This monograph presents a complicated binaural test for loss of hearing due to pathology, either in the brain stem or the cerebral cortex. A special audiometer is used with a grid that can eliminate either the lower or higher frequencies. It is essentially a descrimination test with the use of 41 test words. The interpretation of the results requires a considerable amount of experience, but this test should be investigated by the audiologists, since it may reveal a great deal of valuable information concerning lesions in the cerebrum or brain stem.