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September 1969

Vertex-Response Thresholds to Pure Tones in Guinea Pigs

Author Affiliations

Rochester, Minn
From the Mayo Clinic and Mayo Foundation: sections of otolaryngology and rhinology (Dr. Cody), and physiology (Dr. Bickford). Mayo Graduate School of Medicine (University of Minnesota), Rochester, Resident in otolaryngology and rhinology (Dr. Kern).

Arch Otolaryngol. 1969;90(3):315-325. doi:10.1001/archotol.1969.00770030317012

CODY and Bickford1 have demonstrated that it is possible to measure hearing by means of electric currents from the cerebral cortex, known as cortical-evoked responses. This has provided an objective method (cortical audiometry) for testing hearing without the need of a conscious response by the patient. A similar test in laboratory animals could be significant in the evaluation of normal physiology, effects of various ototoxic drugs, acoustic trauma, and experimental operative procedures.

The introduction of computer techniques which allow the isolation of potentials evoked by sensory stimuli from the electroencephalographic background has provided the otologist with both a useful clinical and research tool. Averaged responses evoked by click stimuli have been recorded from the dura over the auditory cortex in anesthetized guinea pigs.2 However, it has been possible to obtain a small averaged cortical response to click stimuli in awake guinea pigs with scalp electrodes only during curarization.

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