Critical review of the relationship between Assistive Technology and Embodiment

I am used to wearing glasses since primary school. As my eyesight is pretty weak, managing my daily life would not be possible without having such ‘assistive technology’, enabling me to visually sense the world without heavy losses. Since I do team sports, which can damage my glasses, I proceed to wear contact lenses. It is fascinating how these little things have the same power as the comparatively heavy and circumbendibus glasses. For instance, it is possible for me to play handball without the fear of breaking my glasses, or to go swimming and being able to recognize my friends standing 5 meters away from me. However, wearing the lenses for the first few days, my little cousin was looking critically at me, assessing: “You look better with your glasses on. You don’t really look like you without them.” It is highly interesting how my face became strange to him without my glasses. Beside their use of improving my eyesight, did my glasses become a part of me? Apparently, my face is not ‘whole’ for my little cousin when I have lenses on. Does this mean my ‘assistive device’ became a part of my body image for other people? Besides being a tool for better eyesight, glasses have a cultural meaning. People have specific associations with wearers of glasses. One example would be the common stereotype that glasses make a person look more intelligent. Despite the empirical findings are inconsistent throughout the investigated samples (Lundberg and Sheehan, 1994), studies show that people have this stereotype (Edwards, 1987). Depending on the rim of the glasses, they can also decrease and increase attractiveness and trustworthiness (Leder, Forster & Gerger, 2011).

This little introducing story tells us something about the problem area of the relationship between assistive technology and embodiment, namely that there is a surplus of meaning to objects in the world. Glasses are both functional and cultural objects. Same applies for other assistive products. MacLachlan and Gallagher (2004) distinguish four ways in which people are affected by technology in the rehabilitation field: Interacting with technology (e.g. exo-skeletons), listening to the body (e.g. biofeedback), technology of replacement (e.g. organ transplant and prosthesis) and living through technology (e.g. respirator). The story in the beginning and the present classification show the broadness of the area of application, in which assistive technology is used and how it intersects with embodiment. Thus, it is necessary to put a focus in the interest of a deep review. The focus in this essay will lay on technology of replacement, in particular upper limb prostheses. After a definition of the terms ‘embodiment’ and ‘assisitive technology’ and some explaining examples, which will do justice to the broadness of the intersection of both fields, I will outline the functional and cultural relevance of the human hand and which psychological consequences upper limb loss and prosthesis use entails. Thereafter, the focus is on the neurological correlates of body image to understand how integration of foreign objects (in our case: upper limb prostheses) into the body works. It will be shown that integration of a prosthetic into the body image can be improved, when the body receives sensory feedback, which has crucial implications for further development of high tech prostheses. Subsequently, it will be critically discussed how further improvement of assistive technology affects embodiment. As the first part of the argumentation concentrates on embodiment in the sense of incorporation, then, a light will be shed on the social facets of prosthesis embodiment. The needs and concerns of affected persons will be taken into consideration for a both detailed and holistic picture of embodiment and assistive technology. In the end, the balanced discussion will lead to the insight that assistive technology can be embodied in different ways, depending on the individual user. Thus, a broad variety of low tech and high tech products does justice to the individual needs affected persons. The essay finally closes with a brief summary of the content.

The focus on upper limb prosthesis and embodiment is justified for several reasons: Firstly, the broadness of the present issue requests a focus for not ending in a superficial discussion. Secondly, amputation and prosthesis use are phenomena, which concern a considerable part of the population: In Germany, each year 40.000-70.000 people become amputees, whereof approximately 10.000 are affected by upper limb amputation (Mitterhuber, 2012). Upper limb amputation is mostly a consequence of accidents. This essay will deal with upper limb amputation and prostheses, as from an embodiment point of view the human hand is more interesting than the human leg.

Before we go more in depth with the topic, as definition of the central terms in the essay is essential. As a definition can’t be judged in terms of ‘right’ or ‘wrong’, but rather in the term of usefulness, I will try to give a ‘useful’ definition of the central terms in this essay.

Embodiment can be described generally as the ‘identification of an abstract idea with a physical entity’ (MacLachlan, 2004). This idea can appear in various forms, such as the self, music, religion etc. For instance, the abstract idea of ‘the death knocking on the door’ is embodied in the introducing motif of Beethoven’s 5th Symphony. The physical entities here are the instruments playing the motif or the sheet of notation. Another example would be a poster of a super model in a fashion magazine perceived as the incarnation of the abstract idea of ‘beauty’. These examples are sufficient to show the wide range of the impact of embodiment. Problematic about the term of embodiment is that throughout the academic disciplines as cognitive psychology, philosophy or neuroscience, its definition differs. Common to all of them is the interaction of the body and psychic processes, such as thinking, feeling and acting (Bermeitinger in Dorsch, 2014). Since we must experience the world through our bodies, we are necessarily embodied in them (MacLachlan, 2004). Consequently, our bodies and other objects in the world (e.g. statues, paintings or touristic maps) are not only physical entities but rather impregnated with meanings, as we have seen in the previous examples. The notion of trying to understand what an object or body stands for (ergo: what it embodies), has important implications for health, illness and disability. These ‘states’ of the body are to be seen holistic, considering psychic and physic processes. Thus, they imply a healthy or disordered way of ‘ being in the world ’ (MacLachlan, 2004, e.g. p. 129). In a more philosophical context one can argue lapidary that just as the mind affects the body, the body affects the mind. And this is where ‘assistive technology’ steps in.

Assistive technology is described broadly by the World Health Organization (WHO) (2004) as ‘an umbrella term for any device or system that allows individuals to perform tasks they would otherwise be unable to do or increases the ease and safety with which tasks can be performed.’ Through avoiding the term ‘disability’, this definition allows to discuss assistive technology without emphasizing a person’s disability, but rather the barriers that keep persons from fulfilling their potential (Craddock & McCormack, 2002). Assistive products offer a comprehensive range of applications: scooters, wheelchairs, canes or prostheses are probably the most prominent examples in the field of mobility products, whereas highly specific, person-oriented electronic devices, such as ‘tactile sign language’ – transferring computer systems, enabling deaf blind people to communicate remotely, are not present in the general public.

Prosthetic devices are commonly known products in the field of replacement technology. The focus on upper limb prostheses in this essay is due to the importance of the human hand from an embodiment point of view. Well what is so special about it?

The human hand is crucial for sensing the world. It is even deeply embodied in our language (not only in the English language). For instance, to ‘grasp’ something is meant both figurative and literary. Through sensing the world through our hands we grasp our environment when we grow up, we communicate with our hands through gesticulation and touching others, we work with our hands, we use them as tools etc. Comprehensibly, the loss of a hand can be a very traumatic experience. A clinical study examining depression among patients with various amputations illustrates a 35% prevalence of major depressive disorder affected persons (Kashani, Frank, Kashani, Wonderlich, & Reid, 1983). In another study, nearly two third of the patients with amputations (N=72) experienced psychiatric symptoms within 1-2 weeks of amputation (Shukla, Sahu, Tripathi & Gupta, 1982). Patients with a clinical history were excluded. In addition to that, affected persons commonly experience stump pain and phantom pain of the absent limb (Saradjian, Thompson & Datta, 2008). Thus, losing a hand means more than ‘just’ losing a functional part of the body, it means a disturbed ‘being in the world’, containing an immense loss of sensation and (from the point of view of gestalt theory) a loss of body image (Racy,1989).

As pointed out above, hands are an immensely important part of the ‘cultural body’ (MacLachlan, 2014). Indeed, upper limb amputation potentially has a larger impact than lower limb amputation (Baumgartner, 2001). That is because in comparison to the lower limbs, hands are from bigger social importance, in fact regarded as the second most individual and personal part of the body following the face (Saradjian et al., 2008). The aim of a prosthetic device is to ‘restore body image and improve functioning in a cosmetically acceptable way’ (Ham and Cotton, 1991). Upper limb prostheses are functionally and psychologically rated less satisfying than lower limb prostheses (Narang and Jape, 1982). Thus, the demands of function on upper limb prostheses might be higher, as the human hand can perform much more complex operations than the human leg. Concluding to that, it comes to a greater discrepancy between what the person wishes and what the prosthetic device can offer. Therefore it is an interesting question, how future upper limb prostheses could increase satisfaction of affected persons.

Integrating inanimate objects into the body image is a fascinating psychic process involving specific brain areas. It is crucial to get a deeper understanding of it, when talking about prosthesis improvement. Ehrsson, Wiech, Weiskopf, Dolan & Passingham (2007) examined in a laboratory experiment if participants exposed to the ‘rubber hand illusion’ showed emotional arousal when the fake hand was threatened. The illusion was induced by tactual stimulating the hidden ‘real’ hand with a brush with synchronously brushing the visible rubber hand. When the rubber hand was threatened with a needle, the same brain areas (insula and anterior cingulate cortex) were active as if the real hand was threatened. Moreover, the neural response was stronger, the stronger feelings of ownership of the artificial hand were. This has unquestionable implications: When people experience that an artificial limb is part of their own body, they show the same emotional responses as when their real limb is threatened (Ehrsson et al., 2007). In other words, a ‘dead object’ can be fully integrated into our body image. It is important to distinguish between the emotional arousal described here and mere empathy for pain, which does not include feelings of body ownership. For evoking the feeling of body ownership the engagement of the interoceptive system is unalterable (Ehrsson et al., 2007). The interoceptive system imparts information about body parts. For instance, the sense of proprioception represents the position and movement of the body and body parts in the environment (Birbaumer and Schmidt, 2010).

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