Effects of olfactory stimulation on gait performance in frail older adults

Olfactory Dysfunction and Balance Dysfunction are Associated with Increased Falls in Older Adults

OBJECTIVE

This study aims to characterize the association between impairments in olfaction and balance, both of which are mediated in part by the cerebellum, and how this relates to prospective incidence of falls in a cohort of aging adults.

METHODS

The Health ABC study was queried to identify 296 participants with data on both olfaction (measured using the 12-item Brief Smell Identification Test) and balance-related function (measured using the Romberg test). The relationship between olfaction and balance was investigated using multivariable logistic regression. Predictors of performance on a standing balance assessment and predictors of falls were studied.

RESULTS

Of 296 participants, 52.7% had isolated olfactory dysfunction, 7.4% had isolated balance dysfunction, and 5.7% had dual dysfunction. Severe olfactory dysfunction was associated with increased odds of balance dysfunction when compared to those without olfactory dysfunction, even when adjusting for age, gender, race, education, BMI, smoking, diabetes, depression, and dementia (OR = 4.1, 95% CI [1.5, 13.7], p = 0.011). Dual sensory dysfunction was associated with worse performance on a standing balance assessment (β = -22.8, 95% CI [-35.6, -10.1], p = 0.0005) and increased falls (β = 1.5, 95% CI [1.0, 2.3], p = 0.037).

CONCLUSION

This study highlights a unique relationship between olfaction and balance, and how dual dysfunction is associated with increased falls. With substantial implications of falls on morbidity and mortality in older adults, this novel relationship between olfaction and balance emphasizes a potentially shared mechanism between olfactory dysfunction and increased fall risk in older adults; however, further study is required to explore the novel relationship of olfaction with balance and future falls.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:1964-1969, 2023.

Olfactory Stimulation Successfully Improves Swallowing Function of Aged Rats through Activating Central Neuronal Networks and Downstream DHPR-RyR-mediated Neuromuscular Activities

Presbyphagia is age-related changes in swallowing function, which imposes a high risk of aspiration in older adults. Considering olfactory stimulation (OS) can influence behavioral activities by modulating neuronal excitability, the present study aims to determine whether OS could improve the swallowing function of aged rats through activating the central neuronal networks and downstream muscular activities participated in the control of swallowing. Aged male Wistar rats received OS by inhaling a mixture of plant-based volatile molecules twice a day for 12 days were subjected to functional magnetic resonance imaging (fMRI) and c-fos, choline acetyltransferase (ChAT) immunostaining to detect the neuronal activities of the orbitofrontal cortex (OFC) and medullary nuclei engaged in swallowing control, respectively. The functional effects of OS on downstream pharyngeal muscle activity were examined by evaluating the dihydropyridine receptor-ryanodine receptor (DHPR-RyR) mediated intra-muscular Ca2 + expression, and analyzing the amplitude/frequency of muscle contraction, respectively. In untreated rats, only moderate signal of fMRI and mild c-fos/ChAT expression was detected in the OFC and medullary nuclei, respectively. However, following OS, intense signals of fMRI and immunostaining were clearly expressed in the orbitofronto-medullary networks. Functional data corresponded well with above findings in which OS significantly enhanced DHPR-RyR-mediated intra-muscular Ca2 + expression, effectively facilitated a larger amplitude of pharyngeal muscle contraction, and exhibited better performance in consuming larger amounts of daily dietary. As OS successfully activates the neuromuscular activities participated in the control of swallowing, applying OS may serve as an effective, easy, and safe strategy to greatly improve the swallow function of aging populations.

Role of physical therapists and aromatherapy for fall prevention in older people: A narrative review

Falls among older people are usually the result of several causes combined. Identifying all the fall-related factors that apply to a particular individual and providing comprehensive multifactorial intervention is recommended for the prevention of falls among older people. However, the overall net benefit of multifactorial intervention in preventing falls is small, and it does not appear to improve fall-related outcomes, such as the number of fall-related injuries. Therefore, we might require new perspectives to overcome this situation. Here, we raise two novel strategies for fall prevention among older people. One is using physical therapists more actively. The other is using aromatherapy for stabilization of older people. Physical therapists should carry out detailed gait assessment and caregiver education. Aromatherapy is effective in improving balance and mental stability in older people. To overcome refractory geriatric syndrome, there is no choice but to eliminate all preconceived ideas before choosing the best fall prevention strategies. Geriatr Gerontol Int 2021; 21: 445-450.

Medical aromatherapy in geriatric syndrome

Geriatric syndromes are symptoms and signs, such as falls, incontinence, delirium, pressure ulcers, dysphagia and so on, that often threaten the independence of older adults, rather than the disease itself. Although the syndromes are very common in older people, it is difficult to treat those by modern medicine due to their complexity. To mitigate the intractable geriatric symptoms, we review the efficacy of aromatherapy, especially for dysphagia, dyspnea, cognitive dysfunction and falls in geriatric syndrome. Olfactory stimulation using a volatile black pepper oil on institutional residents improved the swallowing reflex, which is a crucial risk factor of aspiration pneumonia. Brain imaging study showed that olfactory stimulation using volatile black pepper oil activated cerebral regions of the anterior cingulate and the insular cortex, which play a role in controlling appetite and swallowing. Also, aromatherapy with volatile l-menthol decreased the sense of dyspnea and improved the efficacy of exercise therapy. The fragrance of the combination of rosemary and lemon oils in the morning, and the combination of lavender and orange oils in the night-time were reported to improve cognition and behavioural and psychological symptoms of dementia, respectively. Also, the combination of lavender and lemon balm oils was reported to be effective for irritability-related agitation in older adults. Furthermore, aromatherapy with lavender fragrance could improve both static and dynamic balance, resulting in a reduction in the number of fallers and the incidence rate in older people. Thus, aromatherapy is a promising remedy for geriatric syndrome. Geriatr Gerontol Int 2021; 21: 377-385.

Comparing the effects of vestibular rehabilitation with and without lavender oil scents as an olfactory stimulus on balance, fear of falling down and activities of daily living of people with multiple sclerosis: a randomized clinical trial

PURPOSE

To evaluate the effect of using lavender oil as an olfactory stimulus with vestibular rehabilitation (VR) on balance, fear of falling down, and activities of daily living of people with multiple sclerosis.

METHODS

Forty participants were randomly assigned into experimental and control groups. The experimental group did the VR exercises while smelling the lavender oil scents. The control group did the VR exercises without it. Both groups did the exercises in ten 45-min sessions. We assessed the participants with the timed up and go (TUG) test, Berg balance scale (BBS), fall efficacy scale - international (FES-I), and the 29-item multiple sclerosis impact scale (MSIS-29). We did the tests at the baseline and after the last exercise session.

RESULTS

The experimental group performed significantly better in the BBS (p = 0.007), TUG (p = 0.045), and FES-I (p = 0.016) tests as well as in the MSIS-29's psychological subscale (p = 0.034) than did the control group.

CONCLUSIONS

Using lavender oil as olfactory stimulus while doing the VR exercises can improve balance and reduce fear of falling down compared to doing the VR exercises without it in people with multiple sclerosis.Implications for rehabilitationIt seems that using lavender oil, as an olfactory stimulus, while doing vestibular rehabilitation exercises can improve balance and reduce fear of falling down in people with multiple sclerosis compared to doing the vestibular rehabilitation exercises without it.This treatment significantly alleviates the psychological effects of multiple sclerosis on daily life such as sleeping problems, feeling unwell, anxious, tense, depressed, etc.

Olfactory Stimulation with Japanese Soy Sauce Improves Upper Limb Performance

BACKGROUND

We have observed changes in body reactions during cooking, which is one of the treatment modalities used in occupational therapy. The perception of food-related odors during cooking may have behavioral effects on human activities through the activation of appetitive motivation.

OBJECTIVES

We investigated whether odor components contained in seasonings could facilitate the human motor system and the specificity of this effect.

METHODS

The subjects were 72 healthy adults, randomly assigned to a water exposure group, a phenylethyl alcohol (PEA, pleasant rose-like odor) exposure group, and a Japanese soy sauce (Koikuchi Shoyu) exposure group (n = 24 each). The subjects' olfactory sense was stimulated by their sniffing of three different test tubes containing 5 ml of water, PEA, or Japanese soy sauce for 20 sec while they were seated. The modified Functional Reach Test (mFRT), which mimics a functional activity that is required in daily living and assesses a reliable measure of sitting balance, was performed prior to and immediately after the sniffing.

RESULTS

Sniffing the soy sauce increased the subjects' mFRT scores. This facilitation effect was odorant-specific and was absent when the subjects were presented with water or PEA.

CONCLUSIONS

Cooking interventions are aimed at improving tool-handling skills such as using knives and chopsticks. The results indicate that treatment interventions using odors of seasonings would be effective for improving subjects' physical functions.

"Low road" to rehabilitation: a perspective on subliminal sensory neuroprosthetics

Fear can propagate parallelly through both cortical and subcortical pathways. It can instigate memory consolidation habitually and might allow internal simulation of movements independent of the cortical structures. This perspective suggests delivery of subliminal, aversive and kinematic audiovisual stimuli via neuroprosthetics in patients with neocortical dysfunctions. We suggest possible scenarios by which these stimuli might bypass damaged neocortical structures and possibly assisting in motor relearning. Anticipated neurophysiological mechanisms and methodological scenarios have been discussed in this perspective. This approach introduces novel perspectives into neuropsychology as to how subcortical pathways might be used to induce motor relearning.

The effect of olfactory stimuli on the balance ability of stroke patients

[Purpose] The present study attempted to identify the effect of olfactory stimulation on the balance ability of stroke patients. [Subjects] Thirty-three (33 males) stroke patients participated in the study. The stroke patients were divided into three groups: a black pepper oil (BPO) group (n=11), lavender oil (LVO) group (n=11), and distilled water (DW) group (n=11). [Methods] Two sessions (control trial/stimulus trial) of Romberg's test (eyes open 1 min/eyes closed 1 min) were conducted on a force platform to measure the data for the COP (center of pressure). Olfactory stimulation was provided at as a stimulus. [Results] With the eyes open, a statistically significant difference was found in average anterior posterior displacement (Ymean) and average medial lateral displacement (Xmean) among the three groups when comparing the groups before and after stimulation. The comparison between the eyes open and eyes closed conditions in each group showed a significant difference in the area of the 95% confidence ellipse (area) and Xmean of the BPO group and in the area of the LVO group (area, Xmean). [Conclusion] The findings indicate that the interaction of brain areas activated by the olfactory stimulation exerts an influence on the balance ability of stroke patients.