Daily auricular stimulation with capsaicin ointment improved cough reflex sensitivity in elderly patients with dysphagia: a pilot study

Identifying Non-Traditional Approaches to Swallowing Rehabilitation: A Scoping Review

In recent years, dysphagia care has shifted toward a more patient-centered approach. This means that dysphagia clinicians are considering more factors in the treatment process including the goals of care, quality of life, and cultural values. The purpose of this scoping review was to examine relevant research and identify dysphagia interventions outside of those traditionally used by dysphagia clinicians that may improve swallowing function. A review of relevant studies was conducted using search terms related to swallowing and treatment. The search yielded 8439 unique studies. Of the 283 articles that underwent a full-text review, 37 articles were included in the final review. These articles highlighted three potential areas of non-traditional dysphagia intervention that may serve to provide holistic care, while also aiming to improve swallowing mechanisms: acupuncture and Eastern medicine interventions, vocal exercises, and physical function exercises. The results suggest that dysphagia clinicians should work collaboratively with other allied health professionals and consider non-traditional approaches to dysphagia care. Through the identification of potentially effective but non-traditional or non-Eurocentric interventions for dysphagia care, clinicians may promote a culturally relevant, patient-centered approach, in turn increasing patient acceptance of treatment plans and compliance. Future research should explore the efficacy and feasibility of these interventions in dysphagia rehabilitation, as well as their effectiveness compared to more traditional approaches.

Transcutaneous auricular vagus nerve stimulation alters cough sensitivity depending on stimulation parameters: potential implications for aspiration risk

Background

Transcutaneous auricular vagus nerve stimulation (taVNS) is considered a safe and promising tool for limb rehabilitation after stroke, but its effect on cough has never been studied. It is known that the ear and larynx share vagal afferent pathways, suggesting that stimulating the ear with taVNS might have effects on cough sensitivity. The specific stimulation parameters used can influence outcomes.

Objective

To investigate the effect of various stimulation parameters on change in cough sensitivity, compared to the reference parameter of 25 Hz stimulation at the left concha (most commonly-used parameter for stroke rehabilitation). Design, setting, and participants: Randomized, single-blind, active-controlled, eight-period cross-over design conducted March to August 2022 at a New Zealand research laboratory with 16 healthy participants.

Interventions

All participants underwent eight stimulation conditions which varied by stimulation side (right ear, left ear), zone (ear canal, concha), and frequency (25 Hz, 80 Hz). Main outcome measures: Change in natural and suppressed cough threshold (from baseline to after 10 min of stimulation) assessed using a citric acid cough reflex test.

Results

When compared to the reference parameter of 25 Hz stimulation at the left concha, there was a reduction in natural cough threshold of -0.16 mol/L for 80 Hz stimulation at the left canal (p = 0.004), indicating increased sensitivity. For the outcome measure of suppressed cough threshold, there was no significant effect of any of the stimulation conditions compared to the active reference.

Conclusion

Since stroke patients often have cough hyposensitivity with resulting high risk of silent aspiration, using 80 Hz taVNS at the left canal may be a better choice for future stroke rehabilitation studies than the commonly used 25 Hz taVNS at the left concha. Treatment parameters should be manipulated in future sham-controlled trials to maximize any potential treatment effect of taVNS in modulating cough sensitivity.

Clinical trial registration

ACTRN12623000128695.

Inhalation Therapy with Nebulized Capsaicin in a Patient with Oropharyngeal Dysphagia Post Stroke: A Clinical Case Report

Dysphagia and aspiration risk are common sequelae of stroke, leading to increased risk of stroke-associated pneumonia. This is often aggravated by stroke-related impairment of cough, the most immediate mechanical defense mechanism against aspiration. In humans, reflex cough can be repeatedly and safely elicited by inhalation of nebulized capsaicin, a compound contained in chili peppers. Could this cough-eliciting property of capsaicin support the recovery of stroke survivors who present with dysphagia and aspiration risk? We present a clinical case report of a 73-year-old man, admitted to inpatient stroke rehabilitation following a right middle cerebral artery infarct with subsequent dysphagia and hospital-acquired pneumonia. A course of daily inhalation therapy with nebulized capsaicin was initiated, triggering reflex coughs to support secretion clearance and prevent recurrence of pneumonia. Clinical observations in each inhalation therapy session demonstrate good patient response, safety and tolerability of nebulized capsaicin in this mode of application. Repeated Fiberoptic Endoscopic Evaluation of Swallowing (FEES) assessments show concurrent improvement in the patient’s swallowing status. Inhalation therapy with nebulized capsaicin may offer a viable treatment to facilitate coughing and clearing of secretions, and to minimize aspiration and risk of aspiration-related pneumonia post stroke. Further investigation in a randomized controlled trial design is warranted.