In this reporting year, 58 patient visits (of healthy normal subjects) have been accomplished towards developing the necessary normal values for new and upgraded auditory evoked potential equipment comparing insert earphones to traditional circumaural headphones. This normative data base permits valid and reliable comparisons and clinical judgments for individual patient and patient populations. In addition, studies using gold foil canal electrodes with and without Electrocochleography, are compared to standard electrodes for enhancement of Wave 1. A major component of this year's work has been the generation of a normative data base for multifrequency tympanometry and the comparison of these data with that generated using otoadmittance instrumentation. The study of the integrity of the middle ear system, based on its biomechanics, promises to add to our understanding of clinical presentation in patients with various types of musculoskeletal disease. Specific data derived from studies of middle ear response on normals of both sexes and across age groups is necessary to begin clinical comparisons with a wide variety of connective tissue disorders such as osteogenesis imperfecta, fibrousdysplasia, ossificans progressiva, and others. The study of cochlear emissions in normals is about to begin. In this population we will examine the effects of changes in ear canal volume and middle ear resonance on cochlear emission amplitude. In addition, we will look at the summating potential/action potential as measured by non-invasive electrocochleography to determine how this end organ potential influences cochlear emissions. Although the assessment of cochlear emission is gaining in popularity as a screening tool for cochlear integrity, little is known about the modification of test technique to elicit optimum response for various populations. Normative data by age and sex and other variables need to be developed in this newly available clinical tool.
