topic 2 - dvlpmt of hearing in infants

3 period of conception to birth

1. period of the zygote

2. period of the embryo

3. period of the fetus

period of the zygote

• begins when egg is fertilized in the fallopian tube

• period of rapud cell division

• ends 2 weeks later when the zygote is implanted in the wall of the uterus

period of the embryo

• from 3-8 weeks after conception

• body parts are formed during this period (including the ear)

• embryo rest in the amnion flled with amniotic fluid

• umbilical cord join embryp to placenta

period of the fetus

• from 9 weeks after conception to birth

• increase in size and system begin to function

• age of viability: 22 - 28 weeks

influences on prenatal dvlpmt

• teratogens

• general risk factors

teratogens

a drug or other substance capable of interfering with the dvlpmt of a fetus, causing birth defect

• may be illicit drugs or things that aren’t ok when pregnant

• ex: cocaine, alcohol, marijuana, caffeine, environmental hazards (asbestos, toxins in air/water)

• teratogens & diseases pass thru placenta & attack fetus (TORCH infections)

how teratogens influence prenatal dvlpmt

• not universally harmful or mutual exlusive - may affect the mother but not the unborn child (depends on timing & regularity of exposure)

• harm particular structures at specific points in dvlpmt

general risk factors

1. nutrition: adequate amount of food, protein, vitamins, & minerals

2. stress: decreases oxygen to fetus & weakens mother’s immune system

3. mother’s age: neither too young (12-13 yr/o) nor too old (35+)

• increased maternal age is a high risk for down’s sydrome

effects of teratogens in weeks 1-2

errors divind zygote and implantation = prenatal death/miscarriage

effects of teratogens in week 3

major congenital anomilies in the C.N.S & heart

effect of teratogegns in week 4-5

major congenital anomalies in the eye & heart

effect of teratogens in week 6

major congential anomalies in the ear, teeth, upper & lower limbs

effect of teratogens in week 7-8

major congenital anomalies in the palate, ear, and external genitalia

effects of teratogen in week 9

functional defects & minor congenital anomalies in the brain, eyes, palate, & teeth

effects of teratogens in week 16

functional defects & minor congenital anomalies in the brain, eyes, teeth, external genitalia

effects of teratogens in week 20-38

functional defects & minor congenital anomalies in the central nervous system

prenatal diagnosis & treatment

• diagnosis: ultrasound, amnicentresis (blood test for clincal markers - looks for things like Down’s), chorionic villus sampling can detect physical deformities & genetic disorders

• treatement: fetal medicine & genetic engineering are experimental

influences on dvlpmt during child birth

1. STD/I - active herpes breakout while passing thru the birth canal may cause hearing loss &/or blindness

2. Get stuck in birth canal

3. Anoxia/Asphyxia - lack of oxygen to the brain

• ex: (miecal cord) - umbilical cord wraps around neck

what does APGAR stand for?

A - activity

P - pulse

G - reflex/grimace

A - appearance/color

R - respiration

APGAR scoring

a score is given at 1 min, 5 min, & 10 min after birth to assess newborn’s health

• 10 minutes is usually only for babies with problems after birth

*there is no correlation btwn APGAR score and IQ or intelligence success outcomes

APGAR scoring scale

• normal: 7-10

• some resuscitative measures required: 4-7

• immediate resuscitation: 2-3

• extremely immediate resuscitation: 0-1

  • may have failure to thrive

assessing the newborn

1. APGAR

2. NBAS - comprehensive assessment of infant

3. newborn hearing screening

• the lower the APGAR score, the longer the delay in screening

4 primary stages of newborn

1. alert inactivity

2. waking activity

3. crying

4. sleeping - half of the newborns sleep is REM, baby sleeping on back may prevent SIDS

birth complications

1. anoxia - lack of oxygen: lads to surgical removal of the fetus (C-section)

2. premature & low birth weight/small for date

• prematurity is less serious than low birth rate

low birth weight babies

babies born who weight less than 3 lbs 4 ounces (1500 grams)

• only 1.5% of babies are low birth weight

causes of low birth weight

1. premature birth (less than 37 weeks

2. intrauterine growth restrictions

• problems with the placenta

• poor maternal health

• birth defects

3. more African-American babies are born low birth weight

4. Age - teen mothers, mothers above 35+

5. multiple births

6. poor mother’s health

7. twins/triplets

symptoms of very low birthweight babies

• low oxygen lvls

• inability to maintian body temp

• difficulty feeding & gaining weight

• infection

• breathing problems (respiratory distress syndrome) - immature lungs

• nuerological problems (bleeding in the brain)

• gastrointestinal problems

• sudden infant death sydrome (SDIS)

long-term problems

• cerebral palsy

• blindness

• hearing loss

• intellectual disability

cause of hearing loss (from prenatal-postnatal)

1. prenatal: conceptin to fetal stage (22-28 weeks or 7 months of prengancy)

• teratogens: alcohol, illicit durgs, caffiene

• poor nutrition

2. perinatal: 22 weeks of pregnancy to 7 days after birth

• complications while in birth canal: active herpes outbreak, anoxia

3. postnatal: after 7 days of brith

• illness/infection, medication in NICU (IV for myosin, vancomyosin)

high risk factors for infant hearing loss

A) - Anoxia/Aphixia: no O² to the brain, umbilical cord wrapped around neck

B) - Bacterial Meningitis: inflammation of the sac around spinal cord

C) - Congenital Perinatal Infections: CMV, syphilis, STD (herpes),

D) - Deformity of head/neck: skin tags or pits at/around the ear, craniofacial diff

E) - Elevated bilirubin: jaundice (high risk of auditory neuropathy)

F) - Family History of Hearing Loss: mom/dad, brother/sister, grandma/grandpa, first cousin, niece/nephew

G) - Gram birth weight: less than 3 lbs 4 ounces (1500 grams)

H) - Had a Transfusion: babies in NICU longer than 5 days (preemie, fetal alcohol syndrome, failure to thrive, etc.) or vancomycin drugs through IV