An IOTA of thumb control for children with cerebral palsy, hemiplegia, stroke

This child-sized device assists children with thumb movements while giving them sensory and visual feedback.
This child-sized device assists children with thumb movements while giving them sensory and visual feedback. (Image: Wyss Institute, Harvard University)
Our ability to use the thumb as an opposable digit is a critical part of what sets us apart as a species. “That’s how you’re holding a pen,” Leia Stirling, PhD, a senior staff engineer at the Wyss Institute for Biologically Inspired Engineering told me recently as we talked about the Wyss’ latest collaboration with Boston Children’s Hospital. “That’s how you hold your phone; that’s how you open a door; that’s what makes us unique.”

It’s also an ability that children who have suffered a stroke or have cerebral palsy or hemiplegia (paralysis on one side of the body) can lose or fail to develop in the first place.

Stirling, along with Hani Sallum, MS, and Annette Correia, OT, in Boston Children’s departments of Physical and Occupational Therapy, are the architects of a robotic device that may improve functional hand use. The device assists children with muscle movements, using small motors called “actuators” placed over the hand joints, while giving them sensory and visual feedback. It’s called the Isolated Orthosis for Thumb Actuation, or IOTA.

IOTA grew out of conversations that Stirling had with Correia as well as orthopedic surgeons Brian Snyder, MD, PhD, and Donald Bae, MD, about how few robotic systems designed for the hand exist, especially for children. As the team would discover, designing robotic systems for anything as complex as the human hand presents huge challenges.

While early interventions—ideally in early childhood—work best when it comes to learning new motor skills after neurological trauma, most existing robotic devices for the hand are made for adults. They tend to be too heavy for children to wear, and their size, covering large parts of the hand and palm, can actually interfere with a child’s ability to manipulate objects.

“Even when devices are made for the pediatric population, they are often made for older teenagers and are created by simply making an adult device smaller,” explains Correia. “What’s exciting is that we had the opportunity to make a device specifically for children that is consistent with their developmental needs.”

Most existing devices are meant to assist movement of all five digits, known as whole-hand shaping. But Correia wanted to focus on the thumb as a key component of grasping. Currently, occupational therapists (OTs) use several treatment approaches, including rigid or semi-rigid orthotics, Constraint Induced Movement Therapy and functional electrical simulation, but these don’t always allow for a full range of thumb motion. Aided by recent advances in materials and technology, Stirling and Sallum made the thumb the focus of IOTA’s design.

The new device fits over a child’s hand with actuators placed over thumb joints. Sensors on the device detect attempts at thumb and wrist movements, relaying the information to a computer housed inside a small, portable control box. The device then helps the child complete the motion. Because IOTA is small enough to leave the palm open, children using it can more freely grasp and interact with objects, forging and strengthening their nerve pathways.

The team hopes that IOTA, incorporated into an OT treatment program, will eventually allow a child to achieve enough dexterity and control to zip up a jacket or hold a pencil unassisted. A pilot clinical study currently underway will examine 15 Boston Children’s patients during visits to the hospital and follow five of them for six weeks as they use the device at home and in the hospital.

Since the current design only fits children 6 to 16 years of age, Correia and Stirling would like to eventually create smaller versions for younger patients. “We’re continuing to bridge the gap between the lab and the treatment area,” Correia says. “We see the IOTA as the first step towards a more complex device.”

Read about another collaboration between Boston Children’s Hospital and the Wyss Institute to build robotic clothing with built-in actuators to help children at risk for cerebral palsy.

  • Lisa C

    What about children with Erb’s or Brachial Plexus Palsy?

    • KKapiga

      Hey Lisa, we reached out to the Boston Children’s OT involved in the story, Annette Correia, for a comment. She passed this along:

      “We are currently focusing on a few, specific populations with the current project, but do agree there may be other populations that would benefit from this.”

      Thanks a lot for commenting

  • lisamarie63

    I was born with no thumbs. I’m 50 and have not had any problems with grabbing objects. My concern with this is that the idea that your thumb is “critically important to your ability to grasp objects” is based only on the experiences of people who have thumbs. Have any other things been attempted to help them to learn other ways of functioning before getting this? I think the idea is great but wonder how much research went into talking to people who have no thumbs before assuming you HAVE to have thumbs to function well.

    • KKapiga

      Hey LisaMarie63, thanks for your question–that’s an interesting point. We checked in with Annette Correia, the Boston Children’s OT involved with the thumb assist device, who let us know that children with hemiplegia often have just as much trouble controlling their fingers as they have controlling their thumb. She passed this along to us:

      “Children with hemiplegia often have difficulty controlling all their fingers and the goal of this device is to assist them with learning to improve the control of their thumbs. There are many types of treatment approaches that can be used to help children with hemiplegia and this is a device that may help some of them in conjunction with other equipment within the therapy sessions. Patients and their families have had an active part of the process and will continue to be part of the development of the device.”

      Hope that helps and thanks for your comment, we always appreciate hearing from our readers.

  • Laura Kraus-Van Cott

    So how does somebody possibly get this device? My daughter is 9 and both her thumbs are almost in her palm. Is it available yet?

    • Hey Laura, thanks for commenting.

      IOTA is currently being piloted at the Boston Children’s Hospital and isn’t widely available to OT patients yet. You may qualify for the pilot, so if you’re interested in having your daughter participate, you can contact Kelly Cakert from The Wyss. She’s reachable by phone at 617-432-7704 or by email at