Understanding Developmental Disabilities

The Concept of Developmental Disabilities

• Interchangeable usage of "disability" with "handicap" or "handicapped" is incorrect
• Handicap refers to a problem a person with a disability or impairment faces when interacting with people, events, and the physical environment
• Society's fear of people with disabilities can lead to avoidance or rejection, knowledge dispels this fear

Developmental Disabilities Defined

• Developmental disabilities encompass conditions causing physical, learning, language, or behavioral impairment
• Kowalski and Gabrielle (2011) state conditions result in substantial functional limitations, manifest in childhood, persist, require continuous medical, educational, and social services, appear before 22, and are lifelong
• Simms and Schum (2011) note diagnoses occur when a child reaches school age, or before nine, when lagging behind peers, some disorders are suspected in young children with delayed speech or limited vocabulary
• WHO and UNICEF (2012) define disability at three levels: impairment in body function/structure, limitation in activity, and restriction in participation
• Cognitive disabilities relate to thought processes and comprehension, including intellectual disability, learning disabilities, Asperger's syndrome, and brain injury

Types of Developmental Disabilities

• Some disabilities are purely physical (congenital deafness or visual impairment) and not intellectual disabilities
• Others are due to cerebral palsy, epilepsy, autism, or disabling conditions, which may or may not include intellectual disabilities
• Developmental disabilities are often first seen as communication disorders, with difficulties in understanding directions or naming objects
• Four main types: nervous system, sensory-related, metabolic, and degenerative disabilities
• Disabilities can include blindness, deafness, learning disabilities, communication disorders, physical and health impairments, emotional/behavioral disorders, and severe disabilities

Nervous System, Sensory-Related, Metabolic, and Degenerative Disabilities

• Nervous system disabilities are birth defects affecting brain, spinal cord, and nervous system function, influencing intelligence and learning; these conditions can also result in behavioral disorders, speech or language difficulties, convulsions, and movement disorders
• Sensory-related disability affects senses (sight, hearing), restricting information gathering, impaired speech mechanics may cause improper voice problems, autism spectrum order (ASD) is a lifelong developmental disability
• Metabolic disabilities are genetic conditions causing metabolism problems, resulting from a defective gene causing an enzyme deficiency
• Phenylketonuria (PKU) is a common metabolic disorder is caused by a specific enzyme, disrupts chemical reactsions
• Hypothyroidism, a hormonal condition, can cause intellectual and developmental disabilities (IDDs) if the child's condition left untreated in an infant
• Degenerative disabilities: Infants appear normal at birth, then lose abilities/functions later; defect not detected until signs of loss of function is observed
• Degenerative disorders can cause physical, mental, and sensory problems, Rett syndrome usually affects girls and results from a genetic abnormality.

Causes of Developmental Disabilities: Newborn Screening

• Public health delivery system aspect: Newborn screening is mandated by Republic Act (RA) 9288 of 2004 (Ensuring Newborn Screening)
• Health practitioners must inform parents/guardians about the procedure before delivery
• Procedure identifies congenital, genetic, or metabolic disorders leading to mental retardation or death if untreated
• Most newborns with metabolic disorders look normal at birth
• Early detection is crucial to prevent irreversible effects
• Newborn screening detects five metabolic disorders: Congenital Hypothyroidism, Congenital Adrenal Hyperplasia, Galactosemia, Phenylketonuria, and Glucose Six Phosphate Dehydrogenase deficiency

Categories of Developmental Disabilities: Biological and Environmental Factors

• Vulnerability is how susceptible the organism is to being injured by a traumatic incident
• Traumatic incidents include teratogens, toxic agents, cell division mutation, and deviations
• Deviations from normal prenatal development cause developmental disabilities during every stage of pregnancy

Biological Factors

• Prenatal examples of the disabilities in development are chromosomal abnormalities (Down syndrome), genetic causes (sickle cell disease), and Rh-incompatibility
• Rh-incompatibility: baby conceived between a Rh-positive father and an Rh-negative mother, mother's blood forms antibodies against the "foreign" positive Rh factor, leads to hemolysis of red blood cells (RBCs), potential consequence of cerebral palsy, deafness, mental retardation, heart failure, or even death if severe
• A difficult birth process can also trigger a developmental disability
• Physical trauma or mechanical injury during birth may injure or damage the brain and impair intellectual functioning; problems that may arise from a precipitous birth or a breech birth may also trigger a developmental disability
• Postnatal Period (newborn, infant, child): child vulnerable to injuries, childhood infections, and malnutrition affect development

Environmental Factors

• Includes nutritional deficiencies of the mother during pregnancy or the child during pregnancy
• Iodine deficiency is associated with congenital blindness, deafness, and intellectual disability
• Folate deficiency can cause neural tube defects, like spina bifida
• Infections, such as the Zika virus (microcephaly), meningitis (hearing loss), and measles (blindness), damage the nervous system
• Toxines: Alcohol and drugs can affect the environment in pregnancy as well as lead (paint, batteries, gasoline)

Considerations for Genetic and Environmental Conditions

• It is essential to consider the interaction between genetic causes and environmental influences which can increase the severity of impairments
• Risk factors are the likelihood of a developmental disability being exacerbated instead of the underlying cause
• Risk factors are results of social determinants; lower socioeconomic children/adults are at an increased risk of poor health and disability due to difficulty accessing healthcare increasing higher risk of infection and increased poverty

Objectives for Preventing Developmental Disabilities and the Role of Harmful Materials

• Important events before and birth can be considered as environmental risk factors: advanced parental age at time of conception and prenatal exposure to air pollution or certain pesticides, maternal obesity, maternal diabetes, or immune system disorders
• Certain factors alone are unlikely to cause autism, will only increase the child's risk when in-combined with genetic factors; this is crucial for medical practitioners of air pollution or an increase of autism
• During the third trimester mothers can be twice as likely to develop ASD if in close distances of a freeway/traffic related pollution according to Volk, Hertz-Picciotto, Delwiche, Lurmann, & McConnell, 2011
• Volk et al., 2014 state children with a mutation in a MET gene may have a greater risk of Autism by high levels of expoure

The Impact of Lead and Mercury on Children

• Strong clinical evidence and experimental animal studies demonstrate environmental toxins that can cause early development from lead and mercury
• Proposed toxins such as thalidomide, Pitocin, and prenatal exposure to drugs like cocaine and alcohol can be triggers of Autism
• Prenatal conditions and Maternal Factors- Problems with a mother's immune system or certain metabolic conditions, or inflammation during pregnancy may be linked with a higher autism risk

Factors That May Lead to Developmental Disabilities

• Two genetic causes of developmental disabilities: brain damage and biochemical imbalance
• Brain damage can be hereditary, innate, and congenital.
• Biochemical imbalance, such as artificial food colors, flavors, preservatives, salicylates, and megavitamins, in the diet, can cause learning disabilities and hyperactivity.