Putting Evidence into Practice for Power Positioning

Last month's Clinical Corner article addressed The Evidence on Tilt, Recline and Elevating Leg Supports. The article reviewed the clinical benefits of tilt, recline and elevating leg supports and summarized the research findings with respect to angles required for redistributing and relieving pressure through tilt and/or recline. This month, let's look at the practical application of power positioning. For what reasons do individuals use their power positioning features? How often are individuals completing pressure relieving movements through power positioning? How can technology assist individuals with pressure management?

Several studies have looked at the way in which individuals use power positioning systems. While funding sources across Canada typically fund power tilt and power recline for pressure redistribution and relief, individuals who use power positioning features have reported that they most commonly use their repositioning system to increase comfort, rest, decrease discomfort, relax or to decrease pain.^1,2,3,4

One study found that individuals who used the power tilt component to rest and decrease pain used large amplitudes of tilt (from 31 to 45 degrees, as defined by the study authors).¹ For the individuals in the study who identified that they used power positioning for pressure redistribution, the majority used small tilt amplitudes (from 0 to 15 degrees) and fewer used middle tilt amplitudes (from 16 to 30 degrees).¹ It is noteworthy that tilt must be greater than about 25 degrees to achieve pressure relief and/or tissue perfusion at the ischial tuberosities,⁵ which means that for individuals who identify using their systems for pressure management, the reported tilt range is not sufficient for this purpose. Another study had similar findings, in that study subjects tended to use small tilt-in-space angles, less than 20 degrees, throughout daily use.³

In terms of frequency of repositioning, another study found that the median study participant tilted once every 27 minutes.⁴ Pressure relieving tilts, defined as a tilt of greater than or equal to 30 degrees for greater than or equal to one minute, however, were performed once every 10 hours, on average.⁴

Study subjects have reported satisfaction with their use of power positioning.^1,6 From a clinical perspective, however, if the frequency of change of position and amplitude of postural change is not sufficient for pressure management, advancements in technology may assist in changing the repositioning behaviours of individuals. For example, some power wheelchair models have alerts that can be programmed into the system to remind individuals to perform a pressure relieving movement. This is akin to the popular wearable fitness tracking devices that provide alerts to move every hour to obtain a certain number of steps within the hour to limit prolonged sitting.

In power wheelchairs, the alert includes an audible and visual reminder to the individual to use the power repositioning system. If a pressure relieving movement is not completed, the alert will sound again, providing another reminder. The frequency of the reminders can be programmed specific to an individual's needs. It is also possible for the technology to record the number of times the pressure relieving movement has been successful in response to the alerts, creating an electronic log. With a client's consent, a clinician may have access to the electronic log, which can provide useful information related to pressure management specific to the individual.

Technology also can be used to program "memory" seating for power positioning to facilitate the tilt and/or recline range required for pressure relief. If we think of the example from vehicles, some models of cars have the ability to "remember" the preferred position of a driver and the press of a button will return the seat position to what has been set for the individual. A similar concept is available in some power wheelchair models. This means that rather than having to hold a joystick or other input device while the actuator of the power positioning moves the seating system through a range to a desired endpoint, one touch of a button or toggle will activate the actuators to take the seating system to the desired position or return it to a programmed upright position. This assists in ensuring that the tilt and/or recline ranges used by individuals meet the requirements for pressure redistribution and relief. For example, one press of a button could take an individual to a pressure relieving position of 35 degrees of tilt with 120 degrees of recline, with the leg supports elevated to 145 degrees. Although memory seating functions come with factory pre-set angles and end ranges, it is possible to program the power positioning functions to what is required for, and tolerated by, an individual.

Advancements in technology allow individuals to continue to use power positioning features for comfort, rest and pain reduction, in addition to promoting the frequency and tilt/recline ranges required for pressure management.

References

1. Lacoste, M., Weiss-Lambrou, R., Allard, M., & Dansereau, J. (2003). Power tilt/recline systems: Why and how are they used? Assistive Technology, 15(1), 58-68.
2. Frank, A.O., De Souza, L.H., Frank, J.L., & Neophytou, C. (2012). The pain experiences of powered wheelchair users. Disability and Rehabilitation, 34, 770-778.
3. Ding, D., Leister, E., Cooper, R.A., Cooper, R., Kelleher, A., Fitzgerald, S.G. & Boninger, M.L. (2008). Usage of tilt-in-space, recline, and elevation seating functions in natural environment of wheelchair users. Journal of Rehabilitation Research & Development, 45, 973-984.
4. Sonenblum, S.E., & Sprigle, S. (2011). Distinct tilting behaviours with power tilt-in-space systems. Disability and Rehabilitation: Assistive Technology, 6, 526-535.
5. Dicianno, B.E., Lieberman, J., Schmeler, M.R., Schuler P. Souza, A.E., Cooper, R., Lange, M., Liu, H., & Jan, Y.K. (2015). RESNA position on the application of tilt, recline, and elevating legrests for wheelchairs literature update. Retrieved from http://www.resna.org/
6. Ward, A.L, Sanjak, M., Duffy, K., Bravver, E., Williams, N., Nichols, M., & Brooks, B.R., (2010). Power wheelchair prescription, utilization, satisfaction, and cost for patients with Amyotrophic Lateral Sclerosis: Preliminary data for evidence-based guidelines. Archives of Physical Medicine and Rehabilitation, 91, 268-272.