From Medscape, August 8th 2023.
Inhaling a pleasant aroma during sleep has been linked to an improvement in memory, small-scale early research suggests. Researchers randomly assigned 43 older adults, aged 60 – 85 years, to receive either nightly exposure to essential oil scents delivered via a diffuser (n = 20; mean [SD] age, 70.1 [6.6] years) or to a sham control with only trace amounts of odorants (n = 23; mean age, 69.2 [7.1] years) for a period of 6 months.
They found that when cognitively normal individuals were exposed to the scent of an essential oil for 2 hours every night over 6 months, they experienced a 226% improvement in memory compared with a control group who received only a trace amount of the diffused scent. A caveat is that several measures of cognitive function were assessed and only one (verbal memory) showed clear improvement. In addition, functional magnetic resonance imaging (fMRI) showed that those in the enriched group had improved functioning of the left uncinate fasciculus, an area of the brain linked to memory and cognition, which typically declines with age.
The study was published online on July 24th in Frontiers of Neuroscience. It concluded “Minimal olfactory enrichment administered at night produces improvements in both cognitive and neural functioning. Thus, olfactory enrichment may provide an effective and low-effort pathway to improved brain health.”