The limbic system – a complex system of nerves and networks in the brain – supports many brain functions, including memory, emotion, and learning. The olfactory system is the only sensory system directly linked to this critical brain region. A new study shows that olfactory stimulation via aromatherapy may enhance limbic system function, potentially preserving or improving cognitive function in older adults.
Researchers assigned 23 older adults (aged 60 to 85) to an olfactory-enriched or control group. Using an aromatherapy diffuser, they exposed the enriched group to seven essential oil scents (rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender – one per night) for two hours per night for six months. They exposed the control group to a similar routine but with minimal amounts of scent. The participants underwent neuropsychological assessments and functional magnetic resonance imaging (fMRI) scans at the study’s outset and again after six months.
The assessments revealed that the participants who received olfactory enrichment demonstrated a 226 percent improvement on learning and memory tests. Notably, only six of the 12 participants improved, five stayed the same, and one did worse, calling the data into question. The fMRIs showed that the enriched group also exhibited enhanced function in the left uncinate fasciculus – an area of the brain that plays a crucial role in memory, language, emotion, and memory retrieval.
These findings suggest that olfactory enrichment administered at night improves cognitive and neural functioning and may provide an effective and low-effort means to improve brain health. This study was very small, so larger trials are needed to confirm the benefits of aromatherapy on cognitive health.