RESNA 26th International Annual Confence
The purpose of this study was to examine exertion and fatigue in people with multiple sclerosis (MS) while performing upper extremity (UE) tasks sitting in custom and off-the-shelf seating systems. Thirteen subjects participated in completing a sequence of UE tasks sitting in an off-the-shelf and a custom seating system. Perceived exertion and fatigue were recorded before and after each sequence of tasks, and a questionnaire was completed at the end of the study. Paired samples t-tests showed that there were significant differences both in perceived exertion and fatigue within the specific seating system and between the two seating systems. This study endorses use of a custom seating system for people with MS to decrease exertion and fatigue while performing UE tasks.
In the management of the progressive impairments and resulting disabilities experienced by people with MS, power mobility aids are frequently provided to assist with household and community mobility (1). Clinical experience supports that motorized scooters are a common first choice of patients and care providers, as scooters are perceived to represent less disability, be more acceptable to the general public and be less costly. However, scooters represent an off-the-shelf seating system affording less postural correction and pelvic and trunk support than a custom seating system.
To date, there has been little research into the functional differences between an off-the-shelf seating system and a custom seating system. MS is usually a progressive disease with resultant fatigue, muscle weakness, and trunk instability (2). Provision of the appropriate seating system, once the need for power mobility is established, may enhance the person's short term and long-term function by maintaining pelvic and trunk stability. In addition, it may represent a financial savings as the custom seating system can be modified to accommodate the changing needs of the person with MS.
Twelve male veterans and one female veteran with MS volunteered to participate in this study. Prior to participation, all subjects provided written informed consent. All used power mobility as their primary mode of mobility. The number of months using power mobility ranged from 1 month to 180 months. Eleven of the subjects used motorized wheelchairs (wc); one subject used a scooter and one subject had both a motorized wheelchair and a scooter. The same study scooter was used for all subjects. Subjects either used their own power wheelchair with custom seating or one was provided in which the seating was customized to that study subject. Each subject provided demographic information and then completed the sequence of UE reaching tasks while seated in the two seating systems. UE tasks are shown in Table 1. The subjects were randomly assigned to begin testing in either the custom seating system or the off-the-shelf system. The tests were performed with the power wheelchair or scooter placed on a 10-degree tilted surface, with the dominant-hand side highest in order to challenge the trunk's endurance and strength. There was a 30-minute rest period between tests in each seating system. There was a 10-minute period of acclimatization when testing a subject in an unfamiliar seating system.
Subjects were asked to rate their level of exertion using the Borg Perceived Exertion Scale and their fatigue using the Fatigue Impact Scale (visual analog scale (VAS)) before and after each testing sequence (3). A questionnaire of four questions was completed after all of the upper extremity reaching sequences were completed, as shown in Table 2.
Descriptive statistics (means, standard deviations, frequencies) were used to examine characteristics of the data. Perceived exertion and fatigue scores were compared between seating systems, as well as before and after each specific seating system using paired samples t-test. In addition, a repeated measures ANOVA was completed to determine change in perceived exertion and fatigue over time.
Motorized scooters are a common first choice of power mobility devices of people with MS and their care providers because scooters are perceived to represent less disability, be more acceptable to the general public, and be less costly. Our study looked at the perceived experiences by people with MS in a motorized scooter with an off-the-shelf seating system and a power wheelchair with a custom seating system for a sequence of standardized UE tasks. Our data demonstrated that that regardless which device the subject started the testing sequence in, their perceived exertion and fatigue significantly increased over the time of testing. Therefore, the sequence of tests represented activity that was overall fatiguing. Our data supports that subjects' experiences with the off-the-shelf seating system required more exertion and was more fatiguing than with the custom seating system. At the completion of the study, subjects' responses to the questionnaire validated the fatigue and perceived exertion data, supporting that subjects felt more stable with greater reach in the wheelchair and that tasks from the wheelchair were easier to perform. This study endorses the hypothesis that while completing UE tasks, the person with MS experiences better pelvic support and better UE function with less fatigue while sitting in a custom seating system.
This study was funded through the Wheelchair and Related Technology Center of Excellence, Pittsburgh Veterans Affairs Healthcare System, Pittsburgh, PA. The motion analysis was performed at the Human Performance Laboratory, Physical Therapy Program, University of Colorado Health Sciences Center, Denver, Colorado.
Donna Jo Blake,
Denver Veterans Affairs Medical Center, PMRS (117)
1055 Clermont St.
Denver, Colorado 80220