March 23, 2009 -- Don't be so quick to blame a late night on the town if a 20-something has difficulty recalling certain information or performing brain-puzzling tasks.
Researchers from the University of Virginia have found that cognitive decline -- a condition most often associated with older or elderly adults -- actually starts to kick in relatively early in adulthood, at age 27.
"[Our] research suggests that some aspects of age-related cognitive decline begin in healthy, educated adults when they are in their 20s and 30s," says study researcher Timothy Salthouse, PhD, in a news release. Salthouse is a University of Virginia professor of psychology.
The findings appear in the February issue of Neurobiology of Aging.
The study revealed that certain cognitive skills peak around age 22, but then slowly decline five years later. Such skills included the ability to make rapid comparisons, remember unrelated information, and detect patterns or relationships.
For the study, the research team asked 2,000 healthy participants ages 18 through 60 to solve various puzzles, recall words and story details after several minutes had passed, and identify patterns in certain letters and symbols.
Researchers retested many participants over the seven-year study period. Among their findings:
- Subtle declines in cognitive skills occurred throughout the study.
- A noticeable drop in abstract reasoning, brain speed, and puzzle-solving test scores occurred at 27.
- Average memory declines could be detected by approximately 37.
Although certain cognitive skills declined in early adulthood, the study also showed that vocabulary and general knowledge skills increased until at least 60. These patterns suggest "how much knowledge one has, and the effectiveness of integrating it with one's abilities, may increase throughout all of adulthood if there are no pathological diseases," Salthouse notes.
However, the researchers point out in a news release that cognitive skills vary great from person to person, and that most people function at an effective level into their final years of life.
As we age, some decline in memory and mental function may be expected. Such age-related cognitive decline is different from dementia and Alzheimer's disease. However, better understanding of cognitive development could lead to improved diagnosis of Alzheimer's and other dementias.
The age when cognitive decline occurs, however, has important implications for the timing of therapies intended to prevent or reverse the condition. According to background information in the journal article, many existing therapies currently target adults over age 60. Yet if cognitive decline really starts in young adulthood, as the study suggests, a great deal of change will likely have occurred by middle age.
"This may affect the likelihood that interventions at that age will be successful because the changes might have accumulated to such an extent that they may be difficult to overcome," the researchers write in the journal report.
The researchers are also evaluating whether health and lifestyle factors, such as social relationships, influence age-related cognitive changes. They hope to continue their research with the same group of participants to gain long-term insight into how the brain changes over time.