ATP Series

A Hierarchy of Driving Controls

Where to Start & How to Proceed When Assessing Power Chair Options

driving controls

Creating a hierarchy of almost anything in the world of complex rehab technology (CRT) is tricky. Most passengers would agree that a first-class seat at the front of the plane beats a seat in the last row, across from the lavatories. But when contemplating a wheelchair or a seating system for a CRT client, the answer is usually It depends — on factors as wide ranging as clinical presentation, prognosis, daily goals, transportation issues, medications and surgeries, etc.

Still, to maximize efficiency during an evaluation, it can help to have somewhere to start.

So when assessing driving controls for a power wheelchair user, what should be tried first? And next?

Starting with the Standard Joystick

An armrest-mounted joystick is standard equipment on a power chair. Is that where the driving control assessment should start?

Of course, it depends.

Robert Norton, director of sales, Specialty Controls, at Sunrise Medical, is well known for his work with Switch It, a driving controls specialist.

“It depends on the scenario,” he said. “Everybody is so individual, but a joystick mounted inline with the arm is the first starting point. Obviously, there are cases where a clinician or an ATP looks at [the client] and says, ‘We know that’s not going to be functional.’ But number one, a proportional control is always preferred, and number two, it’s my opinion that it’s preferable to use the standard joystick, if at all possible. It reduces cost, it reduces pieces of equipment on the chair. If you’re using a standard joystick, you don’t require extra displays, extra wires, extra mounts and the places to run things.”

Jay Doherty, OTR, ATP/SMS, director of clinical education for Quantum Rehab, said the assessment must start with the client.

“When assessing a person for the first time, the team needs to look at where the individual’s most consistent movements on their body are,” he explained. “Once the team knows where the most sustainable movements can be repeated consistently, then they will be able to narrow down what types of input devices can be explored, and the order in which they will explore them. If a person has hand control, then I start with a standard proportional joystick and may consider an adapted handle.”

Doherty said he doesn’t always start by considering a standard hand-controlled joystick, “but I do consider it, as it is an ‘included’ component of the power wheelchair and provides the greatest control over speed regulation and directional control/steering corrections with a proportional type of device.”

Joystick Variations

While many power chair users can use a joystick, not all of them can do so with the joystick in its standard position — at the far end of the right or left armrest. No problem.

“That joystick may be mounted in more of a midline or inset position so that the user has a greater success rate of accessing the joystick, as well as the switches,” Norton said. “A lot of times, someone is just fine with the joystick, but they have a hard time reaching over the joystick to hit the mode or the profile button or the speed button. Especially with the newer joysticks that have the user buttons up on the sides of the display — that’s not always functional for someone to reach. But there are things you can do by adding switches through the ports on the bottom of the joystick to bring those to a better location for the user, while still utilizing the standard joystick.”

The possible locations for a joystick seem almost infinite.

“I’ve seen a standard joystick mounted at midline, inset from the arm,” Norton said. “I’ve seen it mounted as a foot control, or an elbow control for an amputee. There are lots of places you can mount a standard joystick to be functional.”

Doherty suggested that if a client has difficulties accessing the joystick in a standard location, “First, I think the team needs to explore why the individual cannot use the standard proportional joystick in the position it is mounted. Once they understand the reason(s) for the lack of adequate control, they may decide that a different location is more appropriate. There may be programming options that the team will want to consider, such as Center Dead Band (neutral zone changes), limited (short) joystick throw or tremor suppression separately or in conjunction with different mounting options. If the team feels that the individual doesn’t have the strength, range of motion, coordination, motor control, dexterity or muscle endurance to use the standard proportional joystick, then the next step is to consider alternative joystick options, which require less force to achieve full throw.”

Manufacturers offer many joystick variations, making it possible for more clients to succeed with that type of proportional driving control.

“If you have someone who still has functional use of their upper extremities and it’s just a matter of placement, then I would look at a very compact joystick or a mini proportional joystick,” Norton said. “If someone is banging on the joystick without a lot of fine control, then you want something more durable, like a compact joystick. However, if it’s a limitation in strength and range of motion, then we would look at a mini proportional, whether it’s one that has feedback, like the MicroGuide, or the MicroPilot, which [requires] very minimal movement.

“I mounted a mini proportional joystick off of the back cane and brought it around, and a gentleman drove with his cheek because of a very fixed C-curve deformity. That’s where his access point was. He had no functional use of his upper extremities, no functional use of his feet or his head, so we mounted a mini proportional joystick off the back cane, and it came right up to his cheek. And that’s how he drove.”

Switches & Other Options

What’s next if a client cannot use any sort of joystick?

If he’s ruled out joysticks, Doherty said, “There is not a set hierarchy; however, I tend to go through the options as follows: If the person has good upper-extremity movement but doesn’t have adequate control to utilize a proportional device optimally, then switches mounted for use of the hands may be an appropriate option. If the individual has good gross motor movement, I try various switches laid out on a tray. Keep in mind that a wheelchair can be controlled by five, four, three or two switches.

“If the person has good head control, I may look at a proportional chin control or a head array as an option. Both allow full control of the power wheelchair and access to many of the features through just the input device itself, but the proportional device will offer infinite operation that cannot be fully achieved with any switch-operated system, even with the advances in programming ‘proportionality’ we see today.”

After that, Doherty said, “If head-controlled operation is not an option, the team may start looking at the placement of switches at one or more body parts. I recommend identifying which locations have consistent, sustainable and repeatable control. I have placed switches at any number of locations on the body. The tricky part is mounting the switch in a location where it is accessible throughout the day, especially when tone and/or fatigue are evident. Five, four, three or two switches are options to control driving a power wheelchair and still have total control over the other critical components necessary to use it effectively, such as power seating functions.

“If the person can drink through a straw and/or blow through a straw to create bubbles, then sip and puff may be a good option. Sip and puff can also provide full control of the features of the wheelchair and allow independent driving as well. If the person can turn their head left and right, a sip and puff/head array combination may be the most effective and energy-efficient option for all-day use. That combination allows the person to drive forward and reverse with a sip or puff command and turn right and left with the turning of their head to activate the head array pads. This can be set up as a true combination system, where the chair can turn right/left while still moving forward to approximate proportional driving.”

The final option, Doherty said, “is single-switch scanning. This type of driving can be time intensive because the individual driving the wheelchair depends on a scanner to move directions and when.”

Are Some Drive Controls Easier to Use?

At first glance — and to an adult — single-switch scanning might seem quite awkward to use, while the proportional joystick might seem very intuitive to learn. But is that true?

“With little ones who have never driven a vehicle,” Norton said, “their ideas are very much limited to cause and effect: I push a button, I get a reaction. That’s how their toys are, that’s how they interact with their world. They laugh, their parents laugh — and they understand that. A single action gets a single effect. Switched control can be a very intuitive way for a very young child to learn.

“Conversely, if you have an able-bodied adult who experienced an accident and has a spinal cord injury, they’ve driven in the past. More intuitive for them is a proportional control, because [a car’s] gas pedal is proportional, and they understand that the more I push down a gas pedal, the faster I go. So a proportional joystick, or a proportional head control or anything that is proportional is very intuitive to them.”

While switch systems may be easier for very young children to initially learn, Norton added that kids should graduate to proportional controls if they show that ability.

“If they can understand the cause and effect of a switch control,” he said of young children “and get the opportunity to progress to use all four directions, and if they become fully successful at switch driving, then the introduction of a joystick gives them that much more control. They’ll still understand that pushing forward makes me go forward, and there’s a lot of things you can do as far as visual cues. If you’ve always been using a green switch, for instance, to go forward, place a green sticker on the forward section of the joystick, so there’s still the understanding that green means forward.”

Multiple Ways to Find Success

Children aren’t the only clients who could progress through multiple types of drive controls.

“A lot of [amyotrophic lateral sclerosis/ALS] clients, depending at what point they’re evaluated, may be standard joystick users,” Norton said. “But we know that even by the time the chair is delivered, that may not be functional for them anymore. Those are things we have to take into consideration. We may spec out the standard joystick, but we also spec out a head array or a chin control. We understand that is where they are going.

“I’ve received feedback from dealers, specifically for ALS, that funding is not prohibitive when it comes to changing drive controls. Numerous funding agencies have become more educated and understand specifically that with ALS, [changing controls] is going to be a reality. They’re going to need new funding for drive controls very quickly, before any five-year [replacement] cycle.”

The drive options available today make it easier to finetune controls per each client’s unique needs and preferences, Doherty said.

“I haven’t found that one type of switch is more intuitive than another,” he noted. “What I have found is that some individuals need to feel or hear the click of a mechanical switch versus a proximity or electronic switch. I have found that some individuals will press hard on an electronic switch because they don’t feel the switch depress.

“The team really needs to look at individual switches and find what matches the consumer’s needs the best. There are so many choices available today that it really comes down to consumer choice and validated success.”

As for other factors that can impact the drive control selection process, Doherty said, “The amount of force an input requires needs to be looked at closely. Fatigue is a major factor for many of the people who utilize specialty controls. Therefore, this is a critical component that must be assessed during the evaluation process. The individual’s goals as well as their capacities and limitations are the primary consideration in choosing a specialty control input device. The one thing that teams cannot do is make any determination based on diagnosis alone. Every person’s presentation with a particular diagnosis will be different, and a thorough assessment is imperative to allow them to be as independent as possible.”

“Seating is where everything starts,” Norton said. “If someone is not properly positioned, our chances of getting them to be a successful driver are greatly diminished. First and foremost as you’re going through an evaluation, if they’re not properly positioned or if there is a postural issue going on — maybe they have high tone, but they’re going to the doctor to see if they can get a baclofen pump, which we know will greatly change their tone and greatly change their positioning. So that’s a stopping point, honestly, on an evaluation — we’re going to wait until the medical intervention has taken place, and then we’re going to determine how you’re going to drive.”

Despite the array of technology choices, Norton added that the client should remain at the center of the equation.

“We are always looking to match the best product to the client’s function,” he said. “There’s no one product for which we can say, ‘Okay, I’m going to make this work for this client.’ That’s looking at it backward. Look at their function, look at what they’re able to do, and decide which product is going to meet those needs or abilities.”

This article originally appeared in the October 2017 issue of Mobility Management.

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