People who spend a lot of time reading are two and a half times less likely to exhibit cognitive deficits from exposure to high levels of lead, according to a study published in the July 31 issue of Neurology.
It is simple, but astonishing: Scientists at Baltimore’s Center for Occupational and Environmental Neurology claim that the act of reading the written word results in less mental impairment from exposure to potentially toxic lead.
In the study, the Baltimore team recruited 112 men who worked at a lead smelter. Workers who scored highest on reading ability—a measure of what the researchers call “cognitive reserve”–were compared with a group of workers who were poor readers. Both groups had identical blood levels of lead, and exhibited similar lead-related impairments in hand-eye coordination and other motor skills.
However, a battery of psychological tests covering memory, concentration, and attention showed a striking difference when it came to mental deficits associated with lead poisoning. The good readers showed markedly less cognitive impairment than the workers with poor reading skills. Doing puzzles and playing problem-solving games did not seem to confer the same protection, the researchers said.
“This suggests that high cognitive reserve has a protective effect that allowed these workers to maintain their functioning,” said Dr. Margit L. Bleecker, the lead author of the study.
Other factors may influence cognitive reserve, including heredity and social circumstances. However, the researchers believe that the reading test effectively factors out differences in education and income. “A reading test identifies those self-educated individuals that left school early for a variety of sociocultural reasons, and those individuals who graduated high school but are functionally illiterate,” the study asserts.
The theory of cognitive reserve evolved out of earlier research on Alzheimer’s disease, which showed that patients who “exercised” their brains more vigorously tended to show less progressive impairment. Nobody is completely certain about the mechanisms of action in the lead workers, nor is it clear exactly how the concept of cognitive reserve confers such protection on brain cells. It has been suggested that reading somehow helps prepare the brain to function more effectively in the event of damage caused by exposure to toxins or by degenerative nerve diseases.