Exciting but preliminary
Commenting for this article, Donald Wilson, PhD, professor of child and adolescent psychiatry and of neuroscience and physiology, the Child Study Center, NYU Langone Medical Center, New York, said that multiple studies have “demonstrated that problems with sense of smell are associated with and sometimes can precede other symptoms for many disorders, including AD, Parkinson’s disease, and depression.”
Recent work has suggested that this relationship can be “bidirectional” – for example, losing one’s sense of smell might promote depression, while depressive disorder might lead to impaired smell, according to Dr. Wilson, also director and senior research scientist, the Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research. He was not involved with the study.
This “two-way interaction” may raise the possibility that “improving olfaction could impact nonolfactory disorders.”
This paper “brings together” previous research findings to show that odors during bedtime can improve some aspects of cognitive function and circuits that are known to be important for memory and cognition – which Dr. Wilson called “a very exciting, though relatively preliminary, finding.”
A caveat is that several measures of cognitive function were assessed and only one (verbal memory) showed clear improvement.
Nevertheless, there’s “very strong interest now in the olfactory and nonolfactory aspects of odor training and this training expands the training possibilities to sleep. This could be a powerful tool for cognitive improvement and/or rescue if follow-up studies support these findings,” Dr. Wilson said.
A version of this article appeared on Medscape.com.