A Data-Globe and Immersive Virtual Reality Environment for Upper ...

A Data-Globe and Immersive Virtual Reality Environment for Upper Limb Rehabilitation after Spinal Cord Injury Ana de los Reyes-Guzman1, Iris Dimbwadyo-Terrer1, Fernando Trincado-Alonso1, Miguel A. Aznar2, Cesar Alcubilla2, Soraya Pérez-Nombela1, Antonio del Ama-Espinosa1, Begoña Polonio-López3, and Ángel Gil-Agudo1. 1

Biomechanics and Technical Aids Department National Hospital for Spinal Cord Injury, Toledo, Spain 2 AnswareTech, S.L., Madrid, Spain 3 University of Castilla la Mancha, Talavera de la Reina, Spain

Abstract—While a number of virtual data-gloves have been used in stroke, there is little evidence about their use in spinal cord injury (SCI). A pilot clinical experience with nine SCI subjects was performed comparing two groups: one carried out a virtual rehabilitation training based on the use of a data glove, CyberTouch™, combined with traditional rehabilitation, during 30 minutes a day twice a week along two weeks; while the other made only conventional rehabilitation. Furthermore, two functional indexes were developed in order to assess the patient’s performance of the sessions: normalized trajectory lengths and repeatability. While differences between groups were not statistically significant, the data-glove group seemed to obtain better results in the muscle balance and functional parameters, and in the dexterity, coordination and fine grip tests. Related to the indexes that we implemented, normalized trajectory lengths and repeatability, every patient showed an improvement in at least one of the indexes, either along Yaxis trajectory or Z-axis trajectory. This study might be a step in investigating new ways of treatments and objective measures in order to obtain more accurate data about the patient´s evolution, allowing the clinicians to develop rehabilitation treatments, adapted to the abilities and needs of the patients. Keywords—Data-glove, rehabilitation, spinal cord injury, upper limbs, virtual reality.

I. INTRODUCTION Recovery of function after spinal cord injury (SCI) largely depends on the preservation of some anatomic connections, and may also depends on the physiological reorganization of the brain and spinal cord [1]. In people with SCI, upper limbs are affected in more than 50% of cases [2]. In contrast with lower limbs, upper limbs have extensive functionality due to the mobility of numerous joints that can execute fine movements thanks to a complex neuromuscular control. That´s why considerable efforts have been directed towards the development of new upper limb function rehabilitation therapies based on robots, virtual reality, passive workstations, and functional electrical stimulation (FES) systems [3].

Use of virtual reality (VR) has emerged in an effort to promote task oriented and repetitive movement training of motor skills while using a variety of stimulating environments [4]. Comparing with conventional rehabilitation, VR technology increases the range of possible tasks, partly automating and quantifying therapy procedures, and improving patient motivation using real-time task evaluation and reward. Feedback can be provided either after a task, in the form of scores, or during the task using dynamic biofeedback, in the form of visual and auditory cues. There are systems that also provide physical assistance with movement and/or simulate haptic feedback [5]. Some studies affirm that afferent information may change cortical representations and/or improve motor performance in people with SCI. A possible underlying mechanism is that the somatosensory cortex has an important role in cortical reorganization after injury [6]. Therefore, afferent input may contribute to cortical reorganization and, ultimately, to functional recovery via increased communication between the cortex and the corticospinal tract in SCI subjects, which could contribute to improve the execution of functional movements. While a number of virtual data-gloves have been used and have shown promised results in upper limb rehabilitation, in patients with stroke [7-8], as far we know, experiences with people with SCI are scarce. Thus, the goal of this study was to test a data glove, CyberTouchTM, combined with a virtual reality environment, for use in therapeutic training of upper limb movement after SCI. In addition, we wanted to provide objective data, which are obtained through the data glove, in order to adapt the rehabilitation treatments to the patient´s motor capacities; and to assess precisely the rehabilitation process. II. MATERIALS AND METHODS This was a pilot study of two groups: one intervention group (IG) who used the VR system as a complement to

L.M. Roa Romero (ed.), XIII Mediterranean Conference on Medical and Biological Engineering and Computing 2013, IFMBE Proceedings 41, DOI: 10.1007/978-3-319-00846-2_434, © Springer International Publishing Switzerland 2014

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conventional therapy, and one control group (CG) who only was treated with traditional rehabilitations methods. The motion capture system employed was a data-globe, CyberTouchTM, which provides up to 22 high-accuracy joint-angle measurements and vibro-tactile actuators, one on each finger and the palm; and reproduces in real time and in the same orientation the hand movements of the patient on a 3D LCD monitor. It has been observed that the first person view of a virtual representation of the hand induces stronger activation of primary and secondary motor areas associated with sensory motor control as opposed to only performing hand movements in the absence of such a representation [9]. The virtual scene developed for the current project consists of one room, two shelves and a trench (Figure 1).

- GRASP AND RELEASE OBJECTS II: The task was similar to the previous one, but the virtual hand appeared only when the patient was very close to the object to be achieved, almost touching it, thus making the exercise less intuitive because there was less feedback. - REACH OBJECTS: The reaching task consisted of five objects that appeared randomly and disappeared when the subject touched them. The glove provided sensory feedback when the user touched the object. After we have tried the virtual glove with cervical SCI people and saw the great difficulty or not possibility to carry out the grasp and reach virtual reality tasks, we decided to do these virtual activities with high dorsal injuries patients, who have altered the trunk balance, necessary for body postural control and required for generating a stable base upper limb movement required to execute ADL. Finally, six intervention subjects (5 males and 1 female; mean age 54.3±9.86 years, 5.83±2.99 months after injury) and 3 control subjects (2 males and one female, mean age 44.17±22.92 years, 5±1 months after injury) participated in the study. Subject’s demographic and clinical characteristics are showed in the Table 1. Table 1 Subject´s demographic and clinical characteristics (mean and standard deviation).

Fig. 1 Virtual environment. Patient using CyberTouchTM glove in the virtual environment, that consists of one room, two shelves and a trench. The patient has to grasp and release or reach a set of virtual geometric elements.

There is also a reconstruction environment (Figure 2) to visualize the patients’ recordings in order to analyze them.

CG

TG

1/2

1/5

44.17±22.92

54.3±9.86

3/0

6/0

D4 (2), D6 (1)

C4 (1), D4 (4)

ASIA (A-D)

A(3)

A(5), D(1)

Time since injury [months]

5±1

5.83±2.99

Etiology of damage (traumatic/postsurgical/vascular)

2/0/1

4/2/0

Sex (female/male) Age [years] Dominance (right/left) Level of injury (C5C8)

Fig. 2 Reconstruction environment. The figure shows the screen as it is seen by the user, and the direction of the 3 axes. This environment permits to visualize the patients’ recordings in order to analyze them.

It was performed three virtual tasks to improve the patient´s upper limb movements: - GRASP AND RELEASE OBJECTS I: The task consisted of grip and drop three objects (ball, prism and cylinder) placed in front of the subject line. The user had to bend from waist while their trunk went forward and raise the arm to grab objects and drop them into a trench. The glove provides sensory feedback (vibration) by touching objects.

We did not include patients with: pacemaker or similar devices, joint injuries and/or upper limb muscles prior to provoke limitation of movement, cognitive condition and/or psychiatric pathologies, vision problems, technology addiction, epilepsy or pregnancy. Each subject gave informed consent voluntarily. All subjects of the intervention group (IG) participated in the treatment two times per week (on alternate days) for two weeks, 30 minutes per session. There were two types of sessions: GRASP AND RELEASE SESSIONS, which consisted of doing three repetitions of the tasks Grasp and

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A Data-Globe and Immersive Virtual Reality Environment for Upper Limb Rehabilitation after Spinal Cord Injury

release objects I and II; and REACH SESSION, which involved three repetitions of the task Reach objects. At the same period, the users received conventional therapy rehabilitation. Patients assigned to the control group (CG) made only traditional rehabilitation. Both groups were assessed pre-post treatment, with a battery of clinical scales to contrast the final results. We also evaluated the time to complete each session in the IG. A descriptive analysis of the clinical variables was obtained by calculating the mean and standard deviation (SD) for the quantitative variables. Samples were analyzed with Kolmogorov-Smirnov test. After normal distribution was shown, data were analyzed by Mann-Whitney U test (p