Our nose is often a bit neglected by the senses. Wrongly, because there appears to be a strong link between smell and memory. A familiar scent can evoke memories and emotions from times gone by. In fact, nocturnal scent patterns have been shown to give people a huge memory boost.
Scientists of the University of California (UCI) decided to carry out a simple odor test. Two groups of people over 60 without health problems received a scent diffuser and seven different cartridges per week. Every night the diffuser turned on for two hours, filling their bedroom with a pleasant aroma. In total, the participants used seven scents, one for each day of the week. One group was given a light version of the fragrance cartridges, the other group was exposed to a much stronger amount of fragrance oil. After half a year of fragrant sleep sessions, the balance was drawn up by administering a standard memory test and an extensive set of brain scans to the participants.
Bizarrely higher score
The results don’t lie about it. The group that received the strong fragrance oil performed a whopping 226 percent better on cognitive tests than the control group. This was measured with a memory test in which people were asked to remember and name as many words as possible in the correct order. The brain scans showed that there were clearly stronger brain connections between the medial temporal lobe and the prefrontal cortex, where decision-making is located. This whole system becomes increasingly weaker in later life. But this deterioration was much less visible in the group that received the high dose of fragrance oil daily. These participants also reported better sleep quality than the control group.
Scientists have long known that loss of the sense of smell is linked to the development of nearly 70 neurological and psychiatric diseases. These include Alzheimer’s disease and other dementias, Parkinson’s disease, schizophrenia and alcoholism. There is increasing evidence that there is also a link between the loss of smell due to corona and a decrease in cognitive abilities. Previous research has shown that exposing people with moderate dementia to 40 different scents – twice a day over a longer period of time – improves their memory and language skills, relieves depression and improves their sense of smell. The UCI team decided to build on this knowledge and create a simple anti-dementia tool.
smell at night
“From the age of about sixty, people’s sense of smell and memory deteriorate rapidly, that is the reality,” says neurobiologist Michael Leon. “But it is unrealistic to think that people with cognitive disabilities will open, sniff and close eighty different scent bottles every day. Even for people who do not have dementia, this is already a difficult task to maintain.” Lead researcher Cynthia Woo adds: “That is why in our study we reduced the number of odors to seven and the participants only smell one odor per day. We tried to make it as simple as possible by only exposing people to the scents at night. That way they didn’t have to make any time for the experiment during the day.”
“The sense of smell occupies a special place in the brain. It is in fact directly connected to the memory circuits,” says Professor Michael Yassa. “The stimuli of all other senses first pass through the thalamus, but the olfactory stimuli do not. Everyone has experienced how powerful the scent experience can be. You can suddenly relive an old memory very clearly, even if it is from a very long time ago. However, there are no equivalent glasses or hearing aids on the market to compensate for a loss of sense of smell.”
Prevent memory loss
The American researchers want to continue their research into the connection between smell and memory by looking at the impact of their technique on people with a diagnosed form of memory loss. They hope to develop several effective scent methods to combat dementia and other brain diseases. Before the end of the year, the team hopes to have a product on the market that people can use at home.
2023-08-02 06:32:25
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