Study of Home Use of the Jaco Robotic Manipulation Device by Individuals With Tetraplegia (TETRAJACO)

For individuals with complete loss of active and functional upper limb motor abilities required to perform grasping tasks, the restoration of grasping function is a critical priority.

In this context, emerging technologies-and more specifically robotics-offer promising solutions for compensating upper limb motor impairment. The target population primarily consists of individuals with functional tetraplegia , resulting either from high-level cervical spinal cord injury or from severe neuromuscular or peripheral neurological disorders. In the vast majority of cases, these individuals are dependent on powered wheelchairs.

In cases of high cervical spinal cord injury, individuals with tetraplegia present extensive upper limb motor impairment. As a result, they are not eligible for functional reconstructive surgery aimed at restoring elbow extension, wrist extension, or finger opening and closing. Such surgical procedures are generally reserved for individuals with spinal cord injury at or below cervical level 6 (C6).

Neuroprosthetic systems based on functional electrical stimulation (technology that activates muscles using electrical impulses) experienced significant development during the 1990s and early 2000s. Their principle relies on the stimulation of key muscles located below the level of the lesion, provided that the second motor neuron (the peripheral nerve connecting the spinal cord to the muscle) remains intact. These systems enabled active control of the wrist and fingers by stimulating muscles via multiple implanted cables connected to epimysial electrodes (electrodes positioned on the surface of the muscle). However, these devices were withdrawn from the market for economic reasons, leaving many patients without access to this therapeutic option and in a situation of complete dependency on caregivers.

Even for individuals with low or intermediate tetraplegia, or incomplete lesions, life events such as accidents, secondary illnesses, or aging may lead to additional disability and increased dependence. The need to preserve energy or limit physical effort may justify, even in individuals with residual motor capacities, the use of assistive technologies for manipulation.

Assistive robotic manipulation is currently based on three main categories of devices:

Wheelchair-mounted robotic arms Robotic arms mounted on mobile platforms Single-task robotic devices

These systems aim to enable users to perform manipulation tasks either autonomously (full control by the user) or semi-autonomously (selection of pre-programmed tasks). This applies regardless of whether the task is performed within the user's immediate environment or at a distance, and regardless of the interaction modality.

Among these technologies, wheelchair-mounted robotic arms have benefited the most from technological advances over the past 15 years and from more advanced industrial development compared to other robotic devices. Their development is based on two key principles: first, to provide a single robotic solution capable of replacing multiple assistive devices and human assistance; and second, to allow users to carry a substitute for their impaired upper limb (i.e., the robotic arm) into environments that are not specifically adapted.

Historically, the MANUS robotic arm was one of the leading systems in this field. Developed and marketed in the 1990s by a Dutch company, it demonstrated the feasibility of integrating robotics into the functional environment of users and caregivers. Public health authorities supported its deployment by equipping residential facilities and providing shared maintenance services, thereby contributing to the development of an assistive robotics ecosystem.

The MANUS system, now called the I-ARM, is a robotic arm with six degrees of freedom (independent axes of movement allowing three-dimensional motion) and a two-finger gripper. It can be mounted on a wheelchair seat or armrest. Despite improvements in weight, its control interface remains based on step-by-step commands, which are not intuitive and are relatively difficult to use. Control typically relies on a keypad or a two-dimensional joystick for three-dimensional movements. Pre-programmed menus allow more targeted control of the robotic arm.

More recently, the JACO robotic arm, developed by a Canadian company, has emerged as one of the most promising systems in terms of functional benefit and ergonomics. It introduces several technological improvements:

Use of lightweight materials such as carbon fiber Open and customizable control interface adapted to user needs Integration into the powered wheelchair control system Compatibility with environmental control systems (systems that allow users to interact with their surroundings, such as controlling devices in their home) Extended reach (approximately 90 cm) and six degrees of freedom

These features allow users to access objects located on the ground, directly in front of them, or above head level. However, effective use still requires significant user involvement in spatial positioning and grasping strategies. The availability of configuration software allows adaptation of the control interface to the user's motor impairment and the use of graphical interfaces to facilitate arm movement.

Other robotic arms remain confined to research laboratories, either because they have not been developed for commercialization or because they fail to meet ergonomic and functional requirements. These devices are often heavy, bulky, noisy, or impractical, despite their promising technical capabilities.

Published studies consistently highlight the needs of individuals with tetraplegia in terms of assistive technologies. However, no prospective study has evaluated the long-term use of robotic arms in the home environment. Limited evidence suggests improvements in functional independence, quality of life, and reduction in caregiver assistance.

The priority daily activities identified by users include:

Eating and drinking (grasping food, bringing it to the mouth, cutting food, opening containers) Personal hygiene and facial care Dressing and undressing Reaching, grasping, manipulating, and releasing everyday objects located at different heights

Despite these expectations, it is essential that users remain in control of robotic devices and retain decision-making authority. The usability of such technologies is also closely linked to the existence of a structured ecosystem capable of managing the entire process, including design, acquisition, follow-up, and maintenance. Currently, such an ecosystem remains insufficiently developed, which limits user confidence and adoption.

Successful adoption requires independent evaluation of usability and perceived usefulness in real-life or near-real-life environments. In addition, access to these technologies must be supported by appropriate funding mechanisms, and maintenance services must be reliable and responsive. Technical failure of such devices may result in immediate loss of independence for essential daily activities.

The development and implementation of assistive robotic technologies must also consider ethical principles, including functional benefit, quality of life, equitable access, user information, consideration of individual needs and expectations, respect for user preferences, and cost-effectiveness.

Previous findings suggest that the use of the JACO robotic arm may significantly reduce caregiver intervention time, potentially by approximately 41%, corresponding to about 1.5 hours per day.

The present study aims to evaluate the use of the JACO robotic arm in the home environment, focusing on its real-life use, its integration into daily activities, and its impact on functional independence, as well as psychological, social, and family well-being.