Accurate and early detection of small intracanalicular acoustic tumors is difficult with standard Acoustic Brainstem Response (ABR). As a result, expensive enhanced MRI is used to screen patients suspected of having a tumor. Most patients sent for imaging are negative. Development of a compact cost-efficient screening device based on the Stacked Derived-band ABR Amplitude measure is proposed. The aim of this measure is to insure imaging of patients with tumors and substantially reduce imaging of non-tumor patients. Phase I research will demonstrate that clinically acceptable sensitivity and specificity can be achieved and that digital noise masking can be used in this method. In Phase II, we plan to further improve the sensitivity and specificity by optimizing the parameters of the stacked derived- band ABR method. We will test the optimized method on a large clinical population, and validate the method's clinical utility and ease of use in a multi-center study. We will also develop the PC-based prototype (hardware and software) of the screening device. PROPOSED COMMERCIAL APPLICATION The acoustic tumor screening device will be marketed to Otolaryngology and Audiology as a complete diagnostic system as an option on acoustic and multi-modality EP systems. Otolaryngologists and audiologists have the requisite expertise and facilities to administer and evaluate ABR test results, so that this system would require little additional training and no facility development. The screening device will provide significant benefits in terms of improved patient care and reduced diagnostic costs.