DO (IQ) 4 — Questions and Answers
Question 1: During a developmental assessment, a 6-year-old achieves a mental age of 9 years. Using the ratio IQ formula, what is this child's IQ?
- 120
- 150 (Correct answer)
- 133
- 115
Correct answer: 150
Ratio IQ = (mental age / chronological age) × 100 = (9/6) × 100 = 150.
Question 2: A physician is counseling parents whose child has an IQ of 65. Which educational placement is MOST appropriate under IDEA in the US?
- Full-time residential placement in a special school
- Least restrictive environment with individualized education plan (IEP) (Correct answer)
- Home-bound instruction only
- Standard classroom with no modifications
Correct answer: Least restrictive environment with individualized education plan (IEP)
IDEA mandates that students with disabilities receive education in the least restrictive environment with appropriate IEP supports.
Question 3: Which neurotransmitter system has been most consistently linked to cognitive enhancement and IQ-related performance in pharmacological research?
- Dopaminergic and cholinergic systems (Correct answer)
- GABAergic system
- Serotonergic system exclusively
- Histaminergic system
Correct answer: Dopaminergic and cholinergic systems
Dopamine and acetylcholine are central to working memory, attention, and executive function — the cognitive domains most closely correlated with IQ scores.
Question 4: A patient with an IQ of 68 and significant adaptive deficits is being evaluated for informed consent to participate in a research study. The most appropriate first step is:
- Exclude the patient from research participation entirely
- Assess the patient's specific decision-making capacity for this protocol (Correct answer)
- Obtain consent only from the legal guardian without involving the patient
- Administer a higher-stakes alternative consent form
Correct answer: Assess the patient's specific decision-making capacity for this protocol
Decision-making capacity is task-specific; IQ alone does not determine capacity — the physician must assess understanding, appreciation, reasoning, and communication for this specific decision.
Question 5: Which heritability estimate for IQ in adults, derived from twin studies, is most consistent with the current scientific literature?
- 20–30%
- 40–50%
- 60–80% (Correct answer)
- 95–100%
Correct answer: 60–80%
Twin and adoption studies consistently estimate IQ heritability in adults at approximately 60–80%, with environmental factors accounting for the remainder.
Question 6: A physician suspects malingering during an IQ evaluation of a patient claiming disability benefits. Which test is MOST appropriate to assess effort validity?
- Test of Memory Malingering (TOMM) (Correct answer)
- Beck Anxiety Inventory (BAI)
- Hamilton Depression Scale
- Minnesota Multiphasic Personality Inventory-2 (MMPI-2)
Correct answer: Test of Memory Malingering (TOMM)
The TOMM is a widely used performance validity test specifically designed to detect inadequate effort or malingering during cognitive evaluations.
Question 7: Lead exposure during early childhood most directly impacts IQ scores by affecting which brain structure?
- Cerebellum
- Prefrontal cortex and hippocampus (Correct answer)
- Brainstem reticular formation
- Occipital cortex
Correct answer: Prefrontal cortex and hippocampus
Lead preferentially damages the prefrontal cortex and hippocampus, disrupting executive function, working memory, and learning — core IQ-related domains.
DO (IQ) 4
During a developmental assessment, a 6-year-old achieves a mental age of 9 years.
Using the ratio IQ formula, what is this child's IQ?