Assessment of Safety and Acute Effects of a Lower-limb Powered Dermoskeleton in Patients With Neuromuscular Disorders

Patients with neuromuscular disorders display different type of symptoms depending on the type of pathology. Diseases like facioscapulohumeral dystrophy (FSHD), limb-girdle muscular dystrophy (LGMD2b), sporadic inclusion body myositis (SIBM) or Pompe disease (PD) are characterized by severe muscle weakness leading to reduced functional capacities. This leads to a dramatic decrease of quality of life (e.g. reduced autonomy/participation, social isolation, depression) associated with increased fall risk and complications (e.g. trauma, cardio-vascular issues, trauma, chronic pain, loss of bone mass, and weight gain).

However, a residual of level of strength and residual function may be maintained over years, even at severe disease stages allowing transfers and ambulation. However, the maintenance of this type of activity is often associated with substantial compensatory movements, leading to high load on joints, orthopedic complications, and high fall-risk.

In contrast to traditional passive assistive devices such as orthoses, powered assistive devices, frequently termed dermo- or exoskeletons, have a very high potential for compensating muscle weakness and regain mobility and independence. Devices such as the ReWalk® or the Indego® use rigid structures, in parallel to the user's legs, and electric motors to stabilize the human against gravity during standing and walking. Thus far, these systems have been used mostly in clinical environments for gait rehabilitation in neurological conditions (e.g. spinal cord injury, post-stroke syndrome). Their weight, which can range from 13 to 48 kg, can make them difficult to use and transport, thus limiting their applicability beyond clinical environments. However, for assistive devices to be used in everyday life, they must provide assistance across activities of daily living (ADLs) in an unobtrusive manner.

Wearable motion assistance systems, especially those dedicated to lower limbs are highly promising for ambulant patients with neuromuscular disorders (e.g. FSHD, LGMD, SIBM or PD). In these conditions, the prevalence of lower-limb muscle weakness, especially in proximal muscle groups (i.e. providing strength/torque to knees) is very high. In 2014, Bouyer et al. introduced a powered knee exoskeleton, a wearable device designed to increase movement capacity during different task (6MWT, TUG, Stair Test…). This dermoskeleton has been created to enhance and augment mobility through biomechanical assistance using motorized orthopedic supports controlled by computers. This device is mainly based on the interaction of three components: 1) a network to sense the biomechanical characteristics of a specific user; 2) software for movement recognition to characterize gait phases and movement status; and 3) software to control the dermoskeleton joint mechanism to optimize biomechanical assistance. McLeod et al. demonstrated that the KeeogoTM increased performance on the 30STS, SCT and improved motor control, postural control and movement kinetics during the STS task in a chronic stroke survivor with significant hemiparesis. Recently, McGibbon et al. proved that the KeeogoTM is able to deliver an exercise-mediated benefit to individuals with MS that improved their unassisted gait endurance and stair climbing ability. However, the effect of the device on movement parameters and user perception must be specifically investigated, especially considering neuromuscular patients' specificities. We believe that ambulant patients with such disorders may highly benefit from a system that provides mobility assistance like the KeeogoTM. The use of such a device has the potential to shift the loss of ambulation and/or transfer abilities to an higher age and might mitigate disease progression as well as the occurrence of complications. Whether the KeeogoTM may be safe, usable, and efficient in ambulant patients with neuromuscular disorders, remain to be specifically investigated.