Exoskeletons, especially those for the lower limb, have become increasingly popular in recent years. Gait disorders affect 60% of patients with neurological conditions and generally affects their quality of life. Imagine not being able to walk around the park or go to the grocery store and pick up your favourite cereal on the top shelf.  

Advantages 

Some major advantages of powered exoskeletons for rehabilitation needs are[1][3][4]: 

• Preventing muscle atrophy 

• Preventing deterioration of osteoporosis/osteopenia 
• Reduce energy required to move the primary joints as the load is taken by the exoskeleton 
• Target specific joints for rehabilitation purposes 
• Pressure relief 
• Bowel and bladder improvements  

• Reduces risk of hypotension 
• Increase the autonomy of users by allowing independence 
• Improve physiological state of the user 
• Reducing spasticity 

Most research on exoskeletons is being carried out on spinal cord injury (SCI) patients. Generally, less than 5% of these populations can ambulate without physical assistance. Walking using an exoskeleton will encourage these patients to engage in physical activity at an intensity that encourages health benefits. These effects also mitigate the independent health risks that are associated with prolonged sitting[5]. 

Using robotics also allow a standardised training session and enables longer training times. Technology for rehabilitation has relieved therapists from mundane repetitive work that is also physically demanding. It allows them to focus on other aspects of individual therapy and care.  

Drawbacks 

Albeit making significant advances in the past decade, powered exoskeleton technologies still have their shortcomings that are perhaps hindering the rapid adoption of the technology in healthcare. The user-friendliness of the human-robot interaction consisting of the mechanical, control, and feedback mechanisms determines whether the technology is integrated into the clinical setting. 

An average exoskeleton accommodates users of between 150-190cm with a maximum weight limit of 100kg. Most people would be excluded from those criteria alone as being overweight is an arising issue especially for non-ambulatory patients.  

Most exoskeletons are designed to be utilised with elbow crutches. Otherwise, the device will be too heavy and rigid for use during rehabilitation. However, this denies patients of higher-level injuries and those that lack upper limb movements the ability to utilise this technology that will prove beneficial as stated above.  

Because of the need of having supervision and clinical support, most exoskeletons are generally used within clinics and rehabilitation centres. The time taken to don and remove the exoskeleton off also varies but generally needs more than 10 minutes.  

Implications for Research 

The robotics community would greatly benefit from specific policies and guidelines that can speed up the development and adoption of exoskeleton technologies. Exact therapy times for gait training have yet to be decided to achieve optimal outcomes. Future research would need to focus on the optimal training conditions for patients in terms of speed, step length, cadence and more.  

Nevertheless, there needs to be an alignment between therapist-claimed requirements and the actual patient requirements for meaningful technological developments. Fittings should also be designed so they can be donned quickly and fully removable in case patients face an emergency.  

Moreover, there are still questions on the effectiveness of exoskeletons as compared to treadmill-based or end-effector based locomotor training. Can exoskeletons provide better re-loading of the joints to allow muscle activation? How soon could patients after surviving a stroke, SCI or brain injury be exposed to exoskeleton gait training?  

Robotic technologies are not always used alone. A common question for exoskeleton technology would be if the use of virtual reality would enhance the effectiveness of the training.