MEER | Spinal Muscular Atrophy
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Spinal Muscular Atrophy


Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a common, inherited neuromuscular disease that causes low muscle tone (hypotonia) and progressive muscle weakness and wasting (atrophy). All motor skills can be affected by the disease, including walking, eating, and breathing. SMA is a leading cause of death in infants.

It affects approximately 1 in 10,000 babies born in the United States, of any race or gender. Approximately 1 in every 50 Americans is a genetic carrier of SMA. Physical therapists help children with SMA develop muscle strength and movement abilities to function at the highest level possible.

What is Spinal Muscular Atrophy?

Spinal muscular atrophy (SMA) is a genetic (inherited) neuromuscular disease. The large motor nerves of the spinal cord are abnormal in people with SMA because a gene (the Survival Motor Neuron-1 or SMN1 gene) is missing or altered. Without the gene, or with a damaged gene, the nerves do not have a specific protein that allows them to control muscles. The decrease of the SMN1 protein results in improper functioning, and eventually death of the motor nerve cells in the spinal cord. The severity of SMA is related to the amount of the SMN1 protein that is absent in the motor nerve cells (more protein allows for more function). Severity of the disease ranges from mild muscle weakness, to total paralysis and the need for support to breathe.


How Can a Physical Therapist Help?

Evaluation is important for guiding the treatment of a child with SMA. Your physical therapist will conduct a thorough evaluation that includes taking the child’s health history and examining the child’s posture, muscle strength, motor activities that include walking, joint motion, respiratory function, participation with family and friends, and quality of life.

Treatment is important to allow children with SMA to achieve the highest level of independent living and mobility possible, and to prevent or delay the development of complications. Physical therapists work closely with the child and family to develop the most appropriate goals for each child based on functional levels and interests.

Your child’s treatment may include:

Therapeutic Exercises and Strength Training. Physical therapists use different therapeutic exercises to help children with SMA improve and maintain mobility, and prevent or slow the progression of contractures and respiratory failure. Therapeutic exercises may include strengthening and aerobic at levels appropriate for the specific child.


Strengthening Exercises

Your physical therapist can help your child slow any deterioration in muscle strength and prolong your child’s ability to walk. Physical therapists design strengthening exercises to keep children with SMA active and moving. They identify games and fun tasks that can be used during therapy or taught to the family to maintain strength.

Improving Developmental Skills

Your physical therapist will develop strategies to help your child learn developmental skills that will improve:

Head and trunk control

Floor mobility, such as rolling and crawling

Changing positions, such as pulling up to stand Learning upright positions and skills, such as sitting, standing, and walking


Aquatic Therapy or Hydrotherapy

Some physical therapists specialize in aquatic therapy and use the physical properties of water to provide strength training, walking and balance exercises, and aerobic training, without the risk of fatigue or overworked muscles.

Standing Programs

Standing programs for children who can’t walk are used to maintain muscle flexibility and length, prevent contractures, promote musculoskeletal development, and prevent bone-mineral density loss. Your physical therapist can design standing programs to be used at home or at school, as appropriate.


Management of Respiratory Complications

Physical therapists teach parents and caregivers how to perform chest drainage techniques, and help with coughing and breathing techniques to keep children with SMA breathing well. Your physical therapist will provide chest physical therapy as appropriate, and teach the family some blowing games (like bubbles) to improve breathing.

Management of Contractures

Physical therapists help prevent joint tightness (contractures) and increase flexibility in children with SMA by designing specific programs in range-of-motion exercises, positioning, and regular stretching. Your physical therapist may recommend the use of splints, braces, or standing devices, as appropriate.



Physical therapists work closely with speech or occupational therapists to promote healthy feeding in children with SMA. They will help position the child in appropriate head and body postures to allow the most effective feeding.

Management of Scoliosis and Skeletal Deformities

Physical therapists can assist in the prevention or reduction of scoliosis and skeletal deformities by designing specific programs to improve movement, and maintain healthy positioning at all times.

They will recommend wheelchair modifications and the use of braces to ensure the safety and health of each individual child, as needed. If a child requires surgery for scoliosis or other joint deformities, intensive preoperative and postoperative physical therapy can help prevent respiratory complications and loss of strength or function.


Assistive Devices

Many children with SMA require adaptive or assistive devices to help them maintain function at some point during the course of the disease, and especially following surgery. Physical therapists work with other rehabilitation specialists to select and modify assistive devices to meet each individual child’s specific needs. Types of assistive devices range from those that position a child for feeding or playing, to motorized wheelchairs.