Comfort, postural support and/or maintenance, pressure management and function in a wheelchair are all influenced by the person’s ability to physically move themselves by weight shifting and/or repositioning. If the person is unable to independently perform these movements, the use of power positioning devices such as tilt, recline and stand may be added to a power base to facilitate weight shifting or repositioning. The effectiveness of the addition of a power positioning device to a power wheelchair is related to if and how the device is used throughout the person’s day. The studies below have examined how power tilt is used during the day, tracking parameters such as frequency and amplitude of position change.
In their 2009 study, Sonenblum et al. monitored the daily use of power tilt with 16 participants over a one-two week period of time with a secondary purpose of determining if regular pressure relieving tilts (PRT) were being used. PRT were defined as tilts greater than 30° for more than one minute, performed once per hour. The findings indicated great variability in wheelchair and tilt use between participants. This study also found that most participants varied greatly in how much tilt they used, and tilt positions changed frequently throughout the day even if it was only between two different positions within a small range. Participants identified the most common purposes for using tilt as being for comfort/discomfort/pain and rest/relaxation.
In a separate study, Sonenblum and Sprigle (2011a and 2011b) found similar results to the above study in regard to wheelchair occupancy and great variability in the amplitude, duration and frequency of tilt use. All studies found that people spent the majority of time in small to medium tilt position with infrequent pressure relieving tilts (i.e. greater than 30° of tilt). The size of the tilt change (magnitude) was reported to be predominantly small (0-14°) but with a range of frequencies in tilt use, suggesting that some people make small changes in position using tilt but are not using the full range of position changes available in the devices.
There is level 5 evidence (three observational studies, Sonenblum et al. 2009, Sonenblum & Sprigle, 2011a and Sonenblum & Sprigle 2011b) suggesting that on a daily basis, power positioning devices are used for a variety of reasons but predominantly in the small ranges of amplitude, and with great variability of frequency and duration
Patterns of use for power positioning devices are variable but typically in small ranges of amplitude, with the primary reasons for use being discomfort and rest.