Sensory Neuromodulation Protocol for the Treatment of Post-stroke Oropharyngeal Dysphagia.

Study design: Multicenter, experimental, randomized, crossed, double blind study (patient and results analysis).

Aim: To evaluate the effect of different neurostimulation techniques on the neurophysiological and biomechanical swallowing mechanisms of patients with dysphagia associated with chronic stroke and select those techniques with the best results to be evaluated in the second phase of the study (medium-term effects).

Outcome measures:

* Videofluoroscopy: prevalence of impaired efficacy and safety of swallow (penetrations and aspirations), penetration aspiration scale (PAS: from 0 to 8), biomechanical parameters (time to laryngeal vestibule closure, upper esophageal sphincter opening).
* Pharyngeal sensory evoked potentials (pSEP): latency and amplitude of obtained evoked potentials. Higher latency (0 onwards) means worse outcome and higher amplitude (0 onwards) means better outcome.
* Pharyngeal motor evoked potentials (pMEP): latency, amplitude, duration and area of obtained evoked potentials. Higher latency (0 onwards) means worse outcome and higher amplitude (0 onwards) means better outcome.

Treatments and patients: 36 post-stroke patients with oropharyngeal dysphagia (PAS superior or equal to 2) randomized patients in 3 treatment arms (3 groups of 12 patients).

* Active and sham repetitive transcranial magnetic stimulation (rTMS): 90% of the resting motor threshold, 1250 pulses, 5 Hz.
* Active and sham Intrapharyngeal Electrical Stimulation (PES): 75% of tolerance threshold, pulses of 0.2 ms, 5 Hz, 10 min.
* Oral Capsaicin (active intervention, 10-5M, TRPV1 agonist) and placebo solution (sham): 100 mL, single administration.

Administration of study therapies:

The study will be performed in two visits separated for one week. In each visit patients will randomly receive active or sham treatment and a pre-post evaluation of biomechanics of deglutition (with VFS) and neurophysiological mechanisms (swallowing afferent and efferent pathways) will be performed in each visit.

Acute randomized administration -\> 1 active session (pre/post evaluation with VFS/pSEP/pMEP) + 1 separate control session 1 week apart (pre/post evaluation with VFS/pSEP/pMEP).


Eligibility Criteria:
Inclusion Criteria:

* Patients older than 18 years.
* Patients with a diagnosis of stroke of more than 3 months of evolution.
* Patients with clinical signs of dysphagia according to the volume viscosity swallowing test (V-VST).
* Patients capable of complying with the study protocol.
* Explained study and signed informed consent.

Exclusion Criteria:

* History of severe neurodegenerative, digestive diseases, epilepsy or previous seizures.
* Pacemaker or implanted defibrillator carriers.
* Implanted electrode carriers or other stimulation systems.
* Implant carriers or metal plates on the head or neck.
* Cochlear implant carriers.
* Medication pump carriers.
* History of hearing loss associated with noise.
* Cardiopulmonary instability.
* Oropharyngeal dysphagia of structural causes.
* History of head and neck surgery.
* Alcohol or drug dependence.
* Pregnancy or breastfeeding.
* Participate or have participated in another clinical interventionist trial in the 4 weeks prior to inclusion.