Reflections on mirror therapy: a systematic review of the effect of mirror visual feedback on the brain

We know it works, but not quite sure how; trust us. But still no protocols on use.

Reflections on mirror therapy: a systematic review of the effect of mirror visual feedback on the brain

Deconinck FJA
1,2,*
(PhD), Smorenburg ARP
3
(PhD), Benham A
4
(PhD), Ledebt  A
5
(PhD), Feltham MG
6
(PhD), Savelsbergh GJP
5
(PhD)
 
1
 Ghent University (Belgium), Department of Movement and Sports Sciences
 
2
 Manchester Metropolitan University (UK), School of Healthcare Sciences
 
3
 Burke-Cornell Medical Research Institute (USA)
 
4
Bradford Institute for Health Research (UK)
 
5
 VU University Amsterdam (The Netherlands), Research Institute MOVE
 
6
 University of Birmingham (UK), Primary Care Clinical Sciences
 
*Corresponding author: Ghent University Ð
 
Faculty of Medicine and Health Sciences, Department of Movement and Sports Sciences, Watersportlaan 2, 9000 Gent, Belgium
 
Tel.: +32 (0)9 264 91 37
 
E-mail: Frederik.Deconinck@UGent.be
This paper is published in Neurorehabilitation and Neural Repair. The final publication is available at Sage via http://dx.doi.org/[DOI:10.1177/1545968314546134]

 Abstract

Background: Mirror visual feedback (MVF), a phenomenon where movement of one limb is perceived as movement of the other limb, has the capacity to alleviate  phantom limb pain or promote motor recovery of the upper limbs after stroke. The tool has received great interest from health professionals, however, a clear understanding of the mechanisms underlying the neural recovery owing to MVF is lacking.
 
Objective: 

 

We performed a systematic review to assess the effect of MVF on brain activation during a motor task. Methods: We searched PubMed, CINAHL, and EMBASE databases for neuroimaging studies investigating the effect of MVF on the brain. Key details for each study regarding participants, imaging methods and results were extracted.
 
Results: 

 

The database search yielded 347 papers, of which we identified 33 suitable for inclusion. Compared with a control condition, MVF increases neural activity in areas involved with allocation of attention and cognitive control (dorsolateral  prefrontal cortex, posterior cingulate cortex, S1 and S2, precuneus). Apart from activation in the superior temporal gyrus and premotor cortex, there is little evidence that MVF activates the mirror neuron system. MVF increases the excitability of the ipsilateral primary motor cortex (M1) that projects to the ÔuntrainedÕ
 
hand/arm. There is also evidence for ipsilateral projections from the contralateral MI to the untrained/affected hand as a consequence of training with MVF. Conclusion: MVF can exert a strong influence on the motor network, mainly through increased cognitive penetration in action control, though the variance in methodology and the lack of studies that shed light on the functional connectivity between areas still limit insight into the actual underlying mechanisms.