BEHAVIORAL Flashcards
What study compares a group of ppl with a disease to a group of ppl without a disease? What can you calculate?
Case Control Study; Odds Ratio
What study compares a group with a given exposure or risk to a group without that exposure? What can you calculate?
Relative risk
What kind of study is relative risk associated with?
Cohort study–compares 2 groups, one with exposure to one without exposure
What kind of study is odds ratio associated with?
Case Control Study; compares 2 groups one with disease and one without
What is a case control study?
Compares 2 goups of ppl, one with dz and one without? Odds ratio calculated
What is a cohort study?
Study of 2 groups of ppl, one with exposure and one without and sees risk of dz development, calculate relative risk
What kind of study determines disease prevalence?
Cross-sectional study, it collects data from all ppl to assess frequency of dz
What can be calculated from a cross-sectional study?
Disease prevalence, this study is looking at the total number of ppl with the dz
What phase of a clinical trial involves a small number of healthy pts?
Phase I
What phase of a clinical trial involves a small number of pts with the dz of interest?
Phase II
What phase of a clinical trial involves a large number of pts randomly assigned to groups
Phase III
What phase of a clinical trial involves post-marketing surveillance?
Phase IV
What phase of a clinical trial compares the new treatment to the current standard of care?
Phase III
What is TP/(TP+FN)
Sensitivity (the true positive rate)? This is the proportion of ppl with the disease who test positive. That is the number of ppl who tested positive with the disease divided by the number of people who tested positive with the disease plus the ppl who SHOULD HAVE tested positive!
What is TN/ (TN + FP)?
Specificity, the true negative rate? Proportion of ppl who test negative that were negative divided by the people who test negative that should be negative plus those who should have been negative but were positive
How do you calculate sensitivity? PPV?
Sensitivity = TP/ (TP + FN)? PPV = TP/ (TP + FP)
How do you calculate specificity? NPV?
Specificity = TN/ (TN +FP) and NPV = TN/ (TN + FN)
What is the TP/(TP+FP)?
PPV (increases with increased prevalence)
What is the TN/ (TN + FN)?
NPV
How do you calculate incidence rate?
(# of new cases)/ population at risk
How do you calculate prevalence?
(# of existing cases)/ (population at risk)
What is the incidence X average disease duration?
prevalence (higher prevelance for more chronic disease)
Define an odds ratio?
Odds that the group with the disease was exposed divided by the odds that the group without the disease was exposed
How do you calculate odds ratio?
AD/BC i.e. [(A/C)/(B/D)]
How do you calculate relative risk?
[(a/(a+b))/(c/(c+d))]
How is the attributable risk calculation similar to that of the relative risk calculation?
It is the difference between the numerator and the denominator
How do you calculate attributable risk?
(a/(a+b))- (c/(c+d))
Explain in words what the attributable risk means
It is the difference in risk between an exposed group and an unexposed group
What is absolute risk reduction?
The difference in risk of ppl given a Tx vs. those with placebo? i.e. 7% occurrence in placebo but only 5% with Tx = a 2% absolute risk reduction
What is 1/ARR (absolute risk reduction)?
The number needed to treat, i.e. the number of ppl to treat for one person to benefit
How do you calculate the number needed to treat?
1/ARR? Where ARR is the difference between the risk of a group given a Tx vs. a group given placebo
What is 1/attributable risk?
The number needed to harm
How do you calculate the number needed to harm?
1/attibutable risk? Where attributable risk = a/(a+b) - c/(c+d)? That is the difference in risk between an exposed group and an unexposed group
What reduces precision in a test?
Random error
What reduces accuracy in a test?
systematic error
What is Berkson’s bias?
Loss to follow up, a form of selection bias
Nonrandom assignment to participation in a study group
Selection bias
What is recall bias
Knowledge of presence of disorder alters recall
What is sampling bias
subjects not representative of general population
What is the difference between sampling bias and selection bias?
Sampling bias is when the group tested is not representative of the population; Selection bias is when there is NONrandom assignment
What kind of bias is when there is a survey to analyze suicide?
Late look bias
What kind of bias occurs if ppl in 2 diff groups are treated differently?
Procedure bias
What occurs when the group studied changes its behavior owing to the knowledge of being studied
Hawthorne effect
How do you reduce confounding bias
matching? not sure what that means, go with it; crossover studies as well, each group acts as its own control
Mean>median>mode
positive skew
mean<mode
negative skew
Asymmetry with longer tail on right
positive skew
Asymmetry with longer tail on left
negative skew
stating there is an effect or difference when none exists
Type I error (alpha error)
Stating there is not an effect when one does exist
Type II error (beta error)
Why does it make sense that Power = 1- B
Because power is the probability that a test will detect an error when one truly exists? Since beta is the probability of making a type 2 error and a type 2 error is the probability of stating that there is no difference when one exists this makes sense
What is beta?
The probability of comitting a type II error
What is alpha?
The probability of comitting a type I error
How do you increase the likelihood of rejecting the null hypothesis when it is in fact, false?
increase sample size, expected effect size, or precision of test? This is how you increase POWER
What is Z for the 95% CI? The 99% CI?
1.96; 2.58
What is it called when you square pearson’s correlation coefficient?
Coefficient of determination
What is primary disease prevention?
prevent OCCURRENCE, i.e. vaccinate
What is secondary disease prevention?
Early detection, i.e. Pap smear
What is tertiary disease prevention?
Reduce the disability of the disease i.e. chemo and palliative care
When and how can written consent be revoked by the pt?
ANY time, even orally
5 times you don?t need parental consent for minor
1) STD 2) Addiction issues 3) Pregnancy related 4) Emergency 5) prescribing birth control
What are the rules for revoking power of attorney?
Pt can do it ANYTIME even if not competent
Who is the most important surrogate decision maker
spouse, then children, then parent, then adult sibling
What is the main thing you should do if pt has difficulty taking meds?
provide written instructions
What do you do when a child wants to know more about his or her illness?
Parents decide how much info to give
What if a pt who has a mastectomy feels ugly?
Ask why they feel this way, don’t give false hope
An Apgar score less than 4 later in time increases risk of what?
neurological damage
What defines low birth weight?
under 2500 g
When should a baby develop a social smile?
3 months
What should a baby develop stranger anxiety?
7-9 months
When should a baby develop separation anxiety?
12-15 months
At what age should the baby move away from, and then return to, the mother
Rapprochement occurs at age 12-24 mo
When should a baby be able to walk?
12-15 months
How do you know how many blocks a baby should be able to stack?
Age in years X 3 blocks (3 at 1 yr, 6 at 2, and 9 at 3
Calculate BMI
Weight in Kg/ (height in m)^2
BATS Drink Blood
Eyes open = Beta; Eyes closed = alpha, NREM1 = theta; NREM 2 = sleep spindle (and K complex); NREM 3 = Delta; REM = Beta
What nucleus is key to initiating sleep?
Raphe nucleus (serotonergic predominance)
What is the preferred Tx of nocturnal enuresis?
DDAVP > imipramine due to tricyclic AE (convulsions, coma, and cardio)
Where is most of the night spend in sleep?
N2
Where does enuresis and night terror occur?
N3
DOC for night terrors and sleepwalking?
Benzos
What is the principal neurotransmitter in REM?
Ach
What causes the REM of REM?
PPRF acitivity = Paramedian pontine reticular formation
What’s the deal with REM in depressed ppl?
Increased early in the night and increased in general
Nighttime Tx of narcolepsy
Sodium oxybate
Daytime Tx of narcolepsy
Amphetamines and modafinil
