Acoustic neuroma other diagnostic studies: Difference between revisions
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===Hearing test (audiometry)=== | ===Hearing test (audiometry)=== | ||
Audiometry can detect whether the hearing loss is sensorineural or conductive. During the test, the patient wears earphones and hears sounds directed to one ear at a time. A range of sounds of various tones are heard and the patient has to indicate each time they hear the sound.In this test, conducted by a hearing specialist (audiologist), you hear sounds directed to one ear at a time. The audiologist presents a range of sounds of various tones and asks you to indicate each time you hear the sound. Each tone is repeated at faint levels to find out when you can barely hear.Hearing test (audiometry). The patient wears earphones and hears sounds directed to one ear at a time. A range of sounds of various tones are heard. The patient has to indicate each time they hear the sound.The audiologist may also present various words to determine your hearing ability.The audiologist may also present various words to determine your hearing ability. | |||
A variety of audiometric tests were developed in the middle of the century in an attempt to identify patients with increased likelihood of having an acoustic neuroma. That was a worthwhile undertaking when definitive radiographic imaging consisted of some form of either pneumoencephalography or formal arteriography. Such testing is no longer used. Even the auditory brainstem evoked response (ABR) is now infrequently used as a screening test for acoustic neuroma. ABR screening techniques miss 20-35% of acoustic tumors smaller than 1 cm. Moreover, ABR is likely to miss those tumors in patients with excellent hearing, which are the cases most favorable for hearing conservation procedures. | A variety of audiometric tests were developed in the middle of the century in an attempt to identify patients with increased likelihood of having an acoustic neuroma. That was a worthwhile undertaking when definitive radiographic imaging consisted of some form of either pneumoencephalography or formal arteriography. Such testing is no longer used. Even the auditory brainstem evoked response (ABR) is now infrequently used as a screening test for acoustic neuroma. ABR screening techniques miss 20-35% of acoustic tumors smaller than 1 cm. Moreover, ABR is likely to miss those tumors in patients with excellent hearing, which are the cases most favorable for hearing conservation procedures. | ||
Revision as of 17:44, 18 September 2015
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [2]
Overview
Other diagnostic studies
Hearing test (audiometry)
Audiometry can detect whether the hearing loss is sensorineural or conductive. During the test, the patient wears earphones and hears sounds directed to one ear at a time. A range of sounds of various tones are heard and the patient has to indicate each time they hear the sound.In this test, conducted by a hearing specialist (audiologist), you hear sounds directed to one ear at a time. The audiologist presents a range of sounds of various tones and asks you to indicate each time you hear the sound. Each tone is repeated at faint levels to find out when you can barely hear.Hearing test (audiometry). The patient wears earphones and hears sounds directed to one ear at a time. A range of sounds of various tones are heard. The patient has to indicate each time they hear the sound.The audiologist may also present various words to determine your hearing ability.The audiologist may also present various words to determine your hearing ability.
A variety of audiometric tests were developed in the middle of the century in an attempt to identify patients with increased likelihood of having an acoustic neuroma. That was a worthwhile undertaking when definitive radiographic imaging consisted of some form of either pneumoencephalography or formal arteriography. Such testing is no longer used. Even the auditory brainstem evoked response (ABR) is now infrequently used as a screening test for acoustic neuroma. ABR screening techniques miss 20-35% of acoustic tumors smaller than 1 cm. Moreover, ABR is likely to miss those tumors in patients with excellent hearing, which are the cases most favorable for hearing conservation procedures.
An auditory brainstem response test (a.k.a. ABR, BAER, or BSER) may be done in some cases. This test provides information on the passage of an electrical impulse along the circuit from the inner ear to the brainstem pathways. An acoustic neuroma can interfere with the passage of this electrical impulse through the hearing nerve at the site of tumor growth in the internal auditory canal, even when the hearing is still essentially normal. This implies the possible diagnosis of an acoustic neuroma when the test result is abnormal. An abnormal auditory brainstem response test should be followed by an MRI. When an MRI is not available or cannot be performed, a computerized tomography scan (CT scan) with contrast is suggested for patients in whom an acoustic neuroma is suspected. The combination of CT scan and audiogram approach the reliability of MRI in making the diagnosis of acoustic neuroma.