When an aroma gently drifted through the bedrooms of older adults, permeating the air for two hours each night over the course of six months, the impact on memories was profound. The participants in the neuroscientists’ study experienced an astonishing 226% surge in cognitive capacity when compared to the control group.
According to the researchers from the University of California, Irvine, this discovery revolutionizes the well-established connection between scent and memory, offering a straightforward and non-intrusive method for enhancing memory and potentially providing a defense against dementia.
Published in the journal Frontiers in Neuroscience, the study enlisted individuals aged 60 to 85, all free from memory impairments. Each participant received a diffuser and seven distinct cartridges, each containing a different natural oil. Those in the experimental group received full-strength cartridges, while the control group received oils in minimal quantities. Every evening before bedtime, participants inserted a different cartridge into their diffusers, allowing it to release its aroma for two hours during sleep.
The individuals exposed to the enriched fragrance experience exhibited an astonishing 226% improvement in cognitive performance compared to their counterparts in the control group, as assessed using a standard word list test for memory evaluation. Furthermore, these participants reported experiencing more restful sleep.
Upon analyzing brain scans, the researchers discovered greater integrity in a neural pathway known as the left uncinate fasciculus, which deteriorates with age. This pathway connects the medial temporal lobe to the decision-making prefrontal cortex.
For quite some time, scientists have understood that a decline in the ability to detect scents, or anosmia, can serve as an early indicator for the development of nearly 70 neurological and psychiatric conditions, including Alzheimer’s disease, various dementias, Parkinson’s disease, schizophrenia, and alcoholism. Additionally, emerging evidence suggests a potential link between COVID-related loss of smell and subsequent cognitive decline.
In earlier research, individuals with moderate dementia were exposed to up to 40 different odors twice daily over a period of time. The outcomes were remarkable, with improvements in memory, language skills, mood, and olfactory capabilities.
Building upon this knowledge, the UC-Irvine research team embarked on transforming these insights into a straightforward and non-intrusive tool for combatting dementia.
“By making it possible for people to experience the odors while sleeping, we eliminated the need to set aside time for this during waking hours every day,” Cynthia Woo, the study’s first author and a project scientist, said.
The findings confirm the existing knowledge about the relationship between smell and memory, according to the researchers.
“The olfactory sense has the special privilege of being directly connected to the brain’s memory circuits,” said Prof. Michael Yassa and James L. McGaugh. The latter is the chair in the Neurobiology of Learning & Memory as well as the director of CNLM. McGaugh also served as collaborating investigator.
“All the other senses are routed first through the thalamus. Everyone has experienced how powerful aromas are in evoking recollections, even from very long ago.”
After reaching the age of 60, both the sense of smell and cognitive abilities tend to decline.
“But, unlike with vision changes that we treat with glasses and hearing aids for hearing impairment, there has been no intervention for the loss of smell.”
Next, the team intends to examine the effects of the technique on individuals who have been diagnosed with cognitive decline. Furthermore, the researchers express their anticipation that these findings will prompt further exploration of olfactory therapies for memory impairment.
According to a press release from the University, a product developed from their study and designed for home use is anticipated to be available on the market this upcoming autumn.
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