As the global population ages, supporting cognitive and memory functions in older adults has become critical. According to the United Nations, by 2070, the number of people aged 65 and older is projected to surpass 2.2 billion, overtaking the global population of children under 18 for the first time in human history. This demographic shift is particularly pronounced in countries like Japan, where nearly 28.7% of the population is already aged 65 or older, making it the fastest-ageing nation in the world. As life expectancy rises and birth rates fall, the need for adequate cognitive support for older adults becomes ever more pressing, driving researchers to explore innovative strategies for preserving brain function.
One promising approach involves olfactory stimulation, leveraging the powerful link between the sense of smell and the brain’s memory centres. Unlike other senses, olfactory signals bypass the brain’s traditional sensory relay systems and connect directly to regions like the hippocampus and amygdala, which are crucial for memory and emotional processing. This unique neural pathway makes smell a potent trigger for recalling past experiences and emotions. Building on this foundation, a multidisciplinary research team from the Institute of Science Tokyo (Science Tokyo), the University of the Arts London, Bunkyo Gakuin University, and Hosei University in Japan has developed the world’s first cognitive training method for older adults that combines olfactory stimulation with virtual reality (VR). Their groundbreaking study was published in Volume 15 of Scientific Reports on 28 March 2025.
The researchers designed their cognitive training system to provide an immersive, goal-oriented experience that fully engages the brain’s sensory and cognitive networks. Professor Takamichi Nakamoto from Science Tokyo, one of the lead scientists behind the project, explains the rationale: “VR offers a powerful platform for simulating sensory experiences in a controlled, immersive setting. By combining goal-oriented tasks with real-time feedback, our VR-based olfactory training approach can increase cognitive engagement and maximise its therapeutic impact.” The system uses a specialised olfactory display that emits precise scents during VR gameplay, enhancing the realism and cognitive stimulation of the experience.
The training activity is a carefully crafted sequence designed to strengthen multiple cognitive functions. It begins in a lush virtual landscape, where participants use a VR controller to interact with their environment. The exercise starts with a “smell memory” phase, where users encounter a virtual stone statue that, when touched, releases a distinct scent along with a white vapour cloud as a visual cue, reinforcing the link between the smell and the visual stimulus. This is followed by a navigation phase, where players move through the virtual environment, guided by subtle scent trails, to locate a second scent source, a stone lantern. Upon reaching the lantern, they must identify the original scent from three differently scented vapour clouds, testing their ability to match and recall olfactory information.
This innovative training method has shown promising results in early trials. In a study involving 30 older adults aged 63 to 90, just 20 minutes of gameplay led to measurable cognitive improvements. Participants performed significantly better on various cognitive assessments, including the Hiragana Rotation Task, which tests spatial reasoning and visuospatial processing. In this task, players must determine whether rotated Japanese characters match their original forms, improving accuracy scores from 19–82 to 29–85. In a separate word-based spatial memory recall task, where participants memorised word positions within a grid, scores rose from 0–15 to 3–15, demonstrating enhanced memory retention. These gains were validated through rigorous statistical analysis, confirming the effectiveness of the olfactory-enhanced VR approach in boosting cognitive function.
Looking to the future, the research team is optimistic about the broader potential of their approach. They envision a time when olfactory-based VR could become a widely accessible tool for supporting cognitive health, particularly as scent delivery technologies become more affordable and practical for everyday use. This approach could not only aid in maintaining memory and cognitive function in older adults but also potentially slow the progression of neurodegenerative conditions like dementia. Professor Nakamoto notes, “With continued research and technological advancements, we hope to make this form of cognitive training a regular part of mental fitness for older adults, improving quality of life and mental resilience as populations continue to age.”
More information: Takamichi Nakamoto et al, Exploring the effects of olfactory VR on visuospatial memory and cognitive processing in older adults, Scientific Reports. DOI: 10.1038/s41598-025-94693-9
Journal information: Scientific Reports Provided by Institute of Science Tokyo
