1. Screening ABR: Two or more simultaneously channels will consist of the electrode pairs of: 1) contralateral to ipsilateral mastoid prominence; 2) vertex to ipsilateral mastoid; and 3) vertex to contralateral mastoid for better identification of waves. Insert tubephone earphone will be used to introduce an acoustic delay to distinguish CM response from artifact. Rarefaction clicks at 90, (75), 60, (45), and 30 dBnHL will be delivered monaurally to the right and left ears. RE and LE, ≥2 repetitions, ≥2,000 sweeps/repetition. Separate recording to rarefaction and condensation clicks will be obtained at 90 dB. The surface electrical activity will be amplified x10,000 and filtered from 30-3,000 Hz. Latencies and peak-to-trough amplitudes of waves and CM from the outer hair cells in the inner ear of the ABRs will be scored independently by "masked" interpreters (Drs. Oghalia and Popelka).