CDDN CERTIFIED DEVELOPMENTAL
DISABILITIES NURSE (CDDN) EXAM 2026
STUDY GUIDE | PRACTICE QUESTIONS WITH
VERIFIED ANSWERS & RATIONALES |
COMPLETE EXAM PREPARATION PDF
CDDN CERTIFIED DEVELOPMENTAL DISABILITIES NURSE (CDDN) EXAM 2026
STUDY GUIDE
PRACTICE QUESTIONS WITH VERIFIED ANSWERS & EXPERT RATIONALE
DOCUMENT OVERVIEW
• This comprehensive question study guide is designed to prepare nursing
professionals for the CDDN certification exam through evidence-based practice
questions covering all major content domains and clinical scenarios relevant to
developmental disabilities nursing.
• Maximize your learning by studying 15-20 questions daily, reviewing EXPERT
RATIONALE carefully, and identifying weak content areas for targeted review
before taking the certification examination.
QUESTION 1
A client with Down syndrome presents with signs of acute respiratory
distress. Which anatomical consideration should the nurse prioritize when
assessing this client?
A) Down syndrome individuals typically have larger airways requiring larger
endotracheal tubes
B) Hypotonia and midface hypoplasia may contribute to airway compromise and
increased risk of obstruction
C) Down syndrome is always associated with severe cardiac anomalies that
preclude respiratory support
,D) The condition guarantees normal lung capacity despite other physical
characteristics
E) Airway assessment is unnecessary as aspiration is not a concern in Down
syndrome
CORRECT ANSWER: B
EXPERT RATIONALE: Individuals with Down syndrome frequently present with
hypotonia (decreased muscle tone) and characteristic facial features including
midface hypoplasia, which can narrow the airway and increase obstruction risk.
Additionally, the condition is associated with increased prevalence of sleep apnea,
tracheomalacia, and higher rates of respiratory infections. While some individuals
may have cardiac anomalies, these do not automatically preclude respiratory
support. The nurse must carefully assess airway patency and consider positioning,
suctioning, and potential need for specialized airway management in this
population.
QUESTION 2
Which is the most common chromosomal abnormality associated with Down
syndrome?
A) Trisomy 18 (Edwards syndrome)
B) Trisomy 21 (nondisjunction)
C) Turner syndrome (45,X)
D) Klinefelter syndrome (47,XXY)
E) Cri-du-chat syndrome (5p deletion)
CORRECT ANSWER: B
EXPERT RATIONALE: Trisomy 21 resulting from nondisjunction accounts for
approximately 95% of all Down syndrome cases. This occurs when chromosome 21
fails to separate during meiosis, resulting in three copies of chromosome 21
instead of the normal two. Maternal age greater than 35 years significantly
,increases the risk of nondisjunction. The other options represent different
chromosomal abnormalities with distinct clinical presentations and developmental
consequences.
QUESTION 3
A nurse is developing a behavior modification plan for a client with
intellectual disability who engages in self-injurious behavior. Which principle
should guide the initial assessment?
A) Punishment-based interventions are most effective for eliminating self-injury
B) Identifying the function or communicative intent of the behavior is essential
before implementing intervention
C) All self-injurious behaviors respond identically to the same intervention
D) Behavioral assessment is unnecessary; medication is the only appropriate
treatment
E) Self-injurious behavior is a permanent characteristic that cannot be modified
CORRECT ANSWER: B
EXPERT RATIONALE: Functional behavior assessment is the gold standard
approach to understanding the underlying causes and functions of challenging
behaviors in individuals with developmental disabilities. Self-injurious behaviors
may serve multiple functions including communication of needs, attention-seeking,
sensory stimulation, pain management, or escape from demand situations.
Understanding the specific function allows the nurse and interdisciplinary team to
develop targeted, evidence-based interventions that address the underlying cause
rather than merely suppressing behavior. This approach is more humane and
typically more effective long-term than punishment-based strategies.
QUESTION 4
, What is the primary advantage of using augmentative and alternative
communication (AAC) devices for non-verbal clients with developmental
disabilities?
A) AAC devices completely restore normal speech production
B) AAC devices enable individuals to express needs, choices, and participate in
social interaction, enhancing quality of life and reducing behavioral challenges
C) AAC use is only appropriate for individuals with severe intellectual disability
D) AAC devices eliminate the need for any other form of communication
E) Using AAC delays the development of natural speech
CORRECT ANSWER: B
EXPERT RATIONALE: Augmentative and alternative communication devices serve
as vital tools that enable non-verbal or minimally verbal individuals to communicate
their needs, preferences, and desires. By providing functional communication
methods, AAC systems often reduce frustration-related behaviors and increase
social participation. Research demonstrates that AAC use does not inhibit natural
speech development; conversely, it may facilitate it by providing a foundation for
communication. AAC is beneficial across all severity levels of developmental
disability and should be implemented based on individual communication needs
rather than disability severity alone.
QUESTION 5
A client with cerebral palsy presents with increased muscle tone and
exaggerated reflexes affecting mobility. Which type of cerebral palsy is this
presentation most consistent with?
A) Ataxic cerebral palsy
B) Spastic cerebral palsy
C) Dyskinetic cerebral palsy
D) Hypotonic cerebral palsy
DISABILITIES NURSE (CDDN) EXAM 2026
STUDY GUIDE | PRACTICE QUESTIONS WITH
VERIFIED ANSWERS & RATIONALES |
COMPLETE EXAM PREPARATION PDF
CDDN CERTIFIED DEVELOPMENTAL DISABILITIES NURSE (CDDN) EXAM 2026
STUDY GUIDE
PRACTICE QUESTIONS WITH VERIFIED ANSWERS & EXPERT RATIONALE
DOCUMENT OVERVIEW
• This comprehensive question study guide is designed to prepare nursing
professionals for the CDDN certification exam through evidence-based practice
questions covering all major content domains and clinical scenarios relevant to
developmental disabilities nursing.
• Maximize your learning by studying 15-20 questions daily, reviewing EXPERT
RATIONALE carefully, and identifying weak content areas for targeted review
before taking the certification examination.
QUESTION 1
A client with Down syndrome presents with signs of acute respiratory
distress. Which anatomical consideration should the nurse prioritize when
assessing this client?
A) Down syndrome individuals typically have larger airways requiring larger
endotracheal tubes
B) Hypotonia and midface hypoplasia may contribute to airway compromise and
increased risk of obstruction
C) Down syndrome is always associated with severe cardiac anomalies that
preclude respiratory support
,D) The condition guarantees normal lung capacity despite other physical
characteristics
E) Airway assessment is unnecessary as aspiration is not a concern in Down
syndrome
CORRECT ANSWER: B
EXPERT RATIONALE: Individuals with Down syndrome frequently present with
hypotonia (decreased muscle tone) and characteristic facial features including
midface hypoplasia, which can narrow the airway and increase obstruction risk.
Additionally, the condition is associated with increased prevalence of sleep apnea,
tracheomalacia, and higher rates of respiratory infections. While some individuals
may have cardiac anomalies, these do not automatically preclude respiratory
support. The nurse must carefully assess airway patency and consider positioning,
suctioning, and potential need for specialized airway management in this
population.
QUESTION 2
Which is the most common chromosomal abnormality associated with Down
syndrome?
A) Trisomy 18 (Edwards syndrome)
B) Trisomy 21 (nondisjunction)
C) Turner syndrome (45,X)
D) Klinefelter syndrome (47,XXY)
E) Cri-du-chat syndrome (5p deletion)
CORRECT ANSWER: B
EXPERT RATIONALE: Trisomy 21 resulting from nondisjunction accounts for
approximately 95% of all Down syndrome cases. This occurs when chromosome 21
fails to separate during meiosis, resulting in three copies of chromosome 21
instead of the normal two. Maternal age greater than 35 years significantly
,increases the risk of nondisjunction. The other options represent different
chromosomal abnormalities with distinct clinical presentations and developmental
consequences.
QUESTION 3
A nurse is developing a behavior modification plan for a client with
intellectual disability who engages in self-injurious behavior. Which principle
should guide the initial assessment?
A) Punishment-based interventions are most effective for eliminating self-injury
B) Identifying the function or communicative intent of the behavior is essential
before implementing intervention
C) All self-injurious behaviors respond identically to the same intervention
D) Behavioral assessment is unnecessary; medication is the only appropriate
treatment
E) Self-injurious behavior is a permanent characteristic that cannot be modified
CORRECT ANSWER: B
EXPERT RATIONALE: Functional behavior assessment is the gold standard
approach to understanding the underlying causes and functions of challenging
behaviors in individuals with developmental disabilities. Self-injurious behaviors
may serve multiple functions including communication of needs, attention-seeking,
sensory stimulation, pain management, or escape from demand situations.
Understanding the specific function allows the nurse and interdisciplinary team to
develop targeted, evidence-based interventions that address the underlying cause
rather than merely suppressing behavior. This approach is more humane and
typically more effective long-term than punishment-based strategies.
QUESTION 4
, What is the primary advantage of using augmentative and alternative
communication (AAC) devices for non-verbal clients with developmental
disabilities?
A) AAC devices completely restore normal speech production
B) AAC devices enable individuals to express needs, choices, and participate in
social interaction, enhancing quality of life and reducing behavioral challenges
C) AAC use is only appropriate for individuals with severe intellectual disability
D) AAC devices eliminate the need for any other form of communication
E) Using AAC delays the development of natural speech
CORRECT ANSWER: B
EXPERT RATIONALE: Augmentative and alternative communication devices serve
as vital tools that enable non-verbal or minimally verbal individuals to communicate
their needs, preferences, and desires. By providing functional communication
methods, AAC systems often reduce frustration-related behaviors and increase
social participation. Research demonstrates that AAC use does not inhibit natural
speech development; conversely, it may facilitate it by providing a foundation for
communication. AAC is beneficial across all severity levels of developmental
disability and should be implemented based on individual communication needs
rather than disability severity alone.
QUESTION 5
A client with cerebral palsy presents with increased muscle tone and
exaggerated reflexes affecting mobility. Which type of cerebral palsy is this
presentation most consistent with?
A) Ataxic cerebral palsy
B) Spastic cerebral palsy
C) Dyskinetic cerebral palsy
D) Hypotonic cerebral palsy
