DO (IQ) 3 — Questions and Answers
Question 1: An osteopathic physician is evaluating a patient with an IQ of 55. Under DSM-5, this level of intellectual disability is classified as:
- Mild
- Moderate (Correct answer)
- Severe
- Profound
Correct answer: Moderate
DSM-5 classifies intellectual disability with IQ 35–49 as moderate, IQ 50–70 as mild, and IQ 20–34 as severe.
Question 2: A 4-year-old child cannot be reliably tested with standard IQ measures. Which assessment approach is most appropriate for evaluating intellectual functioning in this case?
- Vineland Adaptive Behavior Scales (Correct answer)
- WAIS-IV administered with extended time
- Minnesota Multiphasic Personality Inventory (MMPI)
- Beck Depression Inventory
Correct answer: Vineland Adaptive Behavior Scales
The Vineland Adaptive Behavior Scales assess real-world functioning and are appropriate when standardized IQ testing is not feasible or reliable.
Question 3: Which single gene disorder is the most common inherited cause of intellectual disability in males?
- Down syndrome
- Angelman syndrome
- Fragile X syndrome (Correct answer)
- Rett syndrome
Correct answer: Fragile X syndrome
Fragile X syndrome, caused by CGG trinucleotide repeat expansion in the FMR1 gene on the X chromosome, is the most common inherited cause of intellectual disability.
Question 4: A standard score has a mean of 100 and SD of 15. What is the probability of randomly selecting an individual with an IQ between 85 and 115?
- 50%
- 68% (Correct answer)
- 95%
- 99.7%
Correct answer: 68%
Scores between 85–115 fall within one standard deviation of the mean (100 ± 15), encompassing approximately 68% of a normally distributed population.
Question 5: A physician is assessing an adult who sustained a traumatic brain injury. Pre-injury IQ is estimated using what method?
- Test of Memory Malingering (TOMM)
- Word reading tests such as WTAR or NART (Correct answer)
- Digit span subtests from the WAIS
- Trail Making Test
Correct answer: Word reading tests such as WTAR or NART
Word reading tests (e.g., WTAR, NART) estimate premorbid IQ because word reading is relatively preserved after brain injury.
Question 6: Which of the following is a key limitation of using IQ scores alone to determine competency to stand trial?
- IQ tests are not standardized for adults
- Competency requires functional legal understanding, not just cognitive ability (Correct answer)
- IQ scores are not admissible in US courts
- Competency assessments require an IQ above 80
Correct answer: Competency requires functional legal understanding, not just cognitive ability
Competency to stand trial requires the functional ability to understand proceedings and assist counsel — IQ scores are one data point but do not solely determine competency.
Question 7: A child with phenylketonuria (PKU) who is maintained on a phenylalanine-restricted diet from birth is MOST likely to have:
- Severe intellectual disability (IQ < 20)
- Near-normal IQ (Correct answer)
- Moderate intellectual disability (IQ 35–49)
- Borderline intellectual functioning (IQ 70–79)
Correct answer: Near-normal IQ
Early and sustained dietary treatment of PKU prevents phenylalanine accumulation and allows near-normal cognitive development.
DO (IQ) 3
An osteopathic physician is evaluating a patient with an IQ of 55.
Under DSM-5, this level of intellectual disability is classified as: