Treatment of Acute Post-stroke Oropharyngeal Dysphagia With Paired Stimulation

According WHO, oropharyngeal dysphagia (OD) is a prevalent post-stroke (PS) condition involving the digestive system (ICD-10: I69.391) and an independent risk factor for malnutrition and pulmonary infection; and leads to greater morbimortality and healthcare costs and poorer quality of life (QoL). Currently, OD therapy is mainly compensatory, with low rates of compliance and small benefit, and there is no pharmacological treatment, so new treatments that improve patients' condition are crucial. PS-OD patients present both oropharyngeal sensory and motor deficits, so neurorehabilitation treatments which target both could be optimum. Benefits of paired peripheral sensory stimulation with oral capsaicin or piperine and of central motor noninvasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) will be studied. Pairing sensory peripheral and central stimulation may produce greater benefits. The main aim of the project is to study the efficacy of a novel protocol of paired stimulation on acute PS-OD patients. The investigators will assess the acute application of tDCS/piperine or tDCS/capsaicin in the acute phase of stroke, will improve PS-OD. 2 days randomized crossover study with 60 patients in 3 treatment groups (60 patients in the acute stroke phase divided in 3 study arms). We will assess changes in swallow safety, and neurophysiology of the swallow, hospital stay, respiratory and nutritional complications, mortality and QoL.

* Main hypothesis: Paired neurorehabilitation treatment targeting both pharyngeal sensory and motor components simultaneously through a peripheral pharmacological stimulant (transient receptor potential cation channel \[TRPV1\] agonist, capsaicin) and central stimulation (NIBS) (tDCS) can improve swallowing function in acute PS-OD patients by promoting cortical plasticity, their QoL and reduce OD associated complications.
* Main objectives: to study the efficacy of a novel protocol of paired stimulation on acute PS-OD patients. The investigators will assess the acute application of tDCS/piperine or tDCS/capsaicin in the acute phase of stroke.
* Secondary aims: to assess 1) safety and adverse events; 2) the effects on safety of swallow with a standardized protocol of swallowing evaluation; 3) clinical outcomes at 3 months follow up; 4) the effect of the treatments on spontaneous swallowing frequency and responsiveness to treatment according to stroke characteristics; 5) the effect in the acute phase on functional severity of OD and specific clinical outcomes.
* Design: 2 days randomized crossover study with 60 patients in 3 treatment groups (60 patients in the acute stroke phase divided in 3 study arms). We will assess changes in swallow safety, and neurophysiology of the swallow, hospital stay, respiratory and nutritional complications, mortality and QoL.
* Study population: 60 Acute PS-OD hospitalized patients.
* Inclusion criteria: Adult patients consecutively admitted with recent (\<1month) unilateral hemispheric stroke; impaired safety of swallow (ISS) (V-VST); conscious (NIHSS quest. 1a=0); able to follow the protocol and to give written informed consent (WIC).
* Exclusion criteria: Pregnancy; life expectancy \<3m or palliative care; neurodegenerative disorder or previous OD; implanted electronic device; epilepsy; metal in the head; participation in another clinical trial in the previous month.

Eligibility Criteria:
Inclusion Criteria:

* Unilateral acute stroke (up to 15 days of evolution).
* Impaired safety or efficacy of swallow according the volume-viscosity swallowing test (V-VST).
* Conscious patient (NIHSS 1a = 0).
* Patient able to follow the protocol and give written informed consent or, failing that, by a family member or legal representative.

Exclusion Criteria:

* Pregnancy.
* Life expectancy less than 3m or palliative care.
* Neurodegenerative disorder.
* Comprehension aphasia.
* Dementia (GDS 4 or higher).
* Previously diagnosed oropharyngeal dysphagia (dysphagia not related to stroke).
* Implanted electronic device.
* Epilepsy.
* Metal in the head.
* Patients with suspected or PCR-confirmed SARS-CoV-2 infection
* Participation in another clinical trial in the previous month.