control of virtual environments for young people with learning difficulties
TRANSCRIPT
Control of virtual environments for youngpeople with learning di� culties
T. LANNEN*, D. BROWN and H. POWELL
Department of Computing, Nottingham Trent University, UK
Abstract
Purpose: The objective of this research is to identify therequirements for the selection or development of usable virtualenvironment (VE) interface devices for young people withlearning disabilities.Method: A user-centred design methodology was employed, toproduce a design specification for usable VE interface devices.Details of the users’ cognitive, physical and perceptual abilitieswere obtained through observation and normative assessmenttests.Conclusions: A review of computer interface technology,including virtual reality and assistive devices, wasconducted. As there were no devices identified that metall the requirements of the design specification, it wasconcluded that there is a need for the design anddevelopment of new concepts. Future research will involveconcept and prototype development and user-based evalua-tion of the prototypes.
Introduction
Recent research in virtual environment (VE) applica-tions for people with learning disabilities has highlightedusability di� culties with the computer interface devices,which are used to perform the VE tasks. For example,from an evaluation of VEs, developed to teach indepen-dent living skills to people with learning disabilities, itwas found that individuals diVered in the amount ofsupport required to use the input devices; joystick fornavigation and mouse for interaction.1 This paperdescribes research undertaken to identify the require-ments for the selection or development of usable VEinterface devices for young people with learning disabil-ities.
VIRTUAL ENVIRONMENTS
VEs have been found to be of educational bene®t forpeople with learning disabilities.2, 3 Before describingthese bene®ts, what are VEs? They are three-dimen-sional computer simulations, which respond in real timeto the activity of their users, see ®gure 1. One of the ®rstapplications of VE technology was in ¯ight simulationto train pilots within a safe environment. Their use iscontinually progressing in many areas, such as architec-ture, medicine, rehabilitation and education. There aretwo independent phases of operation within a VE: navi-gation and interaction. Navigation, with 2 degrees offreedom, allows movement forwards, backwards andturning to the left or right. Interaction includes activat-ing VE objects (i.e. opening a door), moving VE objectsfrom one place to another or using one object withanother (i.e. using a spoon to take some sugar from asugar bowl). The sense of presence within a VE is depen-dent on the input and display devices used. A high levelof participant immersion can be achieved using a head-mounted display with a specialised input device, such asa data-glove. Desktop VE systems are also in wide-spread use, which utilise a computer monitor to displaythe VE and standard input devices, such as a joystick,mouse or keyboard, see ®gure 2. This hardware combi-nation can also lead to a sense of presence and generally,desktop systems are preferred when working with peoplewith learning disabilities due to the unresolved healthand safety issues and high cost associated with head-mounted display units.
VE BENEFITS
Research has indicated numerous bene®ts in the useof VEs for the education and training of people withlearning disabilities.1, 2 They encourage active participa-tion in learning and give the user control over the learn-ing process. They facilitate playful activity, by allowingindividuals to learn by making mistakes without suVer-
* Author for correspondence; e-mail: [email protected]
DISABILITY AND REHABILITATION, 2002; VOL. 24, NO. 11-12 , 578 ± 586
Disability and Rehabilitation ISSN 0963±8288 print/ISSN 1464±5165 online # 2002 Taylor & Francis Ltdhttp://www.tandf.co.uk/journals
DOI: 10.1080/0963828011011134 2
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ing the consequences of their errors. VEs are describedin terms of realistic and graphical representations ofthe real world. Hence, they avoid abstract thought,which has been found to be particularly di� cult forpeople with learning disabilities, who are often describedas `concrete thinkers’.3 Finally, they can minimize theeVects of many physical disabilities and allow studentsto take part in activities or visit places that might beinaccessible to them in real life.
MOST SUITABLE INPUT DEVICES
Studies on the most appropriate methods of VEcontrol for people with learning disabilities have beenconducted. Hall4 concluded that a joystick, limited totwo simultaneous degrees of freedom, had the greatestutility in VE navigation tasks. A study by Brown etal.5 found that the joystick was more suitable for naviga-tion tasks than the keyboard or mouse. The touch-
screen and mouse were assessed for interaction tasksand the students coped very well with both devices,however, di� culties were found in using the touch-screen to interact with small objects and with calibrationof this device. From these studies it can be concludedthat, from the range of input devices tested, the joystickand mouse are the most suitable navigation and interac-tion devices respectively.
USABILITY DIFFICULTIES
Neale et al.6 conducted an evaluation of VEs for theeducation of children with severe learning disabilities.The devices utilised in this study were the joystick fornavigation tasks and the mouse or touch-screen forinteraction tasks. It was found that:
. restricted movement space was di� cult to navigateand led to user frustration; and
. teacher assistance was required for some interactiontasks.
It is important to note that participant selection forthis study was based partly on ability to control theinput devices. Although the navigation di� culties foundwere software related, it is the author’s belief that, theoverall usability of the system would be enhanced byre®ning the input devices as well as the software inter-face. In the aforementioned study by Cobb et al.,1 itwas found that individuals diVered in the amount ofsupport required to use the input devices; joystick fornavigation and mouse for interaction. It was also statedthat navigation was found to be one of the most di� culttasks to do. This research by Neale et al.6 and Cobb1 hasshown that there are usability di� culties with the inputdevices, which have been found to be the most suitablefor navigation and interaction tasks, from the range ofdevices tested by Hall4 and Brown et al.5
SOLUTIONS
From the study by Brown et al.5 the following require-ments for input device design or re®nement were identi-®ed: operable by people with ®ne-motor di� culties,modi®able, robust, easy to calibrate and aVordable.Lannen7 developed a prototype interface device, theMojo interactive seat, which meets some of theserequirements: operable by people with ®ne-motor di� -culties, modi®able and aVordable, see ®gure 3. Mojowas compared with a joystick for control of a VE navi-gation task by students with moderate to severe learningdisabilities, some of whom were also physically
Figure 2 A standard input device for controlling virtual
environments.
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impaired.8 From the results it was clear that less disor-ientation occurred when using Mojo, however, bothdevices would require re®nement to provide an adequatesolution to this human-VE interaction problem.
A review of computer interface technology, includingvirtual reality and assistive devices, was conducted.Assistive devices have been designed to improve accessto computers for people with a wide range of disabilities,for example voice and gesture recognition, eye and headtracking and brain wave control. However, no researchhas been found which investigates the use of suchdevices for the control of VEs for people with learningdisabilities. It has also been expressed that the cost ofthe technology mentioned would currently be too greatfor most individuals and some organisations.5
CONCLUSION
The research by Neale et al.6 and Cobb1 showed thatthere are usability di� culties with the joystick andmouse, which were found to be the most suitable devicesfor people with learning disabilities to control VE tasks.However, this research was not speci®c about the kindsof di� culties that are experienced with these devices.Therefore it was decided that the next step would beto conduct a thorough evaluation of the joystick andmouse, in order to identify the speci®c usability di� cul-ties experienced and to clarify how research shouldprogress.
INPUT DEVICE EVALUATION
Aim
To identify the usability di� culties, which youngpeople with learning disabilities experience when usingthe joystick and mouse for VE navigation and interac-tion tasks respectively.
User group
Fourteen students were selected from the ShepherdSchool in Nottingham to form the user group. The usergroup attributes were as follows:
. gender: 7 female and 7 male;
. age range: 7 to 19;
. cognitive ability: 2 moderate/severe and 12 severelearning disabilities; and
. physical ability: co-ordination, gross-motor and ®ne-motor di� culties.
Environment
The evaluations took place at the Shepherd School, intheir `Cyber Cafe ’ room. For some evaluations, theroom was quiet and mostly free from distraction.During the majority of evaluations, other studentswould come and go from the room, but would notattempt to disturb the user.
Equipment
The VEs were displayed on a colour computer moni-tor and a standard two-button mouse was used for inter-action tasks. Initially, the Axys joystick (SuncomTechnologies) was used for navigation tasks. However,as some of the students were experiencing di� culties ingripping the stick on this device, the last 4 students usedthe Wingman joystick (Logitech). The stick on theWingman joystick is much taller and wider than theAxys joystick and is shaped to ®t the hand, see ®gure 4.
Task
Each student was asked to complete navigation andinteraction tasks, using the joystick and mouse respec-
Figure 3 MojoÐinteractive seat for VE navigation.
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tively, within a virtual factory, cafe or supermarket.Demonstrations of the devices and tasks were givenbefore commencing the evaluations.
Assessment measures (AMs)
. misuse of device: non-task related movement,harshness, pressing the wrong buttons, etc.;
. support required: spoken instruction, physicalassistance, etc;
. physical ability: su� cient strength, able to gripproperly, etc.;
. workplace: able to reach, etc.;
. attention: on task, on device, on other; and
. user comments/reactions: positive, negative.
RESULTS: USABILITY DIFFICULTIES
Due to physical ability and device construction eightof the students in the user group were able to controlthe mouse and the joystick they evaluated quite well.However, this group still experienced usability problemswith the devices (identi®ed using AMs 1 ± 3): too muchleft/right rotation, button misuse, base held still byexaminer and grip di� culties with the joysticks; baseheld still to press button and grip di� culties with themouse. In the author’s opinion, these di� culties arelargely due to the construction of the devices and thephysical abilities of the user group, rather than to theuser’s understanding of how to use each device. It wasobserved that the Wingman joystick is easier to gripthan the Axys joystick, due to its size and shape, high-lighting the importance of ergonomic design for increas-ing usability.
Due to cognitive ability
It is the author’s belief that the di� culties experiencedby the remaining 6 members of the user group arerelated to their cognitive understanding of how to use
the devices: random movement and trying to use forinteraction with the joysticks; random movement andfrequent pressing of buttons with the mouse (identi®edusing AM 1). To overcome these di� culties it may benecessary to gain a deeper knowledge of the users’cognitive and perceptual abilities, so that the devicescan be re®ned to an appropriate level of understanding.
Due to task and environment
As the joysticks and mouse were not speci®callydesigned to be used by people with learning disabilitiesto control VEs, there may be certain VE tasks for whichthey are more di� cult to use. This is evident from thisevaluation, as physical help was required with the inputdevices to complete some tasks by 12 of the students.For example, one student required physical assistancewith the Axys joystick to align his position in front ofthe exit doors in the virtual factory. Finally, 5 membersof the user group were distracted by other students andactivities in the evaluation room (identi®ed using AM 5).Design guidelines were suggested, which should help tofocus the students’ attention on the VE, for example,`workstation helps to engage the user’.
CONCLUSION
This evaluation has highlighted the importance ofconsidering the physical and cognitive abilities of theuser group, as well as the tasks that the user mustcomplete with the input devices, and the environmentin which the tasks will be performed, in order to developa usable computer interface device. This theory isbacked up by contemporary human-computer interac-tion (HCI) research, which also stresses that you shoulddesign for the user, the task and the environment.9 Inuser-centred design, the ®rst research activity performedis to `understand and specify the context of use’. Thiscan be achieved by conducting a Usability ContextAnalysis (UCA), which involves a user, task and envir-onmental analysis. Therefore, it was decided that auser-centred design methodology would be employedin order to ascertain the requirements for the selectionor design of usable VE input devices, for young peoplewith moderate/severe learning disabilities.
User-centred design
METHODOLOGY
Usability is a crucial factor in the production of asuccessful human-computer interface and is central to
Figure 4 The Wingman joystick (Logitech) and the Axys joystick
(Suncom Technologies).
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the user-centred design process. The usability of aproduct is de®ned in ISO 9241, part 11 (the British Stan-dard giving guidance on usability) as `the extent to whicha product can be used by speci®ed users to achieve speci-®ed goals with eVectiveness, e� ciency and satisfaction ina speci®ed context of use’. According to the ISO 13407standard (human centred design processes for interactivesystems) the key activities in user-centred design are:
. understand and specify the context of use;
. specify the user and organisational requirements;
. produce designs and prototypes; and
. carry out a user-based assessment.
The user-centred design methodology, which has beenemployed for this research project, was formed bycombining established guidelines on user-centreddesign10, 11 with contemporary human-computer interac-tion and product design research.
(1) Understand and specify the context of use: UCAÐuser, task and environment analysis.
(2) Specify the user and organizational requirements:identify design requirements (from UCA data);product analysis (identify device attributes); anddesign speci®cation (DS).
(3) Technology review: virtual reality, assistive andgeneral computer interface devices.
(4) Produce concept designs and prototypes.(5) Carry out a user-based assessment: produce
evaluation plan (including a usability speci®ca-tion); conduct usability evaluation; and user-derived feedback used to re®ne the prototype(s) .
Steps (1), (2), (4) and (5) are repeated until the usabil-ity metrics, outlined in the usability speci®cation havebeen attained, see ®gure 5.
User group and usability team
A user group of 21 students was selected from pupilswho attend the Shepherd School in Nottingham. Four-teen of these students had previously participated inthe Input Device Evaluation. Students were selectedwho seemed to enjoy using computers and showed anunderstanding of how to use the VEs. The studentsranged from age 7 ± 19, with ®ve primary, eight second-ary and eight from the 16+ department of the school (9of the students were female and 12 were male).
A usability team was formed to advise and monitor theproject development, by reviewing the UCA data, designspeci®cation, concept designs, usability speci®cation and
usability evaluation feedback. This multi-disciplinaryteam included: project advisors; the design engineer;human-computer interaction and special needs experts;a usability specialist and an occupational therapist.
Understand and specify the context of use
This activity was achieved by conducting a UsabilityContext Analysis (UCA), which included a user, taskand environment analysis. The UCA guidelines availablefrom Serco Usability Services12 and the relevant sectionsof the USER®t toolkit11 were utilized for this research.
USER ANALYSIS
Information was gathered about each member of theuser group, on their attributes, which could aVect theusability of the input device: skills and knowledge;physical, cognitive and perceptual abilities; communica-tion; behaviour and motivations. This data wasobtained through various sources, including generalobservation, the students’ educational ®les and norma-tive assessment tests.
User group&
usability team
Usabilitycontext analysis
Product needidentified
User &organizational
Designspecification
Concept andprototype design
User-basedassessment
Meets usabilitymetrics
Technology review
Figure 5 The user-centred design cycle.
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Cognitive ability
In order to gain some understanding of the cognitiveabilities of the user group, two normative assessmenttests were used:
. the BPVS-II (British Picture Vocabulary Scale): a testof receptive English vocabulary, which correlateshighly with verbal intelligence; and
. the MAT-SF (Matrices Analogies Test-Short Form):a test of non-verbal reasoning.
The results from these tests, shown in table 1 andtable 2a, b, indicate that the students in the user groupare in the moderate to severe level of cognitive function-ing.
Physical ability
Details of the ®ne and gross motor abilities of the usergroup were obtained through the QNST-II (QuickNeurological Screening Test) and the students’ educa-tional ®les. The tasks on the QNST-II provide an oppor-tunity to observe the students’ skill in controlling grossand ®ne muscle movements and their motor planningand sequencing abilities. Table 3 shows some examplesof the students’ ®ne and gross motor di� culties.
Perceptual ability
Details of the perceptual abilities of the user groupwere also obtained through the QNST-II, with furtherinput from the students’ educational ®les. The maindi� culties experienced were with spatial awareness,ordering and sequencing, mixed laterality and bilateraltasks (those involving use of both hands).
Task analysis
A hierarchical task analysis, described by Dix et al.13
was carried out. In this process the primary tasks arebroken down into subtasks, which are further brokendown, see ®gure 6. This analysis is used to determinethe product design requirements, which are necessaryto carry out each element of the main tasks.
Environment analysis
Table 1 The results from the BPVS-II
CA Sex AE SS SD Score range
8:04 F 4:04 68 -2 ELS-MLS10:07 F 3:02 40- -4 ELS11:07 F 3:09 41 -4 ELS7:03 M 3:02 63 -2.5 ELS8:04 M 3:02 54 -3 ELS12:10 F 5:08 50 -3.4 ELS14:10 F 3:05 40- -4 ELS15:07 F 7:09 51 -3.3 ELS15:00 M 5:05 40- -4 ELS15:02 M 5:08 40- -4 ELS15:03 M 4:08 40- -4 ELS16:04 M 6:01 40- -4 ELS17:04 F 6:08 42 -4 ELS18:10 F 3:02 40- -4 ELS18:11 F 4:08 40- -4 ELS16:11 M 9:10 64 -2.4 ELS-MLS17:08 M 3:09 40- -4 ELS18:00 M 7:03 47 -3.5 ELS18:09 M 6:05 40 -4 ELS19:03 M 3:04 40- -4 ELS
Average 46 -3.7 ELS
CA=chronological age; AE=age equivalent; SS=standardized score;
SD=standard deviation; ELS=extremely low score; MLS=mode-
rately low score
Table 2a The results from the MAT-SF
CA Sex AE S
8:06 F 6:08 310:09 F 5:00 111:09 F 5:06 17:05 M 6:11 58:06 M 5:00 213:01 F 7:02 115:01 F 55:00 115:09 F 6:04 115:02 M 7:06 115:05 M 6:04 115:05 M 6:11 116:01 M 6:08 116:06 M 6:11 117:06 F 6:08 119:00 F 5:11 119:01 F 6:04 117:01 M 7:02 117:10 M 55:00 118:02 M 6:04 118:11 M 5:11 119:02 M 55:00 1
Average 1
S=stanine
Table 2b Description of stanine scores
Stanine Stanine description
1 At high risk of academic failure2 At risk of academic failure3 Academic problems are possible4 Low average5 Average6 High average7 Academic success is likely8 Superior9 Very superior
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This study included an analysis of the organisational ,technical and physical factors of the environment inwhich the product will be used. By gaining an under-standing of these factors, a computer input device canbe selected or developed to ®t the task environment.Table 4 details a selection of these environment factors.
SPECIFY THE USER AND ORGANISATIONAL REQUIREMENTS
Design requirements were extrapolated from the user,task and environment details obtained through theUCA. These requirements are design decisions, whichshould help to increase the usability of the computerinput device(s) for the user group. Further informationwas required about many of the user group di� cultiesthat were identi®ed during the user analysis. Hence, alist of these di� culties was sent to speci®c members ofthe usability team (occupational and physiotherapist
and an educational psychologist) for their expert know-ledge and suggested design requirements.
A product analysis was then conducted in order todescribe how the design requirements could be metthrough speci®c device attributes. Examples of thedesign requirements and device attributes are shown intable 5.
Design speci®cation
The device attributes were collated in a design speci®-cation and separated into categories, for example,product appearance, ergonomic design, interface andfunctional assistance, cognitive and physical factors.Additional important aspects to a product’s design,which contribute to its success, were added to the designspeci®cation. These include: performance, production,life in service and conformance requirements. Thedesign speci®cation is the main input to the conceptdesign stage of the design process and therefore ensuresthat the design requirements are carried through to theproduction of a usable prototype.
This speci®cation was also sent to the members of theusability team for suggested amendments and additions.A novel idea for the design requirement `teacher assis-tance available’ was oVered: the `driving instructor’, adual control device, which allows the teacher to guidethe learner through the VE.
Table 3 Examples of physical attributes of the user group
Fine motor dif®culties Gross motor dif®culties
Clumsy pen grip: 10 Uses a special chair: 1Slight hand tremor: 3 Cerebral Palsy in legs and right arm: 1Limited wrist movement: 6 Unsteady arm movement: 2Motor planning dif�culties: 19 Co-ordination: 14
Figure 6 Hierarchical task analysis for VE control.
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Technology review
The primary aims of the technology review were toidentify any existing computer interface devices that,with adaptation, could provide a potential solutionand to identify opportunities for innovation. Thefollowing areas were reviewed, with reference to thedesign speci®cation: virtual reality, assistive and generalcomputer interface technology and gaming interfacedevices.
FINDINGS
Several devices were found to possess a few of thedevice attributes in some of the design speci®cation cate-gories. For ergonomic design, the Anir ErgonomicMouse has been designed to help avoid repetitive straininjuries (RSI), to partly satisfy the requirement`conforms to health and safety standards’. The Fire-Storm is a games console, which satis®es `form indicatesinterface’ and `haptic sensation with user action’, whichare interface and function assistance attributes. For thephysical factors category, the Roller II joystick `providesassistance to user actions’, with its latching drag featureand is of a `robust construction’ (see ®gure 7).
The Tilting Games Pad was found to be the `closestconcept’, matching a signi®cant number of the device
attributes listed in the design speci®cation. Visually, itwould appeal to the user group, with its `modern style,attractive colours’. The device is worn by adorning aglove, hence the `form indicates the interface’ (interfaceand function assistance). The user is required to tilt orwave their hand for the software to react, which suggeststhat the cognitive factor `movement in VE same as useraction’ could be ful®lled. However, the user movementsrequired may not be appropriate for all VE applications.
CONCLUSION
This technology review has highlighted interestingsolutions to a number of the device attributes outlinedin the design speci®cation. However, as there were nodevices identi®ed that met all of the device attributes,it can be concluded that there is a need for the designand development of new concepts.
Future research
PRODUCE CONCEPT DESIGNS AND PROTOTYPES
The product design methods described by Baxter,14
for concept and prototype design, will be utilized for thisstage of the design process. Initially, many concepts willbe generated through employment of the concept
Table 4 Environment factors
Organization factor Description
Assistance Teacher/carer may be requiredInterruptions Other students may distract userTechnical Factor DescriptionSoftware to run product Windows and VE platformReference materials Manual for system set-up and maintenancePhysical environment DescriptionAuditory conditions Noise of teachers, students and equipmentHealth and safety Access to workplace, computer use and physical interaction
Table 5 Examples of design requirements and device attributes
UCA details Design requirement
Age range: 7:05 to 19:00 Age appropriate appearance (7 – 19)Slight hand tremor Will not detect unintentional movementsBPVS-II: Extremely low score range Minimum user input for task completionSpatial awareness dif�culties Provides visual cues to interface and functionDesign requirement Device attributesAge appropriate appearance (7 – 19) Modern style, attractive coloursWill not detect unintentional movements Calibration to damp out unintentional movementMinimum user input for task completion One user action=one VE functionProvides visual cues to interface and function Form indicates interface and function
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generation methods, with reference to the design speci®-cation. Concept selection techniques will then be utilizedto select the best concept against the design speci®ca-tion. Storyboards and sketches will be used to presentconcepts to the usability team and user group for modi-®cation and new idea generation. The selectedconcept(s) will go through embodiment design, whichtakes a concept and develops it to the point at which afull working prototype can be made. Finally, engineer-ing drawings, which are the output from embodimentdesign, will be followed to produce the evaluation proto-type(s).
CARRY OUT A USER-BASED ASSESSMENT
A user-based assessment of the prototype(s) will becarried out to evaluate the extent to which the userand organisationa l requirements have been met, and torecommend how the device(s) should be re®ned. Theprocedures, which will be followed, are described inthe `handbook of user-centred design’10 and the `usabil-ity engineering’ section by Faulkner.9
An evaluation plan will identify the resources requiredand the intended methodology, which will describe howthe data will be collected. This planning also involves thepreparation of a usability speci®cation, which lists theusability attributes and usability metrics. The usabilityattributes de®ne the success of the prototype(s) , i.e.user-satisfaction, and the usability metrics determine
how the attributes will be measured. A selected usergroup of students with moderate/severe learning disabil-ities will then use the prototype(s) to complete a pre-de®ned set of tasks within a VE. The results will beanalysed and recommendations made to re®ne theprototype(s).
A process of evaluation, design re®nement and re-evaluation will be carried out until the usability metrics,outlined in the usability speci®cation have been attained.The completion of this study should result in theproduction of a VE interface device for young peoplewith moderate/severe learning disabilities, which satis-®es ISO 9241 (the British Standard giving guidance onusability).
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Figure 7 Roller II Joystick (Penny & Giles Computer products).
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