Mirror writing: a tachistoscopic study of a woman suffering from migraine when writing with the right hand.

An experimental study was conducted with a young woman who had suddenly developed mirror writing in the right hand, which she used for writing. She was not cured for eight years. The patient was ambidextrous and had no medical complaints except for migraine with perceptual and sensory abnormalities, and an enlarged cavity of the septum pellucidum. A previous study using functional magnetic resonance imaging (fMRI), conducted when she imagined letters and wrote letters in the air with either hand, indicated that both her cerebral hemispheres were active. In the present study three experiments were conducted using a tachistoscope to explore the stage in the cognitive process when directional errors emerged. In the experiments, after independently being presented with Attneave's meaningless figures or letters to each hemisphere, participants were requested to do the following: (a) verbally respond whether the orientation of two consecutively shown figures were the same or different and the letters were standard or reversed; (b) distinguish the orientations with right and left hand movements other than by writing (by pushing a button); and (c) reproduce the stimuli (drawing) immediately after the presentation. Results showed a higher rate of incorrect directions only when drawings were reproduced by the right hand. Results also indicated that the woman's inaccurate judgment in direction emerged only when in writing and not at the perceptual level, or when responding with hand movements other than writing. Her migraine was cured after five years following the experiment. The mirror writing was cured 2-3 months later.