Olfactory training with Aromastics: olfactory and cognitive effects

Abstract

Purpose The olfactory system can be successfully rehabilitated with regular, intermittent stimulation during multiple daily exposures to selected sets of odors, i.e., olfactory training (OT). OT has been repeatedly shown to be an effective tool of olfactory performance enhancement. Recent advancements in studies on OT suggest that its beneficial effects exceed olfaction and extend to specific cognitive tasks. So far, studies on OT provided compelling evidence for its effectiveness, but there is still a need to search for an optimal OT protocol. The present study examined whether increased frequency of OT leads to better outcomes in both olfactory and cognitive domains. Method Fifty-five subjects (28 females; Mage = 58.2 ± 11.3 years; 26 patients with impaired olfaction) were randomly assigned to a standard (twice a day) or intense (four times a day) OT. Olfactory and cognitive measurements were taken before and after OT. Results OT performed twice a day was more effective in supporting olfactory rehabilitation and interventions targeted to verbal semantic fluency than OT performed four times a day, even more so in subjects with lower baseline scores. Conclusions OT is effective in supporting olfactory rehabilitation and interventions targeted to verbal semantic fluency. However, it may be prone to a ceiling effect, being efficient in subjects presenting with lower baseline olfactory performance and lower verbal semantic fluency.

Platelet-rich plasma injection in the olfactory clefts of COVID-19 patients with long-term olfactory dysfunction

“…To date, there is no treatment for the long-term OD. Patients are recommended to adhere to an olfactory training protocol [ 8 , 9 ], while some dietary supplements (e.g., omega 3, zinc, and B12 vitamin) may be advised [ 10 ]. In 2019, Yan et al .…”

Does Olfactory Training Improve Brain Function and Cognition? A Systematic Review

“…Oleszkiewicz et al ( 2021 ) Beyond Olfaction: Beneficial Effects of Olfactory Training Extend to Aging-Related Cognitive Decline Healthy Older Adults: N = 68 (M age = 62.8 yrs) • “Simple” OT: n = 26 • “Mixtures” OT: n = 27 • Control Group: n = 15 Entry Criteria • Older adults, aged 50 to 88 yrs • Duration of OT between 3 and 6 months (M months = 4.13) • Participants were randomly selected to be in one of 3 OT groups: 1) “simple” training used 9 single molecule substances, 2) “mixtures” training with 9 multi-molecule odorant mixtures, and 3) a no-contact control group • Participants in the OT groups were asked to sniff each odorant 2x/day for 20 s • Participants were tested before and after OT • Olfaction was assessed with the Sniffin’ Sticks test and a visual analogue scale • Cognition was assessed with the MoCA, Dementia Screening Interview (AD8), and the COWAT • Emotional functioning was measured with the BDI and the PANAS • 3-group pre-post experimental design (over 3 to 6 months) Primary Outcome • Association between OT and olfaction, cognition, and emotion • Odor detection threshold improved in the “simple” training group but not in the other groups • The control group exhibited signs of cognitive decline while the “simple” and multi-molecule” groups did not • The “simple” training group improved on the MoCA • No treatment effect was observed on depressive symptoms or positive/negative affect Strengths • 3-to-6-month intervention period • Used smell journaling to measure treatment adherence • OT adherence was reported • Cognition was assessed Limitations • No long-term follow-up • Small N • Brain imaging was not included 3. Oleszkiewicz et al ( 2022 ) Olfactory Training with Aromastics: Olfactory and Cognitive Effects Total Sample: N = 55 (M age = 58.2 yrs) • Anosmic/Hyposmic Adults: n = 26 ( M age = 59.2 yrs) • Normosmic Adults: n = 29 ( M age = 57.4 yrs) • Standard OT Group: n = 32 • Intense OT Group: n = 23 Entry Criteria • Anosmic/Hyposmic Adults • TDI score < 30.75 • Post-infectious or post-traumatic olfactory etiology • Normosmic Adults: TDI > 30.75 • No acute or chronic sinonasal diseases/ • Other conditions that impede smell • Not pregnant • Nasal endoscopy • Each participant was equipped with an electrical odorant dispenser for 5 odorants. After 3 months, the odorants were changed to 5 new odorants • Randomized to either: 1) Standard OT (sniff each odorant for 30 s 2x/day) or 2) Intense OT (sniff each odorant for 30 s 4x/day) • The duration of the training ranged from 108 to ...…”

“…When a control group receives as much contact/engagement as the experimental group, the ability to derive causation improves. Yet the other eight studies had a variety of comparison groups such as comparing two OT dosages (Oleszkiewcz et al, 2022 ), comparing simple odorants to more complex mixture odorant OT (Oleszkiewcz et al, 2022 ), or comparing the OT to an active group (i.e., Sudoku group; Birte-Antina et al, 2018 ), or a standard no-contact control group (Oleszkiewcz et al, 2022 ). With OT in particular, developing an appropriate contact control condition remains a challenge.…”

COVID-19-Related Quantitative and Qualitative Olfactory and Gustatory Dysfunction: Long-Term Prevalence and Recovery Rate

“…Despite this, given the enormous spread of the disease, it should be considered that, one in 7 patients still complaining of persistence of olfactory or gustatory dysfunction 2 years after COVID-19, may represent an unprecedented burden on health systems and a challenge for the specialists who have to treat these patients. Unfortunately, with the exception of olfactory training [ 13 , 14 ] which should be recommended in all cases of persistent olfactory disorders after the acute event that caused it, other therapeutic strategies are mainly based on weak evidence [ 15 ]. Further efforts are therefore needed to design clinical trials aimed at testing the efficacy of new therapeutic opportunities as well as intense research activity, especially in areas likely to lead to therapies as recently pointed out by a panel of international experts [ 16 ].…”