Use of powered mobile arm supports by people with neuromuscular conditions.

INTRODUCTION Neuromuscular conditions (NMCs) are a prominent cause of bilateral upper-limb weakness. In many of these conditions, the proximal musculature is affected first and the distal last, resulting in a relative preservation of hand function while the ability to lift the limb and make use of that function is lost [1]. The combined prevalence of the four commonest NMCs that cause proximal upper-limb weakness--Duchenne, Becker, facioscapulohumeral, and limb girdle muscular dystrophies--was estimated at 21.8/ 100,000 in a recent study of population prevalence in northern England [2] and so represents a notable proportion of the population. Mobile arm supports (MASs) are a type of assistive technology that enable people with NMCs to make functional use of their hands [3]. They do this by supporting the limb against gravity so the person can use his or her reduced strength to move the limb at the elbow and wrist. Some of the more recent devices have been powered, such as by adjusting the height of the device electronically to allow vertical movement (Neater Arm Support, Neater Solutions Ltd; Buxton, United Kingdom). While these devices have been in use for many years, no qualitative studies have examined user experiences and perspectives of any type of MAS. There are studies using quantitative designs. The largest MAS study was by Haworth et al. in 1978, who investigated a non-powered MAS that operated using a design based on a plastic bearing and swivel arm [4]. All 124 patients fitted in a 6 yr period were included for the retrospective part of the study, and 77 of them participated in a cross-sectional postal survey. They found that 2 of 18 fitted as outpatients and 40 of 106 fitted as inpatients had stopped using their MASs by 12 mo. Two unselected prospective studies on nonpowered MAS use in those with NMCs include before and after comparisons using report, interview, and medical chart data [4-5]. Yasuda et al. noted that 18 of 29 patients were unsuccessful in their use, although the mean length of use in that group was still 2 yr [5]. The development of the Jaeco/Rancho multilink MAS (JAECO Orthopedic; Hot Springs, Arkansas), which includes use of a power-assist arm-height adjuster and arm retractor, has been described and the device developed with the assistance of a user group [3,6]. A series of four uncontrolled studies evaluating the Armon arm support (Armon, Microgravity Products BV; Rotterdam, the Netherlands) also provides feedback for future prototype development [1,7-9]. The Armon arm is a nonpowered MAS that operates using a statically balanced spring mechanism that can be electronically adjusted according to the load. The first of these studies employed a single-group, cross-sectional design in which MAS users were observed completing a series of set tasks or activities of daily living (ADLs) [7], followed by two prospective cohort studies, with possible overlap in participants, reporting on activities completed [1,9]. Finally, a cross-sectional study used a validated outcome measure, the Quebec User Evaluation of Satisfaction with Assistive Technology, and a quantitative interview technique, the Individually Prioritized Problem Assessment [8]. This study showed that users could perform several activities felt to be important by them, noted an average level of content with the device, and highlighted some difficulties with the time taken to supply the MAS and practical difficulties in use. Overall, these studies show that MASs allow users to perform several daily tasks, note specific tasks that can be performed using MASs, demonstrate that type and severity of muscle disease affect use, and provide some insight into difficulties with design and supply through individual comments. The studies also provide information on the technical aspects of design and use. However, they do not include studies of powered MASs (PMASs) or systematically explore the NMC user experience of benefit and problems that would provide us with wider insight into the effects of PMASs on daily life and participation and the range of problems with their use. …