Cochlear Potentials in the Human Being

For many years there have been various attempts to record cochlear potentials from the round window in a human being. Some earlier efforts have met with moderate success. During the past two years, approximately 30 cases have been attempted at the Johns Hopkins Hospital. A multichannel tape recorder has been used to simultaneously stimulate the human ear and record from the round window. The patients all had their tympanic membranes reflected and a small electrode was placed on the round window niche. In most cases, good cochlear potentials were recorded and measured. In addition, clicks were used to stimulate the human ear, and recordings have been made from the round window. The action potentials of the 8th nerve known as N1 and N2 were then recorded. Two groups of patients are now being studied. The first group consists of patients with otosclerosis. A recording is made before mobilization or a replacement of the stapes is done. A second recording is taken after the oval window is free, to show if there has been any objective gain in the cochlear potential. The second group of patients are children with congenital neurosensory hearing loss. Excellent cochlear potentials and 8th nerve action potentials have been recorded in this group. The recording of cochlear potential in man is being used as a diagnostic and exploratory tool in evaluation and understanding of hearing disorders. It is felt that this also gives a valuable tool in understanding some of the basic properties of hearing in the human being.