Left-handed mirror writing following right anterior cerebral artery infarction: evidence for nonmirror transformation of motor programs by right supplementary motor area.

A patient with acquired, pathologic left-handed mirror writing and mirror movements during bimanual coordination is reported. CT demonstrated an ischemic infarction involving the right supplementary motor area, medial prefrontal cortex, and anterior cingulate gyrus with nearly total sparing of the corpus callosum. This case, together with recent experimental findings in monkeys, supports the hypothesis that the supplementary motor area may be responsible for nonmirror transformation of motor programs originating in the left hemisphere prior to execution by the primary motor area in the right hemisphere.