summary: A new study demonstrates that nighttime aromatherapy can boost memory in older adults. For six months, subjects were exposed to the scents of a variety of natural oils for two hours each night and showed an astonishing 226% increase in cognitive performance.
This innovative approach leverages the known link between smell and memory and offers a potential non-invasive strategy to combat cognitive decline and dementia.
Key Facts:
- Participants who received nightly aromatherapy experienced a 226% improvement in cognitive performance, as measured by a standard memory test.
- Neuroimaging studies revealed improved integrity of a brain pathway called the left uncinate fasciculus, which connects memory centers with the decision-making prefrontal cortex.
- The study confirms a direct link between the sense of smell and memory circuits in the brain and highlights the potential of aromatherapy as a non-invasive memory enhancement technique.
sauce: University of California, Irvine
When the scent was wafted into the elderly’s bedrooms for two hours each night for six months, memory soared.
Participants in the study, conducted by neuroscientists at the University of California, Irvine, experienced a 226% improvement in cognitive performance compared to a control group.
The researchers say their discovery turns a long-known link between smell and memory into a simple, non-invasive technique that could enhance memory and ward off dementia.
The team’s investigation The cutting edge of neuroscience.
The project was conducted through the Center for Neurobiology of Learning and Memory at the University of California, Irvine (UCI). Men and women between the ages of 60 and 85 with no memory problems participated. Each participant was given a diffuser and seven cartridges, each containing a different natural oil.
Participants in the enhanced group were given full-strength cartridges. Participants in the control group were given trace amounts of the oil. Each night, participants placed a different cartridge into their diffuser before going to bed and it ran for two hours while they slept.
People in the enhanced group showed a 226% improvement in cognitive ability compared to the control group, as measured by a word list test commonly used to assess memory. Imaging studies revealed better integrity of a brain pathway called the left uncinate fasciculus.
This pathway, which connects the medial temporal lobe to the decision-making prefrontal cortex, weakens with age. Participants also reported improved sleep quality.
Scientists have long known that loss of olfaction, or the ability to sense smell, can predict the development of about 70 neurological and psychiatric disorders, including Alzheimer’s and other dementias, Parkinson’s disease, schizophrenia and alcoholism.
Evidence is emerging linking COVID-related smell loss with subsequent cognitive decline: Researchers previously found that exposing people with moderate dementia to up to 40 different smells twice a day for a period of time improved memory and language skills, reduced depression, and improved olfactory abilities.
The UCI team decided to try and turn this knowledge into a simple, non-invasive tool to combat dementia.
“The reality is that once you reach age 60, your sense of smell and your cognitive abilities begin to decline rapidly,” said Michael Leong, professor of neurobiology and behavior and CNLM fellow.
“However, it is not realistic for someone with cognitive impairment to open, sniff and close 80 scented bottles every day. This would be difficult even for someone without dementia.”
“So while previous research projects have used multiple scents simultaneously, this time we decided to reduce the number of scents to seven and only expose participants to one scent each time,” said Cynthia Wu, first author of the study and project scientist.
“By allowing people to experience scents while they sleep, they no longer need to set aside time during their waking hours each day.”
The researchers say their findings support what scientists have learned about the connection between smell and memory.
“The sense of smell has the unique privilege of being directly connected to memory circuits in the brain,” said Michael Yassa, the James L. McGaugh Professor of Neurobiology of Learning and Memory, director of the CNLM, and co-investigator of the study.
“All other senses first go through the thalamus. We’ve all experienced the power of smell to evoke memories from long ago. But unlike hearing loss, where vision changes are treated with glasses or hearing aids, there has never been an intervention for loss of smell.”
The team next wants to study the impact of this technology on people diagnosed with cognitive disorders, and the researchers hope that their findings will lead to further research into olfactory therapy for memory problems.
Based on their research, a product designed for home use is expected to hit the market this fall.
Funding: This research was supported by Procter & Gamble.
About this news about research on smell and memory
author: Ethan Perez
sauce: University of California, Irvine
contact: Ethan Perez – University of California, Irvine
image: Image courtesy of Neuroscience News
Original Research: Open access.
“Overnight olfactory enhancement using an olfactory diffuser improves memory and alters the uncinate fasciculus in older adults” by Michael Leung et al. The cutting edge of neuroscience
Abstract
Overnight olfactory enhancement using an olfactory diffuser improves memory and alters the uncinate fasciculus in older adults
objective: Cognitive decline in the elderly is becoming a serious problem in society, necessitating the development of inexpensive, simple, and effective home-based treatments. This study was conducted to investigate the use of nocturnal olfactory stimulation to improve cognitive performance in healthy elderly people.
Method: Male and female elderly (no (43) Subjects aged 60–85 years participated in the study and were randomly assigned to either an olfactory enhancement group or a control group. Subjects in the enhancement group were exposed to seven different odorants for 2 hours, once a night, for one week using an olfactory diffuser. Subjects in the control group had the same experience as the subjects in the olfactory enhancement group. Very littleamount of odorant. Neuropsychological assessments and fMRI scans were performed at the start of the study and again six months later.
result: The Rey Auditory Verbal Learning Test showed a statistically significant 226% improvement in the enhancement group compared with the control group, and functional improvement of the left uncinate fasciculus was observed as assessed by mean diffusivity.
Conclusion: Minimal olfactory stimulation at night improves both cognitive and neurological function, and therefore olfactory stimulation may be an effective, low-effort way to improve brain health.
