A 73-year-old man is brought to the emergency department by ambulance after being found to be non-communicative by his family during dinner. On presentation he appears to be alert, though he is confused and cannot follow instructions. When he tries to speak, he vocalizes a string of fluent but unintelligible syllables. Given this presentation, his physician decides to administer tissue plasminogen activator to this patient. This intervention best represents which of the following principles?
Q12
A group of gastroenterologists is concerned about low colonoscopy screening rates. They decide to implement a free patient navigation program to assist local residents and encourage them to obtain colonoscopies in accordance with U.S. Preventive Services Task Force (USPSTF) guidelines. Local residents were recruited at community centers. Participants attended monthly meetings with patient navigators and were regularly reminded that their adherence to screening guidelines was being evaluated. Colonoscopy screening rates were assessed via chart review, which showed that 90% of participants adhered to screening guidelines. Data collected via chart review for local residents recruited at community centers who did not participate in the free patient navigation system found that 34% of that population adhered to USPSTF guidelines. Which of the following has most likely contributed to the observed disparity in colonoscopy screening rates?
Q13
An 8-year-old boy is brought to the physician by his mother for a well-child examination at a clinic for low-income residents. Although her son's elementary school offers free afterschool programming, her son has not been interested in attending. Both the son's maternal and paternal grandmothers have major depressive disorder. The mother is curious about the benefits of afterschool programming and asks for the physician's input. Which of the following statements best addresses the potential benefits of afterschool programming for this child?
Q14
An office team is being observed by an outside agency at the request of management to make sure they are completing all their tasks appropriately. Several of the employees are nervous that they are being watched and take care to perform their jobs with extra care, more so than they would have done during a normal workday. What best describes this behavior?
Q15
A new study is investigating the effects of an experimental drug, Exerzisin, on the duration and intensity of exercise. In the treatment group participants are given daily Exerzisin at the main treatment facility and instructed to exercise as much as they would like on the facility's exercise equipment. Due to an insufficient number of exercise units at the main treatment center, the control subjects are given free access to an outside, private gym. The duration and intensity of exercise in both groups is measured with a pedometer. The perspicacious undergraduate, hired to input all the data, points out that the treatment group may be more motivated to exercise harder and longer because their exercising can be observed by the investigators. To which form of bias is he alluding?
Q16
An investigator, studying learning in primates, gives an experimental chimpanzee a series of puzzles to solve. The chimpanzee solves the puzzle when he is able to place a set of wooden blocks sequentially inside the next biggest block. When a puzzle is solved successfully, a 30-second audio clip of a pop song plays. 15 seconds after that, a tangerine drops into the chimpanzee's room. After 2 days of this regimen, the chimpanzee undergoes functional magnetic resonance imaging (fMRI) of his brain while hearing the audio clip, which shows markedly elevated neurotransmission in the ventral tegmental area and substantia nigra. Which of the following best explains the finding on fMRI?
Study designs US Medical PG Practice Questions and MCQs
Question 11: A 73-year-old man is brought to the emergency department by ambulance after being found to be non-communicative by his family during dinner. On presentation he appears to be alert, though he is confused and cannot follow instructions. When he tries to speak, he vocalizes a string of fluent but unintelligible syllables. Given this presentation, his physician decides to administer tissue plasminogen activator to this patient. This intervention best represents which of the following principles?
A. Tertiary prevention
B. Primary prevention
C. This does not represent prevention (Correct Answer)
D. Quaternary prevention
E. Secondary prevention
Explanation: ***This does not represent prevention***
- The administration of **tissue plasminogen activator (tPA)** during an **acute stroke** is a **therapeutic intervention**, not a form of prevention.
- **Prevention** refers to actions taken to prevent disease occurrence, detect it early, or prevent complications after recovery. Treating an acute, symptomatic event is **acute treatment**, not prevention.
- This is an active medical intervention to treat an ongoing, symptomatic disease process (acute ischemic stroke), which falls under **therapeutic management** rather than any category of prevention.
*Secondary prevention*
- **Secondary prevention** involves **early detection** and treatment of asymptomatic or minimally symptomatic disease to prevent progression (e.g., screening mammography, colonoscopy).
- For stroke specifically, secondary prevention would include interventions **after** the acute event to **prevent recurrence**, such as starting antiplatelet therapy (aspirin, clopidogrel), anticoagulation for atrial fibrillation, statin therapy, or carotid endarterectomy after TIA.
- tPA is given during the acute symptomatic phase, making it treatment rather than secondary prevention.
*Tertiary prevention*
- **Tertiary prevention** focuses on **rehabilitation** and managing established disease to prevent complications and improve quality of life.
- Examples after stroke include physical therapy, occupational therapy, speech therapy, and managing post-stroke complications like depression or spasticity.
- This occurs in the recovery phase, not during acute treatment.
*Primary prevention*
- **Primary prevention** aims to prevent disease before it occurs in healthy individuals.
- Examples include controlling hypertension, managing diabetes, smoking cessation, exercise, and healthy diet - all interventions that reduce stroke risk **before** any event occurs.
*Quaternary prevention*
- **Quaternary prevention** protects patients from **overmedicalization** and excessive or harmful medical interventions.
- It involves avoiding unnecessary testing or treatment that may cause more harm than benefit.
- Administering tPA for acute stroke (when indicated) is evidence-based treatment, not overtreatment.
Question 12: A group of gastroenterologists is concerned about low colonoscopy screening rates. They decide to implement a free patient navigation program to assist local residents and encourage them to obtain colonoscopies in accordance with U.S. Preventive Services Task Force (USPSTF) guidelines. Local residents were recruited at community centers. Participants attended monthly meetings with patient navigators and were regularly reminded that their adherence to screening guidelines was being evaluated. Colonoscopy screening rates were assessed via chart review, which showed that 90% of participants adhered to screening guidelines. Data collected via chart review for local residents recruited at community centers who did not participate in the free patient navigation system found that 34% of that population adhered to USPSTF guidelines. Which of the following has most likely contributed to the observed disparity in colonoscopy screening rates?
A. Recall bias
B. Confirmation bias
C. Reporting bias
D. Hawthorne effect (Correct Answer)
E. Sampling bias
Explanation: ***Hawthorne effect***
- The **Hawthorne effect** is a type of reactivity in which individuals modify an aspect of their behavior in response to their awareness of being observed.
- In this study, participants were aware that their adherence to screening guidelines was being evaluated, likely leading to increased compliance simply due to this awareness rather than the efficacy of the patient navigation program alone.
*Recall bias*
- **Recall bias** occurs when participants disproportionately remember or inaccurately recall past events, often due to their current health status or beliefs.
- This bias is less likely here as colonoscopy screening rates were assessed via **chart review**, an objective measure, rather than participant self-report.
*Confirmation bias*
- **Confirmation bias** is the tendency to search for, interpret, favor, and recall information in a way that confirms one's preexisting beliefs or hypotheses.
- This bias typically affects the researchers or observers, not the participants' behavior in the observed manner, as the question focuses on the participants' increased screening rates.
*Reporting bias*
- **Reporting bias** refers to selective revealing or suppression of information during the reporting of research findings, and can occur when study participants selectively report symptoms or behaviors.
- While participants might selectively report, the data here was gathered through **chart review**, which is a more objective measure of actual behavior, making reporting bias less likely to explain the disparity in screening rates.
*Sampling bias*
- **Sampling bias** occurs when a sample is not representative of the population from which it is drawn, leading to skewed results.
- While there might be some sampling bias in who chose to participate in the free program, the observed disparity is specifically about behavior change in those *being observed*, pointing more strongly to the Hawthorne effect.
Question 13: An 8-year-old boy is brought to the physician by his mother for a well-child examination at a clinic for low-income residents. Although her son's elementary school offers free afterschool programming, her son has not been interested in attending. Both the son's maternal and paternal grandmothers have major depressive disorder. The mother is curious about the benefits of afterschool programming and asks for the physician's input. Which of the following statements best addresses the potential benefits of afterschool programming for this child?
A. High-quality afterschool programming would decrease this patient's risk of developing major depressive disorder.
B. High-quality afterschool programming for low-income 8-year-olds may correlate with decreased ADHD risk in adults. (Correct Answer)
C. High-quality afterschool programming has a greater effect on reducing psychotic disorder risk in adults than bipolar disorder risk.
D. High-quality afterschool programming has a greater effect on reducing ADHD risk in adults than major depressive disorder risk.
E. The patient's family history of psychiatric illness prevents any potential benefits from afterschool programming.
Explanation: ***High-quality afterschool programming for low-income 8-year-olds may correlate with decreased ADHD risk in adults.***
- Research, including systematic reviews and longitudinal studies, indicates that structured, high-quality afterschool programs can lead to improved behavioral outcomes and reduced risk of **ADHD symptoms** persisting into adulthood, especially in **vulnerable populations** such as low-income children.
- These programs foster **social-emotional skills**, provide academic support, and promote healthy development, indirectly mitigating factors associated with ADHD through improved executive function and self-regulation.
*High-quality afterschool programming would decrease this patient's risk of developing major depressive disorder.*
- While afterschool programs provide mental health benefits through **social support** and structured activities, the direct reduction in risk of **major depressive disorder** is less consistently demonstrated compared to behavioral outcomes.
- Given the strong **family history** (both grandmothers affected), genetic factors play a significant role that afterschool programming alone cannot fully mitigate.
*The patient's family history of psychiatric illness prevents any potential benefits from afterschool programming.*
- Family history is a **risk factor** but does not negate the benefits of **preventive interventions** like afterschool programs.
- Evidence-based programs can still provide protective effects on mental health and behavioral outcomes, even in children with genetic vulnerabilities.
*High-quality afterschool programming has a greater effect on reducing psychotic disorder risk in adults than bipolar disorder risk.*
- There is **insufficient evidence** to support significant impacts of childhood afterschool programming specifically on reducing the risk of **psychotic disorders** or **bipolar disorder** in adulthood.
- These conditions have strong genetic and neurobiological components that are not primarily addressed by afterschool interventions.
*High-quality afterschool programming has a greater effect on reducing ADHD risk in adults than major depressive disorder risk.*
- While this comparison has some support in the literature, the **correct answer** is more appropriately hedged and specific to the patient population (low-income 8-year-olds).
- Both conditions can benefit from afterschool programming, but the evidence for **behavioral regulation** and ADHD symptom reduction is more robust and consistent.
Question 14: An office team is being observed by an outside agency at the request of management to make sure they are completing all their tasks appropriately. Several of the employees are nervous that they are being watched and take care to perform their jobs with extra care, more so than they would have done during a normal workday. What best describes this behavior?
A. Pygmalion effect
B. Novelty effect
C. Hawthorne effect (Correct Answer)
D. Observer bias
E. Ringelmann effect
Explanation: ***Hawthorne effect***
- The **Hawthorne effect** describes changes in behavior that occur among individuals who are aware that they are being observed.
- In this scenario, the employees' increased diligence due to being watched by an outside agency aligns perfectly with this psychological phenomenon.
*Pygmalion effect*
- The **Pygmalion effect** refers to the phenomenon where higher expectations lead to improved performance in a given area.
- It focuses on how an observer's expectations can influence the subject's behavior, rather than the subject's awareness of observation itself.
*Novelty effect*
- The **novelty effect** occurs when the initial interest or enthusiasm for a new item or intervention temporarily improves performance, which then wanes over time.
- This effect is related to the newness of a situation, not the act of being observed.
*Observer bias*
- **Observer bias** (also known as ascertainment bias) happens when the observer's expectations, beliefs, or preconceptions influence how they perceive or record data.
- It refers to a bias in the *observer*, not a change in the *observed subject's behavior* due to being watched.
*Ringelmann effect*
- The **Ringelmann effect** (or social loafing) describes the tendency for individual members of a group to become less productive as the size of their group increases.
- This is a phenomenon of reduced individual effort in a group setting, not an alteration in behavior due to being observed.
Question 15: A new study is investigating the effects of an experimental drug, Exerzisin, on the duration and intensity of exercise. In the treatment group participants are given daily Exerzisin at the main treatment facility and instructed to exercise as much as they would like on the facility's exercise equipment. Due to an insufficient number of exercise units at the main treatment center, the control subjects are given free access to an outside, private gym. The duration and intensity of exercise in both groups is measured with a pedometer. The perspicacious undergraduate, hired to input all the data, points out that the treatment group may be more motivated to exercise harder and longer because their exercising can be observed by the investigators. To which form of bias is he alluding?
A. Selection bias
B. Recall bias
C. Hawthorne effect (Correct Answer)
D. Pygmalion effect
E. Lead time bias
Explanation: ***Hawthorne effect***
- The Hawthorne effect describes the phenomenon where individuals modify an aspect of their behavior in response to their awareness of being **observed**.
- In this study, the treatment group may exercise more intensely because they know investigators are watching, potentially confounding the drug's true effect.
*Selection bias*
- **Selection bias** occurs when the selection of subjects for a study, or their likelihood of staying in the study, leads to a sample that does not accurately represent the target population.
- While there are issues with how the control and treatment groups are handled, the specific concern here is about behavior change due to observation, not how initial subjects were chosen or lost.
*Recall bias*
- **Recall bias** is a systematic error caused by differences in the accuracy or completeness of the recollections of past events or experiences by study participants.
- This type of bias is relevant when participants are asked to remember past information, which is not the primary issue in this scenario where current exercise behavior is being observed.
*Pygmalion effect*
- The **Pygmalion effect** occurs when higher expectations placed upon individuals lead to better performance.
- This typically involves an investigator's expectations influencing a participant's performance, rather than the participant's awareness of being observed influencing their own behavior.
*Lead time bias*
- **Lead time bias** is a form of bias that occurs in screening and early detection studies, where earlier diagnosis of a disease (due to screening) makes it seem like patients live longer, even if the treatment doesn't change the actual course of the disease.
- This bias is not relevant here as the study is observing the effects of a drug on exercise, not disease prognosis or survival.
Question 16: An investigator, studying learning in primates, gives an experimental chimpanzee a series of puzzles to solve. The chimpanzee solves the puzzle when he is able to place a set of wooden blocks sequentially inside the next biggest block. When a puzzle is solved successfully, a 30-second audio clip of a pop song plays. 15 seconds after that, a tangerine drops into the chimpanzee's room. After 2 days of this regimen, the chimpanzee undergoes functional magnetic resonance imaging (fMRI) of his brain while hearing the audio clip, which shows markedly elevated neurotransmission in the ventral tegmental area and substantia nigra. Which of the following best explains the finding on fMRI?
A. Positive reinforcement
B. Displacement
C. Negative reinforcement
D. Classical conditioning (Correct Answer)
E. Extinction
Explanation: ***Classical conditioning***
- The chimpanzee has learned to associate the **neutral stimulus** (pop song) with impending **reward** (tangerine) through repeated pairing, leading to an anticipatory **dopamine release** in the **ventral tegmental area (VTA)** and **substantia nigra**.
- This is a form of **associative learning** where a previously neutral stimulus (conditioned stimulus) comes to evoke a response (conditioned response) after being repeatedly paired with a stimulus that naturally evokes that response (unconditioned stimulus).
*Positive reinforcement*
- This involves adding a **desirable stimulus** after a behavior, increasing the likelihood of that behavior occurring again. In this scenario, the tangerine is a positive reinforcer for solving the puzzle, but the fMRI findings relate to the learned association of the song, not directly the puzzle-solving behavior itself.
- While the tangerine acts as positive reinforcement for puzzle-solving, the fMRI finding pertains to the chimpanzee's reaction to the *song* as a predictor of the tangerine, which is a key aspect of classical conditioning.
*Displacement*
- This is an **ego defense mechanism** in psychology where emotions are redirected from a threatening target to a safer, often unrelated, target. It is not relevant to learning or reward pathways in this context.
- Displacement explains how pent-up emotions are released through an alternative, less threatening channel, which is entirely different from the associative learning described.
*Negative reinforcement*
- This involves removing an **aversive stimulus** after a behavior to increase the likelihood of that behavior occurring again. The scenario describes adding a desirable stimulus (tangerine), not removing an undesirable one.
- Negative reinforcement would involve, for example, the chimpanzee solving the puzzle to stop an unpleasant noise, which is not what is happening here.
*Extinction*
- This refers to the **disappearance of a learned response** when the conditioned stimulus is no longer paired with the unconditioned stimulus, or when reinforced behavior stops being reinforced. The fMRI shows a strong response, indicating learning has occurred, not been extinguished.
- If extinction were occurring, the chimpanzee would no longer show a strong neural response to the song after repeated presentations without the subsequent tangerine reward.
