Mirror writing of Chinese characters in patients with Parkinson's disease

Thirty-five patients with Parkinson's disease (PD) and 35 normal subjects were investigated using handedness, the writing part of the Chinese Aphasic Examination Scale. All subjects were instructed to write with their left and right hands. Among them, 19 cases of PD and 19 controls were examined by intelligence, visuo-spatial perception and visual memory tests. Seven of the 35 PD patients (20.0%) and three out of 35 normal subjects (8.6%) showed mirror writing when they were asked to write with their left hand. The percentage of occurrence of mirror writing in PD patients was higher, but not statistically significant, and the degree of mirror writing more severe. Mirror writing in PD may be related to the PD per se, educational level and ageing. In the PD group, the intelligence of the seven cases with mirror writing was significantly lower than the others, but visuo-spatial perception and visual memory showed no significant difference except for the Stick-Frame Test. It is suggested that mirror writing in PD may be related to intelligence but not to visuo-spatial perception and visual memory. In this paper the classification criteria of mirror writing is suggested.