CDIS 3123 1st EditionExam #2 Study GuideChapter 61.An audiometer is an electronic instrument used to quantify hearing sensitivity.2.A transducer is a device that converts energy from one form to another.3.Output transducers on an audiometer convert electrical energy to acoustic/vibratory energy.4.Signals presented via air conduction are transduced by earphones or loudspeakers. Signals presented via bone conduction are transduced by a bone vibrator.5.Advantages of using insert headphones include: reduction in occurrence of collapsing earcanals, reduction in need for masking, and enhanced placement stability.6.The guidelines for maximum possible noise levels for audiometric test rooms are provided by the American National Standards institute.7.An audiogram is a graph depicting hearing sensitivity. This graph demonstrates the intensity level as a function of frequency.8.Hearing sensitivity is measured by determining a person’s threshold for a sound. This refers to the very softest sound that can be heard approximately 50% of the time.9.Audiometric symbols are used to denote specific features of a hearing threshold, such as location, mode of testing, presence of masking, and no response to sound.10. The interaural symmetry of a hearing loss describes the extent to which hearing sensitivity in one ear is the same as or different from the other ear.11. By comparing air-conduction and bone-conduction thresholds, the type or category of peripheral hearing loss can be determined. The three types of peripheral hearing loss include: conductive, sensorineural, and mixed hearing loss.12. A conductive hearing loss is characterized by elevated air-conduction thresholds and normal bone-conduction thresholds. With this type of hearing loss, the problem is in the external ear canal or the middle-ear vibratory system.13. A sensorineural hearing loss is characterized by similarly elevated air- and bone-conduction thresholds. With this type of hearing gloss, the problem is in the cochlea or auditory nerve.14. A mixed hearing loss is characterized by elevated bone-conduction thresholds and air-conduction thresholds that are significantly worse than bone-conduction thresholds. With this type of hearing loss, the problem lies in both the external ear canal or middle-ear vibratory system and in the cochlea or auditory nerve.15. When preparing to test the hearing sensitivity of a patient, the patient should be seated in a sound-treated test booth or room, in a manner that allows the audiologist to view the patient’s responses.16. Prior to beginning a hearing test, an otoscopic examination should be performed to ensure the external ear canal is not occluded with cerumen.17. The test technique for determining audiometric threshold is based on thepsychophysical modified “method of limits.”18. Bone-conduction thresholds are obtained using a bone vibrator placed on either the mastoid or forehead.19. The phenomenon of crossover occurs when sound presented to one ear crosses the head via bone conduction and is perceived by the other ear.20. To eliminate the effects of crossover when testing hearing, the use of masking noise is applied to the non-test ear.21. The reduction in sound energy of a signal as it is transmitted by bone conduction from one side of the head to the opposite ear is known as interaural attenuation. The amount of interaural attenuation found during hearing testing depends on the type of transducer used.22. Masking for bone-conduction is used in most cases because interaural attenuation is negligible.23. In the plateau method of masking, a masking noise is introduced progressively over a range of intensity levels until a plateau is reached.24. In the case of undermasking, a masking noise is present, but the non-test ear is still responding. With an effective level of masking, the intensity of the masking noise is sufficient to prevent the non-test ear from responding. In overmasking, the intensity of the masking noise crosses over to the test ear, elevating the threshold in the test ear.25. A masking dilemma occurs when the effective masking level would be overmasking. This is found in cases where both ears have significant air-bone gaps.26. The presence of air bone gap can often be detected using tuning fork measures.27. With the Schwabach test, the shank of a tuning fork is placed on the mastoid after beingstruck, and the patient is instructed to indicate the presence of sound for the duration it is perceived. A conductive hearing loss is suspected when the patient perceives sound longer than the examiner. A sensorineural hearing loss is suspected when the examiner perceives the sound longer than the patient.28. The Rinne test is performed by comparing the length of time a tine is perceived by air conduction to bone conduction. A negative (Rinne) result occurs when the tone is heardlonger by bone conduction than air conduction, and is consistent with a conductive disorder. A positive (Rinne) result occurs when the tone is heard for the same duration by bone and air conduction, and is consistent with a sensorineural disorder.29. In the Bing test, the loudness of a bone-conducted tone is compared between unoccluded and occluded ear canal conditions. In the case of a conductive hearing loss, occluding the ear canal does not have an effect on loudness perception of the tone, due to an already-present occlusion effect caused by middle-ear disorder. If the tone is perceived to be louder with the ear canal occluded, results are consistent with normal hearing or a sensorineural hearing loss.30. The Weber test is performed by placing the tuning fork in the center of the forehead andasking the patient to indicate in which ear sound is perceived. If the tone lateralizes to the better ear, the loss in the poorer ear is sensorineural. If the tone lateralizes to the poorer ear, the loss in the poorer ear is conductive.Chapter 7 1.The purpose of speech audiometry is to quantify a patient’s ability to understand everyday communication.2. A speech recognition threshold or speech awareness threshold is the lowest level at which speech can be detected.3.The speech recognition threshold is the lowest level at which speech can be detected or recognized.4.The pure-tone average is the average of the threshold levels for the 500, 1000, and 2000 Hz frequencies.5.The word recognition threshold is the average correct repetitions of single syllable words at a fixed intensity level