Blog posts of '2018' 'November'

Power Seat Functions  |  Elevation



Today we will look at the power seat function for elevation.  When we talk about elevation, we are referring to the raising up of the seat pan. You may also hear elevation referred to as seat elevate, or lift. Elevation can be beneficial to the user for functional, psycho-social, and physical benefits.

Let’s start with the functional benefits. The first benefit is the improvement of or independence with transfers.  Many people need to complete lateral transfers, where they slide across from their wheelchair to another surface such as the bed, toilet, or car. The difficulty with lateral transfers occurs when the user has to go from a lower surface to a higher surface. With seat elevate, most transfers out of the wheelchair can now be level or with a slight decline. The seat elevate can also be helpful with sit to stand transfers.

Another great function benefit of elevation is the improvement of the user’s vertical reach.  Often with sitting in a wheelchair, activities or tasks will become overhead.  This means that the user has to be able to reach overhead to complete this task or activity. Seat elevation may allow the user to increase their independence by completing overhead activities, and this can also lead to additional physical benefits. Overhead reaching could increase the user’s risk of shoulder impingement or perhaps the user does not have the strength in their arms or trunk to complete this task or activity, and with seat elevate this will no longer be a problem.  It’s not just about the shoulder.  There is also a large impact on the neck, or cervical spine, with constantly performing overhead activities or looking up throughout the users’ day. Seat elevation can reduce the potential problems of overhead reaching.


Finally, let’s touch on the psycho-social benefits. In a previous blog, I discussed this topic of being able to come to eye level with your peers. This seat elevation allows the user to come to eye level with their peers, promoting the user to be part of the conversation. Seat elevation gives the user the power to choose at what height they want to be.

There are of course are a few limitations even when the user is able to elevate.  Many times, I hear people talk about how with seat elevate they will be able to reach into all of the cabinets in their kitchen.  Now, this could be true, but for many users they can now get up to open the cabinet, and reach the first few items, but they will have difficulty reach all the way into the cabinet.  This is because the user is typically seated back and would have to lean forward in order to reach further into the cabinet. This is one example, but we can see that seat elevate while very beneficial for independence with some functional activities may not provide the solution for all tasks or activities. Last week we briefly discussed ActiveReach™ and its benefits with vertical reach. For those clients that are looking to get that further reach, have better access to their sink and kitchen, and to even further enhance their participation through active posture, ActiveReach™ that includes both elevation and anterior tilt might be the right choice.

Remember, not everyone will need seat elevate, but it is important to assess each individual and determine if the function is appropriate. 



Power Seat Functions: We want to hear from you!



Often when we think about power wheelchairs and their power seat functions, we think of tilt first. Tilt is a great power seat function, but depending on the power wheelchair and the manufacturer, power wheelchairs can have other power seat functions. These power seat functions may include: elevating leg rest, recline, standing, or the Permobil ActiveReachTM.  When we think about power seat functions and their use we might think about how these power seat functions allow the end user to be independent with their pressure management. We might think of power seat functions for health benefits like to assist with decreasing lower extremity swelling, but what about for functional independence and psychosocial benefits? While it is very important to remember that these power seat functions can help assist with pressure management and other health benefits, for the next couple weeks I want to focus on all of the power seat functions and how these functions help benefit end-users in their everyday life.
If you or anyone you know is using a Permobil power wheelchair and uses their power seat functions to increase their independence, get more involved in the community, return to work/school, or maybe just for fun we want to hear from you! Please email with your story and photo, so that we can include you in our next blog!
As a therapist it can be difficult to determine which power seat functions would be reasonable and necessary for my client to have on their power wheelchair.  It is important for us to consider the goals of the client and to determine if a power seat function could help to achieve this goal.  A great example of this is with ActiveReachTM.  Perhaps a client would like to increase their independence in their morning ADLs, activities of daily living.  Many times they might not be able to fully access their sink because the sink is too high.  Or maybe they can use elevate on their wheelchair to raise up closer to the sink, but they are sitting too far back in their chair to fully use the sink.  With ActiveReachTM, they are able to not only elevate, but to tilt forward to allow for full access of their sink.  Clients who couldn’t reach to brush their teeth in the sink before might be able to complete this activity independently because of this power seat function. This is just one example of how a power seat function can assist with independence.
Over the next couple weeks, I look forward to discussing how our users utilise their power seat functions.

Power Wheelchair Suspension: What you need to know and look for



Over the past 3 weeks we have talked about drive wheel configuration and some tips on how to decide which option is right for you. This week we are going to discuss power wheelchair suspension. The suspension can vary from chair to chair even within each manufacturer, but there are some key points that we should discuss.

Most power wheelchairs on the market are going to use compression springs for their suspension. There are two types of compression spring that are typically used: Linear and Non-linear.

Non-linear springs as seen in the photo below allow for changes in compressive load at different points of the range. What this means is that you can have the looser spring coils at the beginning phase to help with climbing over obstacles. The trade-off will be that you will lose some of the overall stability of the chair when not climbing. Many manufacturers will use one non-linear spring as their suspension.

Linear springs on the other hand allow for consistent stability throughout the compression range. For Permobil, these springs are also adjustable. The factory will set the suspension spring resistance based on the weight of the user and then the supplier or manufacturer representative will have the ability to further adjust depending on the needs of the user. With the Permobil M and F series, the suspension will be composed of multiple linear springs to achieve optimal traction and suspension.


Why does this matter? The shape and the coil distance have an impact on how a spring works and effects the user. The better the suspension, the greater the decreased forces on the end-user. This could lead to increased seating tolerance, pain management, spasticity management, and decreases the risk for loss of balance or position in the wheelchair. One of the biggest points that I think about is driving over any uneven terrain whether it is just a sidewalk or grass at a park. It is important that as the chair goes over each bump that this bump is not felt by the user or limited as much as possible. If each bump is transmitted up to the user, then the user will likely not maintain their seated position. They will also feel all this vibration. According to one study by Wolf and colleagues in 2007, this vibration can lead to many impairments including fatigue and pain.




The final thought that I believe is one of the most crucial points to make is that the suspension on the wheelchair should always be there for you or your client. We know how important suspension is and the negative impact that not having this suspension could be to our clients. Therefore, we need to make sure that the wheelchair will maintain its suspension in any position and over all surfaces. No matter what position the user takes the Permobil power wheelchair to, such as elevate, posterior tilt, active reach, or standing, the suspension remains the same. If you want to drive your wheelchair in elevate, active reach, standing, or other positions, you want to be sure that your suspension will continue to support you in those positions and not lock out.

It is important to know that each manufacturer will have different suspension set up on their chairs. As a client, therapist, or carer make sure you ask about the suspension to determine which option is best for you.




Part 2 Power Wheelchairs: 

Where is my Drive Wheel and Why Does it Matter?



The drive wheel on a power wheelchair is the larger wheel if you are looking at your wheelchair or client’s wheelchair.  The location of this drive wheel can have a large impact on how the power wheelchair drives and manoeuvres in different environments.

There are three main types of drive wheel configurations on power wheelchairs: front-wheel drive, mid-wheel drive, and rear-wheel drive. In this blog today, we will focus on mid-wheel drive.


The mid-wheel drive power wheelchair is the most recent technology developed for power wheelchair bases. It attempts to combine the positive aspects of front-wheel and rear-wheel drive into a hybrid product. Mid-wheel drive has many benefits.  The most well-known benefits being the small turning radius and intuitive driving.  The mid-wheel drive power wheelchair has the smallest 360  ĚŠ turning radius which can improve manoeuvrability for many individuals in their home or smaller spaces.  The intuitive driving benefit is due to the placement of the drive wheel. Typically, in the mid-wheel drive, the client will be sitting directly over the drive wheel, which is where the chair will turn/rotate from.  This axis of rotation being directly under the individual is what makes the driving intuitive or often people will say “easier to learn”.  It is important to remember that in some cases the mid-wheel drive may not line up directly below the client and therefore may lose some of that intuitive driving.  The final benefit to discuss for mid-wheel drive is the stability.  Because a mid-wheel drive wheelchair has 6 wheels on the ground, this chair will offer superior stability. This can be the case whether ascending, going up, or descending, going down, ramps or inclines.

While there are many benefits for mid-wheel drive power wheelchairs, there are a couple considerations when deciding if mid-wheel drive is right for you or your client.  In being a superior option for stability, the 6 wheels on the ground also means that more energy from the ground is transferred to the client. Imagine going over a bump, because there are 6 wheels you could feel that bump 3 times versus the 2 of the front-wheel drive.  This could potentially limit the ride comfort for the individual in the chair.  Luckily, depending on each manufacturer, we have suspension to help decrease the impact of having 6 wheels on the ground.  I LOVE talking about suspension and we will have a blog post coming soon to talk all about suspension in power wheelchairs and the importance of the suspension.  The other comment I hear about mid-wheel drive power wheelchairs is the potential for “high centring”.  This term is used to describe when the centre drive wheels lose traction and may not be able to move in certain situations. This is particularly a risk with uneven terrain and was previously the biggest disadvantage of the mid-wheel drive power wheelchair. However, depending on your manufacturer, newer technologies and suspension can compensate and have greatly decreased the risk of this occurring.

The mid-wheel drive power wheelchair is the most popular drive wheel configuration and for good reason.  As technology continues to progress, the mid-wheel drive continues to have greater benefits with less limitations.

Keep in mind that not everyone will benefit from the same drive wheel configuration and it is important to ask questions and complete an evaluation to determine which drive wheel would be best for you or your client.