Tanaka Y, Iwasa H, Obayashi T
Department of Neurology, Jichi Medical School, Tochigi, Japan.
Cortex. 1990 Dec;26(4):665-71. doi: 10.1016/s0010-9452(13)80317-6.
A right-handed Japanese man showed agraphia more marked with the right hand, apraxia confined to the left hand, and right ear extinction on dichotic listening, following damage to the anterior two-thirds of the corpus callosum, the rostral and lower parts of the right medial frontal lobe and a small portion of the left medial frontal lobe. The symptoms were attributed to hemispheric disconnection, on the assumption that the right hemisphere was dominant for language and the left for limb praxis. This case provides good evidence for dissociated lateralization of language and limb praxis in some right-handed individuals. The study of writing performance suggested the following hypotheses: (1) motor engrams for limb praxis and writing may be dissociated, and (2) motor engrams for writing Kana (phonogram) and Kanji (ideogram) letters are represented on both hemispheres, although the hemisphere nondominant for language seems unable to combine graphemes into a correct meaningful sequence.
一名惯用右手的日本男性，在胼胝体前三分之二、右侧额内侧叶的嘴侧和下部以及左侧额内侧叶的一小部分受损后，出现了右手书写障碍更为明显、左手失用症以及双耳分听时右耳听觉消失的症状。这些症状被归因于半球分离，假设右半球在语言方面占主导地位，而左半球在肢体运用方面占主导地位。该病例为一些惯用右手的个体中语言和肢体运用的分离性偏侧化提供了有力证据。对书写表现的研究提出了以下假设：（1）肢体运用和书写的运动记忆痕迹可能是分离的；（2）书写假名（音节文字）和汉字（表意文字）字母的运动记忆痕迹在两个半球均有体现，尽管在语言方面不占主导地位的半球似乎无法将字素组合成正确的有意义序列。
