Using Virtual Environments for Stroke Rehabilitation

Lidia S. Cardoso1, Rosa Maria E. M. da Costa2, Alberto Piovesana2, Michele Costa1, Livia Penna1, Ana Cristina Crispin1, Juliana Carvalho1, Hebert Ferreira1, Manuel Leite Lopes1, Gustavo Brandão1 and Raphael Mouta1

Abstract - The aim of this article is to present partial results of a pilot study that explores computer technology to enhance some cognitive and executive functions of patients who had a stroke. They each experienced activities that stimulate cognitive functions in virtual environments, which present some activities related to day-to-day situations.

I. INTRODUCTION

HE incidence of traumatic brain injury and stroke is very high. The association of the neuroimage and computer technologies provide a major impetus to define strategies

to stimulate the cognitive and executive functions associated to brain damaged areas. Previous studies had discussed the use of computers for cognitive rehabilitation. In this domain, varied virtual environments (VE) have been experimented in clinical treatment of people with different neuropsychiatric disorders. Placing those persons in a VE is a way of enhancing their environmental interaction.

Despite some researchers, which consider that the neuropsychiatric rehabilitation is still a relatively undeveloped field [1], we are observing an increasing interest in this area that explores diverse theories and technologies. Recently, we had some interesting results that are relevant in opening new possibilities to the Virtual Reality (VR) application in treatment of brain damage patients. Katz et al. [2] compared an intervention with a computer based visual scanning tasks and a VE 3D and found that VR intervention surpassed the scanning tasks in effectiveness. Some studies consider that the virtual experience must be combined to real life similar tasks to generate benefit for patients [3], [4]. According to You et al. [5], VR and associated technologies are new promising computer applications to motor recovery in stroke, as observed in Adamovich et al. [6], whom developed a haptic glove associated to a virtual system to train hand motion. In this case, the patients showed improvement in one combination of movement parameters. The authors considered that the system Manuscript received April, 2006. This work was supported in part by the National Council for Scientific and Technological Development (CNPq) under Grant MS/021/2004 and Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ).

1 Authors are with the Universidade Federal do Rio de Janeiro – UFRJ, Laboratório de Neuropsicologia e Cognição - FM/UFRJ Hospital Universitário Clementino Fraga Filho -11º andar, Bl. F, s. 15 Av Brigadeiro Trompowsky, s/n, Cidade Universitária-Ilha do Fundão- 21941-590, Rio de Janeiro - RJ – Brasil (e-mail: lidiacardoso@hucff.ufrj.br)

2 Authors are with the Universidade do Estado do Rio de Janeiro – UERJ, IME – Dept de Informática e Ciência da Computação Rua São Francisco Xavier 524- 6o andar – Bl. B, 20550-013 Rio de Janeiro - RJ – Brasil (e-mail: rcosta@ime.uerj.br)

can be used with patients with hand dysfunction. In general, as cognitive problems rarely occur isolated, we

need to address emotional, social, and behavioral problems simultaneously the cognitive rehabilitation process. Models of cognition, emotion, psychosocial functioning, and behavior have potential value in identifying problems and helping to plan treatment [7], [8]. It is also essential that skills (re)learned within a VE must be transfer to correspondent real-world situations [4]. As the application of RV in this area has these particularities, there are some rehabilitation models that consider the steps involved and must be appropriate to the singularity of VR technology [9], [10].

The rehabilitation process has other key principles like the personal characteristics and results from neuropsychological tests which enable the application of virtual therapeutic strategies [11], [12].

These and other results of latter studies, showed VR to be useful for the improvement of motor and cognitive functions in post-stroke patients. Moreover VR is considered as the most advanced evolution of the relationship between man and computers [13].

The objective of this paper is to describe some results of an experiment made with patients with left cerebral hemisphere stroke.

This paper is organized as follows, in the second Section executive functions are defined; the third Section discusses the role of VR to stimulate the cognitive and executive functions. The forth Section presents initial results of the experiment and the Discussion Section presents some final remarks. All these experiments aim to reorganize the cortical process and some results suggest that VR stimulates cortical reorganization, providing evidence for neuroplasticity [5].

II. THE EXECUTIVE FUNCTIONS

The cognitive dysfunctions can be classified by making distinctions between the loss (partial or complete) of the basic instrumental cognitive functions (such as attention, memory, language, visual-spatial abilities, etc.), and the loss of executive functions (also called central or control functions). These are generally referred to a group of behavioral skills that include: the ability of planning a sequence of actions, the ability of maintaining attention in time, the ability of avoiding the interfering stimuli and using the feedback provided by others, the capability of coordinating more activities together at the same time, the cognitive and behavioral flexibility, and other abilities used to cope new situations and stimuli [14]. “Executive function” refers to the capacities for formulating goals and carrying out plans effectively. They are essential for independent, creative, and socially constructive behavior [15].

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There is a consensus among researchers that executive functions are mainly impaired due to frontal lobe damage.

Frontal lobe syndrome is primarily a consequence of brain injury located in prefrontal cortex area, but many different categories of subjects can be characterized by the same syndrome and by similar symptoms, with different levels of severity and various forms of resulting behavior: patients suffering of different forms of dementia (Alzheimer Disease, Frontal or Frontal-Temporal Dementia, etc). As Damasio [16] pointed out, in the complex everyday life tasks, the same patients may show great limits, decisional problems and inabilities connected with high levels of psychosocial suffering. It has been demonstrated that traditional tests of frontal lobes function may fail to document abnormality: this “diagnostic insensitivity” may cause problems between patients and health care services and can inhibit treatment‘s outcome prediction. Damasio’s famous patient Elliot not only had normal performances in the standard “frontal” cognitive tests, but in the lab assessment he showed normal responses to the proposed social situations, he planned strategies and he demonstrated to be able to evaluate correctly the consequences of actions in social situations. The same patient showed a severe decisional impairment and emotional deregulation in his real life environment, especially related to social situations. Elliot is described as the prototype of the hi-functioning frontal patient who experiments severe problems in his daily life.

From the point of view of cognitive rehabilitation, if we consider that the traditional protocols used in treatment are centered mainly to protect or recover the basic instrumental cognitive functions, we can understand why, in a clinical or lab setting, superior executive cognitive disabilities are today particularly hard to treat and thus, receive a very reduced attention in relation to their real-life consequences.

Cognitive assessment and rehabilitation of executive functions face us with the necessity to transfer our work to real life situations or, as a valid alternative, to be able to build artificial environments that can offer to the subject similar conditions and the same sense of presence.

III. VR IN THE EXECUTIVE FUNCTION REHABILITATION

Cognitive rehabilitation must allow patients to recover their planning, executing and controlling skills by implementing sequences of actions and complex behavioral patterns that are requested in everyday life [17], [1]: with these conditions, VR can be specifically indicated to reach this goal. Moreover VR allows building realistic spatial and temporal scenarios that can be easily used to increase diagnostic sensitivity of standard paper&pencil tests [18].

Due to the great flexibility of situations and tasks provided during the virtual sessions, considering the time, difficulty, interest, and emotional engagement, this new technology allows, besides the diagnostic applications [12], to enhance the restorative and compensatory approaches in the rehabilitation process of cognitive functions inside the traditional clinical protocol.

According to Damasio [16] diagnostic and rehabilitative tools used in labs and clinics often fail to assess and treat the frontal patients because they operate within artificial situations, which are far from reproducing the real situations. In this view, virtual environments appear to be the best solution to make lab situations become closer to the natural setting in the subject’s perception.

This study extends some previous work that explored virtual environments to cognitive and executive rehabilitation with schizophrenic and mental deficiency patients [9], [19]. Next we describe initial results of a VE use for stroke rehabilitation.

IV. METHODS

A. Subjects Six patients, 4 male and 2 female, participated in the

intervention. All patients were right-hand dominant and have had a left hemisphere stroke, which had occurred between 8 months and 2 years prior to this study. These patients participate in a treatment program of a Laboratory of Neuropsychology and Cognition, located in the university public hospital, HUCFF/UFRJ. They are integrated with computers, since they use other computer training programs with multimedia software, developed by the Laboratory researchers staff (Figures 1 and 2). Informed consent was received from all patients, and their rights are protected. B. Procedures

Tasks are designed to executive functions, planning, calculi, short-term memory and attention. Each intervention lasts from 20 minutes to 1 hour per day and consists, besides the virtual environment task, training in 2D software developed to train cognitive functions (Figures 1 and 2).

Fig.1. A 2D software to recognize some goodies

The subjects’ task is to purchase goodies in a virtual

supermarket (Figure 3), in accordance with a product list and an amount of money previously established. This task has five increasing difficulty levels. In the first level the subject receives a list with three items characterized by low price product. In levels 2 to 5, the items list is increased by one

TREINO: COMPRASTREINO: COMPRAS

Queijo Maçã Suco de Cajú

Banana Alface Arroz

Feijão Leite Coca-cola

Lista de Compras

Feira

Carnes / Congelados

Limpeza

Laticínios

Não Perecíveis

Higiene E Perfumaria

Padaria

Bebidas

___

___

___

2

Fig. 2. A 2D software to train attention and memory

product per level, and the prices become more complex. We assume that familiarity with the virtual environment and the cognitive training itself could improve subject’s performance in the task.

Patients are instructed that they have three trials as described above and, at the beginning of each trial, a verbal command is given, by which the subject is instructed about what to do: how to navigate in the store and how to purchase their goodies. When the user chooses an item in the virtual supermarket, a new window appears showing the Brazilian currency (Figure 4). They must choose the correct ones that complete the total price.

Fig. 3. A supermarket view

After that we ask patients to evaluate the experience with

the virtual environment, according to their enjoyment level and task difficulty level, using a short form, a brief survey instrument that had basically the goal of evaluating their perceptions about the tasks in the virtual environment. They are told to evaluate from 1 to 10 the difficulty level, where one indicates no difficulty and ten indicates severe difficulty to execute the task. The same evaluation is applied to the enjoyment level. It is important because this practice requires

a high motivation and interest in the task. We used some clinical measures to assess cognitive

functions. To measure improvement in cognitive function, each patient was evaluated before and after training using 2 clinical measures: the TMT-A and TMT-B and, the Digit Symbol test (to evaluate attention and executive functions). The TMT is one of the most popular neuropsychological tests and is included in most test batteries. It provides information on visual search, scanning, speed of processing, mental flexibility, and executive functions. Originally, it was part of the Army Individual Test Battery (1944) and subsequently was incorporated into the Halstead–Reitan Battery [20]. The TMT

Fig. 4. The display with the Brazilian bills and coins

consists of two parts. TMT-A requires an individual to draw lines sequentially connecting 25 encircled numbers distributed on a sheet of paper. Task requirements are similar for TMT-B except subject must alternate between numbers and letters (e.g., 1, A, 2, B, 3, C, etc.). The score on each part represents the amount of time required to complete the task. The TMT is sensitive to a variety of neurological impairments and processes [15] [21]. C. Results

The subjects expressed their interest in having this therapy; actually, all of them requested an additional VR sessions following their completion of the study. Curiously, a patient’s wife asked us to use the virtual store, too. Two patients with several attentional deficits had problem at the very beginning of the training because they were not able to switch between two tasks: control the mouse and at the same time to accomplish the task itself. Only after the third trial they could complete the task. Tables I, II and III show the patients answers in the five levels of the three trials.

We observed that the patient’s satisfaction level was initially negatively correlated to experienced difficulty in the accomplishment of the task, i.e., bigger the difficulty, minor was the satisfaction. As they became familiar to the task and the environment, their perception of difficulty level decreased and the level of satisfaction increased as well as the number of patients who finished the tasks. Using clinical data, we could observe that subjects with the biggest level of difficulty were

TREINO: ATENTREINO: ATENÇÇÃO E CONCENTRAÃO E CONCENTRAÇÇÃOÃO

ERRADOERRADO

CERTOCERTO

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those with major cognitive deficits. Regard to the accomplishment of the task, we verify that it was related with short memory impairment and executive functions. We could also observe an increase in the number of subjects that accomplished the task, in all the levels.

TABLE I PERFORMANCE AND AFFECTIVE MEASURES IN THE FIVE LEVELS AT THE

FIRST TRIAL IN SIX SUBJECTS TESTED. Level 1º 2º 3º 4º 5º

Number of patients who accomplished

the six tasks

4 4 3 3 1

Perceived difficulty (each patient)

9 9 5 4 3 4

9 7 3 3 4 4

8 8 5 2 4 5

8 8 6 4 5 5

10 9 9 5 5 5

Enjoyment (each patient)

8 9 10 10 10 10

7 8 10 10 10 10

8 7 9 9 10 10

7 6 8 9 10 10

6 6 7 9 10 10

TABLE II

PERFORMANCE AND AFFECTIVE MEASURES IN THE FIVE LEVELS AT THE SECOND TRIAL IN SIX SUBJECTS TESTED.

Level 1º 2º 3º 4º 5º

Number of patients who accomplished

the six tasks

6 6 5 3 2

Perceived difficulty

(each patient)

7 8 4 3 2 3

7 6 3 3 3 3

8 6 5 4 2 2

8 6 6 4 2 2

10 8 8 5 3 2

Enjoyment (each patient)

8 8 10 10 10 10

7 7 10 10 10 10

7 6 8 10 10 10

7 7 7

10 10 10

6 5 8 10 10 10

TABLE III

PERFORMANCE AND AFFECTIVE MEASURES IN THE FIVE LEVELS AT THE THIRD TRIAL IN SIX SUBJECTS TESTED.

Level 1º 2º 3º 4º 5º

Number of patients who accomplished the

six tasks

6 6 5 5 4

Perceived difficulty (each patient)

1 6 3 3 1 2

2 4 3 2 1 2

4 4 3 3 1 3

6 5 4 3 1 3

10 6 5 4 1 4

Enjoyment

(each patient)

10 10 10 10 10 10

10 10 10 10 10 10

10 10 10 10 10 10

10 10 10 10 10 10

10 10 10 10 10 10

V. DISCUSSION

We could realize that the virtual environment is an affordable tool that offers consistent yet modifiable ecologically valid testing and training environments. The environment provides tailored tasks to the individual's need and could provide significant benefits for those with disabilities. It allows the introduction of “gaming” factors into the participation scenario to enhance motivation; patients were motivated to perform the task. Intrinsic motivation and task engagement were promoted through multisensory presentation of tasks and contextualization. It’s known that motivation during rehabilitation is a factor in its success. One reason for this is that patients who are more motivated spend more time and effort into promoting their recovery and that drives neural plasticity, the presumed underlying mechanism of neurological recovery after brain injury. Even our sample being a small one, it could allow us to observe that subjects went through a learning process, as we observed in their performance between first and third trials.

In summary, VR protocols in rehabilitation can offer to clinicians and researchers a practical tool to support the objective measurement of behavior in ecologically valid, safe and controllable environments. This allows for testing and training in simulated “real-world” scenarios without sacrificing the experimental control needed for objective measurement and for the development of treatment hierarchies. These advantages support a number of opportunities for applications in both the clinical and research domains of rehabilitation. These initial results suggest that further research and application of VR will benefit from a well-developed and appropriated working paradigm for applying the technology in rehabilitation. This research seeks precisely to find means of speeding up these periods and providing more motivating opportunities to the patients. However, the value of this kind of cognitive training in relation to traditional one will only be determined via rigorous experimentation with an eye towards enhanced explanation and prediction of cognitive impairments in a patients’ daily life functional environment. We recommend that, in future, additional data on cognitive as well as functional abilities be measured on a larger number of participants, which will help to predict and explain the virtual performance.

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