by Colleen Gillette Smith, PT, DPT, ATP
Wheelchair selection is a very important and weighty decision. For a user, a wheelchair is often his only means of mobility and therefore a crucial component of living his life. If a chair is selected well and meets the user’s needs, the result is freedom. If all options are not considered, and an individual is prescribed a less than optimal chair, the user often has decreased independence and increased frustration. Also, in the current reimbursement climate for complex rehabilitation technology, a user is most likely required to use equipment for 5 or more years. Therefore, it is crucial that we get the right equipment—the first time.
It is imperative that a team-based approach be used to prescribe a chair. The seating therapist brings value to this approach with an array of product knowledge and experience that will help inform decisions. The user, on the other hand, knows better than anyone what his daily needs are and the environments in which he will function. The primary responsibility of the therapist is education. Both therapist and user share the goal of empowering the user to make the best decision to meet his needs and provide the greatest independence. When possible, the user should be afforded the opportunity to trial demonstration equipment within the home and regular environments. All of the following are options that should be considered to increase independence and success.
When selecting a drive system for a power wheelchair, there are many factors to consider: maneuverability, terrain, and past experiences. The drive system refers to which wheels on the chair are powered by the motor, which, in turn, determines how the chair handles in various situations. The options include: front-, mid-, and rear-wheel drive.
How the chair handles and maneuvers in tight spaces is another factor to consider. This is where detailed discussion and/or observation of a user’s home environment is critical. Mid-wheel drive chairs provide the smallest turning radius, and therefore are best able to maneuver tight spaces within the home. Most manufacturers report a range of 20- to 22-inch turning radius for mid-wheel drive. Front-wheel drive chairs, though they have a larger turning radius (from 26 inches to 30 inches), allow for a tighter pivot point. This gives them the best ability to turn sharply into doorways. Rear-wheel drive has the largest turning radius and is unable to make tight turns.
The terrain that the user frequents is the next consideration. Front- and rear-wheel drive chairs usually provide smoother rides outdoors. This is due to the fact that they have independent suspension on each of the four wheels. Front-wheel drive chairs typically handle obstacles the best and are able to navigate steps and thresholds up to 2 inches. This is because the drive wheel encounters the object first and is then able to pull the chair over the obstacle. Conversely, the mid-wheel drive chair has the smaller casters hit the obstacle first and can often cause the drive wheel to float. Mid-wheel drive chairs, however, are considered to handle inclines the best, as they have both front and rear casters that provide stability while ascending or descending. Front-wheel drive also handles inclines well, as the weight is evenly balanced between the motor in the front and the battery in the back. Rear-wheel drive chairs are frequently considered the most unstable on inclines—carrying the majority of the weight in the rear.
Finally, how the chair handles during driving must be considered. All the chairs are comparable at lower speeds. At higher speeds, rear-wheel drive handles the best because the majority of the user’s weight is directly over drive wheels. This can frequently be true of mid-wheel drive chairs as well, depending on the setup. Front-wheel drive is the most difficult to handle at higher speeds due to its need to pull most of the weight behind the drive wheels, sometimes resulting in fish tailing.
With all these factors in mind, a user’s previous experience should also be considered. There is a learning curve involved in operating each drive control. Therefore, experience and preference should be weighed.
There are two base options if ordering a manual wheelchair for an independent user: rigid and folding frame. A folding frame chair has a cross brace that allows the chair to be folded like an accordion without needing to remove the wheels. A rigid frame has a single axle in the base, and is usually folded by removing the wheels and collapsing the backrest toward the seat.
Generally speaking, the weight of a rigid frame is less than that of a folding frame due to the increased metal and hardware involved in the cross brace of the folding frame. This, combined with the overall shape of the frame, frequently results in increased independence in loading and unloading of the wheelchair into a car with a rigid frame chair.
Shoulder pain and pathology is of special consideration for primary manual wheelchair users. To prevent overuse injuries, it is important to consider how to increase efficiency of propulsion and decrease repetitions of pushing. A rigid frame chair accomplishes both of these objectives with the decreased weight of the chair requiring less force to propel and the greater transfer of energy through the chair because it does not have a cross brace. Therefore, a rigid frame chair generally affords greater shoulder preservation.
Usually, a rigid frame chair provides a smoother ride because it has fewer moving parts. The cross brace with hardware in a folding frame allows for play within the frame as it transverses obstacles and uneven terrain. This movement in the frame is transmitted to the user and felt as a rougher ride compared to a rigid frame chair.
Even with these considerations, sometimes a folding frame chair better meets the client’s needs. Again, this is where the client’s knowledge of the specific home environment may influence or change a clinical recommendation.
Power Access Points
When considering a power wheelchair, one of the most important decisions is determining the access point—the placement and type of control that will drive the chair. The access point can be mounted anywhere the client has the greatest strength, endurance, and consistency with activation.
The two main categories to consider for access points are proportional and nonproportional controls. Proportional controls allow for full (360-degree) directional control and allow a gradient of speed control. The farther the joystick is deflected from the center, the faster the chair will move. The most common proportional control device is the joystick. Other options to consider are chin- or tongue-guided joystick, as well as micro-joysticks.
Nonproportional refers to switch-like controls that allow for control of direction, but not speed. Options for nonproportional controls include head arrays and sip-and-puff. A head array is controlled with three buttons: one on each side of the head and one behind. Sip-and-puff access is controlled through a straw inserted in the mouth. Generally, proportional controls are preferred as they allow greater independence and control. However, nonproportional is sometimes indicated with decreased cognition or strength deficits that limit use of a proportional control.
Determination of the best access point frequently requires multiple trials of equipment and most often several follow-up visits. Many aspects should be considered in this decision, including strength, endurance, and cognition. A patient should receive proper training on the device before being tested for appropriateness of prescription.
Manual Access Points
As far as manual wheelchair access points, there are several options that allow for improved manual wheelchair propulsion. Options for the push rims vary from the standard round metal to oval that meets the more natural curve of the hand. Additions can be made to the rims, adding rubber for increased grip or projections from the rim to allow for pushing with the web space of the hand. Furthermore, power assist options can be added to a manual wheelchair to augment each of the user’s pushes.
Power Seat Options
Power seat options increase independence in many activities for the user. These include tilt, recline, seat elevate, power leg elevate, and standing.
Tilt refers to the chair maintaining the seat angle as the back, seat, and foot support all angle backward. Recline refers to only the back moving, which opens the seat angle. Tilt and recline together provide an effective pressure relief for the buttocks. It is widely recommended that pressure reliefs be performed every 30 minutes and maintained for 2 minutes at a time. These seat functions allow the user to independently prevent development of wounds. Other common uses for the tilt feature include: increasing trunk stability during driving and activities, allowing for independent repositioning and posture management, and reducing pain and fatigue in sitting. Recline is useful for bowel/bladder management. It can also provide variable positions for range of motion and tone management.
Seat elevation is a feature on some power wheelchairs, with options up to 14 inches. This option provides great increase in independence in activities such as cooking and cleaning. This results in shoulder preservation and decreased pain, as it reduces overhead reaching and limits the need to overextend the neck to interact with the environment and others. Additionally, this option could increase independence and safety in transfers within the home, as the user would be able to raise or lower to variable heights.
Standing power wheelchairs are becoming more available, allowing users to stand in any environment. This option allows users to stand for socially appropriate reasons—for example, to conduct a presentation or interact with peers at eye level. Additionally, the standing option allows for all of the benefits of therapeutic standing—including improvements in bone, cardiovascular, and bowel/bladder health—without the need for transfer equipment or the assistance of a caregiver.
Team-based decision-making is a comprehensive approach that works well when prescribing adult users. That same approach can also be used for pediatric mobility device users, with the distinction that parents and/or caregivers will become team members who offer valuable input in addition to—or in support of—the pediatric patient. Decisions for pediatric mobility devices must consider not only the user’s physical growth, but that person’s level of cognitive ability, motor impairment, and judgment skills.
The ability to identify obstacles and recognize cause-and-effect actions, such as how/why a switch or joystick operates, can be especially critical for young children who use power mobility devices. Evaluations to assess a pediatric user’s directional concepts and problem-solving skills exceeds the scope of this article, but they are important components of equipment purchase decisions, and require open and honest communication at the highest level of all stakeholders. Once an equipment evaluation is complete, there are plentiful choices on the market to tailor a mobility solution. Power and manual wheelchairs are available with small bases and pediatric seating, as well as versatile frames, all with the common aim of optimizing independence and accessibility.
Whether for adult or child, modern decision-making for mobility devices is a highly informed process that strives to put the user’s satisfaction and well-being as the foremost consideration. Through careful consideration and team-based decision-making, a user can end up with very personalized equipment that affords great independence and freedom. RM
Colleen Gillette Smith, PT, DPT, ATP, has been a physical therapist with the International Center for Spinal Cord Injury (ICSCI) at Kennedy Krieger Institute since July 2012. She completed her Doctor of Physical Therapy at Duke University in Durham, NC, and her bachelor of science in health sciences at Lee University in Cleveland, Tenn. She is experienced at treating patients across the lifespan with various neuromuscular diagnoses, with particular interests in pediatrics and seating and mobility. For more information, contact [email protected].