Tartaric Acid-Induced Cough and the Superior Laryngeal Nerve Evoked Potential1

Abstract

The purpose of this study was to stimulate the laryngeal cough reflex using a nebulized, mild chemical irritant and to record an associated laryngeal evoked potential from the internal branch of the superior laryngeal nerve. The laryngeal evoked potential was obtained on ten normal subjects from the right internal branch of the superior laryngeal nerve. The electrodiagnostic setup included an active electrode placed just below the hyoid bone with a 4-cm separation and distal reference. A ground electrode was placed between the active and reference electrodes. The receptors and internal branch of the superior laryngeal nerve were stimulated by inhalation of a nebulized 20% solution of tartaric acid and normal saline. The time line was triggered by a pneumatic switch on initial inspiration of the nebulized tartaric acid. The electrodiagnostic settings were set at a sweep speed of 1 ms/division, a gain of 10 to 20 microV/division, and 20 to 2,000 filters. There were 132 variables recorded from the internal branch of the superior laryngeal nerve of the ten subjects. The mean peak distal latency was 1.66+/-0.42 ms with a 1.6 median, 1.6 mode, and 0.17 variance. The duration was 0.41 ms, and amplitude was 5.19+/-2.91 microV. In conclusion, the laryngeal evoked potential, the afferent component of the involuntary cough reflex, can be recorded from the internal branch of the superior laryngeal nerve after inhalation of tartaric acid-induced cough.

Acute ischaemic hemispheric stroke is associated with impairment of reflex in addition to voluntary cough

“…One merit of the present study is that subjects with diabetes or previous heavy alcohol use were excluded, because these may affect cough [24,25]. Similarly, application of lidocaine to the pharynx (to allow passage of pressure catheters) can alter cough [26]; therefore, cough tests were performed o90 min after administration. Finally, although ACE inhibitor use was recorded because of the previously described effect on cough [27], it was not found to be a significant independent predictor of cough flow rate in the present study.…”

Assessing the Laryngeal Cough Reflex and the Risk of Developing Pneumonia After Stroke

“…Chemoirritant receptors in the laryngeal aditus, when stimulated, induce an involuntary reflex cough. [7][8][9] This reflex cough is critical to airway protection and the prevention of aspiration pneumonia. After a stroke or other neurological event, the LCR may be weakened or absent.…”

“…[13][14][15][16][17][18][19][20] Chemoirritant stimulation of these receptors elicits an electrophysiological response that has been recorded. 8,9 The internal branch of the superior laryngeal nerve splits into superior, middle, and inferior rami. Branches of the superior ramus distribute to the mucosa of the piriform recess.…”

“…The nebulizer output was 0.2 mL/min. 7,9,10,22,23,25 The test was administered by either a speech pathologist or a respiratory therapist at bedside and required Ϸ10 minutes to complete.Subjects were tested for a maximum of 3 effective inhalations. The subject was asked to exhale and then to place the mouthpiece and take a sharp, deep inhalation.…”

Synthesis, Metal Ions Coordination, Antimicrobial Activity of Some L-Tartaric Acid Derivatives

“…Tartaric acid is a muscle toxin, which works by inhibiting the production of malic acid and in high doses causes paralysis and death 3 . It is used in the medical fields 4 and acting as a preservative after fermentation 5 . Salts of tartaric acid (Rochelle salt) used as mild laxative and tartaric dihydrazides utilized as agrochemicals 6 .…”