A groundbreaking study by neuroscientists from the University of California, Irvine (UCI) has unveiled an astonishing link between fragrance and memory in older adults. Over a six-month period, the simple act of exposing participants to a specific scent for two hours each night led to a remarkable 226% increase in cognitive capacity compared to a control group. This discovery could revolutionize our understanding of memory enhancement and offer a non-invasive approach to fortifying memory and potentially reducing the risk of dementia. The research was carried out under the auspices of the UCI Center for the Neurobiology of Learning & Memory.

The study involved men and women aged 60 to 85 who exhibited no signs of memory impairment. Each participant received a diffuser and seven cartridges, each containing a distinct natural oil. Those in the “enriched” group were provided with full-strength cartridges, while the control group received minimal amounts of the oils. Participants placed a different cartridge in their diffuser before bedtime, allowing it to diffuse for two hours while they slept.

The results were astounding, with participants in the enriched group demonstrating a remarkable 226% increase in cognitive performance compared to their counterparts in the control group. The evaluation was based on a word list test commonly employed to assess memory. Furthermore, brain imaging revealed enhanced integrity in the left uncinate fasciculus, a crucial brain pathway that connects the medial temporal lobe to the prefrontal cortex responsible for decision-making. This pathway typically becomes less robust with age. Additionally, participants reported experiencing more restful sleep.

Scientific knowledge has long recognized that the loss of the sense of smell, or olfactory capacity, can serve as a predictor for the development of numerous neurological and psychiatric conditions, including Alzheimer’s, Parkinson’s, schizophrenia, and alcoholism. Emerging evidence even suggests a connection between the loss of smell due to COVID-19 and subsequent cognitive decline. Prior research has demonstrated that exposing individuals with moderate dementia to a variety of odors on a daily basis can lead to memory improvement, enhanced language skills, alleviated depression, and improved olfactory abilities. Building upon this foundation, the UCI research team sought to transform this knowledge into a practical and non-invasive tool to combat dementia.

Michael Leon, a professor of neurobiology & behavior and a CNLM fellow, emphasized, “The reality is that over the age of 60, the olfactory sense and cognition start to fall off a cliff.” He acknowledged the impracticality of expecting individuals with cognitive impairment to manage daily interactions with 80 different odorant bottles. This task would be daunting even for those without dementia.

Cynthia Woo, the study’s first author and a project scientist, explained their approach: “That’s why we reduced the number of scents to just seven, exposing participants to just one each time, rather than the multiple aromas used simultaneously in previous research projects. 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.”

The research outcomes affirm the well-established connection between scent and memory. Michael Yassa, professor and James L. McGaugh Chair in the Neurobiology of Learning & Memory, who also serves as the director of CNLM, emphasized that the olfactory sense holds a unique privilege by being directly connected to the brain’s memory circuits. Unlike other senses that first pass through the thalamus, aromas have the extraordinary ability to evoke vivid recollections, even from distant memories. Yet, unlike visual or auditory impairments that can be addressed with corrective measures like glasses or hearing aids, there has been no intervention for the loss of smell.

The next phase of the research will explore the technique’s impact on individuals already diagnosed with cognitive decline. Additionally, the researchers hope that their findings will inspire further investigations into olfactory therapies for memory impairments. A product based on their study, designed for home use, is anticipated to enter the market in the upcoming fall, offering hope for those seeking memory enhancement through the power of scent.

By Impact Lab