Neurodevelopmental disorders are a group of disorders that affect the development of the nervous system, leading to abnormal brain function which may affect emotion, learning ability, self-control, and memory. The effects of neurodevelopmental disorders tend to last for a persons lifetime. Types
Neurodevelopmental disorders are impairments of the growth and development of the brain and/or central nervous system. A narrower use of the term refers to a disorder of brain function that affects emotion, learning ability, self-control and memory which unfolds as an individual develops and grows.According to the DSM-5, the neurodevelopmental disorders include the following:
Attention deficit hyperactivity disorder (ADHD)
DLD - Developmental language disorder (formerly known as SLI- Specific Language Impairment)
Communication, speech, or language disorders, expressive language disorder, fluency disorder, social (pragmatic) communication disorder, and speech sound disorder. Autism spectrum disorder (ASD)
Intellectual disabilities (IDs) or intellectual development disorder (IDD, previously called mental retardation) and global developmental delay (GDD)
Motor disorders including developmental coordination disorder, stereotypic movement disorder, and tic disorders (such as Tourettes syndrome), and CAS - Apraxia of speech
Neurogenetic disorders, such as Fragile X syndrome, Down syndrome, Rett syndrome, hypogonadotropic hypogonadal syndromes
Specific learning disorders, like dyslexia or dyscalculia. Traumatic brain injury (including congenital injuries such as those that cause cerebral palsy) and disorders due to neurotoxicants including Minamata disease caused by mercury, behavioral disorders including conduct disorder etc. caused by other heavy metals, such as lead, chromium, platinum etc., hydrocarbons like dioxin, PBDEs and PCBs, medications and illegal drugs, like cocaine, radioactive metals like Po210(which is found in cigarettes), and others.
Because of the temporal and spatial complexity of the developmental trajectory, there are many potential causes of neurodevelopmental disorders that may affect different areas of the nervous system at different times and ages. These range from social deprivation, genetic and metabolic diseases, immune disorders, infectious diseases, nutritional factors, physical trauma, and toxic and environmental factors. Some neurodevelopmental disorders, such as autism and other pervasive developmental disorders, are considered multifactorial syndromes which have many causes that converge to a more specific neurodevelopmental manifestation. Social deprivation
Deprivation from social and emotional care causes severe delays in brain and cognitive development. Studies with children growing up in Romanian orphanages during Nicolae Ceauşescus regime reveal profound effects of social deprivation and language deprivation on the developing brain. These effects are time-dependent. The longer children stayed in negligent institutional care, the greater the consequences. By contrast, adoption at an early age mitigated some of the effects of earlier institutionalization (abnormal psychology). Genetic disorders
A prominent example of a genetically determined neurodevelopmental disorder is Trisomy 21, also known as Down syndrome. This disorder usually results from an extra chromosome 21, although in uncommon instances it is related to other chromosomal abnormalities such as translocation of the genetic material. It is characterized by short stature, epicanthal (eyelid) folds, abnormal fingerprints, and palm prints, heart defects, poor muscle tone (delay of neurological development), and intellectual disabilities (delay of intellectual development).Less commonly known genetically determined neurodevelopmental disorders include Fragile X syndrome.