Remember that Smell

Public article

By E. Joy Bowles BSc. © dementiacareinternational

Take a moment to close your eyes and imagine the smell of a fresh, juicy orange being peeled. What other memories come to mind? Perhaps, like me, you remembered school sports days with oranges being served at half-time. The fact that smells can instantly transport us back to certain memories seems miraculous; but when we look at the way the brain is organised, it makes plenty of sense.

Olfactory nerves in the top of the nose detect scents in the air as we inhale. These olfactory nerves transmit electrical messages to the part of the brain known as the limbic system. This part of the brain is well below the level of our conscious mind and controls many subconscious processes. One part of the limbic system, the amygdale, is responsible for initiating basic urges, such as pleasure, anger or fear. Another part, the hippocampus, plays a role in memory formation. The messages from the olfactory nerves get processed along with emotional and other sensory information that is stored as memories.

In both Parkinson’s and Alzheimer’s diseases, the olfactory bulb is often one of the areas first affected. This means that the sense of smell can be weaker in people in the early stages of these conditions. However, only an extreme change in a person’s ability to smell is likely to be significant; for example, hay fever or a cold can temporarily shut down anyone’s nose! Not all people with these conditions will experience a reduction in the sense of smell.

Dr Tim Betts and other researchers in the UK are using the sense of smell to help patients manage epilepsy. First of all, they train patients to relax. Then, while the patients are relaxed, they give them an essential oil to smell. Next, they train the patients how to automatically put themselves into a state of deep relaxation (autohypnosis), smelling the oil at the same time. Now, when the patients experience pre-fit warning signs, they sniff their oil. This helps them go into the deeply relaxed state, and very often they can avoid having a fit. Some patients have learned to manage their epilepsy using aromas alone.

This ability to link aromas with physical responses is known as “odour conditioning”. It is similar to the famous Pavlov’s experiment in which dogs, conditioned to receive food when a bell rang, still salivated at the bell, even when no food appeared.

It may be possible to use aromas in this way for people with dementia who can still smell. Coordinating different activities with different aromas may help reduce confusion about what is happening. The aromas don’t have to be essential oils, but can be the smell of toast or coffee in the mornings, or a loved one’s favourite perfume or aftershave.

Using the same aroma every night before bed time, particularly if the person likes it and finds it relaxing, can be very helpful in helping him or her settle for the night. However, it is important to check that the aroma is relaxing and not stimulating. For instance, using rosemary, peppermint or lemon at night is probably not a good idea. Lavender is often over-used as a relaxing oil; so perhaps try other relaxing oils like bergamot, Roman chamomile or sweet marjoram as bed-time aromas. Ideally, it should be an oil or, better still, a blend, which is not used at any other time of day, so that the odour conditioning can become strongly related with going to bed.

The best way to create the link between the aroma and bed-time is to vaporise 3 – 4 drops of the oil in a vaporiser about half an hour before the person retires, and to apply 1 – 2 drops of the same oil or blend to their pillow or night clothes. It is important not to have the oil too strong, as any aroma that is strong enough will be stimulating rather than relaxing. If you share the same bed, make sure you like the smell too!