To determine whether the effects of low-level lead exposure persist, we reexamined 132 of 270 young adults who had initially been studied as primary school-children in 1975 through 1978. In the earlier study, neurobehavioral functioning was found to be inversely related to dentin lead levels. As compared with those we restudied, the other 138 subjects had had somewhat higher lead levels on earlier analysis, as well as significantly lower IQ scores and poorer teachers' ratings of classroom behavior. When the 132 subjects were reexamined in 1988, impairment in neurobehavioral function was still found to be related to the lead content of teeth shed at the ages of six and seven. The young people with dentin lead levels greater than 20 ppm had a markedly higher risk of dropping out of high school (adjusted odds ratio, 7.4; 95 percent confidence interval, 1.4 to 40.7) and of having a reading disability (odds ratio, 5.8; 95 percent confidence interval, 1.7 to 19.7) as compared with those with dentin lead levels less than 10 ppm. Higher lead levels in childhood were also significantly associated with lower class standing in high school, increased absenteeism, lower vocabulary and grammatical-reasoning scores, poorer hand-eye coordination, longer reaction times, and slower finger tapping. No significant associations were found with the results of 10 other tests of neurobehavioral functioning. Lead levels were inversely related to self-reports of minor delinquent activity. We conclude that exposure to lead in childhood is associated with deficits in central nervous system functioning that persist into young adulthood.

Since the widespread acceptance of alternative input devices and the development of technology for character recognition, gestures have begun to be investigated as a potential dialog type in software applications. Inter and intra-subject consistency has been reported; however, no one has reported inter-application consistency. This paper begins to take a systematic approach to identifying a minimal set of gestures that would be necessary to operate across a series of applications. Two tasks with 15 subjects in each were conducted on the use of gestures to edit text and spreadsheets using a pencil and paper. By examining people's editing marks in these two situations, this study begins to identify the level to which gestures remain consistent across applications. The results are discussed in relationship to the implementation of an economical gestural interface for an application suite.

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New technologies are being introduced with little regard for potentially unique users such as older adults. As a consequence, such users frequently have trouble operating the controls for these new technologies. As a way around these problems, we asked whether a general set of design guidelines could be generated which would improve older adults' performance on existing audio remote controls. In a series of three experiments, we were able to show that older adults did have much more difficulty operating existing remote controls than younger adults, that a common problem lay behind most of those errors, and that general guidelines for the design of audio remote control interfaces emerged which when implemented led to large improvements in performance. The guidelines can be generalized to the much larger set of remote controls, thereby potentially increasing the independence and well being of many older adults.