What is Down Syndrome?
Down syndrome (DS) is a genetic disorder in which babies are born with an extra copy of chromosome 21. (The disorder also is called Trisomy 21.) Chromosomes determine how a baby grows in the mother’s womb before birth and how the baby’s body functions after birth, and normally, a baby is born with 46 chromosomes. The extra copy of chromosome 21 in babies born with DS changes the typical development of the brain and the body, causing mental and physical challenges.
The average lifespan of a person with DS today, in America and in other developed countries, is approximately 60 years. Although DS continues throughout a person’s lifespan, children and adults can improve their ability to perform movement activities and everyday tasks with the help of physical therapists and other health care professionals. Physical therapists can help prevent some of the complications of DS such as developmental delay, obesity, and lower levels of heart or cardiovascular fitness.
Signs and Symptoms
The symptoms of DS include physical differences and intellectual difficulties that continue into adulthood and can range from mild to severe.
DS may be detected during pregnancy by screening or diagnostic tests. If not detected before birth, Down syndrome usually is detectable at birth by the baby’s physical characteristics.
These physical characteristics include:
Low muscle tone
A single deep crease across the palm of the hand
A slightly flattened facial profile, and an upward slant to the eyes
A chromosomal analysis will be done to confirm the diagnosis.
Almost 50% of babies born with DS will have some type of congenital heart disease, which may be noted at the time of birth or soon after. Natural development is often delayed because the baby has low muscle tone, decreased strength, increased movement at the joints, poor balance, posture difficulties, feeding problems, and poor hand use. Children with DS also often require increased time to learn complex movements, such as riding a tricycle.
Additional symptoms as the baby develops include:
Poor language development and language use
Vision and hearing problems
Possible misalignment of bones at the base of the head and compression of the spinal cord
In later childhood and adulthood, people with DS may develop other symptoms, such as:
Difficulty learning complex movement tasks
Poor cardiovascular health
Early onset of dementia
Physical therapists will work with the family and other health care providers to reduce or prevent these symptoms. Good medical care, strong educational environments that include therapy from preschool through high school and into adulthood, and support from families can help keep adults with DS as healthy as possible. Many adolescents and adults with DS participate in family and community activities and lead happy, productive lives.
How Is It Diagnosed?
Three types of DS have been identified, and all types are diagnosed by a chromosomal analysis, frequently a blood test, ordered by a physician.
Type 1. The most common type of DS is called “Nondisjunction Trisomy 21.” This type of DS occurs when 3 copies of chromosome 21 are present in the fertilized egg. Typically, one copy of chromosome 21 comes from the father and one copy from the mother. When 3 copies are present, the extra chromosome may come from either the mother or the father. As the baby develops, the extra chromosome is copied into every cell in the body.
Type 2. Translocation Trisomy 21 is seen in about 4% of all people with DS. In this type of DS, part of chromosome 21 breaks off during cell division of the fertilized egg and attaches to another chromosome. The total number of chromosomes in the cells is the usual 46, but the extra part of chromosome 21 causes the baby to have the characteristics of DS.
Type 3. Mosaic Trisomy 21 occurs in about 1% of persons with DS. This type of DS occurs when a “nondisjunction” of chromosome 21 takes place in 1 of the cell divisions of the fertilized egg, but not all cell divisions are affected. Some of the baby’s cells contain 46 chromosomes, which is typical, but other cells contain the extra chromosome 21 for a total of 47. People with Mosiac DS may have fewer characteristics of the syndrome.
How Can a Physical Therapist Help?
The child’s physical therapist will perform an evaluation that includes:
Birth and developmental history. The physical therapist will ask questions about the child’s birth and developmental stages (the age he or she held the head upright, rolled over, sat up, crawled, walked, etc).
General health questions. The physical therapist may ask some of the following questions: Has your child been sick or hospitalized? When did your child last visit a physician or health care provider? Were any health concerns shared with you during that visit?
Parental concerns. The physical therapist will ask about your chief concerns. What are you worried about? What do you hope to accomplish first in therapy?
Physical examination. The physical exam may include measuring the child’s height and weight; observing movement patterns; making a hands-on assessment of muscle strength, tone, and flexibility; and testing the child’s balance and coordination.
Motor development tests. The physical therapist will perform specific tests to determine the child’s motor development, such as sitting, crawling, pulling up to standing, and walking. The physical therapist also may screen the child’s hand use, vision, language skills, intellect, and other areas of development.
Referrals. The physical therapist may refer you to other health care professionals who can participate in a team effort to address the child’s needs.
The physical therapist is an important partner in health care and fitness for anyone diagnosed with DS. Therapists help people with DS to gain strength and movement to function at their best throughout all the stages of life.
Therapy may be provided in the home or at another location such as a community center, school, or a physical therapy outpatient clinic. The physical therapist will work with other health care professionals, such as speech/language pathologists or occupational therapists, to address all the individual’s needs as treatment priorities shift.
Specifically, physical therapists work with children with DS to improve muscle strength, balance, coordination, and movement skills to improve daily activities and quality of life. The purpose of early intervention is to prevent a child with DS from developing atypical movement patterns.
Improving strength. The physical therapist will teach you and the child exercises to increase muscle strength. The therapist will identify games and fun tasks that improve strength. As the child grows, the therapist will identify new games and activities to reduce the risk of obesity and increase heart health.
Improving developmental skills. Your physical therapist will help your child learn to master motor skills such as crawling, pulling to standing, and walking. Research has shown that infants with DS can benefit from such activities as walking on a treadmill. Physical therapists can help caregivers support their child’s movement development by providing hands-on training for positioning, movement, feeding, and play. Your therapist also may suggest changes at home to encourage movement development, communication, hearing, vision, and play skills.
Improving balance and coordination. The physical therapist may use equipment such as a firm, round pillow or an exercise ball to improve the child’s ability to hold the head erect or to maintain a sitting position. Bilateral coordination skills, such as jumping, skipping, and dribbling a ball may be incorporated into therapy.
Improve physical fitness. The physical therapist will help determine the specific exercises, diet, and community involvement that can promote healthy living choices and prevent complications of DS such as activity limitations and decreased participation with siblings or peers.
Can this Injury or Condition be Prevented?
The exact cause of the chromosomal changes that result in DS is not known, but the disorder is associated with increasing age in mothers. Women older than 35 years at the time of childbirth have an increased incidence of having a baby with DS. However, due to the fact that younger women have a much greater childbirth rate, the overall majority of babies with DS are born to women younger than 35 years of age.
Excellent prenatal care is important for all pregnant women. Once a child is diagnosed with DS, the physical therapist and other health care professionals can prevent or reduce some of the additional complications that might occur following birth, such as developmental delay; poor strength, posture, and balance; unstable joints; abnormal movement or walking patterns; obesity; or heart and cardiovascular problems.
Real Life Experiences
Jill is a 5-month-old girl with DS and an uncomplicated birth history. Jill’s parents were aware of the diagnosis before her birth, and they have always sought optimal care for her. She is scheduled for surgical repair of a congenital heart defect in the near future.
Jill has had difficulty drinking from a bottle, and her physical therapist has worked with other health professionals to assist the parents with the feeding program best suited for her. She is seen at home by several health care professionals. The pediatric physical therapist has helped the family learn how to get Jill to hold her head upright when she is supported when sitting, and how to get Jill to roll over from her stomach to her back and from her back to her stomach. The physical therapist includes games, such as pat-a-cake, and toys with bright colors to stimulate Jill’s interest, play, and hand skills. The therapist incorporates words and pictures with the treatment sessions to help Jill’s language development.
The family has already asked for information about starting an infant treadmill walking program as soon as Jill has recovered from her surgery and can put weight on her feet to stand. The therapist is using a large ball to encourage Jill to take some weight on her feet now. Jill is placed on her stomach on the ball, facing away from the therapist, and the ball is moved toward the therapist so that Jill’s feet will take some weight against the therapist’s body as the therapist holds her safely on the ball.
As Jill continues to develop during her early years of life, the physical therapist will encourage progression of motor activities such as crawling, walking, climbing stairs, and running. An orthotics (braces for the foot and ankle) assessment will be completed once Jill begins to initiate weight-bearing activities at 7-9 months. Infants with DS are at high risk for delayed standing due to low muscle tone and joint instability, which may result in foot deformity and lifelong mobility impairments. An orthotics assessment is beneficial, in the first year of life, to prevent misalignment.