“Benefits for PWC users include better postural alignment and weight distribution. These benefits are of great importance in the preservation of skin health and pressure distribution”

Research led by Alberto Esquenazi, MD, the Director of the Gait & Motion Analysis Laboratory at MossRehab, is the first to study the effects of joystick control position for wheelchair users. Initial data utilizing pressure mapping, dynamic electromyogram, 3-D kinematics and patient subjective report, shows central driving has multiple physiological benefits over traditional armrest mounted joysticks.

Controls_PWCMossRehab is a member of the Einstein Healthcare Network, the largest independent medical center in the Philadelphia region.

Dr Esquenazi reports on his research: “Traditional Power Wheelchairs (PWCs) use an armrest mounted joystick controller. Such devices force a change in body posture and weight distribution with deleterious effects over time. When operating a PWC with an armrest mounted drive control, the user often leans on the armrest where the joystick is mounted in order to improve drive control. The long term consequences for wheelchair users manipulating a joystick with repetitive motions while seated in awkward postures will often present in the form of muscular skeletal conditions, and be accompanied by pain attributed to inappropriate seating support.”

Conservative estimates of the number of people worldwide who use a PWC exceed one million. The report suggests that almost all users drive with joysticks positioned on their armrest requiring a compromise in posture to do so and indicates the armrest location is a cause of muscular skeletal conditions for PWC users.

The study says that prolonged sitting in a wheelchair exposes a person to a high risk of dangerous and debilitating pressure ulcers and indicates the risk is compounded by driving a PWC with an armrest mounted joystick. Armrest driving causes a shift in weight distribution and an increase in pressure on the same side of the posterior where the joystick is mounted on the PWC. The study suggests that an unbalanced posture caused by lateral joystick location is likely a leading contributor to ulcer formation, especially for people with disabilities such as spinal cord injury, stroke and multiple sclerosis which compromises one’s protective sensation.

The Active Controls Center Drive System used in the study was developed to allow central mounting for PWC joysticks and alternative drive controls. The system is modular and easily removed for access to the seat. Bilateral gel pads provide secondary support surfaces for the hands, wrist and lower arms to facilitate drive control. Together with the PWC armrests, the Active Controls central mounted joystick platform and gel pads support the upper body to encourage a balanced posture and weight distribution, while requiring less muscle force to operate the joystick.

Dr Esquenazi adds, “Using a centre position control, the operator is in a more intuitive and functional position that aligns the visual field with the centre of the chair’s travel path. Operating a PWC with its controls in a centered position will often increase the efficacy of the user. Subjects sit more erect and use less force to drive central mounted controls. They report more comfort while driving them and an improved sense of control over the wheelchair. Other benefits for PWC users include better postural alignment and weight distribution. These benefits are of great importance in the preservation of skin health and pressure distribution, allowing seating products to maximize their function.”

You can see more about the study HERE

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