The Clinical Audiology Unit (CAU) is the sole audiological consultation service for the intramural research programs at NIH. It participates in over 60 protocols from most Institutes in addition to its own protocols. The CAU also supports the ENT service and the Inter-Institute Genetics Program. In FY 93 the CAU completed the clinical assessment data, collection of the NIDCD Waardenburg syndrome (W5) study and was invited to submit a paper on the clinical findings in children with WS, which is in progress. Families with non-syndromic hereditary hearing impairment are also being studied and data collection from patient evaluations is underway. Our responsibilities include the definition of the auditory phenotype associated with various forms of non-syndromic hereditary hearing loss determined to be independent genetic entities. Publication of a collaborative article on staging the severity of the Niemann-Pick disease, type C, and the Pikus sign as a marker to help identify and stage this disorder resulted. The CAU is also collaborating on a study of patients with type III Gaucher's disease by documenting any change in auditory system function from the first group of children who received enzyme therapy. The Ushers syndrome diagnostic study with the NEI was initiated in FY 93. The clinical presentation of type 2 Ushers syndrome is being studied from the perspective of audiovestibular function. The CAU is involved in the study of type 2 neurofibromatosis (NF2). They did a serial audiologic study of families with NF2 previously seen and an evaluation of new family members either affected or at-risk. The association of audiologic phenotypic characteristics with this genotype will be pursued. A publication on audiologic manifestations of type 1 neurofibromatosis (NF1) and NF2 has been accepted for publication. The CAU does long-term follow up of patients with Alzheimer's disease (NIMH) and the aging of Down syndrome patients. The CAU is also doing serial audiologic studies on patients from more than 20 NIAID and NCI protocols who are receiving experimental drug trials or ototoxic chemotherapies. The CAU is developing diagnostic and phenotypic audiologic correlates of olivopontocerebellar ataxia in a new protocol.