December/January 2001

Maximizing Mobility

By Karen Fisher, OTR, ATP, and Gina Ricardo, PT, PCS, ATP

From adaptive strollers to power wheelchairs, the right pediatric mobility systems help disabled kids be kids.

The pediatric rehabilitation profession faces the enormous task of helping children with multiple challenges to develop as normally as possible. These impairments demand intervention by a skilled, knowledgeable, and responsible team of professionals.

The Evaluation

When evaluating a child, several factors must be addressed, such as the user's potential growth. The ability of a wheelchair frame and seating system to grow with the child is essential. Second, children's functional skills, postural control, musculoskeletal alignment, and/or cognition can change as they develop and age. Therefore, the child's mobility system must be adaptable to a variety of positioning options to accommodate these changes.

In all pediatric mobility assessments a child's functional performance must be considered. Children's level of motor control, hand function, ability to access switches, perform transfers, participate in social interaction, and explore their environment, and potential mobility will dictate the most appropriate mobility system. It is often difficult for the family of a child with a disability to accept the need for an assistive device. Ultimately, the child's and the caregiver's acceptance of a mobility system can heavily influence the decision-making process. Also, federal and private funding sources require a mobility system to meet the needs of a child for at least 2 years.

Adaptive Strollers

An adaptive stroller is a seating system that attaches onto a stroller mobility base. On average, adaptive strollers are recommended for children approximately 3 months to 3 years of age. They are usually lighter in weight than manual wheelchairs, and can be folded for transportation. The option of tilt and/or recline is available on most adaptive strollers. The standard seating system can include a solid seat, solid back, headrest, harness, trunk supports, hip guides, seat belt, tray, and foot supports, and can be modified for the more involved child with contoured and/or foamed seating, and dynamic headrests. The base can usually accommodate a ventilator, oxygen tank, and intravenous pole, and most have the option for a bus tie-down system. A parent/caregiver may accept an adaptive stroller more readily than a wheelchair, because it resembles a typical stroller.

There are some limitations with adaptive strollers. The variety of models is limited and self-propulsion is not an option. The frame does not adjust in size, and the seating system has a fixed amount of growth. If children are attending a school program, the stroller does not allow them to be at the level of their peers.

Recommendation of an adaptive stroller must be individualized to each child. It should not be considered based on diagnosis, but by the child's age, size, level of function, and caregiver needs. At Texas Children's Hospital, we have recommended adaptive strollers for children with a variety of special needs, ie, premature infants who require ventilator support, 6-month-old children with spina bifida, 1-year-old children with osteogenesis imperfecta, and 2-year-olds with cerebral palsy who require molded seating and maximum postural support.

Front Wheel Drive

A front wheel drive (FWD) wheelchair is a seating system attached to a mobility base, but is unique in that the larger wheels are mounted in the front portion of the frame with the casters in the rear. This wheelchair can be recommended for children as young as 18 months. This wheel configuration allows for more efficient propulsion by a small child due to the positioning of the tire and a greater surface area of tire exposed. The frames that allow front wheel drive configuration also permit lower seat to floor height to promote independent transfers in and out of the wheelchair and peer interaction. Front wheel drive chairs can accommodate solid or contoured seating, tall push handles, and unlimited supports such as headrest, tray, and removable legrests. These wheelchairs can be converted to a standard rear wheel configuration as the child grows. FWD wheelchairs can also be securely tied down for bus transportation. The seating system can be removed and the frame folded for ease of transportation in a car.

Although the FWD wheelchair promotes independence and is child friendly, there are some drawbacks. Due to the large front wheels, this wheelchair is more difficult for caregivers to maneuver and push up inclines. A ventilator cannot be transported on this type of frame if it is smaller than 14 inches wide.

The FWD wheelchair configuration should be introduced to a parent and child when the child shows initial attempts to mobilize himself and explore the environment. A typical child begins to ambulate at 12 to 15 months and a disabled child should have the same opportunity for independent mobility at a similar age. Children who may benefit from a FWD wheelchair may have diagnoses of spina bifida, cerebral palsy, Down syndrome, or spinal musculature atrophy. The ability for independent mobility at the initial wheelchair evaluation is not crucial, but exploration of the wheels and a working cause and effect relationship is important.

Rear Wheel Drive

A rear wheel drive (RWD) wheelchair can be appropriate for children generally at 5 years of age and older. It may be recommended for children who have potential for self-propulsion or who are dependent for mobility. RWD consists of a seating system on a mobility base (frame). The frame may be foldable, semirigid, or rigid, resulting in various configurations to assist with transportation of the wheelchair. The seating can vary from simple (sling) to more aggressive (contour) and may be removed to fold the wheelchair. Both the frame and seating system can be ordered in various sizes to allow for growth or may be fixed for an older child. There are numerous models available, and the wide variety of accessory options (legrests, brake types, tire sizes, back cane heights, and even one-arm drive) allows the seating team to meet the individual needs of the child. If the wheelchair is wide enough, it can also accommodate a ventilator.

A standard RWD wheelchair is the most common type of mobility device. Standard sizes are available up to 22 inches wide, but then must be custom ordered for larger widths. A semirigid or rigid wheelchair cannot adjust to a child's growth. It is an all too common mistake for a child to receive a nongrowing wheelchair.

Tilt-In-Space Wheelchair

A tilt-in-space (TS) wheelchair can be appropriate for children as young as 1 year old. A TS wheelchair keeps the child's body positioned at a fixed seat to back angle while changing her orientation in space. A TS wheelchair consists of a seating system on a frame in which the frame allows up to 45 degrees of posterior tilt and up to 10 degrees of anterior tilt. Types of TS wheelchairs are numerous and can accommodate most seating systems. Typically, TS wheelchairs range in size from 10 in. wide to 22 in. wide. These wheelchairs can accommodate a ventilator and can be tied down on a bus for transportation. If large wheels (24 in.) are put on a TS wheelchair, self-propulsion is possible but not typical. All TS wheelchair frames have parts that remove or fold down, but only one brand folds sideways when seating is removed. Tilt should not be confused with recline. Recline occurs when the seat to back angle is opened, thus moving the trunk and head supports in relation to the child's body.

A TS wheelchair may be recommended primarily to assist a child with head/trunk control. It is also recommended to assist with pressure relief and to change the position of a child to assist with respiratory function. This type of wheelchair is appropriate for children with cerebral palsy, seizure disorders, Rett syndrome, spinal muscular atrophy, and acquired brain injury.

Power Wheelchairs

A power wheelchair can be considered for children as young as 18 months of age. It consists of a seating system on a mobility base that consists of motors, batteries, and electronics. Independent mobility and/or the potential for mobility is the primary reason to consider powered mobility. A power wheelchair may include a manual or power tilt and/or recline. With the recent technological advances in electronics, a child may be able to operate a power wheelchair through a variety of controls and with body parts, such as hand, head, feet, tongue, and eyebrow. As with other wheelchair bases, a power wheelchair can accommodate most seating systems, a ventilator, and tie-down system for transportation.

As important as independent mobility is for children, the size and weight of a power wheelchair must be addressed by the team. Transportation of the wheelchair by the family may be impossible without the use of a van equipped with a lift or ramp. Power wheelchair accessibility in the home may be hindered by steps or small living quarters. A ramp may allow accessibility depending on the slope of the stairs. It is essential that the family is aware of the responsibilities regarding maintenance and upkeep of a power chair. Some funding sources will purchase both a power and manual chair for one child.

Children who demonstrate motivation to explore their environment, but are unable to propel a manual chair, should be considered for powered mobility. Many children may not demonstrate independent use of a power wheelchair at the initial evaluation, but this does not prevent them from being a power wheelchair candidate. Understanding of cause and effect, reliable motor response to start and stop the wheelchair, and visual attention to the environment are required when recommending a power wheelchair. A child must also show safety awareness for himself and others during the initial evaluation. It is beneficial for the child and family to use a loaner wheelchair in the home or school to decide if powered mobility is appropriate.

Seating Systems

Most pediatric mobility systems accommodate different seating systems, which consist of a seat, back, and supports that provide postural stability and alignment. When recommending a system for a child, a thorough clinical evaluation of the pelvis, spine, muscle tone, postural control, and function must be performed. The team should keep in mind that a seating system will need to change with the child as their postural and functional needs change. Pelvic obliquity and spinal deformities may dictate the most appropriate type of seating. For instance, a child without orthopedic deformity may benefit from planar seating whereas a child with scoliosis and rib hump may require custom contoured seating.

Seating surfaces are categorized into four types: sling, planar, contoured, and custom contoured. Sling upholstery is made from strong fabric that is lightweight and inexpensive, but provides minimal support. Planar seating typically consists of foam covered in a variety of materials resulting in a flat surface without contours. This seating provides firm support for children without significant pelvis/spinal deformities. A planar seat can be modified into an antithrust design, if needed, to maintain optimal pelvic position for children with extensor tone. Contoured seating is available in predetermined sizes and degree of contour that can be made of foam, fluid, air, or any combination of the three. These products provide moderate postural support and pressure relief; however, most do not allow for growth secondary to predetermined sizes.

Custom contoured seating allows for maximum contact between the surface and the body because it conforms to the shape of the child's spine and pelvis. This provides maximum postural support and pressure distribution and can be achieved by different methods. One method involves a seat or back with a cover that can be opened to allow for a variety of foams to be combined, interchanged, or carved to accommodate the child's orthopedic deformities. This is not an optimal solution for the most severe postural deformities. Another method is a foam-in-place method, which entails pouring a liquid foam into a bag that is inserted into the seating system, This foam forms around the child as she is held in the desired position in her wheelchair. This option is fairly inexpensive and can be redone if there are postural changes. However, this method may not provide enough contour for the most severe curvatures and obliquities.

The most aggressive custom contoured seating system involves taking an impression of the child's body, making a mold of the impression, and sending it to the manufacturer to fabricate the seating system. This provides the most support of any method described; however, it is expensive and difficult to modify, and can take a considerable amount of time to receive the product.

Goals

The goal of the pediatric mobility system is dependent on the individual needs of the child and family, which may include mobility (dependent or independent), postural support and alignment, function, and comfort. The ultimate goal of the team is to recommend the most appropriate mobility system.

The pediatric mobility system is not just for mobility. The appropriate pediatric mobility system will provide the child with postural support and alignment to promote visual exploration, upper extremity function, and even independent mobility. A suitable system can provide the child and family with school and community access that would not be otherwise obtainable. The correct pediatric mobility system can facilitate children's primary role, which is to play and interact with their family, environment, and peers. The pediatric mobility system is an integral part of the child's physical development and emotional growth.

Karen Fisher, OTR, ATP, is a clinical specialist and Gina Ricardo, PT, PCS, ATP, is an advanced clinical specialist at Texas Children's Hospital in Houston. They have both been involved in the Seating and Mobility Clinic for 3 years, with Ricardo serving as the clinic coordinator.

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