Working with a group of people ages 60 to 85, researchers at the University of California Irvine gave each of them seven vials, each containing a different natural oil, and a diffuser. One group of the adults received cartridges that had tiny amounts of the oils; the other group’s containers were full.

The instructions: put the diffuser by your bedside, insert a different cartridge into the diffuser each night when you go to bed, and see what happens.

For six months, the diffusers wafted the oils’ scents through participants’ bedrooms for two hours as they slept.

At the end of the study, people who used the full containers showed a 226-percent improvement in their cognitive performance compared to the other group, measured by a common word-list test. 

Brain scans showed that the brains of people using full-strength cartridges strengthened the pathway between the medial temporal lobe, which manages memories of facts and events, and the prefrontal cortex, where thoughts are processed and decisions are made.

The pathway weakens as we age, leading to forgetfulness.

Scientists have long used the loss of the sense of smell as a diagnostic indicator for more than 60 neurological and even psychiatric ailments, ranging from Alzheimer’s and Parkinson’s diseases to alcoholism and schizophrenia.

Earlier tests found that exposing people with slight forms of dementia to as many as 40 different aromas twice a day for an extended period improved their memory and language abilities.

“The olfactory sense has the special privilege of being directly connected to the brain’s memory circuits,” Michael Yassa, one of the researchers, said in a university press announcement. “Everyone has experienced how powerful aromas are in evoking recollections, even from very long ago.”

The group expects to release a product for home use within a few months.

TRENDPOST: Further tests will see how effective aromatherapy can be in improving cognitive abilities in people diagnosed with dementia. Releasing the scents while a person is asleep ensures that no one would have to remember a daytime schedule of sniffing.

The study was funded by Procter & Gamble, no doubt with an eye toward commercial applications.