Interventions to normalize sleep duration and correct sleep disorders have potential to reduce or prevent cognitive decline, according to studies presented here Monday at the Alzheimer's Association International Conference.

Dr. William Thies, chief medical and scientific officer at the Alzheimer's Association, said the studies presented suggested that cognitive health declines over the long term in some people with sleep problems.

"The good news is that tools already exist to monitor sleep duration and quality and to intervene to help return sleep patterns to normal," Thies said.

"If we do this, there is the possibility that we may also help people preserve their cognitive health, but that needs to be tested," he added.

In a study involving more than 15,000 participants, Elizabeth Devore of Boston's Brigham and Women's Hospital and colleagues found that participants who slept two hours more or less per day had lower average cognition than those who slept the recommended 7 hours per day.

"The public health implications of these findings could be substantial, as they might lead to the eventual identification of sleep- and circadian- based strategies for reducing risk of cognitive impairment and Alzheimer's," Devore said.

In another study involving more than 1,300 women that were over 75 years old, Kristine Yaffe of the University of California, San Francisco, and colleagues found that sleep disturbances were associated with increased risk of developing cognitive impairment five years later in elder women.

"They suggest that health practitioners should consider assessing older people with sleep disorders for changes in cognition," Yaffe said.

"In addition, with additional long-term research, treatment of sleep disorders may be a promising method of delaying the development of Mild Cognitive Impairment and dementia," added the researcher.