Effects of Olfactory Stimulation on Past and Future Thinking in Alzheimer's Disease.

Several studies have demonstrated that Alzheimer's disease (AD) is associated not only with difficulty in remembering past events but also with a compromised ability to imagine future ones. Recent empirical research has also demonstrated that odor is an effective cue to alleviate difficulty in remembering past events in AD. We investigated whether odor exposure would help AD patients to imagine future events. To this end, we invited AD patients and control participants to evoke past and future events after odor exposure or without odor. Analysis showed that AD patients and control participants produced more specific and more emotional past and future events after odor exposure than without odor. However, odor exposure did not improve the retrieval time for future thinking in AD participants. This study is the first to demonstrate positive effects of odor exposure on the ability of AD patients to project themselves into the future.