DO (IQ) 2 — Questions and Answers
Question 1: A 10-year-old child scores 70 on a standardized IQ test. According to DSM-5 criteria, which additional finding is required to diagnose intellectual disability?
- Deficits in adaptive functioning in at least one domain (Correct answer)
- A score below 65 on a second IQ test
- Brain imaging showing cortical atrophy
- Onset of symptoms before age 5
Correct answer: Deficits in adaptive functioning in at least one domain
DSM-5 requires both intellectual deficits AND deficits in adaptive functioning (conceptual, social, or practical domains) with onset during the developmental period.
Question 2: Which IQ test is most widely used for assessing adults aged 16–90 in clinical neuropsychological evaluations in the US?
- Stanford-Binet Intelligence Scale
- Wechsler Adult Intelligence Scale (WAIS) (Correct answer)
- Raven's Progressive Matrices
- Kaufman Assessment Battery for Children
Correct answer: Wechsler Adult Intelligence Scale (WAIS)
The WAIS (currently WAIS-IV) is the gold-standard adult IQ test used in clinical and neuropsychological settings.
Question 3: A patient's Full Scale IQ (FSIQ) score is 100. What percentile does this represent in a normally distributed population?
- 25th percentile
- 50th percentile (Correct answer)
- 75th percentile
- 84th percentile
Correct answer: 50th percentile
An FSIQ of 100 is the mean of the normative sample, corresponding to the 50th percentile by definition.
Question 4: Which condition is most commonly associated with an IQ in the moderate intellectual disability range (35–49)?
- Fragile X syndrome
- Down syndrome (trisomy 21) (Correct answer)
- Phenylketonuria (untreated)
- Williams syndrome
Correct answer: Down syndrome (trisomy 21)
Down syndrome typically produces IQ scores in the moderate range (35–70), though there is variability; it is the most common chromosomal cause of intellectual disability.
Question 5: A clinician uses the Flynn Effect to interpret an older IQ test score. What does the Flynn Effect describe?
- Declining IQ scores in populations with higher screen time
- Rising average IQ scores in populations over successive generations (Correct answer)
- Regression of IQ scores toward the population mean over time
- Variability in IQ scores due to test-retest unreliability
Correct answer: Rising average IQ scores in populations over successive generations
The Flynn Effect refers to the observed rise of approximately 3 IQ points per decade across generations in many countries, requiring periodic renorming of tests.
Question 6: A 7-year-old is referred for evaluation of learning difficulties. Her performance IQ is 95 but verbal IQ is 72. This significant discrepancy most suggests evaluation for which condition?
- Autism spectrum disorder
- Dyslexia or language-based learning disability (Correct answer)
- ADHD, combined type
- Dyscalculia
Correct answer: Dyslexia or language-based learning disability
A large verbal-performance IQ discrepancy with low verbal IQ is classically associated with language-based learning disabilities such as dyslexia.
Question 7: Which ethical principle is most directly violated if a clinician uses IQ testing results from a culturally biased instrument to place a minority child in a special education program?
- Autonomy
- Justice (Correct answer)
- Beneficence
- Non-maleficence
Correct answer: Justice
Justice requires fair treatment and non-discriminatory practices; using a biased instrument to make placement decisions disproportionately harms minority populations.
DO (IQ) 2
A 10-year-old child scores 70 on a standardized IQ test.
According to DSM-5 criteria, which additional finding is required to diagnose intellectual disability?