Ralph A. Nelson

Auditory Brainstem Implant: I. Issues in Surgical Implantation:

Most patients with neurofibromatosis type 2 (NF2) are totally deaf after removal of their bilateral acoustic neuromas. Twenty-five patients with neurofibromatosis type 2 have been implanted with a brainstem electrode during surgery to remove an acoustic neuroma. The electrode is positioned in the lateral recess of the fourth ventricle, adjacent to the cochlear nuclei. The present electrode consists of three platinum plates mounted on a Dacron mesh backing, a design that has been demonstrated to be biocompatible and positionally stable in an animal model. Correct electrode placement depends on accurate identification of anatomic landmarks from the translabyrinthine surgical approach and also on Intrasurglcal electrophysiologic monitoring. Some tumors and their removal can result in significant distortion of the brainstem and surrounding structures. Even in the absence of Identifiable anatomic landmarks, electrode location can be adjusted during surgical placement to find the location that maximizes the auditory evoked response and minimizes activation of other monitored cranial nerves. Stimulation of the electrodes produces auditory sensations in most patients, with results similar to those of single-channel cochlear Implants. A coordinated multldlscipllnary team is essential for successful application of an auditory brainstem implant.

Auditory Brainstem Implant: II. Postsurgical Issues and Performance

The auditory brainstem Implant (ABI) restores some hearing sensations to patients deafened by bilateral acoustic tumors. Electrodes are stable for more than 10 years. In most cases nonaudltory side effects can be avoided by judicious selection of the stimulating waveform and electrode configuration. Most perceptual measurements demonstrate that the ABI produces psychophysical and speech performance similar to that of single-channel cochlear implants. ABI patients receive suprasegmental Information in speech and significant enhancement of speech understanding when the sound from the ABI is combined with Ilpreading.

Sensorineural Hearing Loss Associated with Systemic Lupus Erythematosus

Because our recent clinical experiences suggested a possible association between hearing loss and systemic lupus erythematosus (SLE), we prospectively studied the hearing of 30 patients hospitalized because of exacerbation of SLE. Twenty-nine of the 30 patients were receiving immunosuppressive therapy at the time of testing. We found an 8% incidence of substantial, previously undetected hearing loss without attributable cause. Hearing loss could not be correlated to age, sex, disease activity, organ-system involvement, laboratory test abnormalities, or duration of symptoms of SLE. Otolaryngologists treating patients with unexplainable hearing loss—particularly if it is sudden, fluctuating, or rapidly progressive—are alerted to the possibility of underlying systemic autoimmunity. We advise physicians who frequently treat patients with SLE to include questions on hearing in the review of systems and to refer the patient with hearing complaints for thorough otologic evaluation.

The Stacked ABR: A Sensitive and Specific Screening Tool for Detecting Small Acoustic Tumors

The failure of standard ABR measures to detect small (≤1 cm) acoustic tumors has led to the use of enhanced magnetic resonance imaging (MRI) as the standard to screen for small tumors. This study investigates the suitability of the stacked ABR as a sensitive screening alternative to MRI for small acoustic tumors (SATs). The objective of the study was to determine the sensitivity and specificity of the stacked ABR technique for detecting SATs. A total of 54 patients with acoustic tumors identified by MRI that were either ≤1 cm in size or undetected by standard ABR methods, irrespective of size, were studied. A control population of 78 nontumor normal-hearing subjects was also tested. For comparison, two standard ABR measures (IT5 and I-V delay) were also analyzed. The stacked ABR demonstrated 95% sensitivity and 88% specificity; 100% sensitivity was obtained at 50% specificity. Standard ABR measures were much poorer in detecting these tumors. In conclusion, the stacked ABR can be used as a sensitive, widely-available, cost-effective, and comfortable tool for screening SATs.

Impression-material foreign bodies of the middle ear and external auditory canal

Foreign bodies of the ear canal are very common, and a wide variety of objects have been reported.1-3 Involvement of the middle ear is much less common because it requires a concurrent perforation of the tympanic membrane. Sometimes during attempts at extraction, the mass is displaced through the eardrum. A review of the published English language literature failed to uncover any previous reports of impressionmaterial foreign bodies of the external ear and middle ear. There is a single case report in the German language literature.4 We present our experience with four cases of impression-material foreign bodies of the middle ear and external canal.

Impression Material Foreign Bodies of the Middle Ear and Ear Canal

leishmaniasis. The patient received parenteral glucanthime for 16 weeks with good results. After 3 weeks the lesions disappeared and he has remained symptom free for the past year. No mucous bullous lesions have been found, but a few skin lesions have occurred, which have been controlled with oral steroids. Discussion: The first patient did not have any clinical signs of active leishmaniasis but presented several nasal and oral sequelae that might have created a local susceptibility to the development of pemphigus. The second patient had clear signs of the association of both diseases and has responded well to treatment. The exact cause of pemphigus remains unknown. We are intrigued with this uncommon association.

Neuro-Otologic Problems: Evaluation and Treatment

Vestibular rehabilitation techniques have proved to be successful in the treatment of benign paroxysmal positional vertigo (BPPV). BPPV is a common form of dizziness related to disorders of the labyrinth. The most characteristic symptoms of BPPV are spinning sensations, rotatory nystagmus, latency, reversal on return to an upright positionl and a response decline of symptoms on repetition of the provocative movements. More than 1000 patients diagnosed with BPPV have been treated at the Atlanta Ear Clinic with either vestibular habituation exercises or the canaiith repositioning maneuver, or a combination of both techniques. A significant reduction or elimination of symptoms has been demonstrated in 90% of this patient population. The objective of this course is to describe the vestibular rehabilitation process and the canalith repositioning maneuver and how these procedures are utilized in the treatment of BPPV. The history of vestibular rehabilitation, neurophysiology, and indications for use of these treatment procedures will be presented, as will a discussion of the success rates in using these approaches. examples applicable to otolaryngology are given, including the development of clinical pathways. Both advantages and limitations of CQI techniques are discussed. Participants are encouraged to bring examples of CQI success or difficulties from their experience for analysis and discussion. This course fulfills the JCAHO standard that healthcare leaders, such as department and service chiefs, be educated in the principles of CQI. A certificate of completion will be awarded.