Increase of Substance P Concentration in Saliva after Pharyngeal Electrical Stimulation in Severely Dysphagic Stroke Patients - an Indicator of Decannulation Success?

Neurosignals. 2017;25(1):74-87. doi: 10.1159/000482002. Epub 2017 Oct 17.


Background/aims: Substance P (SP) is a neuropeptide, likely acting as a neurotransmitter in the pharyngeal mucosa enhancing the swallow and cough reflex. Pharyngeal Electrical Stimulation (PES) induces a temporary increase of salivary SP levels in healthy adults. Previous evidence suggests that post-stroke dysphagia is related to reduced SP levels. Here, we investigated the effects of PES on SP levels in severely dysphagic stroke patients and a possible link between increase of SP and treatment success.

Methods: 23 tracheotomized stroke patients who could not be decannulated due to severe and persisting dysphagia according to endoscopic evaluation received PES for 10 minutes a day over three consecutive days in this prospective single-center study. If initial treatment failed, repetitive stimulation cycles were provided. Saliva samples were collected before and directly after each PES.

Results: 61% of participants were decannulated after the first treatment cycle. Increase of SP levels post-stimulation was closely related to treatment success, i.e. decannulation with 79% of successfully treated patients showing increase of SP, whereas 89% of unsuccessfully treated patients had stable or decreased SP levels. Applying logistic regression analysis, increase of SP level remained the only independent predictor of decannulation after PES. All 3 repetitively treated patients showed increased SP levels when progressing from the 1st to the 2nd cycle, two of whom were decannulated hereafter.

Conclusions: The physiological mechanism of PES may consist in restoration of sensory feedback, which is known to be crucial for the execution of a safe swallow. SP possibly acts as a biomarker for indicating response to PES.

Keywords: PES; Pharyngeal electrical stimulation; Stroke; Substance P; Tracheal decannulation; Tracheostomy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Deglutition Disorders / etiology
  • Deglutition Disorders / physiopathology*
  • Electric Stimulation
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pharynx / physiopathology*
  • Prospective Studies
  • Saliva / chemistry
  • Stroke / complications
  • Stroke / physiopathology*
  • Substance P / analysis*
  • Tracheostomy


  • Substance P