classifying Articulation and Phonological Errors 

Speech rate and rhythm is normal, No problems with voice and respiration 

Articulation

Decrease in accuracy of articulation as a result of incorrect placement or movement of articulators

types of speech disorders

Typical developmental (before school age) and phonological speech sound disorders (school age and older), Structural and neuromotor speech sound disorders

Typical developmental (before school age) and phonological speech sound disorders (school age and older)

Substitutions (I tee the wabbit—> I see the rabbit), Omissions (boo—> book)

Structural and neuromotor speech sound disorders

Distortions, Additions (galass—> glass)

Types of deletion

• Final consonant deletion (bat—> ba)

• Unstressed syllable deletion (above—> –bove)

• Cluster reduction (step—> –tep)

Types of substitution

Assimilation, Substitution

Assimilation

Regressive (backward) assimilation (dig—>gig), Progressive (forward) assimilation (toad—>toat)

Substitution

Stopping— stop sounds are substituted for fricative (sheep—> teep), Fronting— alveolar sounds are substituted for palatal and velar sounds (came—> tame)

Assessment

identification of the child’s needs and strengths (Hearing test, Oral mechanism evaluation: structure and function, Articulation inventory and phonological processes)

Intervention methods for speech sound production in children

acquisition, generalization

Acquisition

• learning to produce the sound 

  • Minimal pairs: communicative significance 

  • Visual cue: e.g., looking in the mirror 

  • Tactile cues, e.g., touching the lips or throat

generalization

• using the sound in new contexts 

  • In other contexts (can—> back)

  • Longer utterances (words—> phrases —-> sentences)

  • In other context (therapy —> class activities)

  • With other people (clinician —> parents, peers, strangers)

voice disorders

vocal quality, volume, pitch, nasality (“resonance”), vocal fatigue, loss of voice

Voice problems

very common and usually go away quickly on their own 

voice disorders

•  last longer and can benefit from help from a/an…

  • Otolaryntologist (ear, nose, and throat doctor)

  • Speech-language pathologist 

causes of voice disorders

functional, structural, neuromotor

Functional

inefficient use of the vocal mechanisms when physical structures are normal

Structural

damage to the vocal folds

Neuromotor

paralysis or malfunction of the vocal folds due to neurological injury or disease

Visualizing vocal fold health

Acoustic measurements of the voice

Videoendoscopy

Through the mouth: rigid endoscopy, Through the nose: flexible endoscopy

rigid endoscopy

Through the mouth

flexible endoscopy

Through the nose

Functional causes of voice disorders

• Inefficient use of vocal mechanism, using compensatory muscles and excessive vocal force

  • Muscle tension 

  • Diplophonia 

  • Ventricular phonation 

• Can lead to structural damage

Muscle Tension

• Soft volume phonotation 

• Loud volume phonotation

Damage to the vocal folds

• Swollen and irritated, due to overuse or disease

• Benign growths on the larynx

  • Vocal nodules (small bumps)

• Laryngeal cancer 

  • Tumor 

  • Treatment sometimes requires removal of larynx

Vocal nodules

• Small bumps 

• Caused by overuse of the voice

• Most common in young and middle-aged women (20-50)

• Can cause a range of voice problems

Treatment of damage to the vocal cords

• Management of use of voice 

  • Rest the voice 

  • Avoid yelling, coughing, etc. 

  • Learn to project in a way that’s easier on the voice

• Lifestyle changes (diet, stress)

• Surgery (in some cases)

Neuromotor causes of voice disorders

• Stroke or neurological disease (e.g., Parkinson’s disease, amyotrophic lateral sclerosis)

  • Often accompanied by dysarthria 

• Voice-specific neurological disorders, involving paralysis or spasms of the vocal folds

Electrolarynx

 used by people who have no larynx or are unable to use the larynx to speak 

Speech therapy and gender identity 

• Speech-language pathologists work with people to help their voice align with their gender identity 

• Can involve changing pitch and resonance

Dysphagia (difficulty swallowing)

• Mostly affects older adults

• Speech-language pathologists treat dysphagia 

• Swallowing and speech involve many of the same structures

  • Oral mechanism (mouth and tongue)

  • Larynx 

  • Neural systems (e.g., cranial nerves)

• Many disorders involve both speech and swallowing problems

How swallowing works

1. oral preparatory

2. oral transport

3. pharyngeal

4. esophageal

Oral preparatory

• Chew food

• Gather food/liquid into a “bolus” on tongue

Oral transport

Tongue pushes bolus into back of throat (pharynx)

Pharyngeal

• Pharynx contracts to push bolus to esophagus 

• Larynx raises to protect the airway (trachea)

Esophageal

Esophagus contracts to push food into stomach

Aspiration

• Refers to entry of food or liquid into the airway 

• Problems with third (pharyngeal) swallowing stage

• Usually causes choking

• If laryngeal muscles are weak, the patient may not choke (“silent aspiration”)

• Frequent aspiration can cause pneumonia, a major health risk for people with dysphagia

Causes of Dysphagia

Neuromotor, Structural abnormalities or damage to the structures supporting swallowing

Assessing swallowing

• Patient report of difficulties

  • What happens? How often? What types of foods/liquids?

• Bedside testing 

  • Typically, a screening 

  • Yale Swallowing Protocol

• Modified barium swallow 

  • Way of visualizing the swallowing process and identifying causes of aspiration 

  • Patient swallows liquid/food of varying consistencies, containing barium

Dysphagia treatment

• Often involves otolaryngologist (ear-nose-throat doctor and speech-language pathologist

• Interventions led by speech-language pathologist:

  • Changing posture (e.g., chin down)

  • Changing diet (e.g., only eating smooth foods like applesauce and soup)

  • Altering the consistency of food or liquid (e.g., thickening liquids)

  • Exercises to strengthen swallowing muscles 

• Medical interventions 

  • Medications, e.g., to address reflux 

  • Surgery to address structural problems

Stuttering

• Persistent and frequent disfluencies 

• Impacts roughly 3 million people 

• Affects all ages; but typically starts between 2 to 6 years old 

• Can vary throughout someone’s day

• Boys are 2-3x more likely to stutter compared to girls

  • Gender difference increases as they age: boys 3-4x more likely to stutter

Causes of Stuttering

• Developmental stuttering 

  • Many theories; different levels of explanation 

  • Genetic 

  • Neurological features

    • Brain function: more right hemisphere activation (vs. normal fluency)

    • Brain structure: differences in white matter pathways (vs. normal fluency)

    • Less efficient auditory feedback 

• Acquired stuttering 

  • Neurological event (e.g., stroke, toxin exposure)

  • Psychogenic

Physical Signs of Struggle during Stuttering

• Eye blinking 

• Mouth movements 

• Facial movements

• Body or limb movements 

• Vocalizations

Stuttering Treatment

• Direct methods: train fluency directly 

  • Modifying stuttering: stutter more effectively 

    • Help the client stutter more fluently with less effort

    • Improve the person's attitude toward stuttering 

    • Reduce struggle and avoidance 

    • Reduce secondary stuttering behaviors 

  • Modifying speech: speak fluently 

    • Slow down, change the prosody, prolong vowels

• Indirect methods: trying to promote fluency without directly teaching the client how to be “fluent” 

  • Slowing your speech rate (vs. the person who stutters)

  • Praising fluent speech; drawing attention to disfluent speech (children)

  • Delayed auditory feedback

Psychological

• The auditory experience of hearing “what we hear”

• Definition of sound: the disturbance of molecules within an elastic medium

  • This disturbance can be physically measured

  • Consider: properties of the source, the sound itself, and the medium

Types of Waves

• Transverse

• Longitudinal

Sound Waves

• Initial disturbance sets vibrating molecules into motion: molecular disturbance

Sound Sources and Mediums

Depending on the elastic properties of mediums, the sound characteristics will be different

The Outer Ear

• Helix 

• Tragus 

• Concha 

• Anti-tragus 

• Lobe

Out Ear Function

• Outer ear resonance 

  • Concha bowl of the pinna has a resonance of 6-8 dB around 4-5 kHz

  • Pinna effect has a resonance at 2 kHz and above and can vary from 3-8 dB

• This is important for hearing aids

  • The location of the hearing aid microphone may or may not be able to take advantage of these effects

Microphone Location Effects

• Graph from Chasin (1997) shows the amount of gain due to the pinna effect at the microphone for three styles of hearing aids

• Note that the BTE is not able to take advantage of any of the pinna effects as its mic is located above the pinna

External Auditory Canal

• Roughly 25 mm in length

• Outer opening 8-10 mm

• Decreases 5-6 mm in the deeper portions

• Enlarges again when reaching the tympanic membrane

• Outer third of the canal is cartilaginous 

• Inner ⅔ of the canal is bony

The Tympanic Membrane

• Physical characteristics

  • .6 mm in thickness and 8-10 mm in diameter

  • Angle of 45 degrees 

  • Conical in shape 

• Composed of three layers 

  • Outer: keratinized epithelium

  • Middle: fibrous (lamina propria)

  • Inner: mucosal layer 

• Attached to the manubrium in the malleus

The Middle Ear

• Tympanic membrane 

• Ossicular chain 

  • Malleus 

    • Tensor tympani (V)

  • Incus 

  • Stapes 

    • Stapedial muscle (VII)

  • Oval window

The Middle Ear

• Malleus 

• Incus 

• Stapes 

• Tympanic membrane

The Middle Ear Function

• Mechanical purpose

  • Transform acoustical energy into an effective and efficient means of driving the fluid of the inner ear

  • Increases the effective pressure of the sound energy striking the oval window 

• Accomplished by 

  • Great difference between the area of the tympanic membrane (60 mm2) and the stapes footplate (3.2 mm2), and because the malleus and incus combine to form a lever 

Inner Ear

Hearing and balance

• Semicircular canals (balance system of the inner ear)

• Vestibular nerve (balance)

• CN VII

• Cochlea 

• Cochlear nerve (hearing)=

Cochlea (latin: snail)

• Tube coiled around a central axis

  • Modiolus 

  • 2 ½ turns in humans

• 30 mm in length

• Three compartments or scalae

  • Scala vestibuli 

  • Scala media

  • Scala tympani

Scala vestibuli

• Above the scala media

• Bounded by Reissner's membrane

• Oval window opens into vestibule

Scala tympani 

• Below the scala media 

• Bounded by the basilar membrane 

• Round window opens into the scala tympani at the beginning of the basal turn

Scala vestibuli and tympani

• Contain perilymph 

  • Low K+ concentration, high Na+ concentration 

• Connected through the helicotrema

Scala media

• Contains endolymph 

  • High K+ concentration

  • Low Na+ concentration

Organ of Corti

Rests on basilar membrane

Basilar membrane

• Series of linked resonators (turning forks!)

• Stiffness varies from base to apex

  • Stiffer at the base than the apex 

  • One octave every 3 mm

    • Double of frequency 

• Width increases from 0.12 mm at the base to 0.5 mm at the apex

Inner hair cells

• 3500 in humans

• Tips do not touch the tectorial membrane

Outer hair cells

• 12000 in humans

• Tips are strongly embedded in the tectorial membrane

• Electromotile

Inner and outer hair cells

• They and supporting cells form ionic barrier called reticular lamina 

• Separating endolymph from perilymph in tunnel of corti and surrounding areas

Cochlear Mechanics

• Fluids in the inner ear are incompressible 

• Pressure fluctuations in the fluids occur almost instantaneously along the entire length of the cochlea 

• The mechanical impedance of the cochlea varies from base to apex