Stichting Verpleeghuiszorg Nederland, Department of Psychogeriatrics, Naarderstraat 81, 1251 BG Laren, The Netherlands.
Behav Neurol. 1993;6(4):239-42. doi: 10.3233/BEN-1993-6411.
A 75-year-old man with seven years of formal education displayed a syndrome of progressive and severe lexical impairments to word comprehension and production (semantic dementia). While he lost the ability to recognize written arithmetical signs, he could still retrieve the arithmetical facts for addition and subtraction of all number combinations of 1 to 9 and 11 to 19, though his mastery of multiplication tables (2 to 9) was unreliable. Calculation procedures were intact. Over the course of 18 months the components of the calculation system dissolved selectively: arithmetical procedures and number reading were spared, despite increasing damage to the arithmetic fact store. He retained the ability to read the time on analogue clocks. Selective preservation of components of the calculation system in the context of severe language deficits and dementia, supports the independent status of numerical abilities. The dissociation between intact arithmetical procedures and impaired table fact retrieval was paralleled by a dissociation between preserved procedures of phonology and syntax of language and impaired retrieval of content words, suggesting that the core deficit was a degradation of the central semantic store of learned knowledge of both words and arithmetic table facts.
一位 75 岁、接受过七年正规教育的男性患者表现出进行性和严重的词汇理解和产生障碍（语义性痴呆）。虽然他已经丧失了识别书面算术符号的能力，但他仍然可以检索到 1 到 9 以及 11 到 19 之间所有数字组合的加减算术事实，尽管他对乘法表（2 到 9）的掌握并不可靠。计算过程是完整的。在 18 个月的时间里，计算系统的各个组成部分选择性地解体：尽管算术事实存储的损伤不断增加，但算术过程和数字阅读仍然没有受到影响。他仍然能够读取模拟时钟上的时间。在严重的语言缺陷和痴呆的情况下，计算系统的各个组成部分选择性保留，支持了数字能力的独立地位。完整的算术过程与受损的表格事实检索之间的分离，与语言的语音和句法过程保留以及内容词检索受损之间的分离相平行，这表明核心缺陷是中央语义存储库中关于单词和算术表格事实的习得知识的退化。
