Effect of site of stimulation on the guinea pig's electrically evoked brain stem response.

Stimulation by a bipolar modiolus electrode yields a wider dynamic range than does monopolar stimulation at the same site. Stimulation via a single electrode in the scala tympani or scala vestibuli is characterized by a precipitous input-output function, but current passing from one scala to the other generates a discontinuous function with a shallow slope at low intensities and a steep slope at high intensities.