Safwan Jaradeh, M.D.

A new noninvasive method for determination of laryngeal sensory function.

Bock JM, Blumin JH, Toohill RJ, Merati AL, Prieto TE, Jaradeh SS., Laryngoscope. 2011: 121 (1) 158-163

OBJECTIVES/HYPOTHESIS: We report a new surface technique for studying sensory conduction in the superior laryngeal nerve (SLN). STUDY DESIGN: Prospective controlled cohort study at an academic tertiary care hospital. METHODS: Surface stimulation of the vagus nerve 7-10 cm proximal to a surface electrode placed over the cricothyroid muscle was performed in controls and in subjects with needle electromyographic-confirmed laryngeal neuropathy. Cathodal stimulation was applied below the mastoid process behind the sternocleidomastoid muscle. Nerve conduction parameters were determined. RESULTS: Noninvasive SLN evoked potential studies were performed on healthy volunteers (n = 28) as well as neuropathic subjects (n = 27). Compared to controls, the neuropathic subjects had statistically significant differences in baseline-to-peak amplitude, conduction velocity, and intrasubject side-to-side amplitude ratio (P <.01) of their surface evoked laryngeal sensory action potential (SELSAP). CONCLUSIONS: Laryngeal sensory nerve conduction can be determined noninvasively by evaluating SELSAP waveform. This study provides a reproducible method for electrophysiologic evaluation of a sensory branch of the SLN.