Journal of Philosophy and Ethics in Health Care and Medicine, No.6, pp.29-38-, August 2012

Scientific Contribution

Use of Brain-Machine Interfaces as Prosthetic Devices:
An Ethical Analysis
Michio MIYASAKA, Sayuri SASAKI, Mio TANAKA, Jun KIKUNAGA(Niigata University,

E-mail：miyasaka@clg.niigata-u.ac.jp)
Abstract：
Brain-machine interfaces (BMIs) convert internal/neural information into
external/functional control and transduce external/functional information
into internal/neural activity. Ethical arguments over BMIs have often beenconnected with their potential impact on human nature and integrity. In
that context, they are regarded as a threat to personal identity andautonomy in exchange for improved limb and brain function. BMIs can also
be regarded as social resources that enhance the capabilities of bothdisabled and healthy people. This paper argues that non-invasive BMIs canbe morally justifiable within a healthcare context for not only prosthetic use
but also as physical enhancers, as exemplified by Robot Suit HAL. For
example, BMI prosthesis can help recover physical performance in aparalyzed patient or enable a female family caregiver to lift an elderly
relative. A list of suggested central principles, technological requirements,
and power output limitations is provided for at least the early applicationsof prosthetic and enhancement uses of HAL-type BMIs.
Keywords：brain-machine interface, prosthetic, enhancement, autonomy

１．Introduction
Brain-machine interfaces (BMIs), also known as brain-computerinterfaces (BCIs), convert internal/neural information into
external/functional control and transduce external/functional
information into internal/neural activity. Rapid developments inthis relatively new field have resulted in a wide range of29

Journal of Philosophy and Ethics in Health Care and Medicine, No.6, pp.29-38-, August 2012pre-clinical and clinical applications. Schermer has indicated five
BMI categories that are either already possible or underdevelopment: (1) sensory prostheses such as cochlear implants andartificial retinas, (2) deep brain stimulation (DBS) of specific areas
by inserted electrodes, (3) neuroprostheses that enable the controlof objects with thought (e.g., cursors, computers, robotic arms), (4)neurofeedback that detects brain activity to warn of or prevent
physiological episodes (e.g., epileptic attacks), and (5) exoskeletonsthat are worn to provide additional strength and power. 1
In the neuroethics branch of bioethics literature, arguments over
BMIs have often been connected with the potential impact of thetechnology on human nature. 2 - 3 In these arguments, BMIs areseen as a threat to personal identity and autonomy in exchange for
improved limb and brain function. Once BMIs have the capabilityof uploading memories to a chip, for example, personal identity
could be cloned and even immortalized digitally. 4 A third-party
human or machine could also directly control and monitor thethoughts and movements of a person whose brain is connected to acomputer network.
In spite of the negative implications, BMIs are simultaneously
regarded as positive social resources that could enhance thecapabilities of people with disabilities (e.g., an artificial retina forthe visually impaired, DBS for those with Parkinson's disease ordepression). The aim of this paper is to illustrate the moral
arguments with clinical BMI applications for Japanese patientswith neurological disabilities and their families. With the current
positive and negative visions of BMIs, a wide range of perspectives
are needed to cover normative and empirical ethical viewpoints.
２．BMIs as healthcare resources - Robot Suit HAL
The bright horizon of BMIs has inspired international rivalry
since the 1990 ’ s, with Japan attempting to maintain its
competitive position. Japanese neuroscientists have repeatedly
expressed anxiety about losing ground to the United States (US)30

Journal of Philosophy and Ethics in Health Care and Medicine, No.6, pp.29-38-, August 2012and Europe due to insufficient government research funding,which has decreased over the years after peaking in 2000. Whilethe 2007 neuroscience budget was $347 million USD in Japan, it
was $660 million USD in the US and $278 million USD in the
United Kingdom (UK). 5 Scientists also pointed out that the annual
neuroscience budget as a percentage of total expenditures for thelife sciences was only 7% in Japan, but 17% in the US and 19% in
the UK.
Requests for government support led to several major projects
organized by agencies such as the Ministry of Education, Culture,
Sports, Science, and Technology (MEXT), the New Energy andIndustrial Technology Development Organization (NEDO), and theJapan Science and Technology Agency (JST). Robot Suit HAL (forHybrid Assistive Limb) was one of these projects, developed by
Sankai and colleagues at the University of Tsukuba and theventure company Cyberdyne Inc. 6 as part of MEXT’s “21st Century
COE Program” and the government’s “Funding Program forWorld-Leading Innovative R&D on Science and Technology.” HAL
is a union of the neuroprosthesis and exoskeleton BMI categories.
The system is designed to supply deficiencies in muscular
movement according to the user's mental intent, like aneuroprosthetic, but is also worn around the body to provide
strength and power not intrinsically possessed, like an
exoskeleton.
"Robot Suit HAL" is a cyborg-type robot that can expand andimprove physical capability. When a person attempts to move,nerve signals are sent from the brain to the muscles via
motoneurons, moving the musculoskeletal system as aconsequence. At this moment, very weak biosignals can bedetected on the surface of the skin. "HAL" catches these signals
through a sensor attached on the skin of the wearer. Based on
the signals obtained, the power unit moves the joint in unionwith the wearer's muscle movement, enabling support of thewearer's daily activities. 731

Journal of Philosophy and Ethics in Health Care and Medicine, No.6, pp.29-38-, August 2012

On one hand, HAL is a "voluntary control system" that interprets
the wearer's own intentions and provides movement in accordancewith their intentions only. On the other hand, HAL is also a"robotic autonomous control system" programmed to provide
independent, human-like movement.
(1) Benefits to patients – BMIs as prostheses
HAL-type BMIs are expected to benefit a wide range of patients
who have paralysis caused by various etiological factors, as long as
the bio-electrical sensor can read signals from the patient's brain.
Neuroprostheses typically require electrodes or chips implanted
into the brain or other parts of the body, which must be surgicallyremoved for repairs. In contrast, HAL is a non-invasive
neuroprosthesis that can be easily attached to and detached fromthe body. HAL also provides options for patients with more severe
physical conditions. Conventional robotic assistive devices arelimited by the necessity for residual motor ability; however, HAL issignificantly less dependent on residual motor ability because it
detects brain-to-muscle signals via the skin surface. Patients wholack even limited muscle control could be rehabilitated with HAL
as long as brain-to-muscle signals are detectable on their skin.
(2) Benefits to caregivers – BMIs as enhancers
Robotics can benefit caregivers as well as patients in healthcare
settings by providing additional strength and power to accomplish
tasks. Many industrialized countries such as Japan are rapidly
aging and suffer from a shortage of resources for the elderly anddisabled. This scarcity has provoked ethical controversy acrossgenerations and genders over the cost and labor of caregiving. In
Japan, primary caregivers for elderly invalids have predominantly
been female family members. As the family system has shiftedfrom an extended family headed by older parents to older parents
functioning as an independent family unit, the role of primary
caregiver has shifted from younger daughters-in-law to spouses

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(mainly older wives). 8 HAL worn by caregivers can supply theadditional power for even female caregivers to carry their parents
or husbands.
３．Ethical arguments on BMI use(1) Justification of BMIs as enhancers to improve healthcare
Limiting BMIs to therapeutic use only has been widely acceptedin bioethics literature, while BMI enhancement of otherwise
healthy people has less been accepted. As described in the previous
section, however, BMIs can be utilized not only as prostheses forpatients, but also as enhancers for caregivers in a healthcare
setting. Rawls' second principle of justice, fair equality ofopportunity, requires that citizens with the same talents andwillingness to use them have the same economic opportunities
regardless of whether they were born rich or poor. BMI enhancers
can be convincingly justified if the recipients are family caregivers,
who would fit into Rawls' "worst off" groups – that is, theleast-advantaged members – in the context of Japanese healthcare.
If this principle is applied to the enhancement discussion,
caregivers are entitled as the least-advantaged members inhealthcare to use robotic exoskeletons so they can be of thegreatest benefit.
The application of Rawls' second principle of justice tohealthcare issues has also fueled controversy over the definition of“worst off” in a healthcare context, as well as the benefits given
to the worst off compared to others. 9 According to Daniels, Rawls’
claim needs to account for a fair process of setting limits or
rationing care under conditions that comprise reasonableaccountability. 10 It must therefore be demonstrated that HAL canbe utilized with reasonable public expenditures - including initialinvestment costs financed by the government, running costs forelectricity and mechanical maintenance, and subsidies for
distribution of the device - compared to other medical options thatwould provide similar benefits to family caregivers.

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Journal of Philosophy and Ethics in Health Care and Medicine, No.6, pp.29-38-, August 2012

(2) Are BMIs a threat to personal autonomy?
In bioethics literature, autonomy can be defined both narrowly
and widely. Autonomy in the narrow sense is regarded as the rightto make informed and voluntary decisions, which in turn requires
healthcare providers to obtain informed consent from patients. The
wider concept of autonomy requires healthcare providers to see
patient autonomy from multiple angles. European scholars claim
autonomy should be understood as the capacity for (1) creation ofideas and goals, (2) moral insight, “self-legislation,” and privacy,(3) rational decisions and actions without coercion, (4) politicalinvolvement and personal responsibility, and (5) informed
consent. 11
HAL is not immune to the criticism that BMIs can threaten
personal autonomy when it was narrowly conceptualized. As
previously mentioned, all its computer-assisted movement
originates from and is controlled by the patient ’ s own will.
Because neural signals are often unclear and unstable, however,they may need to be compensated for or amplified by computers. In
those cases, the computer calculates what kind of movement andhow much power the patient intends to generate. When a HAL-type
BMI is connected to a computer network, another person on the
network can remotely monitor and even control the patient’s
movements. Taken further, BMIs could easily be converted into
weapons that give its wearers super-human output controlled bythem or someone else. Personal autonomy can be analyzed for
BMIs in a similar manner as conventional automotive vehicles.
Cars today are controlled by not only the driver but also computers.
In four-wheel steering systems, for example, the rear wheels do notturn as far as the front wheels due to computer calculations. Also,a car could theoretically become a weapon if the driver acts in bad
faith or the car is controlled by hacking into its computer system.
Ethical deliberations need to be addressed in both autonomous andheteronomous directions because harm can be done from thereckless handling of the user or outside manipulation by a third

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Journal of Philosophy and Ethics in Health Care and Medicine, No.6, pp.29-38-, August 2012

party. The range of user control must be limited to only thejustifiable purposes of the machine - transportation for a car andprosthesis for HAL. BMI prostheses for paralyzed patients should
therefore be justified as long as power output is within the range ofan average person's movement, while enhancement for caregivers
should be set within the range of daily caregiving (e.g., the powerof a healthy young man to enable a female or older caregiver tocarry one person). In addition, the core system of the BMI should
be secured from heteronomous control by third parties or even a
computer, which illustrates popular BMI concerns discussed in thenext section.
The broader aspects of autonomy can justify prosthetic use of
HAL if the device reinforces the social and political capacities of
the wearer. HAL-type BMIs could provide easier access to social
resources (e.g., a supermarket or hairdresser) or political activities(e.g., attendance at town meetings on a new policy) without the aid
or interference of others. However, use as an enhancer for these
purposes would require further discussion on the extent of humancapacity achievement that would be ethically acceptable. Even if
HAL was used by a family caregiver to assist his/her elderly mother,some aspects of autonomy could be enhanced beyond his/her reachwhen s/he is not in the exoskeleton. This should be viewed as ahuman nature matter, which is discussed in the next section.
(3) Can BMIs alter human nature?
The symbolic impact of BMIs has been frequently discussed inbioethics literature with the implication that the blurry distinction
between man and machine might lead to the creation of cyborgs ormonsters, endangering human morality by demolishing the conceptof the person. 12 Western moral philosophy is often discussed aspresupposing the subjectivity of human mind over human (andnon-human) bodies and objects (such as machines). The modern
concept of subjectivity in Western philosophy first emerged with
Descartes' cogito (I think), which in effect equates a subject with athinking subject, and then expanded with Kant's rational being,

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who is honored with the highest value of dignity as an autonomous
subject as long as he self-legislates moral law. 13 In a previous
study, I noted that European philosophy, especially Kantianism,and current bioethics share viewpoints that dissociate mind frombody and subjectivity from objectivity, leading to absolute humansubjectivity. 14 We as subjects thus (1) have ruling power over not
only cognition, but also the use of our objects, and (2) are neversupposed to be turned into slavish objects. These viewpoints may
explain the concern that BMIs could jeopardize human morality.
Considering that HAL was designed as both a neuroprosthesis
and an exoskeleton, the question is whether it can obfuscate theborder between man and machine to alter the human nature of thewearer. This argument can be connected to the European concept ofautonomy mentioned in the previous subsection, which emphasizeda wide range of individual capacities and social or politicalconditions, as well as a basic principle of integrity. European
scholars proposed the concept of integrity as an independent
principle of bioethics that accounts for the inviolability of thehuman being, referring to "the coherence of life in time and space(in memory and corporeal life) that should not be touched anddestroyed." 15 Rendortff gave four meanings for integrity: (1) anarrative totality, wholeness, and completeness; (2) a personal
sphere of self-determination; (3) a virtue of uncorrupted character,
expressing uprightness, honesty, and good character; and (4) alegal notion, expressing moral coherence of the legal or medical
system. 16
This integrity-based argument supports HAL for not only
prosthetic use but also as an enhancer for caregivers, with some
limitations. First, proposed prosthetic users of HAL would bepatients with paralysis who lack physical wholeness. They are
therefore entitled to recovery of this wholeness by any available
medical procedures, including HAL. Family caregivers who need
HAL-type BMIs can be reasonably assumed to suffer from the hardlabor of caregiving, which is considered to be an uncoerced moral orsocial obligation. These caregivers would thus reasonably require

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HAL to alleviate their burden. However, use of HAL as a prostheticor enhancer requires prudent ethical guidelines to secure thestatus of BMI users as autonomous subjects and prevent them frombecoming heteronomous objects, ruled by a third party or computer.
Practical strategies to prevent an override of the human user's
intentions include monitoring the operation and level of power
support given by the devices, and including a means to shutdown
the device by not only by the wearer but also an external person incase of mishaps.
４．Conclusion and Suggestions
This paper has outlined arguments proposing that boththerapeutic (or prosthetic) and enhancement uses of non-invasive
BMIs can be morally justifiable within a healthcare context, as
exemplified by Robot Suit HAL. I conclude with a list of suggested
central principles, technological requirements, and power output
limitations for at least the early applications of HAL-type BMIs in
healthcare settings:
A. Central principles- safety (do no harm)- autonomy (secure status of the user as the controller)
B. Technological requirements- easy to detach and remove- remote monitoring and shutdown
C-1. Power output limitations for prosthetic use-within the range of an average person’s movement
C-2. Power output limitation for use as an enhancer- within the range of daily caregiving
Acknowledgement

This work was supported by MEXT KAKENHI (22242001).

References

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Journal of Philosophy and Ethics in Health Care and Medicine, No.6, pp.29-38-, August 2012

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