ABSTRACT
Brainstem evoked response audiometry (ABR) permits auditory pathway assessment without the need for voluntary response. Brainstem responses are unaffected by attention, drugs, and most other confounding conditions. Consequently, if ABR could be used to determine hearing threshold in the speech frequencies, it would have great value for patients who are unable or unwilling to respond accurately during behavioral audiometric testing. Utilizing broad band clicks, one can only estimate hearing sensitivity in the frequency range of 2,000 to 4,000 Hz. This is inadequate for medical or legal purposes in which hearing in the speech frequencies must be assessed. Consequently, we have developed a modified ABR technique that permits a more accurate determination of hearing threshold at 500, 1,000, 2,000 and 3,000 Hz, as illustrated in tests on 27 normal ears. This technique has great potential value for neonatal and mentally handicapped populations, as well as for individuals involved in hearing loss litigation.
Subject(s)
Auditory Threshold , Evoked Potentials, Auditory, Brain Stem , Hearing Disorders/diagnosis , Adult , Audiometry, Pure-Tone , Female , Humans , MaleABSTRACT
Neuromas of the facial nerve are uncommon tumors. The majority of cases involve the intratemporal and parotid areas. Since their description in 1930, there have been only 26 cases of intracranial facial neuroma reported in the world literature. Of these, 19 involved the middle cranial fossa, and only seven tumors extended into or originated in the posterior cranial fossa. In this location, the seventh nerve is surrounded by a very delicate and thin arachnoid casing. Thus, although these tumors are encapsulated, there is usually no obvious plane of separation between the tumor and perineurium. As a result, the seventh nerve has been sacrificed routinely. Two patients with posterior fossa facial neuromas underwent total tumor removal with a new surgical technique permitting preservation of the nerve fascicles via a translabyrinthine approach. Each patient has good recovery of seventh nerve function with no evidence of recurrence six and nine years later, respectively. Leaving the nerve fascicles intact appears to result in good reinnervation following total tumor removal. The potential value of this technique is best considered in the context of diagnostic and therapeutic options for facial neuromas in general. Neurotologists should find this a useful addition to their surgical armamentarium for selected cases.
Subject(s)
Cranial Nerve Neoplasms/surgery , Facial Nerve Diseases/surgery , Facial Nerve/physiopathology , Neuroma/surgery , Adult , Aged , Bone Conduction/physiology , Cranial Fossa, Posterior , Cranial Nerve Neoplasms/physiopathology , Craniotomy/methods , Facial Nerve Diseases/physiopathology , Female , Humans , Male , Neuroma/physiopathologyABSTRACT
Profound deafness has received increasing attention in recent years, largely because of the availability of cochlear implants. Consequently, it is especially important for otolaryngologists to remember that a "blank" audiogram does not necessarily mean total or even profound deafness. Patients with far-advanced otosclerosis may have no measurable hearing with routine audiometric testing even in the presence of serviceable sensorineural hearing. Review of nine patients (10 ears) who underwent stapedectomy from 1980 to 1987 reveals that seven of the nine (78%), who had been unable to use a hearing aid preoperatively, obtained serviceable hearing with hearing aids following surgery. Otolaryngologists should depend on a good history and tuning fork examination to avoid being misled by the audiogram, and should not hesitate to offer stapes surgery to patients with far-advanced otosclerosis.
