“As we age, we often have problems with our ability to smell (called olfactory dysfunction). Older people might not be able to identify an odour or differentiate one odour from another. In some cases they might not be able to detect an odour at all.
Odour identification difficulties are common in people with neurodegenerative diseases, including Alzheimer’s disease … But there is emerging evidence that olfactory or “smell training” can improve ability to smell.
Neuroplasticity, our brains’ ability to change continuously in response to experience, may be key to how smell training works.
Neuroplasticity involves the generation of new connections and/or the strengthening of existing connections between neurons (brain cells), which in turn may lead to changes in thinking skills or behaviour. We can see evidence of neuroplasticity when we practise a skill such as playing an instrument or learning a new language.
The olfactory network is considered particularly neuroplastic. Neuroplasticity may therefore underlie the positive results from smell training, both in terms of improving olfactory ability and boosting capacity for other cognitive tasks … using the considerable neuroplasticity of the olfactory network and evidence-based cognitive training techniques, both olfactory and cognitive deficits may be targeted, particularly in older adults at risk of dementia. It seems possible we could train our brains through our noses.”
Effects of olfactory training: a meta-analysis. (Rhinology Journal)
- Abstract: The neural plasticity of the olfactory system offers possibilities of treatment in terms of stimulation of the sense of smell, and different studies have suggested effectiveness of smell training, i.e., daily exposition to certain odors. To obtain reliable and precise estimates of overall treatment benefit on the olfactory function, we meta-analyzed the effects of smell training reported in 13 previous studies. We analyzed the smell training effectiveness across three different olfactory abilities, smell identification, discrimination and threshold for odor detection. We found a significant, positive effect of olfactory training for all olfactory abilities, with large effects of training on identification, discrimination and TDI-score and small-to-moderate effect in the case of threshold for odor detection. Interestingly, the pattern of results differed across Sniffin Sticks subtests depending on the origin of participants smell disorder, and the smell training duration influenced its effectiveness in the case of identification and the TDI score. Although the exact mechanism of olfactory recovery following the smell training still requires further investigation, our meta-analysis showed that such training should be considered an addition or alternative to existing smell treatment methods.