The study involved 18 pilots with an average age of 52. First, the pilots conducted seven practice flights on a flight simulator to train them to perform a complex series of instructions. Then half of them took the drug donepezil for 30 days and half took a placebo. They then took the flight simulator test twice more to see if they had retained the training. The pilots who had taken the drug retained the training better than those who had taken placebo did.
Researchers were testing the theory that declines in cognitive abilities due to aging are caused in part by loss of functioning of acetylcholine. Acetylcholine is a neurotransmitter that relays messages between cells in areas of the brain important for memory and thought. Donepezil is a cholinesterase inhibitor, which blocks the action of an enzyme responsible for breaking down acetylcholine.
Pilots make good test subjects because flight simulators provide reliable, objective data, according to study author Jerome Yesavage, MD, of Stanford University and the Palo Alto VA Health Care System in California.
Another reason to study the effects of aging on pilots' performance is controversy over the Federal Aviation Administration (FAA) law requiring air transport pilots to retire when they reach age 60.
"There's no shortage of opinions about what the retirement age should be," said Yesavage. "However, there's very little data to support those opinions."
Yesavage pointed out that the tasks learned in this experiment were more difficult than those experienced in routine flight operations. "So these results may not be very applicable to the retirement debate," he said.