Developmental Disabilities

Definition of Developmental Disabilities

Developmental disability (also known as neurodevelopmental disability) is an umbrella term that includes a diverse range of diagnoses which arise from an impairment of the central nervous system. This means there are differences in brain development, structures and functioning.

Types of Developmental Disabilities

The Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-V) (American Psychiatric Association, 2013), is a handbook that is used by professionals around the world to diagnose mental disorders. The DSM–V lists the various types:

Intellectual Disabilities:

• Intellectual Disability (Intellectual Developmental Disorder)
• Global Developmental Delay
• Unspecified Intellectual Disability (Intellectual Developmental Disorder)

Communication Disorders:

• Language Disorder
• Speech Sound Disorder (previously Phonological Disorder)
• Childhood-Onset Fluency Disorder (Stuttering)
• Social (Pragmatic) Communication Disorder
• Unspecified Communication Disorder

Autism Spectrum Disorder

Attention-Deficit/Hyperactivity Disorder

Foetal Alcohol Spectrum Disorder

Epilepsy

Specific Learning Disorder

This is a neurodevelopmental disorder that begins during school-age, although may not be recognised until adulthood. For example, dyslexia, dysgraphia and dyscalculia. These disorders can have a range of impacts. For example, difficulties with putting thoughts into written words, spelling, reading comprehension, math calculation and math problem solving. Difficulties with these skills may cause problems in learning subjects such as history, math, science and social studies and may impact everyday activities.

Motor Disorders

• Cerebral Palsy
• Developmental Coordination Disorder
• Stereotypic Movement Disorder
• Tic Disorders
• Tourette’s Disorder
• Persistent (Chronic) Motor or Vocal Tic Disorder
• Provisional Tic Disorder
• Other Specified Tic Disorder
• Unspecified Tic Disorder

Unspecified Neurodevelopmental Disorder (UNDD)

UNDD is a diagnosis given to persons experiencing symptoms of a neurodevelopmental disorder, but the symptoms don’t meet the full criteria for one of the Neurodevelopmental disorders. Symptoms of UNDD could include:

• Failure to reach expected developmental milestones for walking and speech.
• Inability to interact appropriately with peers.
• Poor academic performance.
• Overreaction to frustration compared to peers.
• Emotionally labile in comparison to peers.

Causes of Developmental Disabilities

These disorders are developmental in the sense that delays, disorders, or impairments are severe and last throughout a person’s lifetime. The conditions are a result of a complex mix of factors that may or may not be identifiable. The causes include:

• Before birth related factors such as: genetics; parental health (e.g. infections and diseases the mother might have had during pregnancy); parental behaviours (e.g. smoking, drinking and drug taking during pregnancy) and exposure to high levels of environmental toxins (e.g. lead, mercury).
• Around birth related factors such as low birth weight, prematurity and obstetric complications.
• After birth related factors such as exposure to infections, diseases, malnutrition and injury experienced any time before the age of 18 years.

Symptoms of Developmental Disabilities

Having a developmental disability impacts skills within these areas: 

• Communication
• Cognitive development
• Motor
• Self-direction
• Self-care
• Independent living
• Economic self-sufficiency

Depending on the disorder, type, and degree of disability, the individual has the symptoms will vary in how it presents in each developmental area.

Our blog article 'Communication Strategies for People with Profound and Multiple Learning Difficulties' discusses a range of practical strategies you can use to develop and strengthen communication skills in individuals with Developmental Disabilities.

References

American Psychiatric Association (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.).