None listed
Conditions
Brief summary
Neurological disease, such as stroke, has a devastating effect on sensation in the throat and the cough reflex. Without the ability to detect food or fluid from entering the lungs and eject it with a cough, stroke patients are at a high risk of developing chest infection. There are currently limited rehabilitation options available for improving cough sensitivity. Interestingly, probing the ear canal during a medical examination or having impacted ear wax can cause coughing. Non-invasive auricular stimulation has been found to improve upper limb and swallowing function after stroke, however the effect of auricular stimulation on cough sensitivity is unknown. In a study with a non-patient population, we found that 80 Hz ear canal stimulation resulted in a greater increase in cough sensitivity compared to the standard 25 Hz concha stimulation parameter most commonly used in the literature. The goal of this pilot study is to determine the feasibility of a future definitive randomised controlled trial, by quantifying recruitment and completion rate, completion time, and treatment effect size of auricular stimulation on cough function. A parallel study design will be used where stroke patients will receive 1 of 3 types of stimulation: standard active stimulation (25 Hz, left concha), experimental active stimulation (80 Hz, left canal), and sham stimulation. This research can provide important information for developing a future randomised controlled trial investigating taVNS as a potential rehabilitation approach for reducing silent aspiration and risk of chest infection.
Interventions
Non-invasive auricular stimulation will be delivered to the seated participant using a CE-approved home-use transcutaneous electrical nerve stimulation device. Single-use flexible hydrogel electrodes (RELI-Stick, Soterix Medical, New York, NY, USA) will be placed on the concha or external auditory canal of the left ear, with electrode gel applied on the electrodes. Stimulation intensity will be adjusted at the beginning of each stimulation block as above the participant’s detection threshold and
Non-invasive auricular stimulation will be delivered to the seated participant using a CE-approved home-use transcutaneous electrical nerve stimulation device. Single-use flexible hydrogel electrodes (RELI-Stick, Soterix Medical, New York, NY, USA) will be placed on the concha or external auditory canal of the left ear, with electrode gel applied on the electrodes. Stimulation intensity will be adjusted at the beginning of each stimulation block as above the participant’s detection threshold and below their pain threshold. Delivery of intervention will be performed by a research speech-language therapist, face-to-face and individually with each participant. Intervention will be delivered in a quiet room at the hospital. There will be three conditions: A) standard active stimulation (10 min of 20Hz concha stimulation), B) experimental active stimulation (10 min of 80Hz canal stimulation), and C) sham stimulation (no stimulation). Each participant will be randomly allocated to receive 1 of the 3 conditions. For the two active stimulation groups, the stimulation intensity will be determined for each participant with the electrodes in place, and then stimulation will be delivered at that intensity for 10 minutes. Participants will take part in the baseline outcome measurements (1 session of approximately 15 minutes). After 2-4 hours (on the same day), they will take part in a second session comprising intervention and post-intervention outcome measures, for approximately 30 minutes.
Sponsors
Yusuf Ozgur Cakmak
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Inclusion criteria are as follows: (1) diagnosis of cerebrovascular accident; (2) reduced cough reflex sensitivity (defined as absence of two consecutive strong coughs within 15 seconds of initiating 0.6 mol/L citric acid delivery during clinical natural cough reflex test, on 2/3 trials); and (3) ability to follow study directions and provide informed consent given supported decision-making.
Exclusion criteria
Due to possible effects on cough sensitivity, participants will be excluded if they have history of other neurological or respiratory diseases that might impact cough function; have poorly-controlled reflux; are currently taking opioid pain or angiotensin-converting enzyme (ACE) inhibiting drugs; had a recent (< 2 weeks) acute upper respiratory tract infection; or are a current or previous smoker. Due to safety considerations when receiving auricular stimulation, participants will be excluded if they are pregnant or trying to get pregnant; or have an implanted electrical device (e.g., pacemaker). Due to possible risk of bronchoconstriction during citric acid cough reflex test, participants will be excluded if they have asthma; history of respiratory disease; or intolerance/insensitivity to citric acid or citrus fruits.
Outcome results
None listed