Superior laryngeal nerve evoked potentials: an experimental study in the rabbit.

An experimental model is described for recording laryngeal evoked potentials at the brainstem level through electrical stimulation of the superior laryngeal nerve. Rabbits were divided into two groups according to age: Group 1 consisted of 20 adults (over 6 months old), while group 2 was comprised of 1-month-old rabbits. Under general anesthesia, the superior laryngeal nerve was electrically stimulated and the corresponding evoked potentials were recorded by needle electrodes placed close to the dorsal and ventral aspects of the brain stem. Clear age-related differences were observed for latency, amplitude, and morphology of the potentials. This fact suggests postnatal maturation of the nerve structures, both peripheral and central. Sectioning the superior laryngeal nerve abolished all responses. Adduction of both vocal cords was observed in conjunction with the use of stimulation.