FUNCTIONAL EXAMINATION OF THE EAR 265 is a simple practical method of testing a patient's ability to understand speech which is the function of hearing most important to most people. Tuning Fork Tests Tuning fork tests provide the most reliable method of determining whether deafness is of conductive or sensorineural type. The tuning fork used should be large so that its rate of decay is not rapid and its frequency should be Fig. 145. Barany's noise apparatus. Fig. 146. Testing with tuning fork by air conduction. either 256 or 512 cycles per second. It should have an expanded base for application to the skull. The tuning fork is struck against a resilient surface and then held so that the acoustic axis is in line with the external acoustic meatus (Fig. 146). In this way the sound of the fork is heard by air conduction. If the vibrating tuning fork is held with its base held firmly against the skull the sound is transmitted through the bones of the skull to the cochlea and the sound of the fork is heard by bone conduction. Rime's Test Air conduction in which the sound of the tuning fork is transmitted through the normal sound-conducting pathway is much more efficient than bone conduction in which the sound is transmitted through the bones of the skull to the cochlea. In Rinne's test air condrrtirrn fo tpAtp.d The tuning fork still vibrating is then applied with its base to the mastoid process and the patient is asked which he hears louder. If the sound-conducting patkwayJ^ tuning fork is heard mjichjquder by,air conduction than by bone conduction and Rhine's Test is said to be positive. .If the sound-conducting pathway is"