Affiliations: [a] MEDIAN Klinik Berlin-Kladow, Berlin, Germany | [b] Center for Rehabilitation, The Second Affiliated Hospital of Jiaxing University, Jiaxing, China | [c] Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany | [d] Center for Stroke Research Berlin, Charité – University Medicine Berlin, Berlin, Germany | [e] Medical Faculty, Institute for Biometry and Medical Computer Science, University Magdeburg, Magdeburg, Germany | [f] Center for Rehabilitation Research, University of Potsdam, Potsdam, Germany
Correspondence:
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Address for correspondence: Christian Dohle, MEDIAN Klinik Berlin-Kladow, Kladower Damm 223, 14089 Berlin, Germany. Tel.: +49 30 36503 105; Fax: +49 30 36503 123; E-mail: [email protected]
Abstract: Background:Mirror therapy (MT) was found to improve motor function after stroke, but its neural mechanisms remain unclear, especially in single stroke patients. Objectives:The following imaging study was designed to compare brain activation patterns evoked by the mirror illusion in single stroke patients with normal subjects. Methods:Fifteen normal volunteers and five stroke patients with severe arm paresis were recruited. Cerebral activations during movement mirroring by means of a video chain were recorded with functional magnetic resonance imaging (fMRI). Single-subject analysis was performed using SPM 8. Results:For normal subjects, ten and thirteen subjects displayed lateralized cerebral activations evoked by the mirror illusion while moving their right and left hand respectively. The magnitude of this effect in the precuneus contralateral to the seen hand was not dependent on movement speed or subjective experience. Negative correlation of activation strength with age was found for the right hand only. The activation pattern in stroke patients is comparable to that of normal subjects and present in four out of five patients. Conclusions:In summary, the mirror illusion can elicit cerebral activation contralateral to the perceived hand in the majority of single normal subjects, but not in all of them. This is similar even in stroke patients with severe hemiparesis.
