Exoskeletons in MS rehabilitation are ready for widespread use in clinical practice: Yes

People with multiple sclerosis (MS) show several motor, sensory, and cognitive dysfunctions, which need to be dealt with specific neurorehabilitation approaches. Walk recovery still is the primary goal for these patients, because achieving independent ambulation is a major contributing factor to their quality of life. Although physiotherapy treatments have proven effective in improving gait and balance, conventional overground walking training may result very difficult or even impossible for patients with severe gait problems. ¹

This commentary focuses on whether robotic interventions, aimed at improving functional outcomes in people with MS, are effective and may be widely used in clinical practice. Robot-assisted rehabilitation is definitely the technology that has shown the greatest advances in the last two decades, especially in the rehabilitation field. Generally speaking, the robotic rehabilitation devices are typically based on motor learning, resulting from intensive, repetitive, and task-oriented motor activities that require the patient's effort, attention, and engagement.^1,2 Robotic rehabilitation systems can be divided into end-effector and exoskeleton devices. In the end-effector systems, movements are generated by the most distal segment of the extremity and no alignment between patient–robot joints is required, whereas the exoskeleton systems have a one-to-one correspondence between robots and human joints, and each single joint is guided along a pre-programmed trajectory. Exoskeletons therefore offer higher levels of safety and better training in patients who are severely impaired. ¹ Moreover, gait robotic rehabilitation systems can be classified into stationary (such as the Lokomat, consisting of a powered gait orthosis with integrated computer-controlled linear actuators at each hip and knee joint, a body weight support, and a treadmill) and overground walking systems (also known as powered exoskeletons).^1,2

The use of robotic-assisted gait training (RAGT) has proven effective in potentiating gait parameters, as well as spasticity and other non-motor symptoms, in different neurological disorders, including MS. ³ – 5 In particular, RAGT using stationary exoskeletons can be feasible and efficacious in MS patients with severe disability (Expanded Disability Status Scale (EDSS) 6.5–7.5), as these devices can improve gait speed and resistance, as well as increase muscular strength. Positive outcomes after RAGT have also been found in patients affected by progressive MS, which is known to have a worse prognosis. ⁶

Powered exoskeleton treatment has instead been tested on patients with moderate gait impairment (EDSS <6), who showed an improvement in gait resistance and in the ability to climb up stairs.^2,6 Notably, RAGT is often administered in addition to other conventional treatments, such as physiotherapy, occupational therapy, hydrotherapy, and/or neuropsychological treatments. Then, we may think about this novel approach as an add-on treatment able to further increase functional outcomes, especially in severely affected patients.

In the last few years, different authors have attempted to demonstrate the clinical efficacy of robotics in patients with MS, mainly focusing on motor outcomes. ⁷ – ⁹

In their recent systematic review, Bowman et al. found that RAGT, provided with exoskeleton devices, improves balance and gait outcomes in a clinically meaningful way, thanks to their several advantages in terms of safety, motor assistance, and intensity of training. Then, the authors concluded that RAGT should be used in patients with MS and severe disability in a multimodal rehabilitation context as an opportunity to maximize their functional recovery. ⁷

Although the review by Yeah et al. demonstrated that RAGT is comparable to conventional treatments in improving walking performance, pain, and quality of life, robotics is significantly superior in improving perceived fatigue and spasticity. Given that these latter symptoms are predominant and RAGT is safe and well tolerated by people with MS, this should be considered as a potential treatment also in clinical settings. ⁸

A recent review by the “CICERONE” group has comprehensively investigated all of the main functional outcomes related to the lower limbs after treatment with RAGT in patients suffering from MS. ⁹ This work demonstrates that training with robotic devices, such as Lokomat or Reha-Stim, is feasible and significantly effective in MS patients, due to their potential for improving gait speed, gait resistance, and balance. Moreover, patients affected by spasticity may benefit from this type of training, especially when robotics is coupled with drugs, such as nabiximols, acting as neuromodulators. ¹⁰ Finally, an improvement in several types of other non-motor outcomes including pain, fatigue, depression, and quality of life following RAGT has been found. These data support the idea that RAGT could be used in clinical practice, also considering their effects not only on motor but also (and especially) on non-motor outcomes that negatively affect MS people’s quality of life. Unfortunately, to date, no clear clinical indications on the use of RAGT in individuals with MS have been provided. Based on the available literature data, in order to overcome this important issue, the authors suggest that different training with different approaches and kinds of devices should be used in the different stages of the disease, taking into consideration the patients’ EDSS level. More in detail, patients with an EDSS score of 5.5 to 7.5 would benefit more from stationary exoskeletons, those with a moderate disability (EDSS 3.5–5) should be treated with either end-effectors or powered exoskeletons, whereas patients with mild gait impairment do not need RAGT. ⁹ Specific protocols on RAGT treatment frequency, duration, and intensity are, however, needed to maximize the effect of this training in clinical settings.

In conclusion, based on the existing data, RAGT may be considered a valuable tool for the treatment of patients with MS and it is ready for widespread use in clinical practice. In fact, following this innovative approach, MS patients (especially those with severe disability) can improve not only their motor outcomes, such as gait speed and endurance, but also non-motor symptoms, with regard to spasticity and fatigue, with a consequent betterment of their quality of life.