Why Joystick Location Matters for Power Wheelchair Users

ELKINS PARK, PA (January 7, 2016)—Ground-breaking 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, 3D kinematics and patient subjective report, shows central driving has multiple physiological benefits over traditional armrest mounted joysticks.

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.”

Over One Million People at Risk of Developing Muscular Skeletal Conditions

A PWC provides indoor and outdoor mobility and a positive impact on user self-esteem, participation in social activities, and access to jobs and education. Conservative estimates of the number of people worldwide who use a PWC exceed one million. Almost all users drive with joysticks positioned on their armrest requiring a compromise in posture to do so. The MossRehab Study indicates the armrest location is a cause of muscular skeletal conditions for PWC users.

Unbalanced Body Posture and Weight Distribution Are Contributors to Pressure Ulcer Formation

Prolonged sitting in a wheelchair exposes a person to a high risk of dangerous and debilitating pressure ulcers. The MossRehab study 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. 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. 

Patented Central Mounting System Now Available for Joystick Controls

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 center position control, the operator is in a more intuitive and functional position that aligns the visual field with the center 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.”

Because of the many operational benefits reported for the Center Drive System, therapists are discovering a greater number of their patients are successful drivers with central controls. The awkward posture and additional muscle force required to drive a PWC with a joystick at the end of an armrest prevents some people from using one. Others who have the range of motion and strength to operate a PWC lateral joystick find them difficult to navigate driving their PWCs in crowds, which limits their family and social activities. Central driving controls makes operating a PWC easier and more enjoyable while contributing to greater independence and mobility for new users as well as many existing drivers.

Medical Justifications for Bilaterally Supported Central Controls

The MossRehab research study provides prescribing clinicians with the following clinical benefits of the Active Controls Center Drive System for their clients.

• Improved posture
• Better pressure distribution
• Intuitive proprioception
• Improved wheelchair operation
• Reduced fatigue

Side Mounted Steering Used in the First Automobiles Quickly Evolved to a Centered Steering Wheel

The first automobiles built before 1900 used steering tillers mounted at the side of the driver in front of the two person seat. The body centered steering wheel was a breakthrough which revolutionized automobile design making them easier and safer for more people to drive.

Seventy years ago when the first power wheelchair was developed, it used an armrest mounted joystick control. Although sophisticated PWC seating products, wheelchair ride comfort and support, plus indoor-outdoor performance are all standard issue today for people with complex disabilities, the joystick is still mounted on the armrest. The MossRehab study indicates its position is the cause or contributor of muscular skeletal conditions and pressure ulcers which remain a lingering reality for all PWC users, not just those with complex disabilities. The economic and human costs to treat these conditions are staggering.  

Body centered driving of other motorized vehicles is the norm. It’s how we learn to ride bicycles and drive cars. The MossRehab wheelchair drive control location study now provides the industry with medical justifications why wheelchairs should be the same.

Read the full report here. Visit activecontrols.com and mossrehab.org for more information.