Differential effects of lead exposure on components of verbal memory
Differential effects of lead exposure on components of verbal memory
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DOI：
10.1136/oem.2003.011346
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发表时间：
2005-03-01
影响因子：
4.9
通讯作者：
Bleecker, ML
中科院分区：
文献类型：
--
作者：
Bleecker, ML;Ford, DP;Bleecker, ML
目的：确定需要获取和保留信息的言语学习和记忆是否受到铅暴露的不同影响。方法：对256名平均（SD）年龄41（9.4）岁、工作年限17（8.1）年、会说英语的铅冶炼工人进行Rey听觉言语学习测试（RAVLT），这是一项言语学习和记忆测试。基于长达25年的既往血铅数据，铅暴露变量包括平均（SD）当前血铅（PbB）为28（8.8）马克/分升，工作寿命时间加权平均血铅（TWA）为39（12.3）马克/分升，工作寿命综合血铅指数（IBL）为728（434.4）马克/分升。在控制了年龄和教育成就后，通过多元线性回归对这些慢性和近期铅暴露变量与RAVLT测量的关联进行建模。结果：PbB与任何RAVLT变量无关。TWA和IBL对编码/存储和检索测量的差异有显著的解释作用，但对即时记忆广度、注意力和学习的差异没有显著的解释作用。根据三种公认的临床记忆范式对研究参与者进行RAVLT表现分组，在调整年龄和教育成就后，“广泛性记忆障碍”组的TWA和IBL显著更高。研究发现，“无记忆障碍”组和“检索困难”组的首因性（回忆起列表开头的单词）较强，而“泛化记忆障碍”组在近因性（回忆起列表末尾的单词）方面表现较好。结论：多年的铅暴露而不是多氯联苯干扰了先前学习的语言材料的组织和回忆。慢性铅暴露影响语言信息的编码/存储和检索。
Aims: To determine if verbal learning and memory requiring acquisition and retention of information is differentially affected by lead exposure.Methods: The Rey Auditory Verbal Learning Test (RAVLT), a test of verbal learning and memory, was administered to 256 English speaking lead smelter workers who had a mean (SD) age of 41 (9.4) years and employment duration of 17 (8.1) years. Lead exposure variables, based on up to 25 years of prior blood lead data, included a mean ( SD) current blood lead (PbB) of 28 ( 8.8) mug/dl, working lifetime time weighted average blood lead (TWA) of 39 (12.3) mug/dl, and working lifetime integrated blood lead index (IBL) of 728 ( 434.4) mug-y/ dl. Associations of these chronic and recent lead exposure variables with measures from the RAVLT were modelled through multiple linear regressions after controlling for age and educational achievement.Results: PbB was not associated with any of the RAVLT variables. However, TWA and IBL contributed significantly to the explanation of variance of measures of encoding/storage and retrieval but not to immediate memory span, attention, and learning. Grouping study participants by RAVLT performance according to three recognised clinical memory paradigms showed significantly higher TWA and IBL in the group with "generalised memory impairment'' after adjusting for age and educational achievement. We examined recall mechanisms in each group by serial position in the word list and found stronger primacy ( recall of words from the beginning of the list) in the "no impairment'' and "retrieval difficulties'' groups while the "generalised memory impairment'' group had better performance on recency ( recall of words from the end of the list).Conclusions: Lead exposure over years and not PbB interfered with the organisation and recall of previously learned verbal material. Chronic lead exposure affects encoding/storage and retrieval of verbal information.