The scientists assessed 294 people from the Chicago area who were ages 55 and older, using annual tests to measure thinking and memory and questionnaires about past reading, writing and other mentally stimulating activities. At death, which occurred at an average age of just over 89, they looked at their brains for signs of dementia.
Lead author Robert S. Wilson, PhD, Rush University Medical Center, Chicago, Illinois, told Medscape Medical News that it has been fairly well established that reduced cognitive activity is associated with an increased rate of cognitive decline, but what has not been known is which comes first.
The study results were published this week in the journal Neurology. They showed that mentally stimulating activities across all ages is important for brain health in old age, said Robert Wilson, one of the study authors, of the Rush University Medical Center in Chicago.
It’s not that those activities will keep the brain from decline, but that the rate of decline is slowed, the scientists said. That was true independent of common neuropathic conditions, such as plaques and tangles, they said. Mental activities through life seem to provide a “cognitive reserve,” the scientists said.
Table. Rate of Cognitive Decline vs Average in Highest and Lowest Percentiles of Cognitive Activity in Later and Earlier Life
||Lowest 10% Cognitive Activity
||Highest 10% Cognitive Activity
Higher levels of cognitive activity in childhood, middle age and old age "were associated with slower rate of cognitive decline, together accounting for nearly 15% of variability,” the scientists wrote.