Introductory Chapter: Past, Present, and Future of Prostheses and Rehabilitation

*Shanthini Madhanagopal, Martin Burns, Dingyi Pei, Rohan Mukundhan, Helen Meyerson and Ramana Vinjamuri*

### **1. Background**

A prosthesis is defined as "…a device attached to the stump of an amputated body part due to traumatic or congenital conditions…" [1]. Prostheses have evolved over the past centuries, starting with a wooden toe to the highly mechanized robotic limbs of today. The evolution of prosthesis started in the Egyptian period during which wood was used as a replacement for a missing toe, coconut shell was used as a dental implant, and various other materials were used as an alternative to different body parts. There are various types of prostheses depending on the body part being replaced. These include upper and lower limb (LL) prostheses, neural prostheses (NP), retinal prostheses, maxillofacial prostheses, and various other types. Each prosthesis is designed and assembled based on the person's physical appearance, functional needs, and affordability [2–7]. The history of lower limb prosthesis is outlined in **Table 1**. This is a summary of our findings from [8, 9].

Amputations are estimated to occur between 300 and 500 times per day, leading to an increased usage of prostheses [10]. With increased need there are various factors which impact prosthesis usage, including whether the amputation is unilateral or bilateral, the time duration between amputation and prosthetic fitting, type of prosthesis used, physical health factors such as phantom-limb pain, and the psychological impact of amputation such as perception of symptoms, self-efficiency, balance confidence, treatment cost, and time taken to adapt to the prosthesis. The quality of life post-rehabilitation does not solely depend on the abovementioned factors but also includes functional utility and satisfaction over time. Improvements in quality of life are possible with recent innovations in design tools, materials, and different types of manufacturing, aiding in customizing prosthesis according to patient needs [11]. Novel rehabilitation methods, different types of prostheses, their limitations, and recent advancements will be discussed in this chapter.

#### **2. Virtual reality rehabilitation**

Upper limb (UL) paralysis and other motor deficits are common after a stroke. About 70% of acute phase patients and 50% of chronic phase patients experience such deficits. Upper limb paralysis affects tens of thousands worldwide, and all the forms of paralysis as a whole affect millions [12]. Currently, there is no way to safely cure paralysis. Instead, upper limb paralysis patients undergo rehabilitation treatment


#### **Table 1.**

*Evolution of lower limb prostheses.*

which gradually improves their lost function with exercises and stretches. There are many different approaches to provide treatment, which include working with a physical therapist on hand motor and strength skills and using prosthetic devices, such as robotic exoskeletons. The exoskeleton is a wearable, electrical device that straps onto the impaired arm or hand. It improves the limb's strength and endurance and its motor abilities by allowing the brain and the upper limb to regain communication [13].

In recent years, the use of virtual reality (VR) simulations designed in environments such as Unity has emerged to provide post-trauma and post-stroke rehabilitation. Hardware such as VR goggles and the Leap Motion controller, as well as Cybergloves and joysticks, are used to manipulate objects in virtual reality to provide an alternative to conventional rehabilitation methods. Improvements in retention and ease of use are accomplished by creating more immersive and engaging exercises for patients than the standard approach. Games with goals and challenges, interesting environments, and different types of in-game rewards can provide extra motivation to the patient. There has been a wide variety of studies researching the use of a virtual reality environment for rehabilitation of different impairments. In one study, VR rehabilitation for a 6-DoF ankle prosthetic was used to supplement robotic therapy. Subjects were put into an environment where they needed to navigate a plane or a boat; results showed that the VR group showed a larger increase in walking speed as well as higher retention rates and 28% less audiovisual cues needed during the experiment than those who used the robot alone [14]. Upper limb rehabilitation was also performed for subjects learning to use complex prostheses with multiple dimensions [15]. Games like MindBalance require the subject to control an animated character and balance checkerboards on a tightrope, with a "3 strikes" approach to balance. During a test, subjects achieved 89% accuracy due to the EEG-based BCI performance [16]. Patients who experienced upper-extremity (UE) deficits

**3**

**4. Lower limb prosthesis**

*Introductory Chapter: Past, Present, and Future of Prostheses and Rehabilitation*

access and decreasing the amount of time necessary for rehabilitation.

enabling them to perform activities of daily living (ADL).

Upper limb prostheses are some of the most commonly used prosthetic devices since the human hand and arm is a vital tool for interaction, sensing, and working in an environment. Major limb amputations have been estimated to occur in 1 out of every 300 people in the United States, with 23% involving the upper extremity [19]. Unlike other types of amputation, most UL amputations are due to trauma. The evolution of UL prostheses has been exceptional over the past decades, resulting in highly mechanized devices which improve the quality of life of amputees by

UL prostheses can be classified based on the type of amputation and type of control mechanism. The type of amputation can be classified as trans-humeral, trans-radial, wrist, trans-metacarpal, and trans-phalangeal. Within these types, transradial is the most commonly used UL prostheses as it accounts for up to 10% of upper limb amputation [20]. Based on the type of control mechanism, these devices can be divided into body-powered, externally powered, and hybrid-controlled systems. Bodypowered systems use body movements to control a terminal device or a joint like the elbow. Externally battery-powered systems use electric switches or myoelectric signals for control, activated by residual limb movements or electromyographic signals generated by the residual limb. Hybrid systems combine body and external power control to balance weight, cost, and cosmetics and accommodate different amputation levels. Rejection rates for UL prostheses have been high, ranging from 3 to 60% in most

studies with rates closer to 60%. This rate was shown to correlate to the proximity of amputation with 6% for trans-radial and 60% for shoulder disarticulation [20, 21]. Many studies show that amputees are not satisfied with their prosthetic, thus resulting in high abandonment rates. There are various factors which affect prosthetic usage, and there are a lot of discrepancies between the various studies. For example, a study conducted by Burger et al. in a group of 414 upper limb amputees showed that factors such as level of amputation, loss of dominant hand, and time between prosthesis fitting and amputation play an important role in prosthetic use [22]. Other studies consider factors related to demographic impacts such as education level, level of amputation acceptance, and economic factors such as prosthetic use and training expense. These can be collectively considered as psycho-economic factors [23]. Based on this, the factors being considered have to be

Lower limb prostheses provide support and assist in locomotion for lower limb amputees. Lower limb prosthetics can assist many amputees to regain independence and mobility, thereby improving their quality of life. An estimate of 185,000 lower

better understood to know their actual impact on prosthetic use.

improved forearm extension and movement as well as hand-eye coordination, control and endurance of the UE, strength of the UE, and flexibility through VR [17]. As VR technology develops further, researchers must consider factors such as graphics design to maintain immersion without disorienting the patient. Elements from conventional rehabilitation known to promote good outcomes, such as task repetition [18], must also be incorporated into the design of the games. VR rehabilitation methods are becoming attractive alternatives to conventional physical/occupational therapy. They promise more efficient and less expensive therapies, increasing patient

*DOI: http://dx.doi.org/10.5772/intechopen.89987*

**3. Upper limb prosthesis**

#### *Introductory Chapter: Past, Present, and Future of Prostheses and Rehabilitation DOI: http://dx.doi.org/10.5772/intechopen.89987*

improved forearm extension and movement as well as hand-eye coordination, control and endurance of the UE, strength of the UE, and flexibility through VR [17].

As VR technology develops further, researchers must consider factors such as graphics design to maintain immersion without disorienting the patient. Elements from conventional rehabilitation known to promote good outcomes, such as task repetition [18], must also be incorporated into the design of the games. VR rehabilitation methods are becoming attractive alternatives to conventional physical/occupational therapy. They promise more efficient and less expensive therapies, increasing patient access and decreasing the amount of time necessary for rehabilitation.
