By Janet Raloff
Workers at lead-smelting plants can suffer substantial neural damage from exposure to the toxic heavy metal. Workers who read well, however, experience comparatively less mental impairment, a new study finds.
It’s not that the better readers were smarter, but that they have more “cognitive reserve,” explains study leader Margit L. Bleecker, a neurologist at the Center for Occupational and Environmental Neurology in Baltimore. She says that people typically gain cognitive reserve—better or more resilient neural connections in the brain—through reading, puzzle solving, and other mentally challenging activities.
Her team recruited 112 men at a lead smelter to participate in a battery of neural assessments. After measuring the men’s reading abilities—a rough gauge of cognitive reserve—the researchers split the volunteers into two groups of equal size, consisting of high or low scorers. In other respects—age, number of years worked, educational background—the two groups were similar. Most important, participants in each group exhibited the same range of blood-lead concentrations.
In the July 31 Neurology, the researchers report that in each group, men with higher blood-lead values scored more poorly on tests of hand-eye coordination. That’s typical of lead poisoning. However, men in the better-reading group performed 2.5 times as well on tests of memory, attention, and concentration—tasks not necessarily related to reading.
The brain is like a muscle, Bleecker concludes: Exercising it strengthens it and makes it better able to counter the ravages of disease and poisoning.
