Faculty Bibliography

Distortion product otoacoustic emissions (DPOAEs) for low stimulus levels (< 60 dB SPL) have been reported in adult humans under ideal conditions. In neonates, DPOAEs have been reported only for high-level stimuli. The purpose of this paper was to determine characteristics of the 2f1-f2 DPOAE for low-level stimuli in neonates and to assess the feasibility of obtaining such measures in a noisy environment. Subjects were 19 premature neonates presumed to have normal hearing based on systematic pneumatic otoscopy measures and evoked auditory brainstem responses. For stimuli centered at 2000 and 6000 Hz and presented over a range of 30 to 75 dB SPL, DPOAEs were measured employing linear time averaging for up to 128 time frames at each level. In quiescent subjects, the level of the noise floor was as low as that reported in cooperative adults under ideal conditions (approximately -30 dB SPL), and the functions were identical. That is, valid measures were obtained for very low stimulus levels (30 dB SPL), the rate of growth approached 1 dB/dB, and identical nonmonotonicities (saturation, plateaus, and notches) were observed as those reported for adults. When the noise floor was elevated due to subject activity, no valid data could be obtained for low-level stimuli even though the DPOAEs were at expected levels for high-level stimuli. These results have important implications for the use of such measures in this population because the DPOAEs associated with the metabolically active nonlinear cochlear processes at low stimulus levels may be contaminated with DPOAEs associated with other processes at high stimulus levels.

A 61-year-old woman was examined because of unilateral nonpulsatile tinnitus involving the right ear. CT scanning showed a soft-tissue mass in the hypotypanum. Angiographically, the mass was identified as a fenestrated or duplicated internal carotid artery associated with persistence of the stapedial artery. Embryologic considerations are discussed.

This study examines the relationship of time to cochlear implant patient performance and the effect of device design on patient performance over time. Data were collected for patients who were implanted with Nucleus 22, Smith & Nephew Richards Ineraid, or 3M/Vienna cochlear implants as part of the Veterans Administration study on cochlear implants. Patients were administered a comprehensive audiological test battery prior to implantation, at stimulation, and 3 months, 1 year, and 2 years poststimulation. Results show that patient performance improved over the course of the study, with performance levels with each multichannel implant being similar at the study end point. The Nucleus device produced maximum performance sooner than the Ineraid device did, and performance of the single-channel 3M was consistently below that of the multichannel devices

Since the advent of antituberculous therapy, tuberculosis of the ear has decreased in incidence; but of late, cases of both pulmonary and otologic tuberculosis are on the rise. In addition, the treatment of aural tuberculosis is now more difficult due to resistance to one or more of the routinely used antituberculous pharmacotherapeutic agents. Urban areas and selected populations have been particularly endangered by the re-emergence of this disease. In light of this developing situation, three cases of aural tuberculous infections are presented. Typical and atypical presentations of the disease, including history, signs, symptoms, and radiographic findings are discussed, as are treatment options. The importance of aural tuberculosis as part of the general increase in incidence and resistance of the disease is examined

We attempted to define the minimum blood volume and bacterial concentration required to obtain a positive blood culture with the use of placental blood and an in vitro technique. Known amounts of either Escherichia coli or group B beta-hemolytic streptococci were added to heparinized placental blood specimens. Blood samples of 0.25, 0.5, and 1.0 ml containing bacteria were inoculated into 30 ml of a commercially available broth culture medium, incubated for 24 hours, and examined for bacterial growth. Samples of at least 0.25 ml blood containing more than 10 colony-forming units of bacteria per milliliter resulted in a positive blood culture for 131 of 132 samples. On the basis of these data, we suggest that if 0.25 ml of blood is sampled and the specimen contains more than 10 colony-forming units per milliliter of E. coli or group B beta-hemolytic streptococci, the blood culture is almost certain to be positive

BACKGROUND. Paragangliomas of the head and neck are slow-growing tumors that originate from neural crest cells. Between 7% and 9% of these tumors have a familial occurrence. The suspected gene for familial paragangliomas (FP) is transmitted with an autosomal dominant mode of inheritance with incomplete penetrance, and appears to exhibit genomic imprinting. It has been demonstrated by family studies that individuals who inherit the gene(s) from their father will develop the disease. Through linkage analysis, the gene(s) for FP has been postulated to be located on the long arm of chromosome 11. The discovery of many different genes has been elucidated through the cytogenetic analysis of affected individuals who carry specific chromosome aberrations. This project was designed to look for chromosome abnormalities in several second-generation family members to further assist in the localization of the gene(s) for FP. METHODS. This study involved the cytogenetic evaluation of lymphocytes, fibroblasts, and tumor cells of several second-generation family members from a three-generation family with FP of the head and neck to look for chromosome abnormalities generally, and for abnormalities of chromosome 11 specifically. Standard cytogenetic techniques were used for lymphocyte and fibroblast cultures. Tumor cells were cultured in a collagen matrix with F12 medium supplemented with 3% L-glutamine and 10% fetal calf serum. RESULTS. There were no detectable abnormalities of chromosome 11 in any of the cells. However, nonrandom abnormalities of chromosomes 5 and 7 were seen in some of the tumor cells of one FP patient. To our knowledge, this is the first article which demonstrated the ability to successfully culture FP of the head and neck