Approaches and Techniques Flashcards
4 types of studies (in order of increasing accuracy, validity, and complexity)
case study, cross-sectional, longitudinal, cross-sequential
- case study
- cross-sectional
- longitudinal
- cross-sequential
- in depth focus on issue/phenomenon of interest in real-life context (individual)
- obs/measurement once in sample, provides GMD status, variability w/in group
- repeated measurment/obs of same group over time, info status overtime, rate of change
- mixed cohorts with participants starting and ending at different/same age, obs repeated times
Pros and cons:
1. True longitudinal study
2. Cross sectional
3. Mixed longitudinal
- Req lots of resources (money, time, commitment for both researcher and subjects), changing tech, data of change
- Less resources, stable tech, req careful sample size calculation for accurate calculation of pop, data for status
- Allow measurement of status and change by taking cross sectional data over time but cannot make true inferences on change
Ultrasound for prenatal growth assessment
1. Function
2. Measures
3. Purpose
- Gen images/videos of fetus using hi-freq sound waves
- Fetal number, age, position, deformities, sex
- Allow healthcare providers to evaluate growth and dev for problems and diagnosis
- Onset of pregnancy
- Period of egg
- Embryo
- Fetus
- Difficult to determine, sperm can survive in female repro sys for 2-5, fertilization takes approx 24 hrs, fertilized egg enters uterus in 3-4 days
- First 2 weeks of prenatal dev
- Week 2-8, week 5 cells embedded into uterine wall, foundations for major organs, amniotic sac formed
- Week 9-birth, head straight and more fully dev, ears growing, toes visible, essential organs formed, week 11 heart formed and pumping, brain dev, nerves and muscles work together, 14 weeks sex becomes apparent, week 18 dev essential reflexes, 22 weeks eyes dev, tear ducts and hair form, responsive to ext stimuli, 30 weeks hands formed, kicking, 40 weeks full term, lungs last organ to form
Overdue births:
1. Overview
2. Risks
- normal for the birth to occur a little earlier or later than due date since it is an estimate
- Baby may be abnormally thin due to malnutrition bc
placenta starts to die at 40 weeks
- Somatic cells def and growth
- 3 common measures for infants
- Anthropometric measurements dev
- Non germ cells, req hormonal, metabolic, and other growth factors to function together to grow
- Head circumference, weight, length
- Standardized techniques to systematically measure body using landmarks, positioning, specific instruments
Postnatal growth assessments (purpose and method)
1. Head circumference
2. Infant length
3. Factors influencing weight
4. Factors influencing infant growth
- Relevant from birth-4 yrs to measure brain growth, use tape measure above eyebrows
- Measure growth rate, 1”/month in first six months, 0.5”/month six months to a yr, feet against baseboard, knees straightened
- Born premature/late, singles weigh more than multiples
- Genetics, diet, activity, clinicians look for healthy growth trend and status given their medical history
Post natal growth assessment:
1. Height
2. Waist circumeference
3. Skin folds
- Standing and sitting height, look for abnormal stature, and height as indicator of disease and nutrition level
- Tape measure across belly button on exhale to asses obesity related health risk
- Measure subcutaneous adipose tissue by pinching skin and fat at 12 sites, susceptible to inter rated variability and can be painful if done incorrectly
Jackson Pollock equ
1. Use
2. Conversion
- Diff equ for males and females to determine body density
- % fat, fat-weight, fat free weight, body weight goal
Anthropometric data in gen
1. Assumptions
2. Measurement error
3. Systemic errors
4. Technical errors
5. Participant vari
- Accurate and Reliable data collected using standardized techniques and training
- Intra-rater variability, inter-rated variability, instrument variability
- Consistent over and under measurements (techniques, instruments), bias, control by repeated measurement by different researchers on same subject over multiple periods
- Instruments, user error, or conversions
- Physiological differences, temperament, cooperation with researchers
- Gender diff at diff points in dev
- Body size measurements
- Diurnal variation def and control
1.Minimal diff pre-adolescence, females bigger early adolescence, males surpass females moving forward into adulthood
2. Weight and height
3. Changes in weight and height, heaviest at end of day, tallest in morning, control by collecting data for all participants at same time of day
Ratios:
1. Weight/height
2. Sitting: stature
3. Hip to shoulder
- Indicator of growth, physique, under nutrition, obesity, preadolescence use as healthy weight assessment and nutritional status, adolescence height to weight ratio greater due to growth spurt, post adolescent BMI
- Proportion of height of trunk v. leg
- Bicoastal breadth: biacromial breadth, proportional change in ratio apparent in adolescence, swimmer/gymnasts have smaller ratio
Growth charts
Diff growth charts use diff data, CDC ref children in USA, WHO use more breastfed babies, recommendation to use WHO growth charts during first 2 yrs by CDC and AAP
