Spinal Muscular Atrophy: What is it & How Physical & Occupational Therapy help!

Aug 23, 2021

Written by Namyata Patel, PT, with contributions by Mary Pengelley, DPT, PT.

What is Spinal Muscular Atrophy, or SMA?

The name, spinal muscular atrophy itself explains that it is a disease related to the spinal cord and muscle. The nerve cells that come from the central nervous system (our brain) to the spinal cord which send messages to the skeletal muscular system of the body are being disrupted, and over time the motor neurons progressively shrink and die, causing the muscles in the body to become weak.

In SMA, this nerve cell disruption is caused by a defect in the survival motor neuron 1(SMN1) gene on chromosome 5q. These genes produce SMN protein which maintain the health and normal function of motor neurons in the muscle. In SMA, the body does not produce enough SMN protein to support muscular nerve cell function.

There are 4 different types of SMA, which are categorized by the age of onset:

  • Type I Werdnig-Hoffmann disease: affects babies younger than 6 months, and is the most severe type of SMA. 
  • Type II: affects babies between 7 and 18 months old. Type II is not as severe as Type I, with the life expectancy into adulthood.
  • Type III Kugelberg- Welander disease: appears after 18 months and it is the least severe type of SMA.
  • Type IV: Diagnosed in adulthood and presents with mild symptoms.

Initial diagnosis can be made by prenatal screening, clinical examination, family history, and newborn blood screening. In the US 38 out of 50 states, including Florida, now include SMA screening in their newborn screening.  An older child who may show signs of muscle weakness will need to be evaluated by a neurologist with appropriate testing to rule out other disorders.

How does Physical and Occupational Therapy help?

Physical and occupational therapists can help SMA patients throughout their lifetime by improving their overall quality of life. Starting with an initial evaluation at the time of diagnosis, most often as infants, the therapist will determine a child’s baseline functional abilities, range of motion, and muscle strength. The therapist will provide education and support caregivers and continue to monitor the progression of the condition while providing therapeutic intervention based on a child’s individual needs.

At Progressive Pediatric Therapy, the PT/OT team work together to help children diagnosed with SMA starting in infancy, through toddlerhood, and into school age and teenage years, as they progress through different stages of growth and development. The PT/OT team determine the need for modifications or equipment to support their development and help them live as independent and healthy as possible. 

Some treatment strategies often used to promote independence in play, mobility, and self-care; promotion of health and quality of life; prevention of musculoskeletal changes or deformity include:

  • Use of orthotics to promote alignment and support
  • Splinting for function or to prevent musculoskeletal changes
  • Kinesiotaping
  • Therapeutic exercises and handling techniques
  • Modification of activity
  • Breathing exercises to support and promote respiratory function
  • Aquatic therapy
  • Adapted Equipment such as adapted utensils, tools for self-care
  • Appropriate wheelchair provision

Additionally the OT/PT team will guide families and caregivers in obtaining needed home modifications to maintain the safety and health of not only their children but also the caregivers.  Examples of common home modifications include entry ramps to the home, bathrooms with walk-in showers, and vans adapted with a ramp or lift to allow the child and their wheelchair to be safely transported.

Additional Resources

For more information on Spinal Muscular Atrophy please visit:


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