Abstract: 133 normal children and 113 deaf-mutes in Kindergarten, primary schooland deaf-mute school were asked to write Arabic numerals 1--10 and eightChinese words with eight writing patterns. The result reveals that firstgrade deaf-mute school childen wrote less mirror-words than normal Kin-dergarten children, but in the other compared grade groups there were nosignificant differances. In the age group of 8--10 the deaf-mutes wrotemore mirror-words than normal children, but in the other compared agegroups there were no significant dtfferances. Through analysis we proposetwo key periods of the development of mlrror-writing: 1. development ofthe regulation and control of the brain of 5--6 year olds, 2.first two yearsof education due to the development of writing-skill.

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