In mirror therapy, a mirror is placed beside the unaffected limb, blocking the view of the affected limb. This creates the illusion that both limbs are functioning properly. Mirror theory is based on evidence that action observation activates the same motor areas of the brain as action execution. Observed actions lead to the generation of intended actions, engaging motor planning and execution. Further, evidence suggests that damaged areas of the brain’s motor cortex may improve by viewing movements of intact, functioning limbs.

Strokes can cause much neurological impairment, which may lead to a reduction in the performance of activities of daily living. Current rehabilitation techniques focus on occupational and physical therapy, using guided limb manipulation and task-oriented training. These exercises combine passive and active movement in an attempt to rebuild neuronal connections damaged by the stroke. Adding mirror therapy to traditional therapy enlists visual stimulation showing proper functioning. This points to a large cognitive role in rehabilitation, rather than just physical.

In the current study, 14 stroke patients with lower-limb hemiplegia were randomized to begin traditional rehabilitation therapies with or without the addition of mirror therapy. The study was a crossover design, and patients crossed to the other treatment arm after an initial treatment period. The subjects sat in a chair with a mirrored box placed over their lower limbs. They stepped over a 3-cm high step 10 times, and the angle of the ankle joint, as well as the time required to complete the task, were calculated.

Among this group of patients, the time required to complete the task was significantly shorter in the mirror therapy group, 2.80 seconds compared with 3.19 seconds in the non-mirror group. This translates to an approximate 12% acceleration of movement in the mirror therapy group. There was no significant difference in ankle flexion between the groups.

This is not the first study to report the positive effects of added mirror therapy in stroke patients. A randomized, controlled 4-week trial of 40 stroke patients concluded that hand functioning improved more after the addition of mirror therapy compared to conventional stroke rehabilitation programs. This study measured motor functioning and spasticity using standard instruments for recording physical rehabilitation, including the Modified Ashworth Scale (MAS) and the Functional Independence Measure (FIM). Additionally, a similar study of another 40 stroke patients found mirror therapy enhanced lower-extremity motor recovery. This study measured motor functioning and spasticity using the MAS, the FIM, and measured walking ability. The study presented at the World Stroke Congress is among the first to report speed of movement as a result.

Interestingly, the principles of mirror therapy have been applied to other techniques for stroke rehabilitation and used to develop virtual-reality based therapy systems for physical therapy programs. A recent study reported positive preliminary results from such a method that combines action observation with goal-directed movement imagery.

Hemiplegia is one of the most common consequences of strokes and presents great challenges for rehabilitation. With more evidence focused on visual and cognitive techniques to enhance traditional therapies, the mental and intellectual processes involved in rehabilitation are recognized as important factors in physical recovery. Now, a simple optical illusion could reflect great strides in stroke recovery.

References

Kynan Eng, Ewa Siekierka, Pawel Pyk, Edith Chevrier, Yves Hauser, Monica Cameirao, Lisa Holper, Karin Hägni, Lukas Zimmerli, Armin Duff, Corina Schuster, Claudio Bassetti, Paul Verschure, Daniel Kiper (2007). Interactive visuo-motor therapy system for stroke rehabilitation Medical & Biological Engineering & Computing, 45 (9), 901-907 DOI: 10.1007/s11517-007-0239-1

D ERTELT, S SMALL, A SOLODKIN, C DETTMERS, A MCNAMARA, F BINKOFSKI, G BUCCINO (2007). Action observation has a positive impact on rehabilitation of motor deficits after stroke NeuroImage, 36 DOI: 10.1016/j.neuroimage.2007.03.043

S SUTBEYAZ, G YAVUZER, N SEZER, B KOSEOGLU (2007). Mirror Therapy Enhances Lower-Extremity Motor Recovery and Motor Functioning After Stroke: A Randomized Controlled Trial Archives of Physical Medicine and Rehabilitation, 88 (5), 555-559 DOI: 10.1016/j.apmr.2007.02.034

G YAVUZER, R SELLES, N SEZER, S SUTBEYAZ, J BUSSMANN, F KOSEOGLU, M ATAY, H STAM (2008). Mirror Therapy Improves Hand Function in Subacute Stroke: A Randomized Controlled Trial Archives of Physical Medicine and Rehabilitation, 89 (3), 393-398 DOI: 10.1016/j.apmr.2007.08.162

For a large part of the previous century, it was believed that people with stroke would have to lead a largely dependent life, confined to the wheelchair. They were even discouraged from moving their limbs or exercising. Over the years, rehabilitation for patients with stroke has come a long way. Focus has shifted from basic interventions utilizing strengthening exercises to more advance techniques based on the theories of motor learning and neuroplasticity. This included manual techniques by skilled clinicians as well as the use of equipment such as electrical stimulation modalities, and specialized bikes and treadmill systems — all aimed at optimizing function in patients with impairments. In the past few years, a major step for the field of rehabilitation has been the integration of fields such as assistive technology, robotics and computer sciences with the science of rehabilitation. The amalgam of the above has led to potentially powerful systems that will enhance the functional outcome in patients greatly. The latest entrant into the filed of rehabilitation is virtual reality (VR) systems for rehabilitation. Many of the systems have been tested, released and are now available to hospitals and clinics for use. Clinical trials are ongoing, for upgrading existing technology and for invention of new systems for recovery and rehabilitation.

In 2002, the engineers at Rutgers University have created a VR system that included therapeutic activities aimed at recovery of function in patients with stroke. There are now many versions of this system available, and clinical trials are ongoing to evaluate the extent of efficacy of these systems in recovery of function. Like any VR gaming system, patients will see themselves in a simulated environment. Only, games will be replaced by targeted exercises that will work target various functional muscle groups in the arms and hands. Patients can complete fine motor tasks such as picking up objects, stacking objects, and gross motor tasks such as tapping balloons, catching objects and even reach for objects out of their base of support, thus encouraging balance retraining.

Of late, VR rehabilitation systems are also being evaluated for their use in decreasing neglect in patients with hemiplegia. This is achieved by the system providing visual cues from the affected side, to increase awareness and enhance adaptive relearning. A recent published case study (four participants) suggested that VR systems had the potential for decreasing neglect in patients with stroke. In addition to improvements on the objective tests that were administered, participants also subjectively reported that VR training sessions were helpful and enjoyable. VR systems can even simulate day-to-day situations like crossing a street, cooking, opening doors, etc. This will provide very specific learning of the tasks that are essential activities of daily living. The VR systems are effective as they emphasize active participation by the patient and provide varied environments for task practice while providing immediate feedback of quality. All of these fulfill the requirements of ideal motor practice and motor learning.

Stroke survivors, in my experience, are people who have the most enthusiasm to recover; their zest to go back to doing things they used to love serves as a wonderful motivator at rehabilitation sessions. Preserved cognition, high motivations levels, and a firm conviction to go back to their old routine makes patients with stroke ideal candidates for unique rehabilitation tools. I look forward to the day when these systems are available to most hospitals at an affordable price, with simpler user interfaces so that more and more patients will benefit from the systems.

Reference

Smith, J., Hebert, D., Reid, D. (2007). Exploring the effects of virtual reality on unilateral neglect caused by stroke: Four case studies. Technology and Disability, 19(1), 29-40.