Virtual Reality and Parkinson's

Introduction

Virtual reality (VR) appears to more and more prevalent nowadays. Not only does VR being used in our everyday life for entertainment, but also in clinical settings. There is a substantial research examining the effects of VR on Parkinson’s disease (PD)1 (Dockx, et al., 2016). PD is a neurodegenerative disorder that is traditionally managed by a combination of medication and physical therapy treatment (Dockx et al., 2016). With the gain popularity of the VR system, it could potentially enhance the treatment outcome.

Virtual reality for rehabilitation of gait and balance in patients with parkinson’s

With the advent and recent popularity of VR technology, VR has been proposed as a possible rehabilitation tool in conjunction with traditional physiotherapy approaches. A recent review has illustrated that a sense of control, success, and an appropriate level of challenge are key ingredients that explain a patient’s immersion and enjoyment of VR systems (Lewis, 2012). VR systems optimize motor learning in a safe environment, and can help improve activities of daily living by replicating real-life scenarios (Dockx K et al., 2016).

Within VR, augmented feedback about a PD patient’s performance enables repetitive practice of motor tasks, thus stimulating both motor and cognitive processes simultaneously. VR offers patients with neurological deficits, such as PD, an opportunity to develop new motor strategies, or to relearn motor abilities that were lost due to their injury or disease process. (Goble, 2014; Mirelman, 2013; van Diest, 2013). For example, a patient with PD with akinesia has trouble initiating a step, but will be able to step over an object that appears in their path (Reiss et al., 1995). Using this concept, VR can overlay objects in a patient’s visual field, encouraging the initiation of a step, improving function in these patients, as they are capable of initiating walking (Reiss et al., 1995). Additionally, other VR technologies focus on more broad symptoms, such as being able to improve stride length and improve balance, in safe, controlled environments. An example of VR used in such an environment can be found here: [1]

The Nintendo Wii and Xbox Kinect have been used as VR tools in addressing PD symptoms. The rationale behind using VR systems lies in providing augmented visual and auditory feedback to gradually challenge postural control and balance during a task. This strategy bypasses the deficient motor generation system present in patients with PD, thus improving their motor response (Mirelman, Maidan, & Deutsch, 2013).

When compared to traditional physiotherapy, experiments studying the effectiveness of VR in improving gait and balance outcomes, namely the Six-Minute Walk Test and Berg Balance Scale respectively, have demonstrated that VR based training in PD patients leads to moderate improvements in step and stride length (Dockx K et al., 2016).

An area where VR training may be especially effective for addressing PD symptoms is fall prevention when there is poor input of visual and somatosensory systems (Yen et al., 2011). A possible explanation for this is due to the conditions under which VR training occurs; where the visual and somatosensory systems are being altered and are unreliable, thus forcing the patient to rely on use of their vestibular system for balance.

Scientific rationale and advantages for using virtual reality

1. Enhance motivation/repetition: to learn a motor skill, patients need to motivate to repeatedly practice the skills (Holden, 2005). The use of VR is seen as novel to most people, and with the variety of video game effects, patients are less likely to become bored. Thurs, Patients can tolerate the extensive practice period by changing the visual effects (Holden, 2005).

2. Provide precise feedback: there is extensive evidence that the proprioceptive and exteroceptive feedback can induce profound cortical and subcortical changes associated with motor performance (Holden, 2005). With the use of VR, these feedbacks is augmented through different settings. This can tailor and further enhance the physiological changes in patients with PD.

3. Transferability: one may be concerned that the motor skills learned from VR may not translate to real-world environment. However, there is fair amount of evidence suggests human can learn motor skills and then transfer these skills to real life (Holden,2005). However, there is no definite conclusion when it comes to comparing the motor skills learned from VR versus those learned from real life.

4. Early stage learning: patients with severe PD may have problems learning a new motor skill, especially when it comes to complex performance (Holden, 2005). With the use of VR, patients can benefit from simplifying the task to its key components. In contrast, in a real world environment, there are many distractions that could occur and may slow down the learning, as the patients attempt to distinguish the key aspects of the task (Holden, 2005).

Limitations of virtual reality for Parkinson's disease

VR technology holds some limitations for patients with PD. These include the possibility of cognitive overload, cyber-sickness, or an inappropriate level and content of exercises for rehabilitation of PD (Barry, 2014).

Additionally, home-based VR systems used for rehabilitation may be detrimental to performance, as patients may use compensatory movements to increase game performance. Patients may begin to prioritize game scores over their quality of movement, thus reducing training effects. Future home-based VR systems designed for neurological rehabilitation should ensure that compensatory movements cannot be used to improve game performance (Dockx K et al., 2016).

It still remains unclear how VR systems may be adjusted to the specific needs of PD populations. Commercial VR systems for persons with neurological disorders have yet to be developed. Current systems designed for the general healthy population, such as the Xbox Kinect and Nintendo Wii, can hinder the effectiveness of such interventions and the safety for such populations (Dockx K et al., 2016).

However, VR and physiotherapy interventions both have similar overall effects on gait, balance, and quality of life. In a recent 2016 systematic review, Dockx K et al. concluded that there is only low-quality evidence suggesting that VR can serve as a useful alternative to traditional physiotherapy in improving gait and balance in PD patients.

Future research in virtual reality for Parkinson's disease

VR is still relatively new technology. Few studies have been done, making generalizations to populations outside the research circumstances difficult. Further research is needed to expand the evidence for the use of VR in PD populations.

Future research should aim to examine the effectiveness of VR interventions in different disease stages of PD to determine the usefulness of VR-based interventions in the prevention of physical decline during the early stages of PD, and during the progression of PD in the middle to late stages (Dockx K et al., 2016).

Future research should also focus on providing evidence-based recommendations regarding the frequency, duration, and content of VR interventions for PD populations (Dockx K et al., 2016).