Gnanayutham, Paul

Good, Alice

English

Portsmouth University Research Portal (Pure)

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Disabled Users Accessing Off-The-Shelf Software Using a 
Button Interface 
Paul Gnanayutham and Alice Good 
School of Computing, University of Portsmouth, Buckingham Building, 
Lion Terrace, Portsmouth, PO1 3HE, United Kingdom. 
+44 (0) 23 9284 6404  
paul.gnanayutham@port.ac.uk, alice.good@port.ac.uk 
 
 
Abstract 
   The number of people with brain injuries is increasing, as more people who 
suffer injuries survive. Some of these patients are aware of their surroundings but 
almost entirely unable to move or communicate. Brain-Computer Interfaces (BCIs) 
can enable this group of people to use computers to communicate and carry out 
simple tasks in a limited manner. However BCIs tend to be hard to navigate in a 
controlled manner, and so the use of “one button” user interfaces is explored. It 
may be a useful “rehabilitation stepping stone” for a disabled person before he or 
she attempts to use a more sophisticated interface. This one button concept cannot 
only be used brain injured personnel with BCIs but by other categories of disabled 
individuals too with alternative point and click devices. Hence this paper is written 
as a position paper on future research in the areas of accessibility and usability. 
 
 
1.0 INTRODUCTION 
   People who have suffered a brain injury or some other form of motor impairment 
may have difficulties communicating. In the most extreme case, the patient may be 
non-verbal and quadriplegic. Some patients are cognitively intact but unable to 
communicate at all, which condition is termed "locked in syndrome". The authors 
are particularly interested in improving accessibility for this neglected group of 
people, in areas such as communication, recreation, controlling the environment 
and accessing web and applications using a simplified interface. This paper 
describes work, currently in its initial stages, which aims to provide access to 
off-the-shelf software, using a “one button” interface. “One button games” are 
games in which the only control is a single button, which may be pressed or not 
pressed. At first, this seems a very limiting user interface (Figs 3 & 4). However, 
Berbank-Green [1] discusses one-button games and lists many ways in which 
games can be played using only one button.  A one-button interface, as the name 
suggests, has only one control: a button which can be pressed or not pressed. This 
is the most minimal control a user can exercise, and so is the most “universal”, in 
the sense of being accessible to the maximum number of users [16]. Such an 
interface clearly has its limits, and will not be suitable for all types of software. In 
this paper we discuss contexts in which a one-button interface will bring benefits 
to severely disabled people, by providing an immediately usable interface. 
 
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2.0 BRAIN INJURIES 
   A traumatic brain injury (TBI) is an acquired brain injury caused by trauma such 
as a blow to the head, an impact with a blunt object, or penetration by a sharp 
object [23]. Common causes of TBI are motor vehicle accidents; bicycle accidents; 
assaults; falls and sports injuries [23], [17] (p. 216). The primary mechanism in 
many cases of TBI is diffuse axonal injury, i.e. widespread damage to axons (brain 
cells) caused by shearing or rotational forces [23]. At the microscopic level, the 
direction of the shear may be visible [17] (p. 218). Other causes of brain injury 
which are not classified as TBI are called acquired brain injury (ABI). There are 
many possible causes for an ABI, including: stroke (cerebrovascular accident, 
CVA); Amyotrophic Lateral Sclerosis (ALS); brain tumour; haemorrhage; 
infection; encephalitis; and medical accidents [4]. Powell [24] reports that 
approximately one million people in Britain attend hospital every year as a result 
of head injury. The incidence of disabled survivors is 100-150 per 100,000 – or 
more than 120,000 people in the UK suffering from long-term effects of severe 
head injury. Improvements in road safety have reduced the number of people who 
suffer a head injury. For example, Cook and Sheikh [7] report a 12% reduction in 
bicyclist head injuries in England between 1991 and 1995, ascribed to the 
increased use of bicycle helmets over the period. Reductions in drink-driving and 
increased use of seat belts, crash helmets and air bags have reduced the incidence 
of head injury in many countries [17] (p.216). However, as medical care has 
improved, the number of people who survive a brain injury has increased [23]. 
Powell [24] reports that the number of brain injured people has increased since the 
1970s, because the mortality rate has dropped since that time. When a person 
suffers a moderate or severe brain injury, they will enter a comatose state. During 
this period, it is possible to assess the severity of the injury by gauging the 
responsiveness of the patient. The Glasgow Coma Scale, developed by Jennett and 
Teasdale, is commonly used [23]. Upon regaining consciousness, the patient will 
experience a period of post-traumatic amnesia (PTA). The period of PTA is judged 
to have ended when the patient is able to form new memories [23]. The periods of 
the coma and of the PTA give a reliable indication of the severity of the brain 
injury. A coma period of more than six hours, or PTA of more than 24 hours is 
classed as a severe injury, which accounts for 5% of all head injuries [24]. Other 
methods of evaluation are more suitable for assessing the patient’s longer-term 
prospects of recovery. These include the Rancho Levels of Cognitive Functioning 
[14]. Some patients remain in the comatose state, or transition to a persistent 
vegetative state (PVS). PVS patients are unable to move or communicate, and are 
not aware. Some other patients are cognitively intact and aware of their 
surroundings, but are unable to move or communicate. This condition is known as 
locked-in syndrome. Recent cases have been reported of patients who were 
misdiagnosed as being in PVS, when they were in fact locked in [20]. Monti and 
team [18] describe patients who are outwardly non-aware and non-communicative, 
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but who can answer questions using MRI scanning. As patients diagnosed as PVS 
are more routinely scanned for cognitive activity, so the number of diagnosed 
locked-in patients may increase, and the number of PVS patients decrease 
correspondingly [18]. The consequences of brain injuries fall into three general 
categories: cognitive effects; emotional and behavioural effects; and physical 
effects [4]. Powell [24] lists the effects of brain injury most often noted by 
relatives of the injured person. These effects include personality changes, 
slowness, poor memory, irritability, bad temper, tiredness, depression, rapid mood 
changes, tension and anxiety, and threats of violence. As medical technology 
advances, more people survive brain injury. However, survival is not the same as 
quality of life. Rehabilitation is the process of regaining lost skills, or developing 
coping mechanisms to replace them. Rehabilitation has two stages: the acute stage, 
where medical professionals stabilise the patient. The second stage is where family 
and carers take over. Broadly, successful rehabilitation depends on the severity of 
the brain injury. However, every patient responds differently to treatment, and 
different skills may be regained at different times (e.g. regaining walking and 
remembering skills) [4]. Full recovery (to the same state as before the injury) is a 
reality for mild injuries, but “as a general rule the more severe the injury, the 
longer recovery may take, and the less complete it may be” [4]. However, on a 
positive note, some patients continue to improve, even years after the brain injury 
[4]. 
 
 
3.0 BRAIN COMPUTER INTERFACES 
   A Brain-Computer Interface (BCI) is a system for controlling a computer that 
does not depend on the brain’s normal output pathways such as speech or gestures. 
Instead, a BCI will use any of the bio-potentials which are under the conscious 
control of the user [11]. For people with extremely limited motor ability, a 
brain-computer interface is the only way in which they can use a computer.  
 
3.1 Bio-potentials 
Bio-potentials are electrical signals originating in the brain and nervous system. 
The existence of electrical currents in the brain was first discovered in 1875 by 
Richard Caton [27]. These can be detected and used to control hardware and 
software. Bio-potentials may be detected in two ways: invasive and non-invasive. 
Invasive methods involve surgery to place electrodes within the body or brain; 
non-invasive methods take measurements from the surface of the body. Invasive 
techniques provide higher amplitude signals with improved signal to noise ratio, 
but carry the risks of surgical procedures.  
In this study, we consider the use of only non-invasively measured bio-potentials: 
electroencephalography (EEG), electromyography (EMG), and electrooculography 
(EOG). 
 
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Electroencephalography (EEG) is the measurement of electrical waves produced 
by the brain. The existence of these regular waves was first published by Hans 
Berger in 1929 [2].  
 
These waves have amplitudes ranging from approximately 1uV-100μV at the 
surface of the scalp. The frequencies measure range from approximately 
1Hz-30Hz, the dominant frequency depending on the person’s mental state [6], 
[27].  
 
Electromyography (EMG) is the measurement of electrical signals originating 
from muscle movement. These signals have the same frequency range as EEG and 
an amplitude range of 0.2μV-2000μV [13]. 
 
Electrooculography (EOG) is the measurement of electrical activity caused by 
eyeball movements. The range of frequencies is relatively low, from 
1.1Hz-6.25Hz. The amplitude is higher than EEG, around 1mV-4mV [13]. 
 
Other non-invasively measured bio-potentials may be used for BCIs, but are not 
used in this study. These include evoked potentials, (e.g. P300 and N400); 
steady-state visual evoked potentials; and slow cortical potentials [13].  
 
4.0 COMMERCIALLY AVAILABLE BRAIN COMPUTER 
INTERFACES  
  BCI hardware ranges from devices intended for playing computer games through 
to medical-grade EEG machines (table 1). Table 1 shows currently available 
consumer-level BCI hardware which make it easier to purchase a BCI and the cost 
of such devices also have become much more affordable in comparison to 
previous years. 
 
5.0 DISCUSSIONS - USABILITY FOR ACCESSIBILITY 
   In this study, the Cyberlink™ hardware with Brainfingers software has been 
used as the BCI (Fig. 1). This follows in the footsteps of successful studies [9], 
which have enabled locked-in patients to communicate using an on-screen button 
keyboard. 
 
To move the mouse cursor at will, in any direction, the user must be able to 
consciously control four separate 'channels' of bio-potential: one channel to move 
the cursor up, one to move it down, one for left, and one for right movement. 
Adding the ability to generate mouse button events further complicates the task 
facing the user. This difficulty means, that in practice, BCIs are difficult to use. 
Typically when using Cyberlink™, the mouse cursor moves quickly to a corner of 
the screen and then stays there. This frustrates users, making it even harder to 
bring the cursor back under conscious control. 
 
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These difficulties have been addressed by developing the novel User Interface 
paradigms, Discrete Acceleration and Personalised Tiling [10]. Another approach, 
discussed here, is to make the interface easier to use by reducing the number of 
channels which the user must control. The simplest possible configuration is a 
one-button interface, requiring only one channel of information. To use this kind 
of interface, the user only needs to be able to consciously control one bit of 
information over time. The advantage of such an interface is its simplicity. Being 
the simplest kind of interface, it is as “universally accessible” as possible. 
Cyberlink™/Brainfingers lets the user control the mouse cursor and mouse button 
clicks using bio-potentials. The software is configurable, so that different users can 
control the mouse using different EEG frequency bands, and also EOG and EMG, 
or any other appropriate bio-potential.  
 
In addition, table 1 shows there are many BCIs which have been available in the 
market as games consoles. The cost has come down and these are available to the 
general public at an affordable cost. These BCI consoles have the facility to map a 
limited number of bio-potentials as buttons to a keyboard hence we can click a key 
using our bio-potentials. The original work in this area was where an on-screen 
keyboard was used successfully to communicate with a brain-injured user [9]. The 
on-screen keyboard was a series of buttons, the users choose the appropriate key 
using the chosen bio-potential. This process uses the human computer interaction 
principles on usability and makes complicated software in to accessible software.  
 
Hence we can, 
1. translate web links into buttons that opens in a window that can be used to 
navigate a website; 
2. translate application menu into buttons that open in a window and enable 
the user to choose various options; 
3. translate game control keys into buttons that can enable the user to play a 
game; 
4. have optional text-to-sound added for visually impaired users; 
5. enable the buttons to be chosen one by one or scanned at a convenient 
speed. 
 
Button interfaces not only can be used by BCIs but also by mouse, joystick, 
switch, voice recognition, etc. Thus we can enable brain-injured, motor impaired 
and other motor impaired disabled individuals to access mainstream software, web 
and games with ease so that we can have an inclusive society which doesn’t 
alienate the brain injured from the general public. 
 
SUMMARY AND CONCLUSIONS  
    This position paper described the use of Brain-Computer Interfaces (BCIs) that 
can enable a disabled person to access main stream software. This may be a useful 
“stepping stone” for a disabled person before he or she attempts to use a more 
6 
 
sophisticated interface. This one button concept cannot only be used by brain 
injured personnel with BCIs but also by other categories of disabled individuals 
with alternative point and click devices. This paper doesn’t advocate changing the 
most commonly used applications or games but discusses how it can be made 
accessible thereby making it possible for wider audiences. Hence this paper is 
written as a position paper on future research on accessibility and usability of main 
stream software for the brain injured and motor impaired personnel. 
 
 
REFERENCES 
[1] Berbank-Green, B. (2005) One button games. 
http://www.gamasutra.com/features/20050602/green_01.shtml, Retrieved 29
th
 
April 2011 
 
[2] Bickford, R. D. (1987) Electroencephalography. In Adelman, G. (Ed.) 
Encyclopedia of Neuroscience, Birkhauser, Cambridge (USA), 371-373. 
 
[3] Brain Actuated Technologies, Inc. /Cyberlink, http://www.brainfingers.com, 
Retrieved 29
th
 April 2011 
 
[4] Brain Injury Rehabilitation Trust: Brain Injury (n.d.), 
http://www.birt.co.uk/content.asp?page_id=11, Retrieved 29
th
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[5] Broeders, H. (n.d.) The history of the 15 puzzle, 
http://www.xs4all.nl/~hc11/15puzzle/15puzzen.htm, Retrieved 29
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[6] Bronzino, J. D. (2000) Principles of Electroencephalography. In: Bronzino, J. 
D.  (Ed.) The Biomedical Engineering Handbook. Boca Raton, Florida: CRC 
Press. 
 
[7] Cook, A., and Sheikh, A. (2000) Trends in serious head injuries among cyclists 
in England: Analysis of routinely collected data. British Medical Journal 321: 
1055 
 
[8] Emotiv/EPOC headset, http://www.emotiv.com, Retrieved 29
th
 April 2011 
 
[9] Gnanayutham, P., Bloor, C., Cockton, G., (2004) Soft-Keyboard for the 
disabled. In  Miesenberger, K., Klaus, J., Zagler, W., Burger, D., (Eds.), 
ICCHP2004, July 2004, Springer-Verlag Publishers, Paris, 999 - 1002. 
 
[10] Gnanayutham, P., Bloor, C., and Cockton, G. (2005) Discrete acceleration 
and personalised tiling as brain-body interface paradigms for neurorehabilitation. 
CHI 2005. Portland, Oregon: ACM Press, 261-270  
 
7 
 
[11] Gnanayutham, P., and George, J., (2006), Using Human Computer 
Interaction Concepts to Design Interfaces for the Brain Injured, Chapter 1, pp. 2 -
14, ISBN: 960-6672-07-7, Published by ATINER, 2006 
 
[12] Gnanayutham, P., and George, J., (2008), Analysis of Research 
Methodologies for Neurorehabilitation, ATINER, Greece, 2008, July 2008, 
Athens. 
 
[13] Gnanayutham, P., and George, J., (2009) Brain-body interfaces. In 
Stephanidis, C. (Ed.), The Universal Access Handbook, Chapter 37. Taylor and 
Francis 
 
[14] Hagen, C. (1998) The Rancho levels of cognitive functioning (3
rd
 ed.) 
http://rancho.org/patient_education/cognitive_levels.pdf, Retrieved 29
th
 April 2011 
 
[15] Holtzblatt, R., Wendell, J. B. and Wood, S. (2005) Rapid Contextual Design. 
San Francisco, CA: Morgan Kaufmann 
 
[16] Keates, S., Clarkson, J. (2004) Countering design exclusion. Springer-Verlag, 
London, UK. 
 
[17] Lindsay, K. W., and Bone, I. (2004) Neurology and neurosurgery illustrated 
(4
th
 ed.) Churchill Livingston, Elsevier Ltd. 
 
[18] Monti, M., Vanhaudenhuyse, A., Coleman, M., Boly, M., Pickard, J., 
Tshibanda, L., Owen, A., and Laureys, S. (2010) Willful modulation of brain 
activity in disorders of consciousness. New England Journal of Medicine, vol. 362, 
no. 7, pp. 579 – 589 
 
[19] Neurosky/Mindset headset, www.neurosky.com, Retrieved 29
th
 April 2011 
 
[20] New York Times. (2010) Trace of thought is found in 'vegetative' patient. 
February 3 2010, 
http://www.nytimes.com/2010/02/04/health/04brain.html?partner=rss&emc=rss, 
Retrieved 29
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[21] Nielsen, J. (1993) Usability Engineering. San Francisco: Morgan Kaufmann 
Publishers  
 
[22] OCZ Technology/NIA headset, www.ocztechnology.com, Retrieved 29
th
 
April 2011 
 
[23] Ponsford, J. (1995) Traumatic brain injury: Rehabilitation for everyday 
adaptive living. Hove, UK: Psychology Press Ltd, Taylor and Francis Group 
8 
 
 
[24] Powell, T. (1994) Head injury: A practical guide. Bicester: Winslow Press 
Ltd 
 
[25] Romich, B., Vanderheiden, G., and Hill, K. (2000) Augmentative and 
alternative communication. In Bronzino, J. D. (Ed.) The Biomedical Engineering 
Handbook. Boca Raton, Florida: CRC Press. 
 
[26] Starlab/Enobio headset, www.starlab.es/products/enobio, Retrieved 29
th
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2011 
 
[27] Teplan, M. (2002) Fundamentals of EEG measurement. Measurement Science 
Review, Volume 2, Section 2. 
 
 
 
 
 
  
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Table 1: Commercially available BCI hardware 
 
Name Manufacturer Approx Cost in £ 
Cyberlink™ Brain Actuated 
Technologies Inc [3] 
£1400 
Neural Impulse 
Actuator™ 
OCZ Technology [22] £85 
Enobio® Starlab [26] £3150 
EPOC Emotiv [8] £200 
Mindset Neurosky [19] £130 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
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Figure 1 - Cyberlink 
 
 
 
 
 
  
11 
 
Figure 2 – On-Screen Keyboard 
  
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Figure 3 – Button Interface Game 
 
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Figure 4 – Button Interface Puzzle 
 
 
 
 


(n.d.) The history of the 15 puzzle, http://www.xs4all.nl/~hc11/15puzzle/15puzzen.htm,

Actuated Technologies,

Analysis of Research Methodologies for Neurorehabilitation,

Augmentative and alternative communication. In

Brain-body interfaces. In Stephanidis,

Countering design exclusion.

Discrete acceleration and personalised tiling as brain-body interface paradigms for neurorehabilitation. CHI

Electroencephalography.

Fundamentals of EEG measurement.

Head injury: A practical guide.

http://www.emotiv.com,

One button games. http://www.gamasutra.com/features/20050602/green_01.shtml,

Principles of Electroencephalography. In:

Rapid Contextual Design.

Rehabilitation Trust: Brain Injury (n.d.), http://www.birt.co.uk/content.asp?page_id=11,

Soft-Keyboard for the disabled. In

The Rancho levels of cognitive functioning (3 rd ed.) http://rancho.org/patient_education/cognitive_levels.pdf,

Trace of thought is found in 'vegetative' patient.

Traumatic brain injury: Rehabilitation for everyday adaptive living.

Trends in serious head injuries among cyclists in England: Analysis of routinely collected data.

Usability Engineering.

Using Human Computer Interaction Concepts to Design Interfaces for the Brain Injured,

Willful modulation of brain activity in disorders of consciousness.

www.neurosky.com,

www.starlab.es/products/enobio,

Disabled users accessing off-the-shelf software using a button interface

Name not available

https://researchportal.port.ac.uk/portal/services/downloadRegister/134234/Atiner_final_version.pdf

Disabled users accessing off-the-shelf software using a button interface

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