Intraoperative ABR monitoring provides a measure of reassurance when a surgical procedure places the cochlear nerve or its blood supply in jeopardy. ABR monitoring has demonstrated its place in the operating room during retrolabyrinthine vestibular nerve section for vertigo, and in acoustic neuroma operations, when hearing preservation is a high priority in surgical outcome.
We have found several simple photographic techniques to be helpful in preparing our own near-professional teaching slides. Effective use of different brands of photographic materials is possible, but we present only the ones with which we are most familiar and which we have found simple, economical, and reliable. Slides can be produced in less than 24 hours using the methods presented.
A wealth of information concerning the caloric test has accumulated since the test was introduced more than eight decades ago. Both convective and nongravity-dependent forces on endolymph are believed to underlie the response at the end-organ level. Higher-order influences are equally important and make the test findings highly dependent on specific test conditions. Slow-component eye velocity is the most widely accepted index of vestibular response, although success using nystagmus beat frequency has also been reported. Both bithermal and monothermal calorization sequences have been studied. Standardization of technique and a consensus on methods of interpretation will be necessary for the determination of the optimal clinical caloric test.
The oronasal speculum is a standard nasal speculum with a metal tongue depressor incorporated into one of the handles. It permits the physician to examine the oral cavity and pharynx immediately after examination of the nose without changing instruments.
The measurement of hearing sensitivity during audiometry requires precise presentation of auditory stimuli. In most cases, these stimuli are introduced to the listener via standard earphones. Technical problems associated with these earphones have troubled clinicians for years. An alternative earphone system for audiometry was introduced that uses shoulder-worn transducers with inserts for connection with the external auditory canal. Although insert earphones are not intended to supplant standard earphones, experimental evidence and clinical observations support the advantageousness of these earphones under a variety of clinical conditions.
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