Sunday, February 6, 2011

Early Intervention and Education

The term "early intervention" refers to an array of specialized programs and related resources that are made available by health care professionals to the child with Down syndrome. These health care professionals may include special educators, speech therapists, occupational therapists, and social workers. It is recommended that stimulation and encouragement be provided to children with Down syndrome.

The evaluation of early intervention programs for children with Down syndrome is difficult, due to the wide variety of experimental designs used in interventions, the limited existing measures available that chart the progress of disabled infants, and the tremendous variability in the developmental progress among children with Down syndrome, a consequence in part of the many complicating medical factors. While many studies have been conducted to assess the effects of early intervention, the information is limited and contradictory regarding the long-term success of early intervention for children with Down syndrome.

The decision of what type of school a child with Down syndrome should attend is an important one, made by the parents in consultation with health and education professionals. A parent must decide between enrolling the child in a school where most of the children do not have disabilities (inclusion) or sending the child to a school for children with special needs. Inclusion has become more common over the past decade.

Infants and Preschool Children

Medical care for infants with Down syndrome should include the same well-baby care that other children receive during the first years of life, as well as attention to some problems that are more common in children with Down syndrome. If heart, digestive, orthopedic or other medical conditions were identified during the neonatal period, these problems should continue to be monitored.

Children with Down syndrome may be developmentally delayed. A child with Down syndrome is often slow to turn over, sit, stand, and respond. This may be related to the child's poor muscle tone. Development of speech and language abilities may take longer than expected and may not occur as fully as parents would like. However, children with Down syndrome do develop the communication skills they need.

Parents of other children with Down syndrome are often valuable sources of information and support. Parents should keep in mind that children with Down syndrome have a wide range of abilities and talents, and each child develops at his or her own particular pace. It may take children with Down syndrome longer than other children to reach develop mental milestones, but many of these milestones will eventually be met. Parents should make a concerted effort not to compare the developmental progress of a child with Down syndrome to the progress of other siblings or even to other children with Down syndrome.

Newborns

Babies with Down syndrome often have hypotonia, or poor muscle tone. Because they have a reduced muscle tone and a protruding tongue, feeding babies with Down syndrome usually takes longer. Mothers breast-feeding infants with Down syndrome should seek advice from an expert on breast feeding to make sure the baby is getting sufficient nutrition.

Hypotonia may affect the muscles of the digestive system, in which case constipation may be a problem. Atlantoaxial instability, a malformation of the upper part of the spine located under the base of the skull, is present in some individuals with Down syndrome. This condition can cause spinal cord compression if it is not treated properly.

Down Syndrome and Associated Medical Disorders

During the first days and months of life, some disorders may be immediately diagnosed. Congenital hypothyroidism, characterized by a reduced basal metabolism, an enlargement of the thyroid gland, and disturbances in the autonomic nervous system, occurs slightly more frequently in babies with Down syndrome. A routine blood test for hypothyroidism that is performed on newborns will detect this condition if present.

Several other well-known medical conditions, including hearing loss, congenital heart disease, and vision disorders, are more prevalent among those with Down syndrome.

Recent studies indicate that 66 to 89% of children with Down syndrome have a hearing loss of greater than 15 to 20 decibels in at least one ear, due to the fact that the external ear and the bones of the middle and inner ear may develop differently in children with Down syndrome. Many hearing problems can be corrected. But, because of the high prevalence of hearing loss in children with Down syndrome, an objective measure of hearing should be taken to establish hearing status. In addition to hearing disorders, visual problems also may be present early in life. Cataracts occur in approximately 3% of children with Down syndrome, but can be surgically removed.

Approximately half of the children with Down syndrome have congenital heart disease and associated early onset of pulmonary hypertension, or high blood pressure in the lungs. Echocardiography may be indicated to identify any congenital heart disease. If the defects have been identified before the onset of pulmonary hypertension, surgery has provided favorable results.

Seizure disorders, though less prevalent than some of the other associated medical conditions, still affect between 5 and 13% of individuals with Down syndrome, a 10-fold greater incidence than in the general population. There is an unusually high incidence of infantile spasms or seizures in children less than one year of age, some of which are precipitated by neonatal complications and infections and cardiovascular disease. However, these seizures can be treated with anti-epileptic drugs.

The incidence and severity of these associated medical ailments will vary in babies with Down syndrome and some may require surgery

Prenatal Screening for Down Syndrome

Prenatal screening for Down syndrome is available. There is a relatively simple, noninvasive screening test that examines a drop of the mother's blood to determine if there is an increased likelihood for Down syndrome.

DOWN SYNDROME AND MATERNAL AGE

Researchers have established that the likelihood that a reproductive cell will contain an extra copy of chromosome 21 increases dramatically as a woman ages. Therefore, an older mother is more likely than a younger mother to have a baby with Down syndrome. However, of the total population, older mothers have fewer babies; about 75% of babies with Down syndrome are born to younger women because more younger women than older women have babies. Only about nine percent of total pregnancies occur in women 35 years or older each year, but about 25% of babies with Down syndrome are born to women in this age group.

The incidence of Down syndrome rises with increasing maternal age. Many specialists recommend that women who become pregnant at age 35 or older undergo prenatal testing for Down syndrome. The likelihood that a woman under 30 who becomes pregnant will have a baby with Down syndrome is less than 1 in 1,000, but the chance of having a baby with Down syndrome increases to 1 in 400 for women who become pregnant at age 35. The likelihood of Down syndrome continues to increase as a woman ages, so that by age 42, the chance is 1 in 60 that a pregnant woman will have a baby with Down syndrome, and by age 49, the chance is 1 in 12. But using maternal age alone will not detect over 75% of pregnancies that will result in Down syndrome.

The Occurrence of Down Syndrome

Most of the time, the occurrence of Down syndrome is due to a random event that occurred during formation of the reproductive cells, the ovum or sperm. As far as we know, Down syndrome is not attributable to any behavioral activity of the parents or environmental factors. The probability that another child with Down syndrome will be born in a subsequent pregnancy is about 1 percent, regardless of maternal age.
The incidence of Down syndrome rises with increasing maternal age.
For parents of a child with Down syndrome due to translocation trisomy 21, there may be an increased likelihood of Down syndrome in future pregnancies. This is because one of the two parents may be a balanced carrier of the translocation. The translocation occurs when a piece of chromosome 21 becomes attached to another chromosome, often number 14, during cell division. If the resulting sperm or ovum receives a chromosome 14 (or another chromosome), with a piece of chromosome 21 attached and retains the chromosome 21 that lost a section due to translocation, then the reproductive cells contain the normal or balanced amount of chromosome 21. While there will be no Down syndrome associated characteristics exhibited, the individual who develops from this fertilized egg will be a carrier of Down syndrome. Genetic counseling can be sought to find the origin of the translocation.

However, it is important to realize that not all parents of individuals with translocation trisomy 21 are themselves balanced carriers. In such situations, there is no increased risk for Down syndrome in future pregnancies.

Researchers have extensively studied the defects in chromosome 21 that cause Down syndrome. In 88% of cases, the extra copy of chromosome 21 is derived from the mother. In 8% of the cases, the father provided the extra copy of chromosome 21. In the remaining 2% of the cases, Down syndrome is due to mitotic errors, an error in cell division which occurs after fertilization when the sperm and ovum are joined.