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USMLE STEP 1 > Behavioral Sciences > Flashcards

Behavioral Sciences Flashcards

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USMLE® Step 1 flashcards
1
Q

Relative Risk
Equation
When is it used?
What is it?

A

[a/(a+b)]/[c/(c+d)]
Cohort Studies
(Risk of developing disease in exposed group)/(risk in unexposed group)

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2
Q

Odds Ratio
Equation
When is it used?
What is it?

A

ad/bc
Case-Control Studies
Odds that the group with the disease was exposed to risk factor (a/c)/(Odds that the group without disease was exposed (b/d)

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3
Q

Observer Bias

A

Investigator is affected by prior knowledge

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4
Q

Confounding

A

Exposure-disease relationship can be explained by another variable

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5
Q

Lead-Time Bias

A

Apparent prolongation of survival because of earlier diagnosis

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6
Q

Recall Bias

A

Inaccurate pt recall

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7
Q

Selection Bias

A

Subjects selected biasedly or biased from selective loss of follow up

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8
Q 
Case Control Study
Mode of investigation 
Timeframe 
Design 
Basic Question 
Measurement
A 
Observational 
Retrospective 
Compare groups of people w/ and w/o disease and look for prior exposure or risk factors 
"What Happened?"
Odds Ratio
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9
Q 
Cohort Study 
Mode of investigation 
Timeframe 
Design 
Basic Question 
Measurement
A 
Observational 
Prospective or Retrospective 
Compare a group with a given exposure or risk factor to a group w/o it and look if exposure ↑ likelihood 
Who will or Who has developed disease 
Relative Risk
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10
Q 
Cross Sectional Study
Mode of investigation 
Timeframe 
Design 
Basic Question 
Measurement
A

Observational
Right Now
Collect data from a group of people to assess frequency of disease and relative risk at a particular point in time
“What is happening?”
Prevalence, Relative Risk, Can show Risk Factor Association but not causality

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11
Q

Twin Concordance Study
Design
Measurements

A

Compares frequency with which monozygotic or dizygotic twins develop the same disease
Measures Heritability

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12
Q

Adoption Study
Design
Measurements

A

Compares siblings raised by biological vs adoptive parents

Heritability and influence of environmental factors

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13
Q

Clinical Trial
Population involved
Design
What improves study

A

Experimental study involving humans
Compares therapeutic benefits of 2 or more treatments or treatment and placebo
Randomized, Controlled, and Double Blinded studies are better

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14
Q

Double vs Triple Blind

A

Double: Patients and Doctors do not know whose getting treatment
Triple: Researchers analyzing data do not know who got treatment

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15
Q

Phase I Clinical Trial
Sample
Purpose

A

Small # of health volunteers

Assesses safety, toxicity, and pharmacokinetics

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16
Q

Phase II Clinical Trial
Sample
Purpose

A

Small # of patients w/ disease

Assesses treatment efficacy, optimal dosing, and adverse effects

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17
Q

Phase III Clinical Trial
Sample
Purpose

A

Large # of patients comparing 2 drugs or placebo

Compares new treatment to current treatment

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18
Q

Phase IV Clinical Trial
Sample
Purpose

A

Postmarketing surveillance trial of patients after approval

Detects rare or long term adverse effects

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19
Q 
Sensitivity 
Rate of what?
Formula (2)
Purpose
Use
A 
"SNOUT - SeNsitivity rules OUT"
"PID - Positive In Disease"
True Positive Rate
a/(a+c) = 1-(false neg rate)
Rules out disease
Used for screening in diseases w/ low prevalence
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20
Q 
Specificity 
Rate of what?
Formula (2)
Purpose
Use
A 
"SPIN - SPecificity rules IN"
"NIH - Negative In Health"
True Negative Rate
d/(d+b) = 1-(false pos rate)
Rules in disease
Confirmatory test after positive screening test
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21
Q

Positive Predictive Value
What does it show?
Formula
What does it vary with?

A

Proportion of + tests that are true positives
a/(a+b)
Varies directly with prevalence or pretest probability: high pretest probability –> high PPV

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22
Q

Negative Predictive Value
What does it show?
Formula
What does it vary with?

A

Proportion of negative test results that are true negative
d/(c+d)
Varies inversely with prevalence or pretest probability: High pretest probability –> low NPV

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23
Q

Incidents

A

(New cases over specified period)/(Population at risk)

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24
Q

Prevalence Equations (2)

A

(Existing cases)/(Population at risk)

Incidence x Average disease duration

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25
Q

Prevalence vs Incidence in chronic disease

A

Prevalence > Incidence

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26
Q

When are RR and OR equal?

A

When prevalence is low

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27
Q

Attributable Risk
Equation
What is it?

A

[a/(a+b)]-[c/(c+d)]

Risk in exposed group - Risk in unexposed group

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28
Q

Absolute Risk Reduction (ARR)

What is it?

A

c/(c+d) - a/(a+b)

Event rate in placebo minus treatment groups

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29
Q

Number Needed to Treat
What is it?
Equation

A

Number of pts who need to be treated for 1 patient to benefit
1/(absolute risk)

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30
Q

Number Needed to Harm
What is it?
Equation

A

Number of pts who need to exposed to a risk factor for 1 pt to be harmed
1/(attributable risk)

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31
Q

Precision
What is it?
What reduced precision?
When precision is increased, what happens?

A

Consistency and reproducibility of a test. The absence of random variation
Random error ↓ precision
↑ precision –> ↓ SD

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32
Q

Accuracy
What is it?
What kind of error does it measure?
What reduces accuracy?

A

Trueness of test measurements (validity)
Absence of systematic error or bias in the test
Systemic error ↓ accuracy

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33
Q

Sampling bias

A

Subjects not representative of the general population

A form of selection bias

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34
Q

Late-Look Bias

A

Information gathering at an inappropriate time (i.e. survey to study a fatal disease - only those still alive will be able to answer survey)

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35
Q

Procedure Bias

A

Subjects in different groups are not treated the same way

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36
Q

Hawthorne effect

A

Group being studied changes behavior because they know they are being studied

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37
Q

In a normal distribution, how do measurements of central tendency relate?

A

Mean = Median = Mode

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38
Q

Standard Deviation
What roman numeral?
Percentages?

A

σ
(+1σ) and (-1σ) account for 68% of n
(-2σ) to (+2σ) account for 95% of n
(-3σ) to (+3σ) account for 99.7% of n

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39
Q

SEM
What is it?
How does it vary?

A

σ/√n

SEM will ↓ as n ↑

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40
Q

Positive Skew
How do measurements of central tendency relate?
Which is least affected?
How does graph look?

A

Mean > Median > Mode
Mode is least affected by outliers in the sample
Asymmetrical distribution with long tail on right

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41
Q

Negative Skew
How do measurements of central tendency relate?
How does graph look?

A

Mean < Median < Mode

Asymmetry with longer tail on left

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42
Q

Statistical Hypotheses
Null Hypothesis
Alternative Hypothesis

A

There is no association between the disease and the risk factors (H0)
There is some association between the disease and the risk factor (H1)

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43
Q 
Type I error
Symbol 
What is it?
AKA
What is used to calculate it?
A

α
Error of stating there is a difference when there is not. Accepting H1 and rejecting H0 when H0 is true.
False-Positive Error
Used to calculate p

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44
Q

Type II error
Symbol
What is it?
AKA

A

β
Error that there is not an effect or difference when one exists. Accept H0 when H1 is true
False-Negative Error

45
Q

Power
Equation
What is it?
What increases it?

A

1-β
Probability of rejecting H0 when it is false
Increases with ↑ Sample Size, Expected Effect Size, and Precision of measurements

46
Q

Meta Analysis
What is it?
What does it increase?
What limits it?

A

Pools data and integrates results from several similar studies
↑ statistical power
Limited by quality of individual studies or bias in each study

47
Q

Confidence Interval
Equation
Conventions of CI
How does it relate to Z

A

Range of values in which a specified probability of the means of repeated samples would be expected to fall
Range from [mean - Z(SEM)] to [mean + Z(SEM)]
95% CI corresponds to p=.05
CI = 95%, Z = 1.96
CI = 99%, Z = 2.58

48
Q

If the 95% CI for a mean difference between 2 variables includes 0?

A

There is no significant difference and H0 is accepted

49
Q

If the 95% CI for OR or RR includes 1…

A

H0 is not rejected

50
Q

If the CIs between 2 groups do not overlap…

A

Significant difference exists

51
Q

If the CIs between 2 groups overlap…

A

No significant difference

52
Q

t-test

A

Checks differences between the means of 2 groups

53
Q

ANOVA

A

Checks difference between the means of 3 or more groups

54
Q

χ2

A

Test checks difference between 2 or more percentages or proportions of categorical outcomes (not mean values)

55
Q

Pearson’s Correlation Coefficient
Symbol?
What is its range?
What does it measure

A

r
-1 to +1
The closer it is to 1, the stronger the linear correlation between 2 variables

56
Q

Coefficient of determination

A

r^2

57
Q

Disease Prevention
Primary
Secondary
Tertiary

A

“PDR”
Prevent occurrence
early Detection
Reduce disability from disease

58
Q

Medicare

A

For the Elderly (≥65)

59
Q

Medicaid

A

For the Destitute

60
Q

Autonomy

A

Respect pt as individuals and honor their preferences

61
Q

Beneficence

A

Fiduciary duty to act in patient’s best interests

62
Q

Nonmaleficence

A

Do no harm

63
Q

Justice

A

Treat persons fairly

64
Q

When is parental consent not necessary?

A

Emancipated (married, self supporting, has children, in the military), Emergency, Contraception, Treating STDs, Pregnancy, Treatment of Drug Addiction

65
Q

Can the patient’s family require that a doctor withhold information from a patient?

A

Not if the patient demonstrates decision making capacity

66
Q

Exceptions to confidentiality

A

Harm to others, harm to self, and physician can prevent harm

67
Q

A 17 year old girl is pregnant and requests an abortion

A

Many states require parental notification or consent for minors for an abortion. Unless she is at medical risk, do not advise pt to have an abortion regardless of her age or condition of the fetus

68
Q

A terminally ill pt requests physician assisted suicide

A

No Way! but can give medically appropriate analgesics that coincidentally shorten the pt’s life

69
Q

Suicidal patient

A

Patient can be hospitalized involuntarily

70
Q

Patient says she feels ugly

A

Do not offer falsely reassuring statements like “you still look good”

71
Q

Patient is angry about the wait time

A

Do not explain delay. Just apologize and acknowledge

72
Q

Referral fees for study inclusion

A

Must tell patient

73
Q

Patient is upset with how another doctor treated them?

A

Suggest the pt speak directly with the doctor

74
Q

Patient is upset with how they were treated by office staff

A

Say you will speak with that person

75
Q 
APGAR score
Time 
What is it?
What do scores mean?
What if the score is low?
A

1 minute and 10 minutes
Appearance, Pulse, Grimace, Activity, Respiration
Greater than or Equal to 7 is good.
4-6: assist and stimulate
Less than 4: resuscitate
If <4, there is ↑ risk of long term neurological damage

76
Q 
Low Birth Weight
Definition
What causes it?
Increased risk for what?
Other problems?
Complications?
A

Less than 2500g
Prematurity or intrauterine growth retardation
“PREME C SHIT”
↑ risk for SIDS and overall mortality
Impaired thermoregulation and immune function, Hypoglycemia, Polycythemia, Impaired neurocognitive/emotional development
Infections, RDS, Necrotizing enterocolitis, Intraventricular hemorrhage, persistent fetal circulation

77
Q

Birth to 3 months
Motor
Social
Cognitive

A

Rooting reflex, holds head up, Moro reflex disappears
Social smile
Orients and responds to voice

78
Q

7 to 9 months
Motor
Social
Cognitive

A

Sits alone, Crawls, Transfers toys from hand to hand
Stranger anxiety
Responds to name and simple instructions, uses gestures, plays peek-a-boo

79
Q

12 to 15 months
Motor
Social
Cognitive

A

Walks, Babinsky Sign Disappears
Separation anxiety
Few words

80
Q

12 to 24 months
Motor
Social
Cognitive

A

Climbs stairs, Stacks 3 blocks at 1 year, Stacks 6 blocks at 2 years
Rapprochement
200 words. 2 word phrases at age 2

81
Q

24 to 36 months
Motor
Social
Cognitive

A

Feeds self with fork and spoon. Kicks ball
Core gender identity. Parallel play
Toilet training (pee at 3)

82
Q

3 years old
Motor
Social
Cognitive

A

Rides tricycle (3 cycle at 3). Copies line or circle drawings
Comfortably spends part of the day away from mother
900 words. Complete sentences

83
Q

4 years
Motor
Social
Cognitive

A

Uses buttons and zippers, Grooms self, Hops on 1 foot, Makes simple drawings
Cooperative play, Imaginary friends
Can tell detailed stories and uses prepositions.

84
Q

Sexual changes in the elderly

A

Interest does not ↓
Men have slower erection, ejaculation, longer refractory period
Women have vaginal shortening, thinning and dryness

85
Q

Intelligence changes in the elderly

A

Intelligence does not decrease

86
Q

How age changes sleep patterns

A

↓ REM and slow-wave sleep. ↑ latency and awakening

87
Q

Psychological changes in the elderly

A

↑ suicide rates

Men 65-74 have highest rates in US

88
Q

Organ system changes with age

A

↓ Vision, Hearing, Immune response, Bladder control, Renal, Pulmonary, GI
↓ muscle, ↑ fat

89
Q

Grief
What is it characterized by
Length

A

Shock, Denial, Guilt, Somatic symptoms. May experience illusions
Up to 1 year

90
Q

Pathologic Grief
What is it?
What may they experience

A

Excessive, prolonged (>1 year), delayed, inhibited, or denied grief
May experience depression, delusions, and hallucinations

91
Q

Sexual Dysfunction DDx

A

Drugs, Disease (depression, diabetes), Psychological

92
Q

BMI
Formula
#s

A

(Wt in kg)/(Height in meters)^2
Less than 18.5 is underweight
25 to 29.9 is overweight
Greater than 30 is obese

93
Q

Awake with Eyes Open
Description
EEG

A

Alert and active

Beta (highest frequency, lowest amplitude)

94
Q

Awake with Eyes Closed

EEG

A

Alpha

95
Q

Stage N1 sleep
Percent of sleep
Description
EEG

A

5%
Light Sleep
Theta

96
Q

Stage N2
Percent of sleep
Description
EEG

A

45%
Deeper sleep; Bruxism
Sleep Spindles and K complexes

97
Q 
Stage N3
Percent of sleep
Description 
EEG
What can happen during this stage?
A

25%
Deepest non REM sleep
Delta waves (low frequency, high amplitude). Slow wave sleep
Sleepwalking, night terrors, bedwetting

98
Q

REM sleep
Percent of sleep
Description
EEG

A

25%
Dreaming, Loss of motor tone, Memory processing, Erections, ↑ brain O2 use
Beta waves

99
Q

EEG waveforms in sleep

A

“BATS Drink Blood”

Beta, Alpha, Theta, Sleep spindles, Delta, Beta

100
Q

Brain region in initiating sleep

A

5HT region of Raphe Nucleus

101
Q

Treatment for Sleep Enuresis

A

Oral Desmopressin

Preferred over Imipramine

102
Q

Drugs that reduce REM sleep?

A

EtOH, Benzodiazepines, Barbituates

Also reduce Delta sleep

103
Q

Treatment for night terrors and sleepwalking?

A

Benzodiazepines

104
Q 
REM sleep
When does it occur?
Duration
Change with age?
Neurotransmitters involved 
Findings
A 
Every 90 minutes 
Duration ↑ throughout night 
↓ frequency with age 
ACh --> REM. NE --/ REM
↑ and variable BP and HR. EOM (activity of PPRF), Penile/Clitoral Tumescence
105
Q

Sleep patterns of depressed patients

A

↓ slow wave sleep, REM latency,
↑ REM early in sleep, ↑ total REM sleep
Repeated nighttime awakening
Early-morning awakening

106
Q 
Narcolepsy 
What is it?
Presentation
Sleep cycle 
Genetics 
Treatment
A

Disordered regulation of sleep-wake cycles
Daytime sleepiness, Hallucinations (right before or after sleep), Cataplexy following strong emotional stimulus. Cannot move when you wake up in the morning
REM at beginning of sleep
Strong genetic components
Daytime stimulants (amphetamines, modafinil) and nighttime GHB (sodium oxybate)

107
Q

Circadian Rhythm
Brain centers involved
What does it control
Pathway

A

Suprachiasmatic nucleus (SCN) of the hypothalamus
Controls ACTH, Prolactin, Melatonin, and nocturnal NE release
SNC –> NE release –> Pineal gland –> melatonin

108
Q

SCN regulation

A

SCN regulated by environment (light)

109
Q 
Sleep Terror Disorder 
What is it?
When does it occur?
Population involved 
Memory
Cause 
Course
A 
Periods of  terror with screaming in the middle of the night 
Slow-wave, non-REM sleep
Children
No memory of event 
emotional distress, fever, lack of sleep
Self limited

USMLE STEP 1 (25 decks)

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