Educational Resources

Tilt: When, Why & How Much?

Posterior, Anterior, Lateral: Understanding the Many Functional Uses for Power Tilt

Brad Peterson


Power tilt is so common in today’s Complex Rehab Technology (CRT) power wheelchairs that it can be easy to take for granted. But tilt can be used for a number of reasons and in a wide range of scenarios. And evolving engineering capabilities also make it possible for CRT power chairs to tilt in different directions: posterior (rearward), anterior (forward) and lateral (side to side).

Mobility Management spoke to CRT industry veteran Brad Peterson, VP of U.S. Sales for Amylior, about tilt’s functionality for consumers who use CRT wheelchairs, and how the use of tilt has changed over time.

A Functional History of Tilt

There are many clinical and functional reasons to add tilt to a power chair, but it all started with weight shifting.

“Pressure reduction was, and still is, king,” Peterson said. “That was why tilt first came out: Pressure reduction without changing the hip angle and adding shear to a system or inducing tonal reflexes.”

Today, tilt can support a number of goals.

“In my experience, I’ve seen it used for a lot of different things and usually not just one,” Peterson noted. “Respiration. Pressure reduction. Comfort is huge. I’ve always been a firm advocate of ‘If someone’s not comfortable, they’re going to somehow move themselves into a position of comfort,’ which may compromise everything you’re trying to do for them from a seating and positioning standpoint. So they have to be comfortable.

“We’ve also used it a lot for visual field orientation: For people with fixed open hip angles, a combination of tilt and recline can get them to a more level view. Also, transfers, environmental access, and van entry: People getting into vans can be too tall, or the doors to short so they tilt back a little bit. Environmental access is huge.”

Moving from a client’s head to the client’s lower extremities, “A lot of times you have people who need a very low seat-to-floor height or a very compact chair, but they have interference with their front casters or they have interference with something up front,” Peterson said. “So they have to drive in 5° of tilt for ground clearance or for caster interference to still get the seat-to-floor height or the positioning they need.”

In fact, Peterson pointed out, people who don’t use wheelchairs often still like a bit of tilt. “Most able-bodied people in cars, if they have a power seat, like to feel tilted back a little to let gravity take a bit of the load off of us, for head control and gravity-assisted repositioning.”

That same tactic can apply to power chair users, some of whom are most functional and comfortable while sitting and driving in a slightly posterior tilt position.

A Matter of Degrees

What has also evolved over time is the understanding of what various ranges of tilt can accomplish.

“Over the years, we’ve said you need at least 45° of tilt to elicit adequate pressure reduction, to offload the ITs [ischial tuberosities] and the coccyx and move it somewhere else,” “Peterson said. “It has also been said that optimal pressure reduction occurs with a combination of posterior tilt and recline. Our thinking is evolving based on how often people are using their power positioning and how useful prescribed functions actually are.

“There are some studies out there, not as many as there should be, that show what an effective weight shift or a pressure reduction is. But there are also studies that show that most people don’t use all the tilt they’ve been prescribed. We have to look at why aren’t they using it? Is it just non-compliance? Is it someone who doesn’t want to be tilted that much? Is it someone who can’t, because professionally or school wise or just personally, they can’t spend 15 minutes an hour looking at the ceiling?”

The news that some consumers don’t use the full range of tilt on their chairs has resulted in some funding sources — notably, the Centers for Medicare & Medicaid Services — deciding that larger ranges of tilt aren’t necessarily needed and wouldn’t be as readily reimbursed. Peterson believes the rationale was “Well, people don’t use it, so we don’t need it.’ It’s kind of a slippery slope. Because I think you do need a certain amount of tilt in a well-prescribed, well-fitted, complete system for someone who really has pressure concerns. Twenty degrees of tilt is not going to do it. You have to have at least 40° to 45°, or 30° in conjunction with recline. And that’s where your clinician and your multi-disciplinary team to look at the whole picture is so important.”

That being said, Peterson added, “For some people, 20° of tilt is fantastic. It might give them the visual field, the balance, the stability that they need, or comfort. From a manufacturing standpoint, it also opens up possibilities for cost reduction; it opens up possibilities for reducing the complexities for a chair. A lot of times, if you’re only using 20° to 25° of tilt, you don’t need CG shift. You don’t need that big, sliding, 45° tilt mechanism. You can simplify a chair. It does have a cascading effect on the design of a chair.”

It gets dangerous, though, for funding sources to believe that lower ranges of tilt will work for everyone. “What concerns me,” Peterson said, “is that some people take advantage of a lower cost, and then we compromise the code for the people who really need that 45° of tilt for respiration, pressure reduction, etc.”

Tilt’s New Directions

Tilt no longer just means tilting backward. Anterior and lateral tilt have given seating clinicians and providers more positioning options to choose from.

“What I’ve found in my experience,” Peterson explained, “is that anterior tilt is used a lot for transfers and environmental access. We have a lot of people who use it just to put their feet on the floor for an assisted caregiver transfer. For something like that, you don’t necessarily need a big 45° of anterior tilt. You just need something that will lower the knees in relation to the hips.

“I’ve seen anterior tilt help with tone reduction for people who are hypertonic. If you put them in anterior tilt and you align their shoulders over their hips, their tone will actually decrease; they’re not always extending. And it can also help with visual field orientation: Instead of tilting them back, you tilt them forward.”

Part of the reason anterior tilt can facilitate environmental access is what it does for a client’s ability to reach: “I think what a lot of manufacturers are doing now is not just opening up the seat and back like a seat lift chair and lowering the feet, but also bringing everything forward. So you’re anteriorly tilting them, but you’re also moving the whole seating system forward, and that’s for things like reach and environmental access.

“So anterior tilt, especially now when you can do it without adding a lot of seat-to-floor height, it’s comfort, it’s pain reduction, it’s pressure. There are so many things that anterior tilt can do.”

Peterson called himself “a huge fan” of lateral, or side-to-side tilt. “We all move in different planes,” he pointed out. “So the ability to move yourself anterior, posterior, laterally — I’ve seen quite a few people who could not find comfort or could not reduce their pain or have a sustained sitting tolerance by just posteriorly tilting. They had to posteriorly tilt, laterally tilt, and just be able to move and take pressure off their bodies and spines throughout the day by moving in different directions.”

An Ongoing Evolution

The ability to move in different planes isn’t the only factor of tilt that’s evolving. Peterson said that while using recline with tilt had become extremely popular, it’s becoming more common for clinicians to opt for tilt only in some situations.

“They might do it because they want to simplify it for somebody,” he said. “They might do it because they don’t see an indication for recline. They might do it to reduce complexity. There are a lot of reasons for doing or not doing recline. It’s a solution, something you can pull out of your toolbag and use based on someone’s functional needs.”

Tilt has become very common on power chairs, but Peterson still advocates for a thorough assessment any time tilt is being considered.

“When I first started in this industry,” he noted, “tilt was a big deal. Now, it’s almost like ‘Everybody gets a tilt chair.’ I’m not saying it’s mis-prescribed or over-prescribed. I’m just saying sometimes people forget what you have to look at with a tilt chair. Now you’re getting systems with limited amounts of tilt, which may be perfect for someone. But it also might preclude you from adding to that chair in the future, and you have to look at things like the environment and battery size and all kinds of things when it comes to prescribing any power chair.”

And seating teams should also keep in mind that tilt can initially be disorienting.

“So many times, I put a therapist into a tilt [chair], a tilt/elevator, a tilt/recline, who’s never been tilted. And they grab onto that armrest like they’re about to go over,” Peterson said. “So you have to make sure that [clients] try it, because a lot of times, I think the reason you’re not seeing compliance is because of fear.

“Fear, lack of stability — a lot of people are getting out of their comfort level, especially people with tone. For people with cerebral palsy, fear and stability are big things you should assess for when you’re adding tilt. That’s why a lot of the electronics that people have now allow you to do things like proportional actuators, where you can tilt back at your speed instead of just being at one speed. You can limit how much tilt they have until they get comfortable. You can ease someone into it.”

As common as tilt is, Peterson said it’s not an option that should be automatically applied to every client.

“We try to paint it with a brush,” he said. “But it’s different. Rehab is not black and white; it’s very gray. And using tilt depends on dozens of different things on a case-by-case basis.”

“Tilt, while considered the simplest, most ubiquitous of power positioning functions, brings with it many things to consider, clinically, functionally and environmentally. We must not overlook the function and independence it can unlock, keep exploring and asking questions.”

This article originally appeared in the Jun/Jul 2020 issue of Mobility Management.

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