Needleman H L
Neurobehav Toxicol Teratol. 1982 Nov-Dec;4(6):729-32.
Children attending non-remedial first and second grades were classified according to the concentration of lead in their shed deciduous teeth. Children in the lowest and highest tenth percentile were studied with a detailed neuropsychological battery under blind conditions. Thirty-nine non-lead covariates were controlled either by matching or in the biostatistical analysis. High lead children tended to have significantly lower IQ scores particularly on the verbal scales of the WISC-R, impaired auditory and language processing, increased reaction times at longer intervals of delay. Their teachers who were blind to the dentine lead levels found an increased incidence of disordered classroom behavior in direct relationship to the concentration of lead in their teeth. Quantitative electroencephalographic analysis demonstrated decreased midline alpha and increased midline delta in high lead subjects. Four years later a subsample of these children was followed up and observed during quiet classroom activity. High lead children tended to spend more time off tasks staring at classmates, out the window or at the observer. These observations demonstrate that lead at doses below those which are associated with frank clinical symptoms produce deficits in intelligence, attention, auditory-language function and disordered classroom behavior.
对就读于非矫正性一年级和二年级的儿童，根据其脱落乳牙中的铅浓度进行分类。对处于铅浓度最低和最高十分位数的儿童，在盲态条件下使用一套详细的神经心理测试组进行研究。通过匹配或生物统计学分析控制了39个非铅协变量。高铅儿童往往智商得分显著较低，尤其是在韦氏儿童智力量表修订版（WISC-R）的言语量表上，听觉和语言处理受损，延迟时间较长时反应时间增加。对乳牙铅水平不知情的教师发现，课堂行为紊乱的发生率增加，且与他们牙齿中的铅浓度直接相关。定量脑电图分析显示，高铅受试者中线阿尔法波减少，中线德尔塔波增加。四年后，对这些儿童的一个子样本在安静的课堂活动期间进行了随访观察。高铅儿童往往花更多时间不专注于任务，盯着同学、望向窗外或看着观察者。这些观察结果表明，低于与明显临床症状相关剂量的铅会导致智力、注意力、听觉语言功能和课堂行为紊乱方面的缺陷。
