Go to sleep and smell the roses

3 minute read

A nightly remembrance of things past is not to be sniffed at.

Regular readers of the Back Page may be aware that your correspondent is afflicted with anosmia, so unsurprisingly any research that emerges regarding the sense of smell, or lack of it, is bound to grab our attention.

This week’s offering comes from boffins at the Irvine Center for the Neurobiology of Learning and Memory, University of California, and involves the relationship between smells and dementia.

In a study published in the journal Frontiers in Neuroscience, the researchers examined whether exposing older adults to an array of odours while they slept could boost cognitive capacity and help ward off dementia.

The thinking behind the experiment is based on the proven direct links between the olfactory senses and memory centres in the brain, as evidenced by the capacity of certain smells to trigger vivid memories of past events – a phenomenon known as a Proustian rush

To test the theory, a group of 43 folks, aged between 60 and 85 and not experiencing any memory loss, were split into two groups.

The first cohort were given oil diffusers containing strong-smelling scents, such as eucalyptus, rose, orange and peppermint, which they were asked to activate for two hours as they were heading off to the land of nod.

The second cohort were also given diffusers and the same instructions, but these contained sham cartridges containing little to no scent.

The results, as measured by a word learning test undertaken by all participants at the beginning and end of the six-month study period, were dramatic.

“A statistically significant 226% improvement was observed in the enriched group compared to the control group on the Rey Auditory Verbal Learning Test,” the study authors said.

What’s more, that result was backed-up by imaging that revealed improved functioning in the brain pathway associated with the formation and retrieval of memories, the left uncinate fasciculus, they said.

“The olfactory sense has the special privilege of being directly connected to the brain’s memory circuits,” Michael Yassa, a neurobiology professor at CNLM, said in a statement.

“However, unlike with vision changes that we treat with glasses and hearing aids for hearing impairment, there has been no intervention for the loss of smell.”

While acknowledging the need for further research using a much larger sample size, and including participants with diagnosed memory loss, the authors concluded that “olfactory enrichment may provide an effective and low-effort pathway to improved brain health”.

With a close family history of vascular dementia, your smell-deprived correspondent is now reconsidering his previous scepticism towards aromatherapy and is googling scent diffusers as we speak.

Sending story tips to penny@medicalrepublic.com.au is a non-drug intervention guaranteed to boost your cognitive capacity.   

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