L3: Swallowing Development and Differences Flashcards
bw birth and 12m healthy infants increase in…
length by 50% and weight by 200%
growth is a crude indicator of…
growth occurs when…
nutrition
growth occurs when dietary intake is sufficient and feeding skills are sufficient
infancy and childhood are critical times for …
which requires..
what can disrupt this?
brain and body development
requires sufficient energy and nutrients to meet growth potential
dysphagia and its associated problems can have lasting effects on dev (ex. stature, dev milestones)
describe fetal gut development
fetal gut dev complete at 20 wks GA, but continues to mature physiologically post-natally
describe lung dev
must reach a developmental threshold for ex-utero survival
23 wks GA = primitaive alveoli present, can performa basic has exchange
32-34 WKS GA = resp becomes more efficient
37 wks GA = sufficient surfactant production for resp
alveoli continues to inc over first 2 years
how does the CNS mature?
matures from the bottom up
1st trimester = spinal cord synapses form
2nd trimester = brainstem begins to mature (breathing, heart rate, blood pressure, digestion, sleep)
3rd trimester = cerebral volume and surface area inc (necessary for functional life)
after neurological development, babies are born with survival reflexes, but still…
dependent on caregivers bc cerebral maturation is incomplete
structures of the head and neck of the embryo are …
in place by the end of the 1st trimester
frontonasal process (face maxilla)
branchial arches (mandible, tongue, larynx)
further dev takes place during the first year post natally
infants are NOT….
small adults
infant head and neck stability is provided…
adult head and neck stability..
externally through positioning
provided through internal posture
infants tongues …
adult tongues…
fills the oral cavity
drops down and moves back
infant tongue tip…
adult tongue tip…
protrudes beyond alveolar ridge
behind alveolar ridge
infant fat pads …
adult fat pads…
in cheeks support oral movements
disappear; more lip and cheek movement
infant soft palate..
adult epi…
is large and close to epiglottis
moves down and away
infant larynx is …
adult hyoid and larynx..
high in neck - after 1st year it descends to adult position by 6-7 years; hyoid and larynx share horizontal plane - movement is anterior
on diff planes - movement forward and superior
infant more penetration…
adult entrance to airway…
is possible due to shape of laryngeal inlet, mechanism of laryngeal closure
is more tightly closed
infant valleculae and pyriform sinuses…..
adult valleculae and pyriform sinuses …
are shallow; epiglottis is soft
become deeper; epiglottis firmer
in summary, growth during 1st year:
downward and forward movement of jaw, enlarging oral cavity and inc length of pharynx
obligate nose breather in infancy shifts…
to combination nose and mouth breathing
dentition is dev w/i …
the first year
tonsils may be enlarged during…
early childhood
soft laryngeal cartilages are…
prone to collapse - chin tuck position may not be helpful early on
feeding =
any process involving any aspect of eating or drinking, including gathering and preparing food and liquids for intake, sucking or chewing, and swallowing
provides shared opps for comm and social experience that form basis for future interactions
swallowing =
complex process of transporting saliva, liuuids, and foods from mouth to stomach while protecting the airway
swallowing behaviours begin in ____ and include:
utero
sucking movements, drinking amniotic fluid through digestive tract, thumb to mouth
in neonates and infants, all components of swallowing are
involuntary
oral phase, trigger pharyngeal swallow, pharyngeal phase, eso phase
oral phase comes under voluntary control with
cortical development
brain stem mediated reflexes assist with
oral feeding
some reflexes persist into later ______, and even ____, others diminish to allow for ______
childhood
adulthood
food progression
2 main types of feeding reflexes
adaptive = prepare and direct feeds into gut
protective = keep material out of the airway
rooting =
turn head toward tactile stimulation of lips/cheeks, open mouth
suckling =
anterior-posterior motion of tongue w tactile stimulation of tongue dorsum
tongue protrusion =
push food out of mouth when not mature enough to masticate
tongue lateralization =
push food to side of mouth to be held or chewed
phasic bite =
crude jaw movements to stimulation of gums
gag reflex, coughing, and swallowing are also…
feeding reflexes
oral phase in infants differs dramatically from adults in what ways?
sucking = repetitive tongue pumping (2-7 pumps) to express milk
depends on flow of milk (low/slow flow requires more tongue pumps to create bolus for oral transport)
fluid collects at faucial arches OR in valleculae
infant pharyngeal phase is …
more similar to adults
hyolaryngeal excursion is smaller in infants due to proximity of larynx to tongue base
greater pharyngeal wall movement in infants
describe the typical feeding progression in infants
liquid by nipple for first 4-6m (suckle pattern - gradually shifts to suck)
strained smooth food by spoon at 4-6m (able to sit w minimal support)
lumpy foods by 10-11m (difficult if delayed until 14-16m)
cup drinking bf 12 m - toddler diet of chopped table food by 12-18m
drinking from bottle or breast requires both…
compression (pos pressure) and suction (neg pressure) for max efficiency
drinking from a bottle or breast, the jaw moves slightly…
downward (inc oral cavity and inc neg pressure)
drinking from bottle or breast, the tongue …
creates an anterior seal w nipple, posterior seal w soft palate
anterior tongue elevates and compresses nipple
posterior tongue lowers creating neg pressure
drinking from bottle or breast requires coordination of….
suck-swallow-breathe
patterns appears late in 3rd trimester
nutritive suck pattern differs from the non-nutritive suck pattern
describe non-nutritive suck pattern (NNS)
short jaw excursions
2 sucks/second
rhythm of suck 7-8 sucks per burst w 6-7 sec pause bw
suck:swallow ratio is 6:1 - 8:1
resp rate minimally changed bc of infrequent swallowing
describe nutritive suck pattern (NS)
wide jaw excursions
1 suck per second
rhythm of suck - initially continuous sucking burst for up to 60 sec, then: intermittent sucking bursts of 7-10 sucks w short pauses (2-3 sec); toward end of feed, changes to 2-3 sucks per burst w longer pauses
suck:swallow ratio is 1:1 (suck:swallow may be 2:1 to 3:1 at end of feed)
suck:swallow:breathe ratio is 1:1:1 (i.e. breathing stops during each swallow, then starts again w the next suck)
describe the jaw movements that occur when developing the ability to drink from a cup
wide jaw excursions
biting down on edge of cup for external stability
no biting, internal jaw support
appropriate jaw grading for size of cup
describe the tongue movements that occur when developing the ability to drink from a cup
extension-retraction movement during drinking when cup offered
tongue protrudes slightly under cup for stability
intermittent tongue tip elevation alternates w simple tongue protrusion
fairly consistent tongue tip elevation
describe the lip movements that occur when developing the ability to drink from a cup
upper lip closes on edge of cup
cup held bw lips only; slight lip pursing
easy lip closure w cup is removed from lips
describe the jaw movements that occur when developing the ability to eat puree from spoon
slight jaw movement w sucking pattern
jaw held still and mouth open at presentation
describe the tongue movements that occur when developing the ability to eat puree from spoon
sucking pattern as food approaches
tongue rests quietly to accept spoon
intermittent tongue tip elevation and protrusion
fairly consistent tongue tip elevation
tongue elevation and depression are independent of jaw
tongue moves laterally across lips to clean
describe the lip movements that occur when developing the ability to eat puree from spoon
lips dont assist in clearing spoon
upper lip moves down to assist in clearing spoon
upper and lower lip curl inward in clearing spoon
describe the jaw movements that occur when developing the ability to eat solids
munching - mouth open wide; phasic bite
munching - mouth closed, feeder breaks off
munching - may pull head back to assist
rotary - diagonal rotary movement
rotary -variation in amount of up-down movement and speed
rotary - circular rotary movement
describe the tongue movements that occur when developing the ability to eat solids
front-back movement
up-down no lateralization
gross rolling movements
intermittent protrusion-retraction still occurs
can transfer food from one side to other without pausing at midline
describe the lip/cheek movements that occur when developing the ability to eat solids
lip and cheek tighten asymmetrically
lips are active w jaw, close at sides/centre
can chew intermittently w lips closed
what are the 3 reasons why biomechanics of swallowing change as we age?
structural changes
sensory changes
motor changes
describe the structural changes that occur due to age
ossification of laryngeal cartilages
larynx descends lower in the neck
incidence of cervical arthritis inc
describe the sensory changes that occur due to age
peripheral alterations in sensory perception - touch, taste, smell
ex. bolus may advance further into the UADT prior to swallow initiation
describe the motor changes that occur due to age
decreased muscle strength - change in mass and contractile properties
ex. may need second swallow to clear pharyngeal residue; inc but normal durations
when do changes occur due to age?
> 65 years, demonstrable changes
can occur after 45 years; may be minor until over 80 years
oral changes due to aging: muscle mass and contractibility…
change in muscle mass and contractibility (lips, tongue, jaw, velum)
oral changes due to aging: masticatory function…
number of chewing stroke inc w inc age (and altered dental status); jaw biting force dec
oral changes due to aging: bolus hold position …
more “dipper” swallows
oral changes due to aging: tongue mobility…
reduced due to fatty deposits and inc connective tissue in the tongue
oral changes due to aging: tongue pressures..
mixed evidence, slower rise time to peak
oral changes due to aging: slightly longer…
oral transit time (~1sec)
oral changes due to aging: less flexible response to …
altered viscosity (?sensation)
pharyngeal changes due to aging: suprahyoid m ….
inc connective tissue
hyolaryngeal excursion - reduced max displacement
hyoid movement becomes more superior only (anterior movement dec)
pharyngeal changes due to aging: UES opening…
reduced opening and duration (2 degree to dec HLAE)
lower resting pressure - susceptible to retrograde flow
pharyngeal changes due to aging: normal delay in…
initiating pharyngeal phase
pharyngeal changes due to aging: pharyngeal constriction may…
be maintained
pharyngeal changes due to aging: slightly longer..
pharyngeal transit time (~1sec)
pharyngeal changes due to aging: slight increase in…
freq and extent of residue
pharyngeal changes due to aging: laryngeal closure …
penetration into vestibule inc in freq w age, but not inc in aspiration
airway closure - inc in duration (inc apnea)
esophageal changes due to aging: deteriorates more…
sig than oropharyngeal function
esophageal changes due to aging: transit and clearance are…
slower and less efficient
motor activity dec w age
reduce amplitude of eso contractions due to smooth muscle thickening
stasis inc
coordination w resp changes due to aging:
- lungs lose..
- apneic period …
elasticity and lung volumes reduce w age
inc in age (and w bolus volumes)
altho changes in aging are noted, they are still considered…
normal
loss of muscle strength (force) and speed results in inc but normal swallow durations vs young
possible the younger indvs demonstrate _____ reserve, and ________ is reduced w age
neuromuscular
neuromuscular reserve
ex. HLAE = more than enough displacement in young, less in older age but still functional
possible that younger indvs demonsrate neuromuscular ____ and this _____ is reduced w age
flexibility
flexibility
ex. UES opening is not affected by bolus volume in older age, but maintained pharyngeal constriction clears bolus relatively well
swallowing biomechanics demonstrate sig…
including in…
normal variability
the timing of events
Kendall et al 2000’s 4 most stable components of swallow:
onset of arytenoid movement toward epi before UES opening
UES opening prior to/simultaneous w bolus head arrival at UES
max larynx to hyoid approx always after UES opening
max pharyngeal constriction after max UES opening
Molfenter et al 2014 2 most stable swallow components:
timing bw laryngeal vestibule closure and UES opening
timing bw max laryngeal-hyoid approx and UES opening
healthy swallow is characterized by
flexibility and accommodation
systematic variability in swallowing by altering…
volume
viscosity
taste
delivery/ingestion method
systematic variability w age
volume effects oral by…
tongue contour changes to accommodate inc volume
tongue to hard palate pressures = no efffect
volume effects pharyngeal by…
tongue base retraction - occurs later w inc volume
airway closure - longer apneic period w inc volume
UES opening = occurs earlier, longer duration w inc volume
hyoid displacement (movement) mixed evidence = no diff vs greater displacement w larger volumes (> in males)
volume effects coordination by…
oral and pharyngeal phases more simultaneous w inc volumes
viscosity effects oral by…
tongue to palate pressures = inc w viscosity
tongue musculature = inc activity w inc viscosity
viscosity effects pharyngeal by…
tongue base retraction = inc pressure w inc viscosity
pharyngeal constriction = inc pressure w inc viscosity
VP closure, airway closure, and UES opening = durations inc w inc viscosity
viscosity effects coordination by…
initiation of pharyngeal phase = accumulation of bolus in valleculae as mastication of solid continues
taste/chemosensory effects oral by…
tongue pressure = inc w sucrose, salt, citric vs water
also inc w carbonation +/- taste
taste/chemosensory effects pharyngeal by…
hyoid displacement = inc in muscle activation in the suprahyoid m w sour
effect of delivery method: sequential cup drinking involves….
anticipatory elevation of the larynx as cup approaches lips
effect of delivery method: sequential cup drinking events are…
maintained across all swallows
lips maintain seal on cup
airway closure maintained across all swallows; happens earlier vs teaspoon delivery
VP closure maintained across all sequential swallows
effect of delivery method: sequential cup drinking involves repetitive…
events
tongue repeatedly propels boluses
tongue base retracts to PPW after each bolus
during “chug a lug” or chugging a liquid…
larynx is pulled forward, UES opened volitionally, hold breath to close airway
dump material from oral cavity into esophagus
how does one do straw drinking?
suction (neg pressure) in oral cavity
= lip strength to seal around straw
= velum lowered against tongue back, and cheek/face and jaw m contract to create suction
bolus can accumulate as inferiorly as hypopharynx = airway closure must be maintained across multiple sips/swallows
distinguishing bw different from disordered ….
informs SLP practice
diagnostic element (candidates for therapy)
can be harnessed to bring about purposeful changes in swallowing biomechanics
