The neuronal correlates of mirror illusion in children with spastic hemiparesis: a study with functional magnetic resonance imaging.
To investigate the neuronal activation pattern underlying the effects of mirror illusion in children/adolescents with normal motor development and in children/adolescents with hemiparesis and preserved contralateral corticospinal organisation.



The type of cortical reorganisation was classified according to results of transcranial magnetic stimulation. Only subjects with congenital lesions and physiological contralateral cortical reorganisation were included. Functional magnetic resonance imaging was performed to investigate neuronal activation patterns with and without a mirror box. Each test consisted of a unimanual and a bimanual motor task.



Seven children/adolescents with congenital hemiparesis (10-20 years old, three boys and four girls) and seven healthy subjects (8-17 years old, four boys and three girls) participated in this study. In the bimanual experiment, children with hemiparesis showed a significant effect of the mirror illusion (p<0.001 at voxel level, family-wise error corrected at cluster level) in the dorsolateral prefrontal cortex and anterior cingulate cortex of the affected and unaffected hemispheres, respectively. No significant effects of the mirror illusion were observed in unimanual experiments and in healthy participants.



Mirror illusion in children/adolescents with hemiparesis leads to activation of brain areas involved in visual conflict detection and cognitive control to resolve this conflict. This effect is observed only in bimanual training. We consider that for mirror therapy in children and adolescents with hemiparesis a bimanual approach is more suitable than a unimanual approach.
Support Centre for Advanced Neuroimaging (SCAN), University Institute of Diagnostic and Interventional Neuroradiology, In-selspital, University of Bern, Switzerland.
Christian
C
Weisstanner
Department of Neuropaediatrics, Development and Rehabilitation, University Children's Hospital, Inselspital, University of Bern, Switzerland; Institute of Human Movement Sciences and Sport, ETH Zürich, Switzerland.
Stefanie
S
Saxer
Support Centre for Advanced Neuroimaging (SCAN), University Institute of Diagnostic and Interventional Neuroradiology, In-selspital, University of Bern, Switzerland.
Roland
R
Wiest
Neurocentre of Southern Switzerland, Lugano, Switzerland.
Alain
A
Kaelin-Lang
Support Centre for Advanced Neuroimaging (SCAN), University Institute of Diagnostic and Interventional Neuroradiology, In-selspital, University of Bern, Switzerland.
Christopher J
CJ
Newman
Department of Neuropaediatrics, Development and Rehabilitation, University Children's Hospital, Inselspital, University of Bern, Switzerland.
Maja
M
Steinlin
Department of Neuropaediatrics, Development and Rehabilitation, University Children's Hospital, Inselspital, University of Bern, Switzerland.
Sebastian
S
Grunt
D000293:Adolescent; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping; D002648:Child; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006225:Hand / Q000503:physiopathology; D006801:Humans; D007088:Illusions; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009044:Motor Cortex / Q000503:physiopathology; D009128:Muscle Spasticity / Q000503:physiopathology*; D009473:Neuronal Plasticity / Q000502:physiology; D010291:Paresis / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000534:rehabilitation; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D055815:Young Adult