Normal Values in Hearing and Balance Testing

Background: \- Researchers at the National Institutes of Health give many tests of hearing and balance. These tests can help detect problems that affect hearing or balance. It is important to know exactly how healthy people perform on each of these tests. This information will indicate when a test result is normal and when a test result shows a problem. Researchers also want to determine the best methods for each test. Objectives: \- To test different types of hearing and balance tests, and collect information on normal values for each test. Eligibility: \- Healthy volunteers between 5 and 80 years of age. Design: * This study will require a single visit to the National Institutes of Health Clinical Center. It will include both screening tests and study tests of hearing and balance. Sometimes, a second visit may be required if a test is designed to measure the same thing on 2 different days. Each visit will last between 2 and 5 hours, depending on the number of tests scheduled per visit. * Participants will have a physical exam and medical history. They will also have basic tests to check for normal hearing and balance. * Participants may have different hearing tests, including the following: * Auditory Evoked Potentials to study how the ears and brain handle sound information. * Auditory Processing Tests to study how a person processes complex sounds like speech in background noise. * Tests of middle ear and inner ear function. * Participants may have different balance and inner ear tests, including the following: * Balance test on a tilting platform. * Different tests to measure how well the eyes, ears, and brain work together to help maintain balance. * Treatment will not be needed as part of this study.

* INCLUSION CRITERIA: Healthy adult volunteers: * Healthy adults, aged 18-80 years * Able to provide informed consent * Normal hearing sensitivity, defined as pure-tone thresholds less than or equal to 25 dB HL, or when the pure-tone threshold exceeds 25 dB HL, it must be less than or equal to the median threshold for the appropriate gender- and age-based group, for 250-8000 Hz (Morrell et al, 1996, ISO-7029, 2000). * No air-bone gaps in excess of 10 dB for 500-4000 Hz. * Normal middle ear function as indicated by normal 226 Hz tympanograms bilaterally, defined as middle ear pressure between more or less 100 decaPascals, and peak compensated static compliance between 0.3-1.5 milliliters * American English as a first language for those participating in study tasks evaluating auditory processing. * Able to refrain from caffeine and alcohol for 48 hours before vestibular study sessions because both agents may modify the test results. EXCLUSION CRITERIA: * History of auditory and/or vestibular disorders (e.g., Meniere s syndrome, labyrinthitis). * Evidence of active outer or middle ear disease or anomaly (e.g. otitis media, stenotic ear canal, otorrhea) * History of chronic (fluid in middle ear for more than 4 months) or recurrent otitis media (more than 4 episodes of acute otitis media in one year) * History of ear surgery other than PE tubes * Current PE tubes * History of treatment with ototoxic medications (e.g. cisplatin, aminoglycoside antibiotics) * Unable to discontinue medications that can interfere with vestibular test results for the 48 hours immediately preceding a vestibular study session. These include any and all anti-dizziness medications (such as Antivert), prescription pain medications (such as Percocet), prescription headache medications (such as Imitrex), sleeping pills (such as Ambien), anti-seizure medications (such as Topamax), and/or antihistamines (such as Benadryl). * Current diagnosis from the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) of a psychiatric disorder or on medications for a psychiatric disorder in the past two years, including any or all antidepressants, anxiolytics, or psychostimulant drugs. * Cognitive impairment as evidenced by a score \