Usmle Behav Science

Front 1

Case control Study

Back 1

Observational and Retrospective

Compares a group of people with disease to a group without, and asks what happened?

Measures odds ratio

Front 2

Cohort study

Back 2

Observational and Prospective.

Compares a group with a given risk factor to a group without to assess whether the risk factor increases the likelihood of disease. Asks, what will happen?

Measures relative risk

Front 3

Cross-sectional Study

Back 3

Observational.

Collects data from a group of people to assess frequency of disease and related risk factors at a particular point in time. Asks, what is happening?

Measures disease prevalance. Can show risk factor association with disease, but does not establish causality.

Front 4

Twin concordance study

Back 4

Compares the frequency with which both monozygotic twins or both dizygotic twins develop a disease.

Measures heritability.

Front 5

Adoption study.

Back 5

Compares sibling raised by biologic vs adoptive parents.

Measures heritability and influence of environmental factors.

Front 6

Phase I clinical trial

Back 6

Small number of patients, usually healthy volunteers.

Assesses safety, toxicity, pharmacokinetics

Front 7

Phase II clinical trial

Back 7

Small number of patients with disease of interest.

Assesses treatment efficacy, optimal dosing, adverse effects.

Front 8

Phase III clinical trial

Back 8

Large number of patients randomly assigned to either th etreatment under investigation or to the best available treatment/placebo.

Compares new treatment to standard of care. More convincing if double blinded.

Front 9

Infectious diseases reportable to the state

Back 9

Hep A, B, C
HIV
Salmonella
Shigella
Syphilis
Measles
AIDS
Rubella
Tuberculosis
Chickenpox
Gonorrhea

Front 10

Leading causes of death of infants

Back 10

congenital abnormalities
premature/low birth weight
SIDS
maternal complications
respiratory distress syndrome

Front 11

Leading causes of death ages 1-14

Back 11

Injuries
Cancer
Congenital anomalies
Homicide
Heart disease

Front 12

Leading causes of death, ages 15-24

Back 12

injuries
Homicide
Suicide
Cancer
Heart Disease

Front 13

Leading causes of death ages 25-64

Back 13

Cancer
Heart disease
Injuries
Suicide
Stroke

Front 14

Leading causes of death ages 65+

Back 14

Heart Disease
Cancer
Stroke
COPD
Pneumonia
Influenza

Front 15

Informed consent requires 3 things legally:

Back 15

1. Discussion of pertinent information
2. Patients agreement to plan of care
3. Freedom from coercion

Front 16

Exceptions to informed consent (4)

Back 16

1. Patient lacks decision-making capacity or is legally incompetent
2. Implied consent in an emergency
3. Therapeutic privilege - witholding information when disclosure would severly harm the patient or undermine informed decision-making capacity
4. Waiver - patient waives the right of informed consent.

Front 17

Decision making capacity

Back 17

1. Patient makes and communicates a choice
2. Patient is informed
3. Decision remains stable over time
4. Decision is consistent with patient's values and goals
5. Decision not result of delusions or hallucinations

Front 18

Exceptions to confidentiality

Back 18

1. Potential harm to others is serious
2. Likelihood of harm to self is great
3. No alternative means exist to warn or protect those at risk
4. Physcians can take steps to prevent harm (warn public of infectious diseases, Tarasoff - warn those at risk of harm, child/elderly abuse, impaired drives, suicidal/homicidal patients.

Front 19

The 4 D's of malpractice

Back 19

For civil suit under negligence
1. Physician had DUTY to the patient
2. Physician breached the duty (DERELICTION)
3. Patient suffers harm (DAMAGE)
4. Breach of duty causes harm (DIRECT)

Front 20

5 Tanner Stages of Sexual Development

Back 20

1. Childhood
2. Pubic hair begins to develop (adrenarche), increase size of testes, breast tissue elevation.
3. increase pubic hair, darkens, becomes curly, increase penis size/length
4. increase penis width, darker scrotal skin, development of glans, raised areolae
5. Adult , areolae are no longer raised

Front 21

Effects of Stress

Back 21

Production of free fatty acids, 17-OH corticosteroids, lipids, cholesterol, catecholamines, affects water absorption, muscular tonicity, gastrocolic reflex, mucosal circulation

Front 22

Sensitivity

Back 22

Proportion of all people with a disease who test positive.
Value approaching 1 is desireable for ruling out disease and indicates low false-negatives.

Used for screening.

= a / (a+c)
= 1 - false negatives

Front 23

Specificity

Back 23

Proportion of all people without disease who test negative
Value approaching 1 is desirable for ruling in disease and indicates low false-positive rate.
Use as confirmatory test after positive screening test.

= d / (d + b)
= 1 - false postives

Front 24

Postive Predictive Value

Back 24

Proportion of positive test results that are true positive

Probabiliyt that person actually has the disease given a positive test result

= a / (a+b)

If the prevalence of a disease is low - even tests with high specificity and sensitivity will have low positive predictive values.

Front 25

Negative predictive value

Back 25

Proportion of negative tests that are truly negative.
Probability that person is disease free given a negative test result.

= d / (c+d)

Front 26

Odsds ratio

Back 26

for case control studies

Odds of having disease in exposed group, divided by odds of having disease in unexposed group.

Approximates relative risk if prevalence not too high

= (a/b) / (c/d)

Front 27

Relative risk

Back 27

Relative probablity of getting a disease in the exposed group compared to the unexposed group

Calculated as percent with disease in exposed group divided by percent with disease in unexposed group.

RR = [a/(a+b)] / [c / (c+d)]

Front 28

Attributable risk

Back 28

The difference in risk between exposed an unexposed groups, or the proportion of disease occurances that are a result of exposure.

= a/a+b - c/c+d

Front 29

Type I error alpha

Back 29

Stating that there is an effect when non exists.

Mistakenly accept the experimental hypothesis and reject the null hypothesis.

p= probability of making such an error, judged against alpha, a present level of significance (0.05)

Front 30

Type II error beta

Back 30

Stating that there is not an effect or difference where one exists.

Power - likelihood of finding a difference if it exists = 1 - beta

Front 31

Sleep stages

Back 31

Awake, alert, active - Beta EEG
(highest frequency, lowest amplitude)
Awake, eyes closed - Alpha EEG
1. Light sleep - Theta
2. Deeper sleep - Sleep spindles and K complexes
3. Deepest, non-REM sleep - Delta EEG (lowest frequency, highest amplitude)
sleepwalking, night terrors, bedwetting
REM - Beta EEG
Dreaming, loss of motor tone, possibly a memory processing function, eretions, inc brain O2

Front 32

Some key facts about sleep

Back 32

Serotonergic predominance of raphe nucleus key to initiating sleep.

NE reduces REM sleep

Extraoccular movements during REM due to activity of PPRF

Benzodiazepine's shorten stage 4 sleep; useful for night terrors and sleepwalking

Imipramine is used to treat enuresis because it decreases stage 4 sleep