语义性痴呆患者语义记忆障碍特征研究

Semantic memory study on patients with semantic dementia

目的探讨语义性痴呆(SD)患者语义记忆障碍的特点,揭示语义记忆的神经解剖机制。方法对9例早期SD患者(病程≤3年)进行详细的神经系统查体、影像学检查和语义记忆评估。语义记忆评估选用常见的动物(生命类)和日常用具(非生命类),统计每一例SD患者对物体名称和功能记忆的正确比例,比较患者对生命类和非生命类物体记忆之间的差异。结果临床上早期SD患者出现广泛的语义记忆损害,所有患者均无感觉或运动方面的症状及体征,颅脑磁共振检查发现所有患者均以左侧颞叶前部萎缩为主,初级感觉皮层和运动皮层正常。所有患者对生命类和非生命类物体的名称及功能均有遗忘,对名称的遗忘更严重。2例患者对生命类物体名称和功能的遗忘较非生命类物体严重,另2例对非生命类物体名称和功能的遗忘重于生命类。结论颞极是语义记忆储存的主要部位,此部位损害后,各种语义记忆普遍受损。语义复合体(名称、知觉和功能)中物体的功能较词语表征更加核心和牢固。部分SD患者存在"语义范畴特异性损害",而且模式并不固定。

Objective To explore the features of semantic memory in patients with semantic dementia （SD） and reveal the neuro-anatomy mechanisms of＇semantic memory. Methods Detailed neurological examination, brain images and semantic memory assessment were performed in 9 SD patients in early stage （ disease duration ≤ 3 years） . Semantic memory assessment included living things （ common animals） and non-living things （ daily utensils）. The percentage of correct naming and function memory for the 2 category things were calculated. The difference between the memory for living things and non-living things were determined. Results All patients developed marked semantic memory impairment in the early stage. No patients complained any sensory or motor symptoms. Detailed neurological examination revealed no signs involving the sensory or motor system. Brain magnetic resonance images disclosed left anterior temporal lobe atrophy in all patients. All patients impaired in the naming and functional memory both for the living things and non-living things, with a more severe deficit in naming. Two patients preformed worse for living things than non-living things. Another 2 cases more impaired in memory for non-living things. Conclusion Current study suggests that semantic memory storage in the left temporal pole. Damage in the left temporal pole will result in extensive semantic memory deficit. The function of objects is the core of the semantic complex （ name, perception and function）. Some SD patients shows ＂category-specific semantic deficit＂ for living things or non-living things.