Karim’s Success Story: A Long Term Field Trial of a New Folding Supportive Pediatric Wheelchair

By Dave Calver

Following the World Health Organization’s call for manufacturers to offer affordable assistive products, Participant developed the Cub to fill a widely acknowledged product gap. Cub is a modular, folding, tilt-in-space wheelchair with a full range of postural support devices and good all-terrain performance. The Cub will be offered with tiered pricing to be affordable for children everywhere. Through a co-creative process, the design received input from over 200 people from 40 countries, including therapists, caregivers, users, DPO representatives, NGO representatives, and government representatives. Designers developed the Cub with extensive experience in developing pediatric wheelchairs for the USA, Japan, low-income settings, and global markets. The field trial occurred in two phases (three weeks and 8 months) in Medellin, Colombia, starting in January 2021.

We selected four users from a pool of 15 candidates to allow for feedback from a wide range of perspectives. The users had previously used a good quality product, so their basis of comparison was reasonably high. The following are the criteria used during selection: a variety of user environments, transportation modes used regularly, ability and presentation, ability to self-propel, and openness and comfort with discussing their experiences and goals.

Children in the trial group: 

  • Karim (Client #1) - Cerebral Palsy, entirely relies on his caregivers and parents for all his activities of daily living (positioning, feeding, and mobility)

  • Client #2 - Cerebral palsy, has reasonable sitting balance with asymmetry of postures, able to self-propel limited distances on very flat, smooth surfaces, reliant on assistance for most activities of daily living.   

  • Client #3 - Congenital disability (not CP but undiagnosed), flaccid muscles, low tone and spasticity, lacks control of his torso, head, and extremities, and is reliant on assistance for all activities of daily living. He is reliant on his wheelchair for mobility and postural support when he is not lying down.   

  • Client #4 - Cerebral Palsy, limited controlled movements of arms, a high level of tone, and presents with mixed spasticity and uncontrolled movement of her extremities. Relies on the wheelchair for mobility, and caregivers for all activities of daily living (feeding, washing, positioning, etc). 

We provided users with a fully working prototype that passed ISO 7176 double drum and tip-over testing and was safety tested following the WHO WSTP Safe and Ready checklist.

The Short Term Trial was three weeks. During the trial we visited the families to make adjustments, to train on Cub’s use, and to collect their experiences and thoughts about Cub. On these visits, our wheelchair technician noted that the prototypes were significantly easier and faster to adjust than comparable chairs that he had used in the Colombia and Canada markets.

We collected data after three weeks of regular use by using two methods. First, the families were interviewed in their homes so that issues related to their environment, daily habits, transportation, etc., could be video recorded. These videos are helpful for product development. Second, all families gathered for a focus group meeting at the end of the trial.

Design Changes Noted from the Short Term Trial:

Some issues, like the tilt release smoothness, were related to the quality of the prototypes. Actionable changes included: 

  • Improve safety by adding double lock mechanisms to the recline release lever and tilt release lever. Because the Cub design bridges the specific categories of a Supportive Pediatric Wheelchair, which typically includes a recline lock, and a Supportive Stroller, which does not have recline locks, special considerations are necessary. Devices in the Supportive Pediatric Wheelchair category typically have double lock mechanisms. This makes them safer for use in classroom settings as it is more difficult for a classmate to activate the release. Double locks may be inconvenient for Supportive Strollers, which are not typically used in classrooms. 

  • Lengthen the back of the armrests, so there is no gap between the armrest and the chair back. Similarly, add a new short-wide armrest accessory for dependent users. We noted other dimension modifications for other Postural Support Devices.

  • Add a strap with a quick-release buckle to keep the seat folded during transport and reassembly. This strap attaches to the push handle and, like on a job stroller, can also be used as a wrist leash to prevent runaway hazards.

  • The stationary base, made of plywood, was unused and rejected by the families. The parents felt that it was unnecessary. It was not high enough to make feeding easier than while the seat module was attached to the mobility base. It was also not low enough for the Users to engage with siblings in play on the floor.

Long Term Trial:

Karim, Client 2, and Client 3 kept their chairs for the long-term trial. Client 4’s chair was returned to the lab to study the wear effects and to redevelop some parts. (As an incentive for participation in the trial, all users will receive factory-made units at no cost.) After seven additional months of use, we gathered data from the users, and caregivers gave feedback via phone, video, and in-person interviews.

Before using Cub, Karim could not fully participate in family gatherings as he would often get fatigued from sitting in his wheelchair. Karim’s sitting posture was poor, making his feeding even more difficult. With Cub, life has been fun for him. Not only can he comfortably travel with the family to the beach due to the easy foldability feature of the chair to fit in the car, but he also has better access to his friends. “Karim’s participation in school and family activities has increased a lot. Cub has made everything easier for him”, Aline, Karim’s mother. Karim now has a healthy and well-maintained posture.

“[Client 3] adjusted to the chair much more quickly than I expected. He can now happily spend many hours in the chair, making it possible for him to go to school and go out in the neighborhood with his cousins. He can do many things he could not previously do,¨ Client 3’s mother. Before the trial, Client 3 spent most of his time in bed. He was not comfortable with being carried in public. As a result, he experienced an unusually dramatic increase in activity outside the home and socialization with friends and family.

“[Client 2] showed significant improvement in her sitting posture and dramatically improved her neck and head control. She can now spend more time with the family and follow our conversations', Client 2’s mother. For Client 2 and her family, the chair was easy for transportation in taxis (similar in size to a Volkswagen Golf). Before receiving the prototype, Client 2 would use a typical non-supportive stroller, which was visibly uncomfortable and harmful to her posture. With the prototype, Client 2 regularly went to physical therapy, to the indoor shopping mall, out for walks on the rough sidewalks of the neighborhood while using the All Terrain accessory, and to other treatments such as speech and language therapy. Client 2’s primary caregiver, her mother, could also go out more quickly for essential appointments, such as with her doctor.

Generally, from the long-term trial, we observed that the design was suitable for the peri-urban environments, with rough sidewalks, shopping malls, and buildings that are not wheelchair accessible. Both users were out in the community significantly more than the baseline. The chair was comfortable for all-day use. Caregivers liked the easily removable and washable upholstery. 

In regular wheelchair provision, users abandon wheelchairs because of poor fit, mechanical problems, or because they do not provide enough benefit or comfort to the user. To hear that the chairs were still in daily use after eight months was a good feedback point.

Clinically all the users showed significant improvement in their seated postures, endurance, and comfort. They also showed improved function in their upper extremities, and the improved arm function opens up many possibilities for school, self-feeding, grooming, and playing with friends.

A more formal, long term trial of 15 chairs is planned for late 2022 in Bangalore, India, through our partner, Mobility India.

In summary, Dave Calver, who is Chief Clinical Officer with Participant, noted, “We could not have been happier with the outcomes and presentations of the four clients in their chairs. Cub accommodated and supported these four very different children quite well. Guaymas and Medellin provided various terrains and environments ideal for testing Cub’s features and durability. We are grateful to our friends at Whee, a fantastic organization dedicated to education and advocacy around disability and rehabilitation in Medellin. And, we are grateful to Estímulos LPS, a pediatric rehabilitation center in Medellin. And, we are grateful to the DIF clinic in Guaymas. All gave remarkable support and introduced us to many wonderful families and their kids. Their support and assistance are invaluable in our mission to continue developing affordable and excellent assistive products, and we look forward to working with them again in the future.”