Sakurai Yasuhisa
Department of Health Care, Mitsui Memorial Hospital, Tokyo, Japan.
Takuma Neurology Clinic, Tokyo, Japan.
Front Hum Neurosci. 2025 Sep 4;19:1664803. doi: 10.3389/fnhum.2025.1664803. eCollection 2025.
The Japanese language has a unique writing system that consists of (morphograms, derived from Chinese characters) and (phonograms, a simplified form of kanji representing syllables). A kanji character has two distinct ways of reading: -reading (Chinese-style pronunciation) and -reading (native Japanese pronunciation). Some kanji words have irregular -reading called . Furthermore, kana characters have two script forms: (cursive form) and (square form), each of which is used for different purposes. Because of these features, Japanese individuals with alexia and agraphia show characteristic symptoms. Lesion-to-symptom analyses and functional imaging studies developed beginning in the 1970s have reported the following findings: (1) kanji-kana dissociation in alexia/agraphia: pure alexia for kanji or kana, lexical agraphia for kanji, and phonological agraphia for kana; (2) dissociation in alexia: predominant -reading and reading impairment in semantic dementia and selective -reading impairment in the extensive posterior middle temporal gyrus lesion; and (3) allographic agraphia between and .
日语有一套独特的书写系统，它由（表意文字，源自汉字）和（表音文字，汉字的一种简化形式，代表音节）组成。一个汉字有两种不同的读法：音读（中国式发音）和训读（日语本土发音）。一些汉字词有不规则的音读，称为熟字训。此外，假名有两种书写形式：平假名（草书形式）和片假名（方形形式），每种形式用于不同的目的。由于这些特点，患有失读症和失写症的日本人表现出特征性症状。从20世纪70年代开始的病变与症状分析以及功能成像研究报告了以下发现：（1）失读症/失写症中的汉字-假名分离：对汉字或假名的纯失读症、对汉字的词汇性失写症以及对假名的语音性失写症；（2）失读症中的诵读困难分离：在语义性痴呆中主要是音读和训读受损，而在广泛的颞中回后部病变中是选择性音读受损；以及（3）平假名和片假名之间的全字性失写症。
