Reflexes in Infants: Types, Ages, and Responses in Developmental Assessment

categories of reflexes

primitive or postural

Primitive reflexes

important for survival- sometimes not as important today, present at birth or prenatally

Postural reflexes

more complex, thought to help gain/maintain posture, possibly leading to muscle tone and motor development

3 characteristics of reflexes

stereotyped

involuntary response to specific external stimuli

cant be adaptive or learned.

4 factors for testing for neurological disfunction

PAUN P- preservation: present to long A- absence: doesnt present when it should U- unequal bilateral response N- not conforming to amplitude norms not happening at the correct strength of response

Palmar grasp age

0-4 m

Palmar grasp stim

pressure to palm

infant must be awake and in quiet state

Palmar grasp response

wrap all four fingers around stimuli

after four months it becomes voluntary

Plantar grasp age

0-12m

plantar grasp stim

pressure to ball of foot

plantar grasp response

toes wrap tightly around stim

Rooting/searching reflex age

0-3m

rooting/searching reflex stim

pressure to cheek near mouth

Rooting/searching reflex response

turn head towards stim to help find location of food source

What is the rooting/searching reflex coupled with

sucking reflex

sucking reflex age

0-3m

sucking reflex stim

pressure to lips

sucking reflex response

start to suck to find food source

Moro reflex age

0-6m

moro reflex stim

infant is held in supine position and given the illusion that they are falling (dropping hands to lower head or body, shaking the table they are resting on)

moro reflex response

extension of all limbs followed by immediate flexion of all limbs

Startle reflex age

6-12m

startle reflex stim

infant is held in supine position and given the illusion that they are falling (dropping hands to lower head or body, shaking the table they are resting on)

startle reflex response

only flexion of all four limbs

Asymmetric Tonic neck reflex age

0-3m

Asymmetric Tonic neck reflex stim

supine position on stable surface manually turn head left or right

Asymmetric Tonic neck reflex response

both limbs on the same side as the head turn extend while the opposite limbs flex

Asymmetric Tonic neck reflex postural or primitive

primitive

startle reflex postural or primitive

primitive

moro reflex postural or primitive

primitive

rooting reflex postural or primitive

primitive

sucking reflex postural or primitive

primitive

palmar grasp reflex postural or primitive

primitive

plantar grasp postural or primitive

primitive

Stepping reflex postural or primitive

postural

stepping reflex age

1-5m

stepping reflex stim

grab baby by trunk dragging them along the support surface

stepping reflex response

show alternating leg movements, like a stepping motion

crawling reflex postural or primitive

postural

crawling reflex age

0-3or4 months

crawling reflex stim

prone position on support surface apply pressure to bottom of a foot - both feet simultaneously

crawling reflex response

start to make a crawling motions especially is you alternate feet- extend both legs out toward the pressure/pushing back

swimming reflex postural or primitive

postural

swimming reflex age

0-5m

swimming reflex stim

hold in horizontal position over surface

swimming reflex response

start to preform a doggy paddle

parachute and propping age

4m-1y+

parachute and propping primitive or postural

postural

parachute and propping stim

hold by belly horizontally tipping forwards or backwards

parachute and propping response

forwards: lower their arms

backwards: lower their legs

pullup reflex age

3m to 1y

pullup reflex primitive or postural

postural

pullup reflex stim

seated position help by hand tipping backwards or tipping them forward

pullup reflex response

baby flexes arms or extends arms to keep themself stable

genetic note on reflexes

by definition are genetic but there are cultural variations

gametes

egg (23 chromosomes)

sperm (23 chromosomes)

zygote

fertilized egg

male sperm

y

swim fast

genetically WEAK

lighter and more fast since they only carry the Y which is much smaller

female sperm

X

swim slow

genetically strong

germinal period of prenatal development

conception to when the blastocyte embeds in the uterine wall

abt 2 weeks

embryonic period of prenatal development

weeks 3-8 after conception

at week 8 the embryo switches from yolk sac to placenta for nutrients

individual organs form

fetal period period of prenatal development

8w-38w or birth

teratogens

environmental agents that cause harm during prenatal development

teratogen examples

drugs

diseases

environmental hazards (toxins)

sensitive periods

time where organism is the most vulnerable to outside agents

-embryonic (earlier exposure is worse)

sensitive periods example

thalidomide

anti-nausea drug

babies born with major limb deformities

only if used between 4-6 weeks post conception

dose amounts

larger amount of the teratogen will likely lead to larger negative impacts

dose amounts example alcohol consumption

modifies cell functioning, reduces oxygen availability, causes widespread cell death in brain

because it crosses through the placenta into fetuses blood stream/amniotic fluid and stays in the system longer because it takes longer to metabolize it

alcohol consumption effects on newborns - smaller amounts and less frequency

alcohol-related neurodevelopment disorders (ARND)

fine motor issues, clumsiness, motor delays

alcohol consumption effects on newborns - higher amounts and higher frequency

fetal alcohol syndrome (FAS)

mental impairments, attention problems, facial abnormalities, impaired motor abilities

smoking effects on fetus

interfers with blood and oxygen flow

smoking effects on newborn

low birth weight, stunted growth, low IQ, hearing deficits

amount of impact follows dose-response and sensitive periods

parasitic diseases- toxoplasmosis - teratogens disease

found in cat feces ad undercooked meats

impact on fetus/pregnant woman: mild flu-like symptoms

impact on newborn: mental, motor, visual impairments

listeriosis

caused by listeria

bacteria in soil and water contaminated by veg and animals

impacted on fetus/pregnant woman: flu-like symptoms

impact on newborn: increased risk of miscarriage, premature delivery, death

zika virus

aedes species mosquito

impact on fetus/pregnant woman: mild illness.no illness

impact on newborn: microcephaly

environmental hazards/toxins

x-rays

lead paint

pesticides

air pollution

hazards to prenatal development

age - 35+: increased risk of down syndrome

nutrition: folic acid, malnutrition/fetal growth

obesity

stress

neural tube disease

lack of sufficient folic acid can lead to malformation of neural tube (brain and spinal cord)

formation of neural tube

the blastocyte forms the 3 layers: ectoderm, mesoderm, endoderm

notochord-neural plate-> neural crest -> neural tube

anencephaly

no brain development

neural tube disease

cephal end doesn't zip up correctly causing giant holes in the neural tube

spina bifida

damage to spinal cord

caudal end: holes in bottom of neural tube-less holes=less deficits

paralysis from the waist down can happen

neural tube disease

genetic hazards to prenatal development

gene-based disorders

chromosomal disorders

gene-based disorders

inherited from your parents

ex. fragile x syndrome

chromosomal disorders

problems with cell division

ex. fragile x syndrome

fragile x syndrome

defective FMR1 gene on the x chromosome

mostly effects biological males severely

signs and symptoms of fragile x syndrome

intellectual disabilities

long ears and face

behavioral challenges

speech and language difficulties (nonverbal)

sensory sensitivities

females who have it are very shy

motor impairments with fragile x syndrome

hypotonia

delayed motor milestones (abt 1 y)

poor balance

poor motor planning

down syndrome

extra pair of chromosomes 21st

mental impairments: top age of 8

hypotonia- double jointed and low muscle tone

those who live past 40 tend to develop Alzheimer's

delays in gross and fine motor control

poor balance and motor coordination