exam 3 Flashcards
Nervous System (NS)
• The “control system” for our body
• Responsible for all movements involved in speech
production
• Normal functioning NS required for normal speech
• NS disruptions result in abnormal speech
• NS disruptions can also result in language and cognitive
disorders
NS Divisions
- Central Nervous System (CNS)
- brain and spinal cord
- Peripheral Nervous System (PNS)
- somatic system
- cranial and spinal nerves
- autonomic system
- sympathetic division (activating)
- parasympathetic division (dampening)
Brain Tissue: Glial Cells
- Made of connective tissue
- Known as the “supporting cells”
- Four main functions:
- Surround neurons and hold them in place
- Supply nutrients and oxygen to neurons
- Insulate one neuron from another
- Destroy and remove dead neurons (waste)
Brain Tissue: Glial Cells
Astrocytes
Oligodendrocytes
Schwann cells
Microglia
Astrocytes
ost common type; connect blood and
nerve cells
Oligodendrocytes
found in the CNS; forms myelin
sheath (insulation layers that wrap around nerve cells)
Schwann cells
found in the PNS; forms myelin sheath
Microglia
found in CNS; clean up waste and harmful
organisms
Brain Tissue: Neurons
Specialized nerve cells that processes and transmits
information through electrical and chemical signals
The core component of the NS
Basic structure across all neurons
Neuron Structure
• Cell body (or soma): made up of a nucleus surround
by cytoplasm
• Organelles are specialized microstructures located in
the cytoplasm
• Dendrites: short projections that branch off the cell
body; transmit nerve impulses towards the cell body
• Axon: extends off the cell body; transmit nerve
impulses away from the cell body
• Myelin sheath wraps around most axons
• Nodes of Ranvier: interrupt myelin sheath; speed up
rate of nerve transmission
• Terminal branches: axon divides at its endpoint;
branches end in terminal buttons
• Terminal buttons: contain neurotransmitters; the
site of communication from with nerve cells
Neuronal Communication
Synapse: gap between nerve cells
• Axo axonal synapse: synapse between an axon and
another axon
• Axo somatic synapse: synapse between an axon and
cell body (soma)
• Axodendritic synapse: synapse between an axon
and dendrite
• Communication accomplished by neurotransmission
Neurotransmission
An electrochemical process
◦ At rest, more positive ions (Na+ and K+) outside cell and
more negative ions (Cl-) inside cell
◦ Imbalance creates voltage across cell membrane, resting
membrane potential (RMP)
◦ Depolarization: Na+ enters cell, reversing electrical
charge to positive
◦ Repolarization: K+ leaves cell, reverting electrical
charge to negative
Central Nervous System
Protective tissue and fluid that surrounds the brain and
spinal cord
Three layered system:
1. Dura matter: outermost layer; tough connective
tissue; blood vessels
2. Arachnoid matter: delicate tissue; no blood vessels
3. Pia matter: delicate vascular tissue closest to the brain
CNS: Hemispheres
• Left hemisphere and right hemisphere
• Connected by nerve pathways, known as the corpus
callosum
CNS: Cortex
• Outermost layer of brain • “Gray matter” • Convoluted surface, with many folds: • Gyri: raised tissue • Sulci: shallow depressions • Fissures: deep grooves * Increase surface area without increasing space. • Neocortex: 95% of cortex. Responsible for higher order thinking and processing
CNS: Lobes of the Brain
Sulci and fissures separate cortex into four lobes:
1. Frontal
2. Parietal
3. Temporal
4. Occipital
Brodmann areas: 52 functional areas of human cortex
(including areas most important for speech & hearing) *
Caveats to Broadmann’s Area
1.Areas in brain are not completely separated and
boundaries are not precise
2. Identified areas in brain are not the only brain site for a
particular function
3. Lobes in left and right hemispheres are not identical in
either structure or function
Frontal Lobe
• Largest lobe in the brain.
• Motor and higher mental functions:
• Speech and language; Problem solving; Attention; Memory;
Personality and emotion; Symbolic function; Social behavior.
• Areas associated with speech & hearing:
• Motor strip(#4)
• Premotor area & supplementary motor area (#6)
• Broca’s area (#44, #45)
Parietal Lobes
- Sensory functions:
- Touch; Pressure; Pain; Proprioception; Temperature
- Areas associated with speech & hearing:
- Primary somatosensory area (#3, #2, #1)
- Somatosensory association area (#5, #7)
- Angular gyrus (#39)
- Supramarginal gyrus (#40)
Temporal Lobes
- Understanding functions:
- Hearing; Memory; Language (understanding and formulating).
- Areas associated with speech & hearing:
- Primary auditory cortex (#41)
- Auditory association area (#42)
- Wernicke’s area (#22)
Occipital Lobe
- Reception and processing of visual information
- Areas associated with speech & hearing:
- Primary visual area (#17)
- Visual association area (#18, #19)
Cerebrum
• Main mass of brain • “White matter” • Myelinated nerve fibers involved in the transmission of information • Deep in cerebrum, are pockets of gray matter: • Basal nuclei • Thalamus • hypothalamus
Cerebrum: Basal Nuclei
• AKA Basal Ganglia
• Composed of the caudate nucleus, globus pallidus,
putamen, and substantia nigra
• Primary functions to regulate motor control (balance,
posture, coordination) and precise voluntary
movements
• Damage to the basal nuclei is seen in conditions like
Parkinson’s Disease and Huntington’s Disease
Cerebrum: Thalamus
• A collection of motor function nuclei and sensory function nuclei. • The “gateway to consciousness” • And a “relay station” • Thalamic nuclei critical to speech and hearing: • Ventral anterior nuclei (VA) • Ventral lateral nuclei (VL) • Medical geniculate body • Lateral geniculate body
Brain Stem
- Midbrain
- Pons
- Medulla
Connects brain to spinal cord
Reflex control (e.g., respiration, body temperature,
swallowing, digestion)
Site of origin for cranial nerves
Reticular activating system: controls alertness
and consciousness
Cerebellum
• White matter mass, overlaid by cortex
• Two hemispheres, connected by nerve bundle
• Ipsilateral control
• Receives sensory information and sends motor
information
• Involved in balance, posture, background muscle tone,
and coordination of voluntary movement
Spinal Cord
Continuous structure, divided into: 1. Cervical (neck) 2. Thoracic (chest) 3. Lumbar (lower back) 4. Sacral (pelvis) 5. Coccygeal (tail bone) Contains cell bodies for the spinal nerves (31 pairs) that run to all muscles in bod
Spinal Cord
• Adult cord 42-45 cm long, 1 cm diameter
• Covered by the meninges
• White matter on outside and gray matter on inside
(reverse)
• Gray matter:
• Butterfly-shape, with anterior and posterior horns
• White matter:
• Funiculi: myelinated sensory and motor pathways bundled into
one large tract; dorsal, ventral, and lateral x2
Cranial Nerves
• 12 pairs
• Transmit information to and from face and neck
regions
• Most cell bodies of CN arise from brain stem (III-XII)
• Numbered according to their order of emergence in
the brain stem
• Six are critical for speech and hearing!!
CN for Speech and Hearing
- CN V: Trigeminal
- CN VII: Facial
- CN VIII: Auditory
- IX: Glossopharyngeal
- X: Vagus
- XII: Hypoglossal
Brain Imaging Classification
- Brain structure (anatomy)
- X-rays (i.e., CT)
- Imaging techniques (i.e., MRI)
- Brain function (physiology)
- Electrical measures
- Biochemical measures
- Physiologic measures
Computerized Tomography (CT)
• X-ray technique.
• Sensitive to tissue density:
• Denser tissue absorbs more radiation à
lighter image
• Brain CT:
• Skull is white (high density)
• Brain matter is gray (intermediate density)
• Cerebral ventricles are black (low density)
• Constructed from lots of scans as x-ray rotates around
head
• Used to define normal and abnormal structures:
• diagnose tumor, head trauma, degenerative disease,
stroke
• Advantages:
• Short imagine times
• Painless (and minimally invasive)
• Extremely accurate images
• Disadvantages:
• Radiation
Magnetic Resonance Imaging (MRI)
• Imaging technique
• Exposure to a very powerful magnet which changes
alignment of hydrogen atoms in organ cellular
structure
• Different tissues within the brain contain different
amounts of water (and hydrogen)—produces tissue
contrast
• Computer transforms information to representation of
structures
• Used to diagnose brain diseases and disorders
• Advantages:
• Does not use ionizing radiation
• Very high degree of spatial resolution
• Depicts anatomy in greater detail than CT: more sensitive and
specific for abnormalities within brain
• Disadvantages:
• Higher cost
• Long imaging times
Imaging Brain Function
Techniques are based on cerebral blood flow, cerebral
metabolism of O2 and glucose, & electrical properties
of neural function
All techniques depend on changing brain activity during
use. Whenever a task is conducted there are local
changes in neural function
Functional Magnetic Resonance Imaging
fMRI
• Measures brain activity by detecting associated changes
in O2 and blood flow
• Hemodynamic response: the increase in regional
blood flow:
• Neural activity uses O2 and requires increased blood flow
to replace depleted O2 levels
• Highlights regions of the brain linked to critical
functions such as speaking, moving, sensing, or planning
• Advantages:
• Safe and non-invasive
• Allows examination of changes in individual brain function
over time or during different activities
• Useful for rehabilitation (document recovery)
• Disadvantages:
• Slow scanning process
• Noisy scanner
Positron Emission Tomography (PET)
• Quantifies the distribution of a radioactive tracer in
brain
• Inhaled substance (oxygen, nitrogen, carbon, & fluoride)
• Eliminates from body in 6-24 hours
• Amount of tracer in area of interest will depend on
the regional cerebral blood flow (rCBF)—related to
neural activity
• More active, absorb more tracer
• Inactive, absorb less tracer
• Color-coded representation:
• Red = high levels of activity
• Purple/black = little/no activity
• Advantages:
• Short scan time
• Disadvantages:
• High radiation exposure
• Decreased spatial resolution compared to other
techniques
Electroencephalography (EEG)
Records the electrical potentials (activity) generated by
the brain via electrodes placed on the scalp
• Computerized techniques allow quantification of the
activity (qEEG)
• Analyzed by Fourier analysis, shows dominant
frequencies of brain activity
• Event-related potentials (or EP) are brain potentials in
response to a stimulus
EEG and EP
Advantages:
• Relatively inexpensive
• Excellent temporal resolution
• records brain activity in response to specific stimulus
• Disadvantages:
• Averages electrical brain signals, preventing precise
specification of underlying neural structures
Transcranial Magnetic Stimulation (TMS)
Magnetic field produced by coils placed on the head
creates a current & stimulates cortical neurons to fire
• Examines neurotransmission along nerve tracts
TMS
• Useful for evaluating and treating neurological
disorders e.g., Parkinson’s disease, Multiple Sclerosis
• Also useful for depression
• Advantages:
• Safe and noninvasive
• Disadvantages:
• Rare occurrence of induced seizures and syncope
(fainting)
Near-infrared spectroscopy
NIRS
Measures oxygenated and deoxygenated areas in the
brain with diodes (hemoglobin concentration changes
can be detected through the near infrared light)
NIRS
- Advantages:
- Portable
- Can be used with infants
- Some wireless instrumentation available
- Engage in functional activities
- Disadvantages:
- Only measures cortical areas
- Potentially painful
- Difficulty with individuals who have hypersensitivities
Brain Imaging Techniques in COMD
• Application for disorders of speech, language and hearing
disorders.
• Assists with diagnosis:
• Provides an index of brain function in neurological disorders
e.g., CVA, Parkinson’s Disease, Alzheimer’s Disease, MS, etc.
• Assist with treatment:
• Evaluate efficacy of treatment over time.
• Compare different
Current studies (NIRS)
• Stuttering • Concussion • Performance on attention and memory tasks before and after concussion was the same • Neural activation before and after concussion differed • Conversational Studies • Acoustic patterns • Neural patterns
Current studies
NIRS and Eye-tracking
26 Current studies (NIRS and Eye-tracking) • Agent Rest • Syntactic processing • Verbal working memory • Reading and Comprehension • Bilingualism • Different patterns of activation compared to bilinguals • Different patterns of activation depending on age of exposure to second language
Stuttering/Fluency Disorders
• PET, SPECT, qEEG have shown differences in rCBF
between non-fluent and fluent speakers
• Findings have suggested that a complex neural network
of structures does not function normally in non-fluent
individuals
Parkinson’s Disease (PD)
Brain imaging used to diagnose and treat PD. Also to
measure progression and severity of disease
• PET shows degeneration in substantia nigra (early
detection) and increased metabolism in basal nuclei
• fMRI shows reduced activation in the supplementary
motor area and motor cortex
• EP has been used to monitor cognitive changes associated
with PD
Outer Ear
- Pinna (or auricle):
• Flap on outside of head - External auditory meatus (or ear cannel)
• Tube leading from pinna to ear drum
Outer Ear: Pinna
• Made of flexible elastic cartilage, as well as a soft lobule (lobe) on inferior portion. • Attached to head via ligaments. • Primary function: • Direct sound waves into the ear canal • Secondary functions: • Assists with localization of sound (two pinnae) • Protects entrance to ear canal
Outer Ear: External Auditory Meatus
Leads from pinna to tympanic membrane.
• Made of bone (medial) and cartilage (lateral).
• Inside lined with layer of epidermis and lateral portion
contains glands that secrete cerumen and cilia.
• Protects middle and inner ear.
• Lubricates ear and protect insects entering.
• Moves dust and small particles out of the ear.
Tympanic Membrane (TM)
• Also known as ear drum.
• Thin, semi-transparent membrane separating outer and
middle ear.
• Concave shape, with tip (umbo) facing middle ear.
• Vibrates when sound (acoustic pressure) waves hit it.
• Converts pressure waves to mechanical vibration via
connection with malleus.
Middle Ear
1. Tympanic cavity (or tympanum) and epitympanic recess (or attic) 2. Ossicles: three small connected bones: Malleus Incus Stapes 3. Eustachian tube 4. Muscles Tensor tympani Stapedius Mi
Middle Ear: Ossicles
MALLEUS
“hammer” shape, with manubrium
• Manubrium embedded in TM, head
extends into epitympanic recess
• When TM vibrates in response to sound pressure, the
malleus vibrates as well, beginning the ossicular
vibratory chain.
Middle Ear: Ossicles
INCUS
- connected to malleus, which sets incus into vibration
- attached to head bone
- also called anvil
Middle Ear: Ossicles
STAPES
Head of stapes connects with incus (lenticular process)
Footplate of stapes covers the oval window (opening
to inner ear)
Vibrating incus sets stapes into
vibration
Also called stirrup
Mi
Middle Ear: Eustachian Tube
• Long tube (approx. 35 mm), connecting middle ear
cavity to nasopharynx
Pharyngeal end of tube is normally closed (opens for
swallowing and yawning).
• Middle ear end of tube is normally open.
• Keeps middle air space ventilated (equalizes air
pressure) and drained (clears mucus by draining into
pharynx) .
Middle Ear: Muscles
TENSOR TYMPANI
Runs parallel to eustachian tube.
Contracts to move malleus inward, tensing the TM and
damping vibration in the ear ossicles, thereby reducing
the perceived amplitude of sound.
Approx. 20 mm in length.
Middle Ear: Muscles
STAPEDIUS MUSCLE
Contracts to pull stapes posteriorly and tense
membrane in oval window
Stapedial reflex: contracts strongly in response to
intense sound (80 dB +), stiffening membrane and
reducing amplitude of vibration
Less effective in noisy environments
Approx. 1 mm in length
I
Inner Ear
- Cochlea
- Vestibule
- Semicircular canals
Inner Ear: Cochlea
Bony, spiral canal with 2 ¾ turns around bony core,
called modiolus.
• Inside is membranous canal, called cochlear duct.
• Space between bony canal and membranous canal is
filled with fluid, called perilymph.
• Membranous canal filled with fluid, called endolymph.
• Base of cochlea is the basilar membrane (BM)
• Roof of the duct is the vestibular
• Scala vestibuli: space above vestibular
• Scala tympani: space below BM
• Organ of corti: sitting on BM (lined
with inner and outer hair cells)
Inner Ear: Basilar Membrane
Width of BM increases from base (0.04 mm) to apex
(0.36mm)
Opposite to width changes of bony cochlea
Stiffness of BM increases from base to apex (100x
more stiff).
BM more responsive to high frequencies at base and
lower frequencies at apex
See Figure 9.5, pp. 293
Inn
Inner Ear: Vestibule
• Central portion of inner ear • Located behind the cochlea, and in front of the semicircular canals • 5 mm in length • “Entrance hall”
Inner Ear: Semicircular Canals
Three canals/rings which house the sense organs for movement of the body in space. • Horizontal/Lateral • Anterior/Superior • Posterior
Inner Ear: Semicircular Canals
HORIZONTAL CANAL
Shortest (12-15 mm) of the three canals
Detects rotation of the head around transverse body
plane
e.g., when you turn your head to the left and
right hand sides before crossing a road
Inner Ear: Semicircular Canals
ANTERIOR CANAL
15-20 mm, vertical in direction
Detects rotation of the head around coronal body
plane
e.g., when you move your head to touch your
shoulders, or when doing a cartwheel
Inner Ear: Semicircular Canals
POSTERIOR CANAL
18-22 mm, vertical in direction
Detects rotation of the head around sagittal body
plane
e.g., when nodding your head
How WeHear
Sound travels from the outer ear to the inner ear…
Traveling wave vibration
from basal end to apex of cochlea
Basal Portion
best amplitude response to high frequencies
Apex
most sensitive to lower frequencies due to greater width and higher compliance
Tontotopic organization
frequency arrangement along basiliar membrane
Cochlear Function
cochlea performs a fourier analysis on incoming sounds
Types of Hearing Loss
CONDUCTIVE HEARING LOSS -outer and/or middle ear disorder SENSORINEURAL HEARING LOSS -inner ear disorder MIXED HEARING LOSS -combined outer and/ or middle ear with inner ear pathologies
Conductive Hearing Loss
- loss caused by interference with the flow of air pressure waves down the ear canal, across the ear drum, or through the ossicles
- most conductive losses are not permanent; usually treated medically
- if conductive loss is not treatable (deformed or absent middle ear structures), hearing aid use may be a good option
- primary problem is loss of loudness
Common Hearing Disorders of The Middle Ear
-Eustachian tube dysfunction
-tympanic membrane perforation
-otitis media
most common cause of conductive hearing loss
most common in young children but can occur at any age
seen in nearly 70% of children under age two
-external otitis media
extremely painful (aka swimmers ear)
Otitis Media
Associated Hearing Loss
- some hearing loss generally is present when fluid is present.
- loss is usually mild to moderate in degree, with hearing levels averaging about 25-30dB
- hearing loss is generally conductive and temporary. hearing loss fluctuates and returns to normal when the effusion resolves
- amount of hearing loss is influenced by the quantity and density of fluid in the middle ear
Signs and Symptoms of Otitis Media
- Acute OME: fever, congestion, pulling or rubbing a hurting ear, infection, lethargy, or crying for no apparent reason
- illness may cause tiredness, with drawl, lethargy, distractibility, protesting, or clinging behavior.
Optimal Health and Learning Environment
OTITIS MEDIA
-minimize spread of germs (wash adult and children’s hands frequently, wash toys a child mouths before anther child plays with them)
-Decrease exposure to environmental risks (cigarette smoke, prop baby up while feeding)
-follow medial recommendations/ antibiotics completion
-increase saliency of speech signal
face to face interactions
seat child close to person speaking
get child’s attention before speaking to him/her
check with child to be sure he/she understands
-reduce background noise
-modify acoustic environment as needed
Other Disorders Associated with Conductive Hearing Loss
- wax impaction in the ear canal
- atresia/microtia
- otosclerosis and ossicular fusion
- ossicular chain discontinuity
- cholesteatoma
- genetic or syndromic conditions
Sensorineural Hearing Loss
- loss due to problems in the cochlea, the auditory nerve, or any of the nerves linking the cochlea to the auditory cortex of the brain
- Sensorineural hearing loss is nearly always permanent
- some sounds are hot heard, some are heard but may be distorted
- the outer and middle ears may appear normal
- amplification is nearly always beneficial
Causes of Sensorineural Hearing Loss
- drug induced damage to the cochlea (ex. antibiotics such as gentamicin, chemotherapy drugs)
- traumatic damage of the cochlea (ex. noise induced trauma, head injury, penetrating injury to the inner ear)
- age related damage to the cochlea (presbycusis)
- tumor on the auditory nerve (acoustic neuroma)
- certain infections, such as meningittis
- maternal rubella
Hearing Aids
- The microphone picks up the sound from the environment
- the sound is sent to an amplifier inside the hearing aid
- the hearing aid processor amplifies the sound according to program input
- there mush be some outer hair cell survival in order for the sounds to be amplified
Cochlear Implants
- electronic device to stimulate auditory nerve directly
- surgically implanted electrode array into cochlea; microphone; signal processor and external transmitter
- must handle wide range of frequencies
- must be able to resolve rapid change in formats
Degree of Hearing Loss
- normal 0-15
- slight 16-25
- mild 26-40
- moderate 41-55
- moderate-severe 56-70
- severe 71-90
- profound >91
Immittance
-how easily a system can be set into vibration by a driving force. Includes to reciprocal concepts:
ADMITTANCE: how easily energy is transmitted through a system
IMPEDANCE: how a system opposes the flow of energy through it
-immitance is measured and displayed on a tympanometer, producing a graph of immittance,called tympanogram
Tympanometry
-assess a movement of the tympanic membrane in response to changing pressure
does not directly measure tympanic membrane movement
does measure amount of reflected sound or amount of sound passing through the middle ear
Tympanogram Types
- Normal (Type A)
- Negative Pressure (Type C)
- Flat (Type B)
- Hypermobile TM (Type Ad)
- Hypomobile TM (Type As)
Measurement Parameters
-probe tone frequency implications for testing frequency 256 Hz 1000 Hz -Static compliance the height of the peak -Tympanometric peak pressures the pressure at which the peak occurs -Equivalent ear canal volume estimate of volume between the probe tip and the tympanic membrane
What are Otoacoustic Emissions
- sounds measured in the external ear canal that are generated by the outer hair cells in the cochlea
- measurement of extremely low-intensity sound created by the cochlea as it process incoming sound
- spontaneous: 35-60% of people have OAE w/out incoming signal
- evoked (eoae)-produced by everyone w/normal hearing across the lifespan
- most valuable use–neonatal screening
Detection of OAE’s
- OAE’s are absent in hearing losses of approx. 30 dB HL or greater
- can have absent OAE due to middle ear fluid or blockage in the ear canal
- an absent OAE does not tell us anything about the degree of hearing loss
Factors Affecting Test Outcome
-probe insertion snug and deep -condition of the ear canal blocked with debris, stenosis -middle ear status effusion, negative pressure, other pathology -noise internal (breathing, movement) external (fan, loud talking) -cochlear function
Auditory Brainstem Response
- Diagnostic assessment-can identify degree type, and configuration of hearing loss
- a response generated from the auditory nerve, measured up the auditory pathways of the brainstem, in response to a stimulus presented to the ear
- typically, electrodes are placed on the scalp, one high on the forhead and one on each ear lobe. Placement can vary somewhat
How is Auditory Brainstem Response Measured
- the ear is stimulated with brief audiotry signals such as clicks, narrow band noise, or tonebursts
- stimulation can be air conduction or bone conduction
Auditory Pathway
The signal is measured as it travels through the
ear structures, along the auditory nerve, and up
the brainstem to the language centers of the
brain.
Measurements of Interest
Latency ◦ Time (in milliseconds) aser the onset of the sFmulus for peaks to occur. ◦ Each wave corresponds to one or more neural generators Amplitude ◦ Robustness of response Several parameters are examined to determine if the ABR is normal: ◦ Absolute latency ◦ Interwave latency ◦ Latency-intensity funcFons ◦ Waveform morphology and replicability 6
Speech Perception
Auditory access AcousFc analysis Phonemic Perception ◦ Consonants ◦ Vowels ◦ Diphthongs ◦ Fricativs ◦ Liquids and Glides ◦ Stops ◦ Nasals ◦ Influence of coarticulation
Hearing Loss
Impaired hearing affects the ability to
discriminate between like acousticelements
Result is trouble idenFfying (& then producing)
the acousFc-phoneFc features of speech
Person with hearing impairment does not receive
the mulFple cues to percepFon: formant
frequencies, formant transiFons, & spectral
characterisFcs
Deglutition
“The entire act of placing solid or liquid substance in
the oral cavity, propelling it back to the esophagus, and
allowing it to make its way through to the stomach”
(Hixon, Weismer, Hoit).
Esophageal Sphincters
• Upper esophageal sphincter (UES) is the entrance to
the esophagus
• Lower esophageal sphincter (LES) is the exit of the
esophagus
• “Zones of high pressure” rather than precise
anatomical structures
Esophagus Conditions
- Gastroesophageal reflux disease (GERD)
- Esophagitis
- Barrett’s esophagus
- Esophageal cancer
- Esophageal ulcer
Stages of Swallowing
- Oral preparatory phase
- Oral transit phase
- Pharyngeal phase
- Esophageal phase
Oral Preparatory Stage
• Sensory recognition of food approaching
• Salivation beings (helps break down food)
• Food/drink introduced into the oral cavity
• Lips/teeth/tongue remove bolus from utensil
• Oral cavity is moist, mouth closed, nostrils open
• Liquid or solid is manipulated into a cohesive unit (bolus) in
preparation and then positioned on the tongue for transport
• Labial seal prevents food from spilling out of the oral cavity
• Nose breathing due to closed mouth
Oral Transit Phase
• Begins when tongue initiates posterior movement of bolus
• Bolus is moved back due to the tongue midline sequentially
squeezing against hard palate
• A-P rolling action of tongue midline
• Tongue elevation progresses sequentially more posteriorly
to push the bolus backward
• Sides and tip of tongue are anchored to alveolar ridge
• Sensory receptors in oropharynx and tongue are
stimulated and pharyngeal swallow is triggered
Pharyngeal Phase
Complete closure of VP port to prevent material entering nasal cavity
• Elevation & anterior movement of hyoid & larynx
• Closure of VFs
• Epiglottis inverts to further protect airway
• Top to bottom contractions of pharyngeal constrictor muscles
• Tongue base to posterior pharyngeal wall contact delivers bolus to
pharynx
• Food/liquid is directed around the epiglottis
• Relaxation of cricopharygeus muscle & opening of UES region
• Opening of cricopharyngeal sphincter to allow material to pass from
pharynx to esophagus
More Details of Pharyngeal Phase
Airway protective events • Velopharyngeal closure • Closure of the true vocal folds • Eversion of the epiglottis • Bolus propulsive events • Progressive contraction of pharynx • Generation of pressure behind bolus
Esophageal Phase
• Begins when bolus enters UES and ends when it passes
into stomach via LES
• Bolus is moved down the esophagus via peristaltic
wave motion
• Assisted by gravity
• Dilation of LES
Dysphagia
• Dysphagia refers to the clinical term used to describe
swallowing disorders
• Many different causes
• Most often organic (structural or neurogenic)
• Sometimes functional or psychogenic.
• Many different types
Organic dysphagia
- Structural:
- Tumors
- Diverticular
- Osteophytes
- Tissue deformation
- Congential malformations
- Neurogenic
- Stroke (CVA)
- Traumatic Brain Injury
- Parkinson’s disease
- Multiple Sclerosis
- Huntington’s disease
- Alzheimer’s disease
The Professional Team
Speech-Language Pathologist • Radiologist • Gastorenterologist • Otolaryngologist • Dietitian • Occupational therapist • Others depending on the nature of the dysphagia (e.g., neurologist, physical therapist)
Dysphagia Symptoms:
Patient Perspective
- Coughing and choking
- Food catching in throat
- Food coming out nose
- Chewing difficulties
- Weight loss
- Drooling
- Change in voice or speech
- Recurrent pneumonia
Dysphagia Symptoms:
Clinical Perspective
• Categorized according to the swallowing phase that is
affected
Oral Preparatory Stage Symptoms
- Incomplete or reduced lip seal
- Inefficient bolus preparation
- Buccal pocketing of food
- Reduced lingual control
- Reduced mastication
- Prolonged oral preparation time
Oral Transit Stage Symptoms
- Poor A-P transfer
- Increased oral transit time
- Excessive gagging
Pharyngeal Stage Symptoms
- Delayed pharyngeal swallow response
- Laryngeal penetration
- Aspiration
- Reduced hyolaryngeal elevation
- Nasal regurgitation
Esophageal Stage Symptoms
- Odynophagia
- Feeling of fullness or chest discomfort
- Regurgitation
Assessment
- Clinical Bedside Swallow Examination
* Videofluroscopic Swallow Study
Clinical Bedside Swallow Evaluation
Three main steps:
1. Review medical history—look for indicators and risk
factors
2. Oromechanim exam—look for abnormalities with
anatomy and physiology
3. Food/liquid trial—what you start with depends on how
patient presents
Thickened Fluids
• Nectar thickened: Should pour in a continuous
stream without “breaking” into drops.
• e.g.,
• Honey thickened: Sticks to the sides of a cup like
honey. Pours very slowly.
• e.g.,
• Pudding thickened: Will hold its shape when
scooped with a spoon.
• e.g.,
Videofluroscopic Swallow Study
Also known as a modified barium swallow (MBS):
• Patient given food/fluids containing barium sulfate.
• X-ray captures moving images of the bolus as pateitn is
swallowing it.
• Helps to identify aspiration (most important)
• Also shows which phase of swallow is disrupted
VFS
Advantages
• Provides clear detail of swallow phases and where
impairments are occuring
• Enables the SLP to see the extent of aspiration
Disadvantages
• Radiation from x-ray machine
• Possible allergic reaction to barium
Treatment
- Postural techniques
- Techniques to enhance oral sensation
- Swallowing maneuvers
- Diet changes
Postural Techniques
- Head Back
- Chin Down
- Head Tilt
Postural Techniques: Head Back
What: Patient places head backward
When: Inefficient oral transit (reduced posterior
propulsion of bolus by tongue) but good airway
protection
Rationale: Uses gravity to assist clearance of the oral
cavity
Postural Techniques: Chin Down
What: Patient touches chin to neck
When: Delayed pharyngeal swallow, reduced tongue
base retraction, and/or aspiration/penetration
Rationale: Pushes tongue base backward, closer to
pharyngeal wall; narrows airway entrance; pushes the
epiglottis posterior
Postural Techniques: Head Tilt
What: Patient tilts head to side that is strong and
without weakness
When: Unilateral oral and pharyngeal weakness on
same side
Rationale: Directs bolus down stronger side
Oral Sensation Enhancement
Techniques
- Downward pressure on spoon
- Present different temperature bolus
- Present a sour bolus
- Present a larger volume of bolus
- Present a bolus requiring chewing
- Tactile stimulation
When: Reduced oral sensation, delayed
pharyngeal swallow
Swallowing Maneuvers
- Supraglottic swallow
- Effortful swallow
- Mendelsohn maneuver
Swallowing Maneuvers:
Supraslottic Swallow
What: Patient is told to take a breath and hold it while
swallowing and then coughs after the swallow
When: Reduced or late vocal fold closure
(aspiration/penetration)
Rationale: Results in the voluntary closure of VF
before, during, and after the swallow
Swallowing Maneuvers:
Effortful Swallow
What: Patient is directed to squeeze hard with
throat/neck muscles during swallow
When: Delayed oral transit, delayed pharyngeal swallow,
reduced VF closure
Rationale: Increases tongue driving force by causing
exaggerated tongue retraction; increases posterior
tongue movement; propels bolus through pharynx
Swallowing Maneuvers:
Mendelsohn Maneuver
What: Patient told to pay attention to way the
Adam’s apple goes up/down during swallow.
Learn to use muscles to keep larynx elevated for
several seconds after the swallow
When: Reduced laryngeal excursion and limited
UES opening
Rationale: Raising larynx assists with opening
the UES (and prolongs opening)
Diet Changes
Should be the last compensatory strategy examined.
This should only be done if all other compensatory
strategies and postural strategies are ineffective or the
patient is unable to follow the directions.
When: Poor oral control, delayed pharyngeal swallow,
aspiration/penetration, inefficient bolus preparation.
