1. A New Approach Parameterization of Cognitive Disabilities Ivo Ramos Maia Martins*1, María Fernanda Cabrera-Umpiérrez*2, Maria Teresa Arredondo*3, Ana María Navarro Cerdá2 * Life Supporting Technologies, ETSIT- UPM Avda. Complutense 30, Madrid, Spain 1 email@example.com 2 firstname.lastname@example.org 3 email@example.com # Asociación ITACA Instituto ITACA, Universidad Politécnica de Valencia. Camino de Vera s/n. 46022. Valencia (Spain) 2 firstname.lastname@example.orgAbstract— This paper focuses on the description of the approach validated within VERITAS, focusing on those models that canused to parameterize the cognitive user models developed under represent the different cognitive, psychological and perceptionthe FP7 EU Founded project VERITAS: Virtual and Augmented processes of elderly, cognitive impaired and physical impairedEnvironments and Realistic User Interactions To achieve people.Embedded Accessibility DesignS. The methodology definedconsists on the identification of standards, rules and guidelines In order to create cognitive models of the target users thatfound on the literature to categorize the cognitive attributes. To can be used within VERITAS accessibility tools, it iscomplete the parameterized cognitive user model it was created a necessary to identify which are the cognitive andrelationship between ACT-R parameters, the affected tasks and psychological functions and corresponding parameters (e.g.the cognitive parameters. A research on existing ACT-R models reaction time, perception, attention, working memory, etc.)is still being carried out in order to obtain functions and values that are related with the defined VERITAS cognitivethat can be suitable for the VERITAS parameterized cognitive impairments and to define recommendations, guidelines anduser models table. The development of the previous method will values that will support the designers and developers’provide useful information to complete this parameterization. decisions at the moment of creation of new products andFutures steps will consist on the integration of the parameterizedcognitive user models into the virtual user models. services. Our paper will focus on the methodology used to define the I. INTRODUCTION relevant cognitive parameters within the context of VERITAS. The use of existing models of the cognitive architecture Nowadays there is a continuous ageing of the European Adaptive Control of Thought-Rational (ACT-R) and thepopulation. It is very important to provide the maximum of relationship with existing medical studies are the main focusindependence to elderly people and people with cognitive of our study.impairments such as cognitive ageing, Alzheimer andParkinson Disease. The development of products and services II. STUDY DESCRIPTION & METHODOLOGYaccessible to everyone is the correct way to achieve thepopulation requirements in the future. The study description will help to understand the context of With this objective, VERITAS project is aiming to this study within VERITAS project as well as the usedoperationalize and revolutionize the accessibility testing at all methodology for modeling VERITAS users.stages of creation of new products in the considered five A. VERITAS User Modelling Methodologyindustrial domains (Automotive, Smart Living Spaces, Virtual user modelling is considered as the core researchWorkplaces, Infotainment and Healthcare) ¡Error! No se issue in VERITAS. The virtual user models will be generatedencuentra el origen de la referencia.. based on existing standards and guidelines but also based on a The goal is to introduce simulation-based and virtual reality multisensorial platform designed and implemented withintesting at all stages of the design process in order to ensure VERITAS that will “sense” the needs of real users withthat future products and services can be “universally” used, disability by measuring their behaviour in simulatedincluding people with disabilities and elders. For creating VR environments .tools with high acceptability amongst users, not only physical, Since, virtual user modelling with disabilities is consideredbut also cognitive and psychological models that represent the a very challenging task which is not yet fully developed, notcognitive capabilities should be integrated in the design even at research level, VERITAS will follow an innovativeprocess. approach of generating virtual user models based on Different theories of human cognitive & psychological combining the results of three different but complementary (inmodelling and interaction should be therefore integrated and most of the cases) approaches. Thus the Virtual user
2. modelling process of VERITAS consists of the following generate, including relevant parameters, measurements andsteps: metrics found in literature and computational modelling - Abstract User Models (AUM) creation that can be approaches. implemented within VERITAS based on Analysis of These models will be - in a second step - refined with the existing models, medical studies, guidelines, Multisensorial platform. methodologies and existing practices, User needs and The Multisensorial platform is used to fine tune the virtual well known accessibility guidelines and standards. models with the result of the interaction of real users and the An AUM represents the different facets of a virtual environments and to provide feedback for quantitative disability. evaluation and verification of the user models .  - Appropriate Task models implementation, based on On one hand, an initial research was made in order to UIML/USIXML language, when users performing determine the most relevant cognitive processes in the context specific tasks and interactions of the cognitive disabilities to be used for representation of the - Iterative update and verification of the models using abstract cognitive user models. These processes were divided the implemented VERITAS multisensorial platform. in two major groups: basic and higher-level processes. - Generation of Generic Virtual User Models (GVUM), The basic cognitive processes are composed by reaction by merging the Abstract User Model with the time, attention (which is subdivided in selective, divided and affected tasks per disability. sustained), memory (subdivided in semantic, episodic, - Creation of the Virtual User Models, by instantiating procedural and working) and perception (subdivided in visual, the GVUM, which represents a specific user with a auditory and haptic).The higher-level group is composed by disability/s. decision making, orientation, and speech and language . Once the relevant cognitive processes were selected, the In the following scheme, the steps followed in VERITAS following step was to determine how the different cognitive for creating a model can be seen: disabilities - Alzheimer, Parkinson and cognitive ageing - affects on the cognitive processes. With this aim, a deep research in medical literature was performed. Table 1 represents the change or affect of the cognitive processes in the normal elderly, early DAT, and early PD. The losses are qualitatively indicated by the + sign. A greater number of crosses indicate a more pronounced degree of severity . TABLE I COGNITIVE PROFILES OF THE ELDERLY AND PATIENTS WITH DEMENTIA OF ALZHEIMER’S TYPE (DAT) AND PARKINSON’S DISEASE (PD) Figure 1 - Representation of the architecture of the VERITAS SP1, methodology to create the virtual user models Ontologies will be used to provide a powerful and growingspecification of the abstract user models. An abstract usermodel stored in the ontology will include the type of userdisability, user capabilities, user needs, characteristics fromcognitive user models, physical user models, behavioural &psycholological user models, guidelines and standards. In the following sections, each element of this schema willbe further detailed under the cognitive perspective.B. Abstract Cognitive User Models An Abstract User Model (AUM) is a descriptiverepresentation of the different dimensions of a human being.In Veritas, a cognitive abstract user model of each cognitivedisability categorizes the representative features of thecognitive and psychological facets of an individual:definitions, types, cognitive functional limitations that may
3. On the other hand, under the perspective of VERITAS measured by comparing the results of the model with thedomains (Automotive, Smart Living Spaces, Workplaces, results of people doing the same task .Infotainment and Healthcare), existing approaches (mainly ACT-R is a hybrid cognitive architecture: its symboliccomputational and cognitive architecture models such as structure is a production system, whereas the subsymbolicACT-R, GOMS, GOMS-Simple, ACT-Simple, EPIC, SOAR, structure is represented by a set of massively parallelPUM, ANNs, Fuzzy Logic and Markov) that address and/or processes that can be summarized by a number ofmodel aspects of the cognitive processes were analyzed . mathematical equations, with parameters. The subsymbolic A state of art with the strengths and weaknesses of these equations control many of the symbolic processes. Formodeling approaches was performed. This analysis pointed instance, whether (or how fast) a fact can be retrieved fromout ACT-R as the most promising and extended modelling declarative memory depends on subsymbolic retrievalapproach, that is consistent with the Abstract User Model equations, which take into account the context and the historyintended in VERITAS: an explicit descriptive model of human of usage of that fact.1cognition and behaviour that can be afterwards parameterized. ACT-R architecture allows, through the subsymbolicIn the following section a complete analysis of ACT-R as structure with parameters, and the symbolic structure (taskreference cognitive architecture will be shown. models) the generalization of new situations, users and domains, which means that allows a wide variation amongC. The ACT-R research approach models. The cognitive architectures are theories to simulate andunderstand how the human mind works. They are based on D. Cognitive moderators in ACT-R: Disabilities as overlayscognitive psychology theories and assumptions and are An overlay is a technique for including a theory of how aimplemented in a computer program that uses knowledge moderator (ie: aging) influences cognition across all modelsrepresentations to reproduce the human thinking  . within a cognitive architecture . An overlay is an The Adaptive Control of Thought-Rational (ACT-R) was adjustment or set of adjustments to the parameters orthe selected cognitive architecture to obtain the missing values mechanisms that influence all models implemented in theand parameters for the different disabilities. It provides a architecture to reflect changes due to an altered mental state orconceptual framework for the creation of the models of how due to long term changes such as development . The mainpeople will perform the tasks. It reproduces assumptions about idea of an overlay is to change the architecture in such athe human cognition based on facts resultant from psychology manner that the behavior of all models developed under thatexperiments. ACT-R uses a modular organization, which architecture will be affected.means that the cognition emerges from the interaction of In many architectures, such as the one described here,independent modules, each of them is related with a function ACT-R, there are a set of mechanisms and a number ofand specific regions of the brain (Figure 2). parameters that play a role in the model’s functioning; an overlay will modify a combination of parameters and mechanisms to represent situation specific but relatively long acting changes to information processing. For example, an eyeglasses overlay would allow more inputs to be passed to the vision processor; a caffeine overlay could increase processing speed by 3% and improve vigilance by 30% . Overlays are based on popular theories and studies about cognitive and behavioural moderators that can be applied to cognitive architectures. The goal is to specify mechanisms that can be implemented within the architecture or changes to current mechanisms to simulate the effect of the cognitive impairments on embodied cognition. These theories are typically not cast as additions to the knowledge necessary to perform a task (it would mean creating a cognitive model), but are described as changes to how people process information under a psychological state. Thus, they make suggestions about process, about how the mechanisms of embodied cognition change across all tasks under this facet. In the case of VERITAS, an analysis was performed in Figure 2 - ACT-R 6.0. Each ACT-R module is associated with a function order to determine these overlays: the values of the parameters (from the subsymbolic structure) per cognitive disability that Different models written in ACT-R are created per eachtask. Beside the incorporation of the ACT-R’s view ofcognition it is necessary to incorporate assumptions about theparticular task. The veracity of these assumptions can be 1 http://act-r.psy.cmu.edu/about/
4. were related with the cognitive processes (high level and low- TABLE II RELATION BETWEEN ACT-R (SGP) PARAMETERS AND VERITAS COGNITIVElevel) detected in the AUM. PARAMETERS After that, a wide literature research has been conducted inorder to extract the values of these parameters for the differentVERITAS end-users: elderly and cognitive impaired indifferent domains. For example, the ACT-R parameter activation spread (:ga)of the goal module is related with the VERITAS basiccognitive process memory. According with the research madeso far it is possible to say that the value of the activationspread parameter (:ga) for moderate Alzheimer is 0,68. Currently, an ongoing research is focusing on extractingproduction task models that correspond to the primitivecognitive task models defined in VERITAS, The final development of the ongoing research will provideuseful information to complete the parameterized cognitiveuser models. One of the major difficulties is the largeunpredictability and variability that different persons with thesame cognitive problem can have while performing the sametask. To improve the obtained results, would be necessary alarge research in collaboration with psychologists and users inorder to develop ACT-R models per each task.E. Virtual User Models The creation of Virtual User Models is considered as thecore research issue in VERITAS. They will be generated froman instantiation of the Generic Virtual User Models . Their creation is based on the result of the unification of the The ACT-R parameters listed in the table II, intrinsicallyAbstract User Models, the collection of parameters, the ACT- (meaning at a subsymbolic level) correspond to a specificR productions that are related with the primitive tasks, the ACT-R module (Figure 2), which, at the same time, areresult of the measurements and the feedback of real users related with the different cognitive processes relevant forobtained with the Multisensorial Platform. VERITAS previously described. Literature has shown that two disabilities may share the same parameters and value – for instance, medical literature shows that Parkinson and Alzheimer at level 1 have the same CRD value –. In those cases, we can use analogy to transfer the value of the corresponding ACT-R parameter of a specific disability (Alzheimer) to the same parameter of the other disability (Parkinson). The use of results from medical studies is then a useful way Figure 3 - Process of creation of the Virtual User Model to obtain values for overlaying the equations that represents the cognitive processes. The Generic Virtual User Models will be used by the user So far we have 5 ACT-R (sgp) parameters related withmodel generator to create instances of the Virtual User cognitive ageing, 12 related with Alzheimer’s disease and 5Models per each application scenario (Figure 3) . related with Parkinson’s disease. All these values are related The Virtual User Models will be described with the use of as well with the VERITAS cognitive processes and primitiveontologies for the representation of the Abstract User Models tasks.and UIML/USIXML files for the association of the virtualusers with tasks. The final step is their inclusion on the IV. CONCLUSIONS AND NEXT STEPSsimulation platform in SP2 (Innovative VR models, tools and Though the study is not yet finalized, so far we are able tosimulation environments) . conclude that it is possible to find ACT-R studies related with the VERITAS cognitive parameters which will be relevant to III. RESULTS model VERITAS end-users with cognitive impairments. Table II shows the list of the ACT-R (sgp) parameters Mostly, the parameters are values and ranges.found so far in literature and medical studies that are It is also important to refer that with the research in medicalconnected with VERITAS primitive tasks and cognitive studies related with the disabilities previously referred, weprocesses. were able to find values (i.e. CDR of Alzheimer studies with
5. the Parkinson’s disease) that were useful to use as well in theACT-R modelling process. Finally, it has to be mentioned that to improve the obtainedresults and to extract missing values, a large research incollaboration with psychologists and users would be necessaryin order to develop ACT-R models per each task. ACKNOWLEDGMENT Authors thank the VERITAS consortium for theircontribution to this work. REFERENCES VERITAS project (IST- 247765) Annex I- Description of Work 2009. V. Kolodyazhniy, M. Delahaye, Mariya Goranova Valkova, Karel Van Isacker, Andrean Lazarov, Maria de las Mercedes Fernandez- Rodriguez, Tamara Aguilar, Rocío Zaragoza, Ana Navarro, Juan Carlos Naranjo, Héctor Galán. VERITAS project (IST- 247765) Deliverable D1.4.1 - Abstract Cognitive User Models 2010 Anderson, J., Bothell, D., Byrne, M., Douglass, S., Lebiere, C., & Qin, Y. (2004). An integrated theory of the mind. Psychological Review, 111(4):1036–1060. Ritter, F. E., Reifers, A. L., Klein, A. C., & Schoelles, M. J. (2006). Lessons from defining theories of stress. In W. Gray (Ed.) Integrated Models of Cognitive Systems. New York, NY: Oxford University Press. Jones, G., Ritter, F. E., & Wood, D. J. (2000). Using a cognitive architecture to examine what develops. Psychological Science, 11(2), 93-100. Hans-Joachim Wirsching. VERITAS project (IST- 247765) Deliverable D1.6.1 - Implementation of VERITAS virtual user model platform 2010. Abel Serra, Juan Carlos Naranjo and Ana María Navarro, Eleni Chalkia. VERITAS project (IST- 247765) Deliverable D1.6.2 - UIML/USIXML task modelling definition 2010.