Working memory deficiencies in adults associated with low-level lead exposure: implications of neuropsychological test results.
BACKGROUND
Although lead exposure has steadily decreased in the last few years, some lead is still used in the metal processing industry, mostly for wall paints and plumbing. Recent studies on children showed neurobehavioral effects of low-level exposure, but little is known about the neurocognitive effects of lead concentrations in the upper reference range on adults.


METHODS
The neuropsychological effects of lead exposure were examined in 39 adult outpatients at the Unit of Environmental Medicine (UEM), University Hospital, Aachen, Germany. All patients underwent a comprehensive medical examination, including psychiatric. Venous blood and urine samples were collected and tested for heavy metals and selenium. Since the neuropsychological examination was not expected to reveal any severe abnormalities, only specific attentiveness functions were analyzed (alertness, working memory, flexibility, intermodal comparison) since these areas were the likeliest to show objectifiable effects. The tests were conducted using a standardized computerized battery.


RESULTS
Lead blood levels ranged from 1 to 65.6 microg/l (mean 27.4 +/- 16.2 microg/l). Although the neuropsychological test results of all patients were within the normal range, there were significant correlations between blood lead levels and the speed of information processing for working memory.


CONCLUSIONS
The results indicate working memory dysfunctions in adults, the severity of which correlates directly with blood lead levels, supporting the hypothesis that increased blood lead levels can also be associated with measurable neurocognitive abnormalities.
Kunert
Hanns Jorgen
HJ
Department of Psychiatry and Psychotherapy, University of Aachen, Germany. hjkunert@ukaachen.de
Wiesmüller
Gerhard Andreas
GA
Schulze-Röbbecke
Roland
R
Ebel
Hermann
H
Müller-Küppers
Markus
M
Podoll
Klaus
K
D000328:Adult; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000097:blood / Q000633:toxicity* / Q000652:urine; D005260:Female; D005858:Germany; D006801:Humans; D007854:Lead / Q000097:blood / Q000633:toxicity* / Q000652:urine; D008297:Male; D008568:Memory / Q000187:drug effects*; D009483:Neuropsychological Tests
D004785:Environmental Pollutants; D007854:Lead