Mirror writing in cerebrovascular disease

Abstract

Mirror writing is a script that runs in a direction opposite to normal and in which each individual letter is also reversed. Many authors have reported that mirror writing occurs in normal children, demented elderly patients, and patients with cerebrovascular disease (CVD), Parkinson's disease (PD), or essential tremor (ET). Although the precise mechanism of mirror writing has not been defined, Tashiro and his co-workers have proposed a hypothesis for a neuronal mechanism of mirror writing in which the thalamus plays a major role. We compared the incidence of mirror writing in patients with CVD having thalamic lesions and patients with CVD having lesions in areas other than the thalamus. Furthermore, we compared both groups of patients with patients with PD or ET and with normal subjects. Thirty-one patients with CVD (10 with thalamic lesions and 21 with other lesions), 34 patients with PD, 18 patients with ET, and 84 healthy volunteers were included in this study. All subjects were right-handed. We asked them to use their right hands and left hands to write letters in the right-to-left and left-to-right directions, respectively. We found mirror writing in some patients when the left hands was used. Mirror writing was seen in 12.9% of patients with CVD (10.9% with thalamic lesions, 14.3% with other lesions), 26.5% of patients with PD, 33.3% of patients with ET and 8.3% of normal subjects. A high incidence of mirror writing was found in patients with ET or PD. However, we did not observe a relationship between mirror writing and damage to the thalamus. These results suggest that mirror writing might be influenced by numerous neurologic and psychologic factors. © 1998, The Showa University Society. All rights reserved.