Effect of Aging, Gender and Sensory Stimulation of TRPV1 Receptors with Capsaicin on Spontaneous Swallowing Frequency in Patients with Oropharyngeal Dysphagia: A Proof-of-Concept Study

The impact of physical therapy on dysphagia in neurological diseases: a review

A neurogenic dysphagia is dysphagia caused by problems with the central and peripheral nervous systems, is particularly prevalent in conditions such as Parkinson's disease and stroke. It significantly impacts the quality of life for affected individuals and causes additional burdens, such as malnutrition, aspiration pneumonia, asphyxia, or even death from choking due to improper eating. Physical therapy offers a non-invasive treatment with high efficacy and low cost. Evidence supporting the use of physical therapy in dysphagia treatment is increasing, including techniques such as neuromuscular electrical stimulation, sensory stimulation, transcranial direct current stimulation, and repetitive transcranial magnetic stimulation. While initial studies have shown promising results, the effectiveness of specific treatment regimens still requires further validation. At present, there is a lack of scientific evidence to guide patient selection, develop appropriate treatment regimens, and accurately evaluate treatment outcomes. Therefore, the primary objectives of this review are to review the results of existing research, summarize the application of physical therapy in dysphagia management, we also discussed the mechanisms and treatments of physical therapy for neurogenic dysphagia.

Complications of oropharyngeal dysphagia in older individuals and patients with neurological disorders: insights from Mataró hospital, Catalonia, Spain

Background

Oropharyngeal dysphagia (OD) significantly impacts older individuals and neurologically compromised patients, hindering safe ingestion of food and liquids. Despite its prevalence, OD remains underdiagnosed and undertreated, leading to severe complications such as malnutrition, dehydration, respiratory infections, and aspiration pneumonia (AP), and increases hospital readmissions.

Objectives

This study analyzes the intricate relationship between OD and various clinical complications in older individuals and patients with neurological disorders.

Methods

Utilizing retrospective analysis and narrative review, our work consolidates findings from prior studies on Hospital de Mataro's dysphagia patient cohort. Revisiting OD's intricate association with clinical complications, it presents data via odds ratios (OR), incidence ratios (IR), and hazard ratios (HR) from univariate and multivariate analyses.

Results

Five studies (2001-2014) involving 3,328 patients were scrutinized. OD exhibited independent and significant associations with various complications among older patients. Older individuals with OD faced heightened 1-month (ODDS 3.28) and 1-year (OR 3.42) mortality risks post-pneumonia diagnosis. OD correlated with a 2.72-fold risk of malnutrition, 2.39-fold risk of lower respiratory tract infections, 1.82-fold pneumonia readmissions (IR), and 5.07-fold AP readmissions (IR). Post-stroke OD is linked to neurological impairment (OR 3.38) and respiratory (OR 9.54) and urinary infections (OR 7.77), alongside extended hospital stays (beta coefficient 2.11).

Conclusion

Oropharyngeal dysphagia causes and significantly exacerbates diverse clinical complications in older and post-stroke patients, emphasizing the urgent need for proactive identification, comprehensive assessment, and tailored management. Acknowledging OD's broader implications in general medical practice is pivotal to improving patient outcomes and healthcare quality.

Comparing biomechanics and neurophysiology between different phenotypes of patients with oropharyngeal dysphagia

The pathophysiology of oropharyngeal dysphagia (OD) across patient phenotypes may differ. The aim of this study was to compare the biomechanics and neurophysiology of swallowing between healthy volunteers (HVs) and patients with dysphagia as a consequence of aging (OOD), post-stroke (PSOD), Parkinson's disease (POD), or dementia (DOD). A retrospective study including 35 HVs and 109 OOD, 195 PSOD, 78 POD, and 143 DOD patients was performed. Videofluoroscopic data of signs of impaired efficacy and safety, penetration-aspiration scale (PAS) score, and the biomechanics of laryngeal vestibule closure (LVC) and opening (LVO) and of upper esophageal sphincter opening (UESO) were collected. Neurophysiology was assessed with pharyngeal sensory evoked potentials and neurotopography maps. All OD phenotypes showed signs of impaired efficacy and safety of swallowing, increased PAS score (p < 0.001), and delayed time to LVC (p < 0.0001). OOD (p < 0.0001), PSOD (p < 0.0001), and POD (p = 0.0065) patients also had delayed time to LVO, and OOD (p = 0.0062) and DOD (p = 0.0016) patients to UESO. Regarding neurophysiology, all phenotypes presented impaired pharyngeal sensitivity, a significant reduction in cortical activation, and impaired sensory input integration. Additionally, only PSOD was associated with impaired conduction of sensory stimuli. In conclusion, we found common but also specific pathophysiological elements. These results improve our understanding of OD pathophysiology and may help pave the way for phenotype-specific treatments.

Exploratory analysis of swallowing behaviour in community-dwelling older adults using a wearable device: Differences by age and ingestant under different task loads

Objective

To develop a new method of evaluating swallowing behaviour.

Methods

Sixty-nine healthy participants were divided into a younger (16 males and 16 females, mean age 39.09 ± 12.16 years) and older (18 males and 19 females, mean age 71.43 ± 5.50 years) group. The participants ingested water and yoghurt twice (directed and free swallowing) at rest and after performing simple daily life tasks (calculation and exercise). To measure swallowing frequency, we employed a smartphone-based, portable and neck-worn swallowing-sound-monitoring device. This device monitors swallowing behaviour continuously by collecting biological sounds from the neck without imposing behavioural restrictions. A neural network model of swallowing sound identification by deep learning was used for the subsequent evaluation. This device was used to obtain two types of saliva-swallowing sounds associated with different ingestants, at rest and after performing a stimulating task. Furthermore, we assessed the associated subjective psychological states.

Results

The younger group showed a higher directed swallowing frequency (for both water and yoghurt) than the older group did. Regarding the type of ingestant, the swallowing frequency for yoghurt was higher during free swallowing in both the young and the older groups. 'Feeling calm' was reported significantly more often in the older group after swallowing yoghurt following exercise.

Conclusions

Swallowing status in daily life was measured non-invasively using a wearable mobile device. It is important to consider the type of ingestant, daily living activities, and age when assessing swallowing.

Brain and Pharyngeal Responses Associated with Pharmacological Treatments for Oropharyngeal Dysphagia in Older Patients

Impaired pharyngo-laryngeal sensory function is a critical mechanism for oropharyngeal dysphagia (OD). Discovery of the TRP family in sensory nerves opens a window for new active treatments for OD. To summarize our experience of the action mechanism and therapeutic effects of pharyngeal sensory stimulation by TRPV1, TRPA1 and TRPM8 agonists in older patients with OD. Summary of our studies on location and expression of TRP in the human oropharynx and larynx, and clinical trials with acute and after 2 weeks of treatment with TRP agonists in older patients with OD. (1) TRP receptors are widely expressed in the human oropharynx and larynx: TRPV1 was localized in epithelial cells and TRPV1, TRPA1 and TRPM8 in sensory fibers mainly below the basal lamina. (2) Older people present a decline in pharyngeal sensory function, more severe in patients with OD associated with delayed swallow response, impaired airway protection and reduced spontaneous swallowing frequency. (3) Acute stimulation with TRP agonists improved the biomechanics and neurophysiology of swallowing in older patients with OD TRPV1 = TRPA1 > TRPM8. (4) After 2 weeks of treatment, TRPV1 agonists induced cortical changes that correlated with improvements in swallowing biomechanics. TRP agonists are well tolerated and do not induce any major adverse events. TRP receptors are widely expressed in the human oropharynx and larynx with specific patterns. Acute oropharyngeal sensory stimulation with TRP agonists improved neurophysiology, biomechanics of swallow response, and safety of swallowing. Subacute stimulation promotes brain plasticity further improving swallow function in older people with OD.

Transient receptor potential channels as an emerging therapeutic target for oropharyngeal dysphagia

Oropharyngeal dysphagia is a serious health concern in older adults and patients with neurological disorders. Current oropharyngeal dysphagia management largely relies on compensatory strategies with limited efficacy. A long-term goal in swallowing/dysphagia-related research is the identification of pharmacological treatment strategies for oropharyngeal dysphagia. In recent decades, several pre-clinical and clinical studies have investigated the use of transient receptor potential (TRP) channels as a therapeutic target to facilitate swallowing. Various TRP channels are present in regions involved in the swallowing process. Animal studies have shown that local activation of these channels by their pharmacological agonists initiates swallowing reflexes; the number of reflexes increases when the dose of the agonist reaches a particular level. Clinical studies, including randomized clinical trials involving patients with oropharyngeal dysphagia, have demonstrated improved swallowing efficacy, safety, and physiology when TRP agonists are mixed with the food bolus. Additionally, there is evidence of plasticity development in swallowing-related neuronal networks in the brain upon TRP channel activation in peripheral swallowing-related regions. Thus, TRP channels have emerged as a promising target for the development of pharmacological treatments for oropharyngeal dysphagia.

Gustatory stimulus interventions for older adults with dysphagia: a scoping review

BACKGROUND

Gustatory stimulus interventions have been shown to improve swallowing function in older adults with dysphagia. However, the optimal intervention strategies as well as their effects and safety remain unclear.

AIMS

To explore current evidence regarding gustatory stimulus interventions for dysphagia in older adults.

METHODS

Nine electronic databases (PubMed, Web of Science, Embase, CINAHL, Cochrane Library, China National Knowledge Infrastructure, Wanfang Database, China Science and Technology Journal Database, and Sinomed) were searched from their inception to August 2022.

RESULTS

This review identified 263 articles, and 15 met the inclusion criteria. The types of gustatory stimulus interventions included spicy (n = 10), sour (n = 3), and mixed (sour-sweet) stimuli (n = 2), with most studies focusing on spicy stimuli. The most frequently reported spicy stimulus was capsaicin. Further, the most commonly reported intervention frequency was thrice a day before meals for 1-4 weeks. The stimuli concentrations and dosages could not be standardized due to the among-study heterogeneity. These studies reported 16 assessment tools and 42 outcomes, which mainly included videofluoroscopy and swallowing response time respectively. More than half of the included studies reported no adverse effects of gustatory stimulus interventions.

CONCLUSION AND DISCUSSIONS

Gustatory stimulus interventions improved swallowing function in older adults with dysphagia. However, assessment tools and outcomes for dysphagia should be standardized in the future, and explore personalized interventions based on different diseases and their stages, to determine the most cost-effective interventions, and to prevent its complications.

Effect of Capsaicin Atomization on Cough and Swallowing Function in Patients With Hemorrhagic Stroke: A Randomized Controlled Trial

BACKGROUND

Patients with hemorrhagic stroke have high mortality and disability rates. Nevertheless, early rehabilitation interventions can improve their outcomes. We aimed to apply capsaicin atomization as early intervention to patients with hemorrhagic stroke and explore improvements in cough and swallowing functions.

METHOD

Patients with hemorrhagic stroke were randomly divided into the control group, which received routine care, and the intervention group, which underwent the capsaicin solution nebulization scheme in addition to routine care. Differences in the presence/absence of cough reflex and number of coughs in response to capsaicin, the presence/absence of swallowing reflex in response to water, the presence/absence of postswallow residue, substance P (SP) concentration, and pulmonary inflammation between the two groups were determined before and after the intervention.

RESULTS

A total of 53 patients with hemorrhagic stroke were included. Results showed no statistically significant difference in cough reflex in both groups after the intervention (p > .05). The degree of cough in the intervention group was stronger than that in the control group (p = .046). No statistically significant difference was observed in the number of patients with swallowing reflex in response to water between the groups (p > .05). The presence/absence of postswallow residue of the intervention group was stronger than that of the control group (p = .032). No statistically significant difference was observed between the Glasgow Coma Scale scores of the groups after the intervention (p > .05). SP in the intervention group was significantly increased (p = .031). The Clinical Pulmonary Infection Score was significantly lower in the control group, and the difference was statistically significant (p = .028).

CONCLUSIONS

Capsaicin nebulization can help enhance the number of coughs in response to capsaicin, reduce postswallow residue, and increase the level of SP in patients with hemorrhagic stroke and has a positive effect on pulmonary inflammation. This study provides intervention points for cough and swallowing rehabilitation after a hemorrhagic stroke.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21956903.

Spontaneous Swallowing Frequency in Post-Stroke Patients with and Without Oropharyngeal Dysphagia: An Observational Study

Oropharyngeal dysphagia (OD) is a frequent complication after stroke (PSOD) that increases morbidity and mortality. Early detection of PSOD is essential to reduce morbidity and mortality in patients with acute stroke. In recent years, an association between reduced spontaneous swallowing frequency (SSF) and OD has been described. Likewise, the reduction of saliva substance P (SP) concentration has been associated with an increased risk of aspiration and a decrease in SSF. In this study we aimed to compare SSF, salivary SP concentration, hydration and nutritional status in post-stroke (PS) patients with and without OD. We included 45 acute PS patients (4.98 ± 2.80 days from stroke onset, 62.22% men, 71.78 ± 13.46 year). The Volume-Viscosity Swallowing Test (V-VST) was performed for clinical diagnosis of OD. SSF/minute was assessed through 10-min neurophysiological surface recordings including suprahyoid-electromyography and cricothyroid-accelerometry. Saliva samples were collected with a Salivette® to determine SP by ELISA. Hydration status was assessed by bioimpedance. Nutritional status was evaluated by Mini Nutritional Assessment Short Form (MNA-sf) and blood analysis. Twenty-seven PS patients (60%) had OD; 19 (40%), impaired safety of swallow. SSF was significantly reduced in PSOD, 0.23 ± 0.18 and PSOD with impaired safety, 0.22 ± 0.18 vs 0.48 ± 0.29 swallows/minute in PS without OD (PSnOD); (both p < 0.005). Nutritional risk was observed in 62.92% PSOD vs 11.11% PSnOD (p = 0.007) and visceral protein markers were also significantly reduced in PSOD (p < 0.05). Bioimpedance showed intracellular dehydration in 37.50% PSOD vs none in PSnOD. There were no differences for saliva SP concentrations. SSF is significantly reduced in PSOD in comparison with PSnOD. Acute PSOD patients present poor nutritional status, hydropenia, and high risk for respiratory complications.

Assessment and treatment of neurogenic dysphagia in stroke and Parkinson's disease

PURPOSE OF REVIEW

Neurogenic dysphagia worsens quality of life and prognosis of patients with different neurological disorders. Management of neurogenic dysphagia can be challenging. This review provides a comprehensive overview of current evidence on screening, diagnosis, and treatment of neurogenic dysphagia in stroke and Parkinson's disease, suggesting clues for clinical practice.

RECENT FINDINGS

The pros and cons of diagnostic techniques are discussed in the light of updated evidence. Findings from recent meta-analyses of different treatment approaches, including traditional dysphagia therapy, peripheral and central neurostimulation techniques, and treatment with botulinum toxin, are critically discussed, emphasizing inconsistencies and controversial issues.

SUMMARY

Screening tests and clinical swallow examination should be routinely performed in neurological patients at risk for dysphagia. In patients testing positive for dysphagia, first-line instrumental investigations, represented by fiberoptic endoscopic evaluation of swallowing or videofluoroscopic swallow study, should be performed to confirm the presence of dysphagia, to assess its severity, and to inform the treatment. Second-line and third-line instrumental methods can be used in selected patients to clarify specific pathophysiological aspects of oropharyngeal dysphagia. Treatment strategies should be personalized, and combination of traditional dysphagia therapy with innovative treatment approaches may increase the chance of restoring effective and safe swallowing.

Biomedical and Antioxidant Potentialities in Chilli: Perspectives and Way Forward

Worldwide, since ages and nowadays, traditional medicine is well known, owing to its biodiversity, which immensely contributed to the advancement and development of complementary and alternative medicines. There is a wide range of spices, herbs, and trees known for their medicinal uses. Chilli peppers, a vegetable cum spice crop, are bestowed with natural bioactive compounds, flavonoids, capsaicinoids, phytochemicals, phytonutrients, and pharmacologically active compounds with potential health benefits. Such compounds manifest their functionality over solo-treatment by operating in synergy and consortium. Co-action of these compounds and nutrients make them potentially effective against coagulation, obesity, diabetes, inflammation, dreadful diseases, such as cancer, and microbial diseases, alongside having good anti-oxidants with scavenging ability to free radicals and oxygen. In recent times, capsaicinoids especially capsaicin can ameliorate important viral diseases, such as SARS-CoV-2. In addition, capsaicin provides an ability to chilli peppers to ramify as topical agents in pain-relief and also benefitting man as a potential effective anesthetic agent. Such phytochemicals involved not only make them useful and a much economical substitute to wonder/artificial drugs but can be exploited as obscene drugs for the production of novel stuffs. The responsibility of the TRPV1 receptor in association with capsaicin in mitigating chronic diseases has also been justified in this study. Nonetheless, medicinal studies pertaining to consumption of chilli peppers are limited and demand confirmation of the findings from animal studies. In this artifact, an effort has been made to address in an accessible format the nutritional and biomedical perspectives of chilli pepper, which could precisely upgrade and enrich our pharmaceutical industries towards human well-being.

Oropharyngeal Capsaicin Exposure Improves Infant Feeding Performance in an Animal Model of Superior Laryngeal Nerve Damage

Sensorimotor feedback is critical to safe and effective swallowing. Because of this, sensory interventions have the potential to treat dysphagia. One such treatment may be found in capsaicin, which activates the internal branch of the superior laryngeal nerve (iSLN). The iSLN initiates the pharyngeal swallow, and a more sensitive iSLN should more readily elicit swallowing and improve swallow safety. We explored the neurophysiological mechanism by which capsaicin improves swallow performance using an infant pig model with a unilateral iSLN lesion. Using high-speed videofluoroscopy, we collected oropharyngeal kinematic data while pigs suckled on bottles, before and after applying capsaicin to the posterior tongue and valleculae. We found that capsaicin application decreased maximal bolus sizes, which improved swallow safety. Furthermore, capsaicin improved performance when infant pigs swallowed more moderately sized boluses. However, capsaicin did not change swallow frequency, the number of sucks prior to each swallow, nor total pharyngeal transit time (TPT). Similarly, excursions of the hyoid, thyroid, and posterior tongue were unchanged. TPT and hyoid and thyroid excursions maintained relationships with bolus size post-capsaicin, suggesting that these variables are less sensitive to sensory intervention. The timing and extent of posterior tongue movement were only correlated with bolus size pre-capsaicin, which could imply that capsaicin fundamentally changes in relationships between tongue movements and bolus size. Our results provide insight into the neural control of swallowing and capsaicin's mechanism of action, and suggest that capsaicin may be beneficial in treating acute infant dysphagia.

Antioxidant, Anti-Obesity, Nutritional and Other Beneficial Effects of Different Chili Pepper: A Review

Fruits and vegetables are important components of a healthy diet. They are rich sources of vitamins and minerals, dietary fibre and a host of beneficial non-nutrient substances including plant sterols, flavonoids and other antioxidants. It has been reported that reduced intake of fruits and vegetables may increase the risk of non-communicable diseases (NCDs). Chili pepper, is a common and important spice used to enhance taste and nutrition. Over the years, reports have shown its potential as antioxidant and an anti-obesity agent. Obesity is a serious health concern as it may initiate other common chronic diseases. Due to the side effects of synthetic antioxidants and anti-obesity drugs, scientists are now focusing on natural products which produce similar effects to synthetic chemicals. This up-to-date review addresses this research gap and presents, in an accessible format, the nutritional, antioxidant and anti-obesity properties of different chili peppers. This review article serves as a reference guide for use of chili peppers as anti-obesity agents.