**4. Some barriers and issues in virtual environment applications**

Despite all the strides in virtual environment applications, research still shows inconsistencies in the reports on research efforts in virtual environments. One main contention is whether skills gained in virtual environments transfer to real-world conditions. This argument has come to the forefront in the widely use of virtual environment for therapeutic applications. For example, efforts to promote functional recovery through therapeutic interventions like neurofacilitation techniques, progressive strengthening, biofeedback and electrical simulation, after the occurrence of stroke, have yielded inconsistent results (Duncan, 1997; Feys et al., 1998; Merians et al., 2002; Richards & Pohl, 1999). O'Sullivan and Schmitz (1994) argued that these inconsistencies stemmed from inadequate training and skills in performing these procedures in order to ensure the validity and reliability of the tests. Wilson, Foreman and Tlauka (1996) reported that internal representations resulting from exploration of simulated space transferred to the real environment. Kozak et al. (1993), Deutsch, Latonio, Burdea and Boian (2001), argued that although subjects trained on a motor task in a virtual environment demonstrated the ability to improve performance in that environment, the learning did not always transfer to the real-world task. Jack et al. (2001) attributed this problem to the current paucity of investigation into the use of VR for motor skill training. These inconsistencies indicate that research in motor task training and transfer of that task to the real-world environment is neither fully understood nor entirely conclusive (Jack et al., 2001). These conflicting findings need to be more carefully explored in order to ascertain the usefulness of VR as an enhancement to traditional therapy. Fox and Fried-Oken (1996) also observed that many questions relating to the generalization of new learning to the natural environment remained largely unanswered.

Recent studies have shown that virtual reality technology can be used to provide this treatment approach based on its capability to create an integrated, interactive, motivating environment in which practice intensity and feedback can be manipulated to effect functional recovery or improvements in patients following stroke (Liepert et al., 2000; Merians et al., 2002; Taub, Uswatte & Pidikiti, 1999;).

#### **5. A virtual environment case study**

The author conducted a case study to justify his own belief on this inconclusive subject. The research undertaken also aims to justify or not research efforts in virtual environments

Virtual Environments in Physical Therapy 9

Information about a scenario of interest to the patients was gathered. The VR system was used to present this scenario in the form of an environment where the patients performed a VR-based exercise in order to induce the therapy needed to correct their gait problems. The VR system was employed to present the patients with VR tasks (in the form of a painting exercise) closely linked with the therapy needed to correct or improve any abnormality in their walking patterns. This stage model phase modeled all the primitives, visual and audio, of both the task-specific exercise and the VR environment as formalized in the scenario stage. The virtual reality task was based on a painting exercise, which served the purpose of inducing the therapeutic movements needed for the functional recovery or improvements of the lower extremities of the patients. The VR-based painting exercise was employed for the purpose of simulating visually immersive therapy exercise on a PC without having to

Research has recently been focused on the painting process and virtual reality technology (Lin, Baxter, Scheib & Wendt, 2004), and the clinical community for the work agreed that the painting task is capable of inducing the movement patterns that are closely linked with the therapy needed to correct ambulatory problems, especially in ankle and foot movements. The painting exercise induced in the leg the complex strokes associated with physical painting in the real world. A graphical user interface provided the therapist with a simple and minimal set of keystrokes with which the VR exercises were manipulated for the appropriate level of exercise difficulty for each patient. The VR-based painting exercise presented the patients with windows of different sizes to be covered. The patients were required to cover the windows with 'red blinds' using their hemiplegic legs. The window's color, initially cyan over a blue background, becomes red over a blue background when completely covered. The therapist viewed the painting process on a computer screen as the patient performed the exercise within a virtual environment using the head mounted display. The author designed a 'LegMouse' and a 'LegPad' (Akinladejo, 2005), which the patient used to accomplish the painting exercise. The LegPad was attached to the patient's hemiplegic leg for movements on the LegMouse. The LegPad was designed, in consultation with the clinical community, with a hemispheric base in order to allow dorsiflexion, plantar flexion, inversion and eversion movements of the ankle joints. As the patient moved his or her leg with the LegPad over the LegMouse, the painting program caused the cursor on the computer screen to 'paint' a defined window. There were four different window areas, each corresponding to the task difficulty level that the patient was performing. The painting process stopped whenever the cursor moved outside a window area. Thus the patient was constantly challenged with the task of keeping the cursor within the window area in the virtual environment, and also with the task of moving his or her hemiplegic leg in all directions for the painting process to continue. These movements (e.g., dorsiflexion and plantar flexion movements) helped to induce in the leg the therapy needed to correct or improve ambulatory problems in the ankle joint thereby leading to better walking skills. Some images that present the patient's view of the systems is presented. The painting exercise was modeled using OpenGL, an environment for developing portable, interactive 2D and 3D graphics applications. This application programming interface (API) is widely used on a number of computer platforms for innovative developments through its broad set of rendering, texture mapping, special effects, and other powerful visualization functions available for application developers (http://www.opengl.org/about/overview.html). OpenGL is a truly open, vendor-neutral, multiplatform graphics standard that provides consistent visual display results on any OpenGL API-compliant hardware irrespective of the

physically use real paints, brushes, boards or papers.

applications as alternative intervention techniques for motor rehabilitation for researchers and clinicians involved in rehabilitation engineering. The study specifically focused on the effect of using virtual environment to improve ambulatory function in stroke patients, and investigated whether the skills gained from the environment transfer to real-world conditions. A virtual reality system was developed to train stroke patients with lower extremity problems (Akinladejo, 2005, 2007). The product of the research study was developed using the i-glasses PC 3D HR Head Mounted Display and the Polhemus electromagnetic tracker system.

Fig. 3. The Author with the i-glasses PC 3D HR Head Mounted Display and the Polhemus electromagnetic tracker system (Akinladejo, 2005)

Fig. 4. The Author with sensors of the Tracker system on his legs. (Akinladejo, 2005)

applications as alternative intervention techniques for motor rehabilitation for researchers and clinicians involved in rehabilitation engineering. The study specifically focused on the effect of using virtual environment to improve ambulatory function in stroke patients, and investigated whether the skills gained from the environment transfer to real-world conditions. A virtual reality system was developed to train stroke patients with lower extremity problems (Akinladejo, 2005, 2007). The product of the research study was developed using the i-glasses PC 3D HR Head Mounted Display and the Polhemus

Fig. 3. The Author with the i-glasses PC 3D HR Head Mounted Display and the Polhemus

Fig. 4. The Author with sensors of the Tracker system on his legs. (Akinladejo, 2005)

electromagnetic tracker system (Akinladejo, 2005)

electromagnetic tracker system.

Information about a scenario of interest to the patients was gathered. The VR system was used to present this scenario in the form of an environment where the patients performed a VR-based exercise in order to induce the therapy needed to correct their gait problems. The VR system was employed to present the patients with VR tasks (in the form of a painting exercise) closely linked with the therapy needed to correct or improve any abnormality in their walking patterns. This stage model phase modeled all the primitives, visual and audio, of both the task-specific exercise and the VR environment as formalized in the scenario stage. The virtual reality task was based on a painting exercise, which served the purpose of inducing the therapeutic movements needed for the functional recovery or improvements of the lower extremities of the patients. The VR-based painting exercise was employed for the purpose of simulating visually immersive therapy exercise on a PC without having to physically use real paints, brushes, boards or papers.

Research has recently been focused on the painting process and virtual reality technology (Lin, Baxter, Scheib & Wendt, 2004), and the clinical community for the work agreed that the painting task is capable of inducing the movement patterns that are closely linked with the therapy needed to correct ambulatory problems, especially in ankle and foot movements. The painting exercise induced in the leg the complex strokes associated with physical painting in the real world. A graphical user interface provided the therapist with a simple and minimal set of keystrokes with which the VR exercises were manipulated for the appropriate level of exercise difficulty for each patient. The VR-based painting exercise presented the patients with windows of different sizes to be covered. The patients were required to cover the windows with 'red blinds' using their hemiplegic legs. The window's color, initially cyan over a blue background, becomes red over a blue background when completely covered. The therapist viewed the painting process on a computer screen as the patient performed the exercise within a virtual environment using the head mounted display. The author designed a 'LegMouse' and a 'LegPad' (Akinladejo, 2005), which the patient used to accomplish the painting exercise. The LegPad was attached to the patient's hemiplegic leg for movements on the LegMouse. The LegPad was designed, in consultation with the clinical community, with a hemispheric base in order to allow dorsiflexion, plantar flexion, inversion and eversion movements of the ankle joints. As the patient moved his or her leg with the LegPad over the LegMouse, the painting program caused the cursor on the computer screen to 'paint' a defined window. There were four different window areas, each corresponding to the task difficulty level that the patient was performing. The painting process stopped whenever the cursor moved outside a window area. Thus the patient was constantly challenged with the task of keeping the cursor within the window area in the virtual environment, and also with the task of moving his or her hemiplegic leg in all directions for the painting process to continue. These movements (e.g., dorsiflexion and plantar flexion movements) helped to induce in the leg the therapy needed to correct or improve ambulatory problems in the ankle joint thereby leading to better walking skills. Some images that present the patient's view of the systems is presented. The painting exercise was modeled using OpenGL, an environment for developing portable, interactive 2D and 3D graphics applications. This application programming interface (API) is widely used on a number of computer platforms for innovative developments through its broad set of rendering, texture mapping, special effects, and other powerful visualization functions available for application developers (http://www.opengl.org/about/overview.html). OpenGL is a truly open, vendor-neutral, multiplatform graphics standard that provides consistent visual display results on any OpenGL API-compliant hardware irrespective of the

Virtual Environments in Physical Therapy 11

supply a patient research number (PRN). If a PRN is not found, the system will give opportunity to either re-enter another PRN or add the current PRN to the database. There is an optional button to exit the program. If a PRN is found or is added, the system then leads the user to the Task Difficulty Level (TDL) screen where the user will specify the appropriate VRbased task that the chosen patient will undergo. The tasks range from one (1) the easiest to four (4), the most difficult. If an invalid TDL is entered, the system will default to TDL1.

The clinician can opt to change the patient from this screen or exit the program. The appropriate TDL choice leads to the exercise mode, where the patient performs the chosen exercise at its TDL level. The exercise mode displays the name of the current patient, the exercise type he or she is performing, the target time for that exercise and the time the patient starts the exercise. The exercise is to cover a window area with a blind, in the form of paint. The TDL of the VR exercise presents the patients with four different rectangular windows that they need to cover with a red blind. As the patients move the cursor over the window using their legs, the window is being covered with the red blind; hence, the patients paint the window area with the mouse until the window is completely covered. The system informs the patients once the window is completely covered, and displays the target time to complete the chosen TDL, the patients' start time, stop time and time taken to cover the window. The user can reset the exercise for the patient or exit the system using the exit button. On exit, the system writes the patients exercise data in an output file, which the author exports to an external application for analysis. The task difficulty level is influenced by the fact that the windows are of different sizes and the 'paint brush' has varying sized tips. These pose challenges in terms of the time and effort required to cover the windows. For example, TDL 1 has a wider window size and a thicker paintb\rush, while TDL 4 has a

Fig. 5. The Interface for the Clinician. (Akinladejo, 2005).

smaller window size and a thinner paintbrush.

operating system. It offers complete independence from network protocols and topologies. Application developers are well shielded from underlying hardware as OpenGL drivers ensure proper encapsulation of hardware primitives, thus giving them ample flexibilities for innovative designs. The OpenGL standard provides language binding for C++ and Java, the two main languages employed for the research study. The virtual exercise system incorporated performance-based target levels to increase the patients' motivation (Jack et al., 2001). Feedback mechanisms informed the patients on the target levels and their actual performance on the VR system, and the therapists employed the GUI-based interface to tailor exercise difficulty to the patients' specific problems. The feedback provided an avenue for encouraging the patient to accomplish more trials in the virtual environment. To encourage motivating environment, the author identified, through interviewing the patients, that music will make the scenario of interest to them, and combined an audio system with the painting exercise, in a way that presented an interesting and motivating environment where the patients were unaware of the technology behind the VR-based exercise, just because they wanted to 'play the game' on the computer and enjoy the music.
