We examined 340 normal ears and cases of sensorineural deafness with electrocochleography using click stimuli (duration: 0.5 standard deviation of a population; repetition rate: plus or minus 10/sec; N=1 000, alternately positive and negative; analysis time: 31 standard deviation of a population). The latency of N-1 is a function of the sound pressure level and of the age of the subject. The intensity of N-1 (in mu-v) is a function of hearing level and is influenced by the presence of recruitment. The pure-tone audiogram is a function of the ECOG threshold and of the shape of the reaction obtained at maximal stimulation intensity.