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What is the “Memory Seating” function on a powered wheelchair?

Numerous studies have demonstrated the benefits of standing for wheelchair users. There are anatomical, physiological and social benefits, all of which can improve participation in activities of daily living.1

However, there are different types of sit-to-stand systems on wheelchairs. Some are simple mechanical options - generally on manual wheelchairs - and others are electrically powered, more typically seen on powered wheelchairs.  These systems have varying degrees of technical sophistication. A basic powered seating system (even one with recline, tilt and sit-to-stand) may not be suitable for many individuals due to range of motion, pain or health needs. These users require a more specialised series of seat movements, i.e. ‘kinematics’, for safe and comfortable use. If there is not a good biomechanical alignment with the seat because of the intermediate positions when moving between seating positions, the effect of having powered seating could be harmful rather than beneficial.

In order to respond to these needs, advanced powered seating enables the highest level of consistency and configurability. In the Sunrise Medical range, this is available in our Sedeo Pro Advanced seating system, available on the Q700 series of powered wheelchairs. The system has programmable memory positions with a wide range of adjustments, to return to the same position, every time. This is the "Memory Seating" function. It is also possible to define one of the saved Memory Seating positions (for example the ‘relax’ or ‘lie down’ setting) as an intermediate position. This allows the system to follow the same sequence of movements in between positions every time. In this way we have maximum configurability of the kinematics for moving forward, upright or back in space according to the specific requirements of the wheelchair user. This is referred to as the “trajectory”, or sequence, of the memory seating.

How does a Memory Seating trajectory work?

On the powered standing Q700Up M and Q700Up F (midwheel and front wheel drive) models the memory positions are:   

  • Standing
  • Relax
  • Lie-down
  • Anterior tilt, or ‘transfer’ position
  • Sitting
  • Memory 5, a free programmable position 

They are the same on the Q700F and Q700M with Sedeo Pro Advanced seating, but without the standing function.

Once the mechanical adjustments have been made to suit the user's body shape, and the Memory Seating positions have been established, it is possible to set the Memory Seating trajectory to move between significant seat position changes. The principle is simple: all you have to do is set the chair's electronic parameters so that it passes through one of the memory positions before reaching the final position. This creates a defined trajectory. For example, starting from the Sitting position, the wheelchair passes through the Lie-Down position before reaching the Standing position. 

How does a specific Memory Seating trajectory setting benefit the wheelchair user?

The transition through a personalised intermediate position has a dual purpose. One is that it maintains the body's position in the chair for stability when returning to drive. For example, when moving in and out of anterior tilt, an intermediate position like the tilted and reclined “Relax” option helps keep the pelvis positioned back on the seat. This also can enhance comfort and reduce friction on the skin.

In fact, in a traditional sit-to-stand seat movement, despite appropriate mechanical adjustment of the knee supports, there is often a forward slide when moving into standing.2 This can lead to a displacement or tilting of the pelvis, accompanied by shearing, joint or muscular stress and excessive pressure on the knees and shins. The same thing can happen when returning the previous sitting position.

By moving to the Lie-Down position first, the chair will lengthen and therefore extend the user's body, then tilt the seat forward in the same way as a standing table used in rehabilitation. This makes it possible therefore to stand up slowly and progressively

In the Relax position, the chair tilts the seat backwards and opens the backrest, while compensating for the leg rest. In this way, the user is well positioned fully back in the seat. As the seat tilts forward, the wheelchair gradually unfolds, allowing the user to reach a standing position in one fluid motion. Use of the trajectory function for Memory Seating positions provides comfort but, more importantly reduces the risk of skin breakdown by maintaining posture during the raising process.3

It is even possible to choose one Memory Seating trajectory for raising and another one for lowering. Note that once a trajectory has been established for raising, the wheelchair will always pass through this intermediate position whatever its original position. For lowering, the seat movement action may vary depending on certain electronic parameters.  These can be modified using the programming software.

Direction of forces when moving into standing or anterior tilt.
Direction of forces when moving into standing or anterior tilt.

Are the Memory Seating positions themselves customisable?

Yes! Full programmability is a key feature of the memory positions. The preferred position can be saved at the touch of a button.  This way the factory setting is overwritten and the chair will always adopt the position (standing, sitting, relax, etc.) best suited to the user.  Memory Seating positions can also be renamed or deleted if certain ones are not required.

Want to know more about how to programme Memory Seating functions? Read this article explaining the procedure. 

Clinical Support Information Citations

1. Arva, J., Paleg, G., Lange, M., Lieberman, J., Schmeler, M., Dicianno, B., ... & Rosen, L. (2009). RESNA position on the application of wheelchair standing devices. Assistive Technology, 21(3), 161-168.

2. Kobara, K., Fujita, D., Osaka, H., Ito, T., & Watanabe, S. (2013). Influence of distance between the rotation axis of back support and the hip joint on shear force applied to buttocks in a reclining wheelchair’s back support. Prosthetics and orthotics international, 37(6), 459-464.

3. Dicianno, B. E., Arva, J., Lieberman, J. M., Schmeler, M. R., Souza, A., Phillips, K., ... & Betz, K. L. (2009). RESNA position on the application of tilt, recline, and elevating legrests for wheelchairs. Assistive Technology, 21(1), 13-22

Alexandre Marechal - Sunrise Medical France

Alexandre Marechal - Sunrise Medical France

OT - Key Account Manager

As an occupational therapist specializing in the treatment of spinal cord injuries, Alexandre joined the Sunrise Medical France team as a product specialist before taking up his current position as Key Account Manager. His aim is to use the experience he has gained in his various roles and his vision as a therapist to offer quality advice and support to distributors, prescribers, and clients.