Mirror therapy is a form of motor imagery in which a mirror is used to convey visual stimuli to the brain through observation of one's unaffected body part as it carries out a set of movements. The underlying principle is that movement of the affected limb can be stimulated via visual cues originating from the opposite side of the body. Hence, it is thought that this form of therapy can prove useful in patients who have lost movement of an arm or leg including those who have had a stroke.
NOTE: Some of the effects of mirror therapy on the brain have already been demonstrated. In a crossover study on healthy individuals, Garry, Loftus & Summers (2004) showed that viewing the mirror image of one's active hand increased the excitability of neurons in the ipsilateral primary motor cortex (pictured below in yellow) significantly more than viewing the inactive hand directly (no mirror). As well, a trend toward significance was found in favour of viewing a mirror image of the active hand compared to viewing the active hand directly (no mirror). This study was not included in the in depth review below as it involved only neurologically healthy patients (non-stroke).
Authors*: Adam Kagan, B.Sc.; Samuel Harvey-Vaillancourt, PT U3; Shahin Tavakol, PT U3; Dan Moldoveanu, PT U3; Phonesavanh Cheang, PT U3; Elissa Sitcoff, BA BSc; Nicol Korner-Bitensky, PhD OT