Mirror, Mirror on the Wall – Stroke Rehabilitation

Stroke patients may have a new tool in their rehabilitation shed: a mirror. A study presented at the 6th World Stroke Congress in Vienna, Austria, in September 2008 suggests that adding mirror therapy to traditional rehabilitation programs may speed the recovery of stroke patients. Mirror therapy is used to treat phantom limb pain after amputation, but may now enhance the rehabilitation of hemiplegia after a stroke.

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