In addition to the loss of function and mobility, paralysis can cause psychological disorders and quality-of-life issues. There are several assistive devices on the market to help paralyzed people with function and mobility, but they are limited by the lack of bipedal walking.
Active exoskeletons rely on an external power source, and they improve function and mobility in people with limb paralysis.
Passive exoskeletons augment strength and movement to prevent occupational injuries in industrial workers.
Recent advances in technology suggest an individual will be able to effectively control an exoskeleton with their brain signals only in the near future.
Recently, advances in research and technology have led to the development of highly advanced exoskeletons aimed at facilitating bipedal locomotion and improving function and quality of life.
How exoskeletons function
An exoskeleton is a wearable robotic suit with an integrated system of computers that controls levers and motors aligned with major body joints to restore and augment movement. In addition, they can be used by an able-bodied person for mechanical assistance when performing repetitive and physically demanding tasks. Each of these functions is unique to a specific type of exoskeleton.
Types of exoskeletons
A battery-powered exoskeleton uses an external power source in the form of a wearable backpack and motors at the hip and knee joints. This type of exoskeleton comes with a remote-control watch where the user selects the type of movement (from a list of pre-programmed movements) they would like to perform, and the suit then does the movement for them. For instance, by selecting a standing option, the suit will automatically help the user to stand.
One of the many benefits of this type of exoskeleton is that it can be used for up to eight hours on a single battery charge, thus allowing the user to function for a longer duration. However, it is limited in that the user cannot perform movements that are not pre-programmed into the device. Brain-controlled exoskeletons have since been developed to address this limitation.
Brain-controlled exoskeletons utilize surgically implanted electrodes on either side of the somatosensory cortex – an area of the brain that generates movement. The electrodes detect movement signals and relay them wirelessly to multiple sensors in the motors of an exoskeleton. The signals activate the motors to initiate the movement matching the movement command generated by the brain. The sensors are also useful in detecting the position of the user in space and the joints, related to each other. One obvious benefit of this type of exoskeleton is that it does not limit the user on the type of movement they can perform. However, a brain-controlled exoskeleton requires longer periods of training for safe and effective use.
Passive exoskeletons are wearable assistive devices made of springs and carbon fiber bands that provide mechanical support when performing repetitive and/or physically demanding tasks. They are used for preventing work-related musculoskeletal disorders, primarily in the automotive, construction, and logistics industries. The latest passive exoskeleton has three components: back, arms, and legs. The user can wear and use these separately or as a full suit.
The back piece has springs (or carbon fiber bands) that run along the spine. They function by absorbing energy while bending towards a heavy object and springing back to assist in the lifting. This makes the weight feel lighter than it is, therefore allowing the user to perform repetitive lifting tasks without overloading and possibly straining their back muscles. The arm piece also has springs that get activated to support the arms whenever they are at shoulder level or above. This piece is particularly useful for workers performing repetitive overhead movements. Lastly, the leg piece has standing and sitting modes that allow the user to lock their standing position or sit without activating their leg muscles, respectively. The leg piece is useful for people in jobs requiring them to stand for long periods.
The evidence-based benefits of using passive exoskeletons include:
- Decreased incidence of occupational injuries.
- Decreased healthcare utilization.
- Decreased number of days taken off work because of injuries.
- Increased employee productivity.
The bottom line
Innovative exoskeletons have proven to solve some of the pressing challenges commonly seen in healthcare and industrial settings. Previously, a paralyzed person would be condemned to a lifetime of disability and would not have a slim chance of walking again. For industrial workers, years of repetitive heavy lifting and injuries meant living with some form of disability and chronic pain. Exoskeletons now provide disabled people with an opportunity to be functional again. In addition, it protects healthy individuals from injuries and disabilities. This innovative system of springs and carbon fiber bands has shown positive results to date. In consideration of these findings and advances in the research of brain-controlled exoskeletons, the future could be exciting for people with limb paralysis.