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What Are Developmental Disabilities?

Developmental disabilities are a variety of conditions that may become apparent during childhood or before the age of 22 and cause mental or physical limitations. These conditions include autism, cerebral palsy, epilepsy, intellectual disabilities, and other neurological impairments.

People with developmental disabilities may not learn as quickly as others or express themselves clearly. Others may have limited ability to take care of their physical needs or limited mobility. Many have more than one disability.

Developmental disabilities have a variety of causes, which can occur before, during or after birth. Those occurring before birth include genetic problems, poor prenatal care or exposure of the fetus to toxic elements, drugs or alcohol. Occurrences during birth, such as a cut off of oxygen to the baby, or accidents after birth, like car accidents causing traumatic brain injury, also can cause developmental disabilities.

It is difficult to define the limits of people with disabilities, as experts in the field continue to discover extraordinary abilities within them. While people who have developmental disabilities face a more challenging future than most, they still can enjoy a full and active life. What they need most is encouragement, understanding and the willingness of others to help them maximize their opportunities for becoming part of their community.


The degenerative brain disorder strikes more than four million Americans each year, and as the population ages, that number is expected to rise dramatically. The disease attacks brain neurons, or nerve cells, progressively interfering with a person’s emotions, movement coordination, and memory. Simple tasks become increasingly difficult; familiar faces become those of strangers. This dementia robs victims of their relationships and their self-sufficiency, and often, loved ones feel its devastation just as strongly.

Attention Deficit Disorders

An attention-deficit disorder (ADD) is a developmental disorder characterized by developmentally inappropriate degrees of inattention, over activity, and impulsivity. Symptoms are neurologically based, arise in early childhood and are chronic in nature in most cases. Symptoms are not due to gross neurological impairment, sensory impairment, language or motor impairment, intellectual disabilities or emotional disturbance. Three main traits characterize ADD: (1) poor sustained attention or vigilance; (2) impulsivity or difficulty delaying gratification; and (3) hyperactivity or poorly regulated activity. Increased variability of task performance and problems complying with rules are often key features.


A childhood disorder present before the age of three years, which is characterized by withdrawal, self-stimulation, cognitive deficits and language disorders.

Behavior Disorders/Emotional Disturbance

Many terms are used interchangeably to classify children who exhibit extreme or unacceptable chronic behavior problems. These children lag behind others their age in social development and are often isolated from others either because they withdraw from social contact or because they behave in an aggressive, hostile manner. Behavior disorders result from persistent negative social interactions between the child and the environment. Behavior disorders generally consist of four clusters of traits, including conduct disorders, anxiety-withdrawal, immaturity and socialized aggression.


Describes a condition in which a person has loss of vision for ordinary life purposes. Visually impaired is the generic term used by some individuals to refer to all degrees of vision loss.

Brain Injury

Describes a condition where there is long-term or temporary disruption in brain function resulting from injury to the brain. Difficulties with the cognitive, physical, emotional or social functioning may occur.

Cerebral Palsy

Cerebral palsy is a group of conditions that result in limited or abnormal functioning in the parts of the brain that control movement. Cerebral palsy usually is caused by brain injury before or during birth. However, brain damage or injury at any time of life can have the same effect.


Dementia is the loss of mental functions — such as thinking, memory, and reasoning — that is severe enough to interfere with a person’s daily functioning. Dementia is not a disease itself, but rather a group of symptoms that are caused by various diseases or conditions. Symptoms can also include changes in personality, mood, and behavior.

Developmental Disorders

Serious delays in children’s development of one or more areas of functioning.

Down Syndrome

Describes a chromosome disorder, which usually causes a delay in physical, intellectual and language development. Usually results in intellectual disabilities.


Epilepsy applies to numerous nervous system disorders that result in abnormal electrical discharges of brain cells. This produces seizures that may cause convulsive movements, or partial or total loss of consciousness. Only a small percentage of people with epilepsy also have intellectual disabilities.

Fetal Alcohol Syndrome

A condition affecting the children of mothers who consumed large quantities of alcohol during pregnancy; it can involve cognitive delays, attention difficulties, and physical and emotional disability. Deficits range from mild to severe, including growth retardation, brain damage, intellectual disabilities, anomalies of the face and heart failure.

Hearing Impairment

Hearing impairment or deafness is decreased or absent ability to perceive auditory information. While some cases of hearing loss are reversible with medical treatment, many lead to a permanent disability. Of vital importance are the age at which the hearing loss occurred, as this may interfere with the acquisition of spoken language. Hearing aids and cochlear implants may alleviate some of the barriers caused by hearing impairment.


A condition characterized by enlargement of the head due to the increased accumulation of fluid in the brain. When children with hydrocephalus are not treated promptly, they will have below normal intelligence, physical disabilities and a variety of other medical problems. The most effective treatment is the surgical insertion of a shunt, a flexible tube placed in the brain which diverts the flow of fluid from the brain to another region of the body where it can be safely absorbed.

Intellectual Disabilities

People with intellectual disabilities show delays in learning, a slower pace of learning, and difficulty in applying learning. Approximately 200,000 people in New York State are thought to have intellectual disabilities. intellectual disabilities can result from a variety of factors, among them premature birth, genetic abnormalities, malnutrition, exposure to toxic agents and social deprivation.

Learning Disabilities

Impairment in a specific mental process which affects learning.


Cephalic disorders are congenital conditions that stem from damage to, or abnormal development of, the budding nervous system. Cephalic is a term that means “head” or “head end of the body.” Congenital means the disorder is present at, and usually before, birth.

Muscular Dystrophy

The muscular dystrophies are a group of genetic and hereditary muscle diseases; characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue. In some forms of muscular dystrophy, cardiac and smooth muscles are affected. The muscular dystrophies are the most common hereditary diseases.

Multiple Sclerosis

A disorder of the central nervous system marked by weakness, numbness, a loss of muscle coordination, and problems with vision, speech, and bladder control. Multiple sclerosis is thought to be an autoimmune disease in which the body's immune system destroys myelin. Myelin is a substance that contains both protein and fat (lipid), serving as a nerve insulator and helping in the transmission of nerve signals.

Parkinson’s Disease

A chronic neurological condition named after Dr. James Parkinson, a London physician who was the first to describe the syndrome in 1817. PD is a slowly progressive disease that affects a small area of cells in the mid brain known as the substantia nigra. Gradual degeneration of these cells causes a reduction in a vital chemical known as “dopamine.” This decrease in dopamine is what causes the symptoms of the disease.

A disorder that affects nerve cells (neurons) in the part of the brain controlling muscle movement. Symptoms include trembling, muscle rigidity, difficulty walking, and problems with balance and coordination.

A progressive disorder of the nervous system marked by muscle tremors, muscle rigidity, decreased mobility, stooped posture, slow voluntary movements, and a mask-like facial expression.

Prader-Willi Syndrome

Prader-Willi Syndrome (PWS) is a complex genetic disorder that is typically categorized by a chronic feeling of hunger that can lead to excessive eating and life-threatening obesity.

Skeletal Dysplasias (Dwarfism)

Skeletal dysplasias are bone and cartilage disorders that affect the growth and development of the skeleton and result in short stature and dwarfism. Most of these are genetic conditions. With early intervention from specialists, patients can avoid or minimize the many complications associated with these disorders.

Spina Bifida

Spina bifida describes birth defects caused by an incomplete closure of one or more vertebral arches of the spine, resulting in malformations of the spinal cord. The spinal membranes and spinal cord may protrude through the absence of vertebral arches (called a cleft). These malformations fall into three categories: spina bifida occulta, spina bifida cystica (myelomeningocele) and meningocele.

Tourette’s Syndrome

Tourette’s Syndrome is a neurobiological disorder characterized by tics (involuntary, rapid, sudden movements and/or vocal outbursts that occur repeatedly). The symptoms change periodically in number, frequency, type, and severity - even disappearing for weeks or months at a time. Some common examples of motor tics include eye blinking, head jerking, shoulder shrugging and facial grimacing. Vocal tics include throat clearing, barking noises, sniffing and tongue clicking.

Traumatic Brain Injury (TBI)

Open and closed head injuries resulting in impairments in one or more areas, including cognition; language; memory; attention; reasoning; abstract thinking; judgment; problem-solving; sensory; perceptual and motor abilities; psychosocial behavior; physical functions; information processing and speech. The term does not apply to brain injuries that are congenital, degenerative or induced by birth trauma.