CDDN Certified Developmental
Disabilities Nurse Exam 2026 | 300
Practice Questions with Answers,
Rationales & Complete Study Guide PDF
CDDN — Certified Developmental Disabilities Nurse Exam 2026
300 Practice Questions with Answers & EXPERT RATIONALE
This practice guide contains 300 exam-style questions designed to mirror the CDDN
certification exam. Work through each question carefully, review the EXPERT
RATIONALE for every correct answer, and revisit any topic where you feel less
confident before sitting the actual exam.
DOMAIN 1: HEALTH PROMOTION & DISEASE PREVENTION
Question 1
A nurse is caring for an adult with Down syndrome. Which health screening is MOST
important to prioritize annually?
A. Liver function tests
B. Bone marrow biopsy
C. Thyroid function tests
D. Serum calcium levels
E. Pulmonary function tests
Correct Answer: C. Thyroid function tests
EXPERT RATIONALE: Individuals with Down syndrome have a significantly higher risk of
thyroid disorders, particularly hypothyroidism. Annual thyroid screening is a standard
recommendation in clinical guidelines for this population.
,Question 2
Which immunization is particularly emphasized for adults with developmental
disabilities living in group homes?
A. Yellow fever vaccine
B. Typhoid vaccine
C. Rabies vaccine
D. Influenza vaccine
E. Japanese encephalitis vaccine
Correct Answer: D. Influenza vaccine
EXPERT RATIONALE: Adults with developmental disabilities in congregate living settings
such as group homes are at increased risk for influenza transmission. Annual influenza
vaccination is strongly recommended to reduce morbidity and mortality in this
vulnerable population.
Question 3
A nurse is educating caregivers about obesity prevention in individuals with Prader-
Willi syndrome. Which intervention is MOST critical?
A. Encouraging high-protein snacks between meals
B. Providing unrestricted access to food to reduce anxiety
C. Implementing strict environmental controls on food access
D. Administering appetite suppressants daily
E. Scheduling meals every two hours
Correct Answer: C. Implementing strict environmental controls on food
access
,EXPERT RATIONALE: Prader-Willi syndrome is characterized by hyperphagia and an
insatiable appetite due to hypothalamic dysfunction. Strict environmental food controls
are essential to prevent life-threatening obesity in this population.
Question 4
Which of the following BEST describes primary prevention in the context of
developmental disabilities nursing?
A. Early detection of complications in known conditions
B. Rehabilitation after a health event
C. Preventing the onset of illness or injury before it occurs
D. Managing chronic conditions to slow progression
E. Providing palliative care support
Correct Answer: C. Preventing the onset of illness or injury before it occurs
EXPERT RATIONALE: Primary prevention focuses on stopping a disease or injury from
occurring in the first place. In developmental disabilities nursing, this includes
immunizations, health education, and environmental safety measures.
Question 5
A nurse notes that a client with intellectual disability has not had a dental
examination in three years. This BEST reflects a gap in which level of care?
A. Tertiary prevention
B. Palliative care
C. Secondary prevention
D. Primary prevention
E. Crisis intervention
Correct Answer: D. Primary prevention
, EXPERT RATIONALE: Regular dental examinations are a primary preventive measure.
Individuals with developmental disabilities often face barriers to routine dental care,
making nurse advocacy for preventive dental visits essential.
Question 6
Which condition is MOST commonly associated with atlantoaxial instability in
individuals with Down syndrome?
A. Scoliosis
B. Hip dysplasia
C. Cervical spine instability
D. Knee joint deformity
E. Foot drop
Correct Answer: C. Cervical spine instability
EXPERT RATIONALE: Atlantoaxial instability involves excessive movement at the junction
between the first and second cervical vertebrae and is a well-documented concern in
Down syndrome due to ligamentous laxity. Screening is recommended before
participation in certain sports.
Question 7
A nurse is planning a health fair for adults with developmental disabilities. Which
topic addresses the HIGHEST priority health disparity in this population?
A. Travel health
B. Cosmetic dermatology
C. Reproductive health
D. Occupational therapy referrals
E. Vision care only
Disabilities Nurse Exam 2026 | 300
Practice Questions with Answers,
Rationales & Complete Study Guide PDF
CDDN — Certified Developmental Disabilities Nurse Exam 2026
300 Practice Questions with Answers & EXPERT RATIONALE
This practice guide contains 300 exam-style questions designed to mirror the CDDN
certification exam. Work through each question carefully, review the EXPERT
RATIONALE for every correct answer, and revisit any topic where you feel less
confident before sitting the actual exam.
DOMAIN 1: HEALTH PROMOTION & DISEASE PREVENTION
Question 1
A nurse is caring for an adult with Down syndrome. Which health screening is MOST
important to prioritize annually?
A. Liver function tests
B. Bone marrow biopsy
C. Thyroid function tests
D. Serum calcium levels
E. Pulmonary function tests
Correct Answer: C. Thyroid function tests
EXPERT RATIONALE: Individuals with Down syndrome have a significantly higher risk of
thyroid disorders, particularly hypothyroidism. Annual thyroid screening is a standard
recommendation in clinical guidelines for this population.
,Question 2
Which immunization is particularly emphasized for adults with developmental
disabilities living in group homes?
A. Yellow fever vaccine
B. Typhoid vaccine
C. Rabies vaccine
D. Influenza vaccine
E. Japanese encephalitis vaccine
Correct Answer: D. Influenza vaccine
EXPERT RATIONALE: Adults with developmental disabilities in congregate living settings
such as group homes are at increased risk for influenza transmission. Annual influenza
vaccination is strongly recommended to reduce morbidity and mortality in this
vulnerable population.
Question 3
A nurse is educating caregivers about obesity prevention in individuals with Prader-
Willi syndrome. Which intervention is MOST critical?
A. Encouraging high-protein snacks between meals
B. Providing unrestricted access to food to reduce anxiety
C. Implementing strict environmental controls on food access
D. Administering appetite suppressants daily
E. Scheduling meals every two hours
Correct Answer: C. Implementing strict environmental controls on food
access
,EXPERT RATIONALE: Prader-Willi syndrome is characterized by hyperphagia and an
insatiable appetite due to hypothalamic dysfunction. Strict environmental food controls
are essential to prevent life-threatening obesity in this population.
Question 4
Which of the following BEST describes primary prevention in the context of
developmental disabilities nursing?
A. Early detection of complications in known conditions
B. Rehabilitation after a health event
C. Preventing the onset of illness or injury before it occurs
D. Managing chronic conditions to slow progression
E. Providing palliative care support
Correct Answer: C. Preventing the onset of illness or injury before it occurs
EXPERT RATIONALE: Primary prevention focuses on stopping a disease or injury from
occurring in the first place. In developmental disabilities nursing, this includes
immunizations, health education, and environmental safety measures.
Question 5
A nurse notes that a client with intellectual disability has not had a dental
examination in three years. This BEST reflects a gap in which level of care?
A. Tertiary prevention
B. Palliative care
C. Secondary prevention
D. Primary prevention
E. Crisis intervention
Correct Answer: D. Primary prevention
, EXPERT RATIONALE: Regular dental examinations are a primary preventive measure.
Individuals with developmental disabilities often face barriers to routine dental care,
making nurse advocacy for preventive dental visits essential.
Question 6
Which condition is MOST commonly associated with atlantoaxial instability in
individuals with Down syndrome?
A. Scoliosis
B. Hip dysplasia
C. Cervical spine instability
D. Knee joint deformity
E. Foot drop
Correct Answer: C. Cervical spine instability
EXPERT RATIONALE: Atlantoaxial instability involves excessive movement at the junction
between the first and second cervical vertebrae and is a well-documented concern in
Down syndrome due to ligamentous laxity. Screening is recommended before
participation in certain sports.
Question 7
A nurse is planning a health fair for adults with developmental disabilities. Which
topic addresses the HIGHEST priority health disparity in this population?
A. Travel health
B. Cosmetic dermatology
C. Reproductive health
D. Occupational therapy referrals
E. Vision care only
