Certified Developmental Disabilities Nurse (CDDN) Practice
Exam 2026 | 200 Questions with Answers & Rationales |
DDNA Certification Test Bank – Verified A+ Study Guide
Question 1. Which of the following best defines a developmental disability
according to the Developmental Disabilities Assistance and Bill of Rights Act?
A. A physical or mental impairment that manifests before age 22, is likely to continue
indefinitely, and results in substantial functional limitations in three or more major life
activities
B. A mental illness diagnosed in adulthood
C. A temporary condition caused by injury
D. A learning disability that only affects academic performance
Correct Answer: A
Rationale:
The Developmental Disabilities Assistance and Bill of Rights Act defines a developmental
disability as a severe, chronic disability that: is attributable to a mental or physical
impairment or combination; manifests before age 22; is likely to continue indefinitely;
results in substantial functional limitations in three or more major life activities (self-care,
receptive/expressive language, learning, mobility, self-direction, capacity for
independent living, economic self-sufficiency); and reflects the need for lifelong services.
Option B is incorrect. Option C is temporary. Option D is too narrow.
Question 2. Which of the following is the most common genetic cause of
intellectual disability?
A. Down syndrome
B. Fragile X syndrome
C. Fetal alcohol syndrome
D. Autism spectrum disorder
Correct Answer: A
Rationale:
Down syndrome (trisomy 21) is the most common chromosomal cause of intellectual
disability, occurring in approximately 1 in 700 live births. Fragile X syndrome (B) is the
most common inherited cause of intellectual disability. Fetal alcohol syndrome (C) is a
,preventable cause. Autism spectrum disorder (D) is not primarily an intellectual
disability, though it can co-occur.
Question 3. A nurse is caring for an adult with Down syndrome. Which of the
following health conditions should the nurse monitor for most closely?
A. Atlantoaxial instability
B. Hypertension
C. Diabetes insipidus
D. Glaucoma
Correct Answer: A
Rationale:
Atlantoaxial instability (AAI) occurs in approximately 10-20% of individuals with Down
syndrome due to ligamentous laxity at the C1-C2 vertebrae. It can lead to spinal cord
compression and requires monitoring, especially before surgery or sports participation.
Hypertension (B), diabetes insipidus (C), and glaucoma (D) are not the most common
concerns.
Question 4. Which of the following is a characteristic physical feature of Fragile X
syndrome?
A. Long face, large ears, and prominent jaw
B. Small stature and webbed neck
C. Rocker-bottom feet and clenched fists
D. Brushfield spots and epicanthal folds
Correct Answer: A
Rationale:
Fragile X syndrome is characterized by a long narrow face, large ears, prominent jaw,
macroorchidism (enlarged testicles in males), and hyperextensible joints. Option B
describes Turner syndrome. Option C describes trisomy 18 (Edwards syndrome). Option
D describes Down syndrome.
Question 5. A nurse is assessing a child with autism spectrum disorder (ASD).
Which of the following is a core diagnostic feature?
A. Deficits in social communication and interaction
B. Recurrent panic attacks
C. Grandiose delusions
D. Compulsive rituals only
,Correct Answer: A
Rationale:
ASD is diagnosed based on persistent deficits in social communication and social
interaction across multiple contexts, plus restricted, repetitive patterns of behavior,
interests, or activities. Panic attacks (B), grandiosity (C), and compulsions alone (D) are
not core features of ASD.
Question 6. Which of the following is the most appropriate communication
strategy for a nonverbal adult with intellectual disability?
A. Speaking loudly and slowly
B. Using augmentative and alternative communication (AAC) devices
C. Ignoring the person until they speak
D. Speaking only to the caregiver
Correct Answer: B
Rationale:
AAC devices (e.g., picture boards, speech-generating devices) are evidence-based tools
for nonverbal individuals to communicate. Speaking loudly (A) is not helpful. Ignoring
(C) is disrespectful and ineffective. Speaking only to the caregiver (D) violates the
patient's right to communicate.
Question 7. Which of the following medications is commonly used to manage
seizures in individuals with developmental disabilities?
A. Levetiracetam
B. Fluoxetine
C. Haloperidol
D. Lithium
Correct Answer: A
Rationale:
Levetiracetam (Keppra) is a broad-spectrum antiepileptic drug commonly used in
individuals with developmental disabilities. Fluoxetine (B) is an antidepressant.
Haloperidol (C) is an antipsychotic. Lithium (D) is a mood stabilizer.
Question 8. A nurse is caring for a person with cerebral palsy. Which of the
following is the most common type?
, A. Spastic cerebral palsy
B. Athetoid cerebral palsy
C. Ataxic cerebral palsy
D. Mixed cerebral palsy
Correct Answer: A
Rationale:
Spastic cerebral palsy accounts for approximately 70-80% of cases and is characterized
by increased muscle tone and stiff, jerky movements. Athetoid (B), ataxic (C), and mixed
(D) types are less common.
Question 9. Which of the following is a common secondary condition in adults
with spina bifida?
A. Hydrocephalus
B. Latex allergy
C. Both A and B
D. Hypertension only
Correct Answer: C
Rationale:
Individuals with spina bifida commonly have hydrocephalus (requiring shunt
management) and latex allergy (due to repeated exposure to latex products during
surgeries). Hypertension (D) is not a primary secondary condition.
Question 10. A nurse is developing a care plan for a person with intellectual
disability who engages in self-injurious behavior. Which of the following is the
first-line intervention?
A. Physical restraint
B. Functional behavioral assessment
C. Medication
D. Seclusion
Correct Answer: B
Rationale:
A functional behavioral assessment (FBA) identifies the antecedents, behaviors, and
consequences to understand the function of the behavior and develop positive behavior
support strategies. Restraint (A), medication (C), and seclusion (D) are not first-line and
may be contraindicated.
Exam 2026 | 200 Questions with Answers & Rationales |
DDNA Certification Test Bank – Verified A+ Study Guide
Question 1. Which of the following best defines a developmental disability
according to the Developmental Disabilities Assistance and Bill of Rights Act?
A. A physical or mental impairment that manifests before age 22, is likely to continue
indefinitely, and results in substantial functional limitations in three or more major life
activities
B. A mental illness diagnosed in adulthood
C. A temporary condition caused by injury
D. A learning disability that only affects academic performance
Correct Answer: A
Rationale:
The Developmental Disabilities Assistance and Bill of Rights Act defines a developmental
disability as a severe, chronic disability that: is attributable to a mental or physical
impairment or combination; manifests before age 22; is likely to continue indefinitely;
results in substantial functional limitations in three or more major life activities (self-care,
receptive/expressive language, learning, mobility, self-direction, capacity for
independent living, economic self-sufficiency); and reflects the need for lifelong services.
Option B is incorrect. Option C is temporary. Option D is too narrow.
Question 2. Which of the following is the most common genetic cause of
intellectual disability?
A. Down syndrome
B. Fragile X syndrome
C. Fetal alcohol syndrome
D. Autism spectrum disorder
Correct Answer: A
Rationale:
Down syndrome (trisomy 21) is the most common chromosomal cause of intellectual
disability, occurring in approximately 1 in 700 live births. Fragile X syndrome (B) is the
most common inherited cause of intellectual disability. Fetal alcohol syndrome (C) is a
,preventable cause. Autism spectrum disorder (D) is not primarily an intellectual
disability, though it can co-occur.
Question 3. A nurse is caring for an adult with Down syndrome. Which of the
following health conditions should the nurse monitor for most closely?
A. Atlantoaxial instability
B. Hypertension
C. Diabetes insipidus
D. Glaucoma
Correct Answer: A
Rationale:
Atlantoaxial instability (AAI) occurs in approximately 10-20% of individuals with Down
syndrome due to ligamentous laxity at the C1-C2 vertebrae. It can lead to spinal cord
compression and requires monitoring, especially before surgery or sports participation.
Hypertension (B), diabetes insipidus (C), and glaucoma (D) are not the most common
concerns.
Question 4. Which of the following is a characteristic physical feature of Fragile X
syndrome?
A. Long face, large ears, and prominent jaw
B. Small stature and webbed neck
C. Rocker-bottom feet and clenched fists
D. Brushfield spots and epicanthal folds
Correct Answer: A
Rationale:
Fragile X syndrome is characterized by a long narrow face, large ears, prominent jaw,
macroorchidism (enlarged testicles in males), and hyperextensible joints. Option B
describes Turner syndrome. Option C describes trisomy 18 (Edwards syndrome). Option
D describes Down syndrome.
Question 5. A nurse is assessing a child with autism spectrum disorder (ASD).
Which of the following is a core diagnostic feature?
A. Deficits in social communication and interaction
B. Recurrent panic attacks
C. Grandiose delusions
D. Compulsive rituals only
,Correct Answer: A
Rationale:
ASD is diagnosed based on persistent deficits in social communication and social
interaction across multiple contexts, plus restricted, repetitive patterns of behavior,
interests, or activities. Panic attacks (B), grandiosity (C), and compulsions alone (D) are
not core features of ASD.
Question 6. Which of the following is the most appropriate communication
strategy for a nonverbal adult with intellectual disability?
A. Speaking loudly and slowly
B. Using augmentative and alternative communication (AAC) devices
C. Ignoring the person until they speak
D. Speaking only to the caregiver
Correct Answer: B
Rationale:
AAC devices (e.g., picture boards, speech-generating devices) are evidence-based tools
for nonverbal individuals to communicate. Speaking loudly (A) is not helpful. Ignoring
(C) is disrespectful and ineffective. Speaking only to the caregiver (D) violates the
patient's right to communicate.
Question 7. Which of the following medications is commonly used to manage
seizures in individuals with developmental disabilities?
A. Levetiracetam
B. Fluoxetine
C. Haloperidol
D. Lithium
Correct Answer: A
Rationale:
Levetiracetam (Keppra) is a broad-spectrum antiepileptic drug commonly used in
individuals with developmental disabilities. Fluoxetine (B) is an antidepressant.
Haloperidol (C) is an antipsychotic. Lithium (D) is a mood stabilizer.
Question 8. A nurse is caring for a person with cerebral palsy. Which of the
following is the most common type?
, A. Spastic cerebral palsy
B. Athetoid cerebral palsy
C. Ataxic cerebral palsy
D. Mixed cerebral palsy
Correct Answer: A
Rationale:
Spastic cerebral palsy accounts for approximately 70-80% of cases and is characterized
by increased muscle tone and stiff, jerky movements. Athetoid (B), ataxic (C), and mixed
(D) types are less common.
Question 9. Which of the following is a common secondary condition in adults
with spina bifida?
A. Hydrocephalus
B. Latex allergy
C. Both A and B
D. Hypertension only
Correct Answer: C
Rationale:
Individuals with spina bifida commonly have hydrocephalus (requiring shunt
management) and latex allergy (due to repeated exposure to latex products during
surgeries). Hypertension (D) is not a primary secondary condition.
Question 10. A nurse is developing a care plan for a person with intellectual
disability who engages in self-injurious behavior. Which of the following is the
first-line intervention?
A. Physical restraint
B. Functional behavioral assessment
C. Medication
D. Seclusion
Correct Answer: B
Rationale:
A functional behavioral assessment (FBA) identifies the antecedents, behaviors, and
consequences to understand the function of the behavior and develop positive behavior
support strategies. Restraint (A), medication (C), and seclusion (D) are not first-line and
may be contraindicated.
