Dietary supplement comprised of ß-carotene, vitamin C, vitamin E, and magnesium: failure to prevent music-induced temporary threshold shift.

This study examined potential prevention of music-induced temporary threshold shift (TTS) in normal-hearing participants. A dietary supplement composed of ß-carotene, vitamins C and E, and magnesium was assessed using a randomized, placebo-controlled, double-blind study design. Dosing began 3 days prior to the music exposure with the final dose consumed approximately 30-min pre-exposure. There were no group differences in post-exposure TTS or music-induced decreases in distortion product otoacoustic emission (DPOAE) amplitude. Transient tinnitus was more likely to be reported by the treatment group, but there were no group differences in perceived loudness or bothersomeness. All subjects were monitored until auditory function returned to pre-exposure levels. Taken together, this supplement had no effect on noise-induced changes in hearing. Recommendations for future clinical trials are discussed.

Radiotherapy and radiosurgery for skull base tumors.

Tumors arising in the vicinity of the skull base are relatively uncommon; however, lesions that may be successfully treated by radiotherapy and radiosurgery include temporal bone chemodectomas, schwannomas, juvenile angiofibromas, pituitary adenomas, and meningiomas. This article reviews treatment techniques and results and discusses the pertinent literature.

Treatment of paragangliomas with radiation therapy.

Paragangliomas of the head and neck may be treated successfully with surgery, radiation therapy, or stereotactic radiosurgery. The choice of treatment depends on the location and extent of the tumor, the presence of multiple tumors, the age and health of the patient, and the preference of the patient and attending physician. This article reviews the role of radiation therapy in the treatment of patients with paragangliomas of the head and neck.

Magnetic resonance imaging in the search for retrocochlear pathology.

OBJECTIVES: The purpose of this study is to evaluate the incidence of retrocochlear pathologic conditions that may be seen with full, contrast-enhanced magnetic resonance imaging of the brain, relative to more limited studies of the internal auditory canals (IACs) in patients with unilateral hearing loss or tinnitus with or without dizziness. METHODS: A retrospective study was performed on all patients who had a magnetic resonance imaging of the brain and otologic symptoms over a 7-year period. RESULTS: Abnormalities were found in 11 of 128 patients with only auditory symptoms and in 63 of 282 patients with auditory symptoms and/or dizziness (P = 0.005). Treatable lesions may not have been identified with a limited IAC study in 3 of 128 patients with only unilateral auditory symptoms, and 21 of 282 patients with dizziness (P = 0.045). CONCLUSIONS: Limited MRI of the IACs may serve as an adequate screening test for retrocochlear pathologic conditions in patients with unilateral auditory symptoms and no dizziness.

Selective vestibular ablation by KTP laser in endolymphatic hydrops.

OBJECTIVES AND HYPOTHESIS: Vertigo, the cause of disability in many patients with Ménière's disease, may be the result of the effects of endolymphatic hydrops on the semicircular canals. We hypothesize that intractable vertigo may be controlled by destruction of the semicircular canal neuroepithelium using visible light lasers without the need for extensive fenestration of the bony labyrinth. This study was designed to assess the cochlear effects of potassium titanyl phosphate (KTP) laser-assisted triple semicircular canal ablation (TSCA) in endolymphatic hydrops. STUDY DESIGN: Randomized, prospective, and controlled. METHODS: Forty-one adult guinea pigs underwent either a unilateral endolymphatic duct occlusion to induce hydrops or a sham procedure. Ten weeks after induction of the hydrops, a KTP laser-assisted TSCA or a sham surgery was performed. RESULTS: Electrocochleographic thresholds to clicks and tone-bursts (2-20 kHz) did not change significantly up to 4 weeks after TSCA in hydropic ears. Cross-sectional histology confirmed the presence of hydrops and the ablation of the semicircular canals. Cochlear whole-mounts for hair cell counts showed no significant loss of outer or inner hair cells in hydropic ears treated with TSCA. CONCLUSION: KTP laser-assisted TSCA can be performed in the guinea pig model of endolymphatic hydrops without significant loss of hearing. Evaluation of this technique may be warranted in patients with intractable Ménière's disease.

Middle ear prosthesis displacement in high-strength magnetic fields.

HYPOTHESIS: Middle ear prostheses made from nonmagnetic, magnetic resonance (MR)-compatible metals reportedly displace ex vivo in the presence of high magnetic fields used in MR imaging (MRI). The authors postulate that the prosthesis displacement seen with "nonmagnetic" MR-compatible prostheses ex vivo may not be clinically significant in vivo. METHODS: Middle ear prostheses made from ferromagnetic (420F stainless steel) and nonmagnetic MR-compatible metals (316L stainless steel and platinum) were examined for magnetic field interactions at 4.7 Tesla (T). Ex vivo testing consisted of measurements of the translational and rotational motion of the prosthesis induced by the static magnetic field. In vivo testing was assessed by implanting prostheses in cadaveric temporal bones and performing clinical MRI sequences. Prosthesis displacement was measured semiquantitatively. RESULTS: Angular deflection was observed in all samples made from nonmagnetic stainless steel. The negative control (platinum) demonstrated no deflection, and the positive controls (ferromagnetic stainless steel) deflected >90 degrees. Torque analysis showed movement in five of five nonmagnetic stainless steel prostheses. Prostheses made from nonmagnetic stainless steel remained in place without appreciable loosening in vivo after MRI. Prostheses made with known ferromagnetic properties were displaced at 4.7 T but not at 1.5 T. CONCLUSION: Middle ear prostheses made from low-magnetic stainless steel do move in the presence of high magnetic fields ex vivo; however, this does not appear to be clinically or statistically significant in vivo at 4.7 T. Magnetic resonance imaging should be undertaken with caution in individuals with prostheses made from stainless steel with strong ferromagnetic properties.

Definitive radiotherapy in the management of chemodectomas arising in the temporal bone, carotid body, and glomus vagale.

PURPOSE: To evaluate the results of treatment for 71 patients with 80 chemodectomas of the temporal bone, carotid body, or glomus vagale who were treated with radiation therapy (RT) alone (72 tumors in 71 patients) or subtotal resection and RT (8 tumors) at the University of Florida between 1968 and 1998. METHODS AND MATERIALS: Sixty-six lesions were previously untreated, whereas 14 had undergone prior treatment (surgery, 11 lesions; RT, 1 lesion; or both, 2 lesions) and were treated for locally recurrent disease. All three patients who received prior RT had been treated at other institutions. Patients had minimum follow-up times as follows: 2 years, 66 patients (93%); 5 years, 53 patients (75%); 10 years, 37 patients (52%); 15 years, 29 patients (41%); 20 years, 18 patients (25%); 25 years, 12 patients (17%); and 30 years, 4 patients (6%). RESULTS: There were five local recurrences at 2.6 years, 4.6 years, 5.3 years, 8.3 years, and 18.8 years, respectively. Four were in glomus jugulare tumors and one was a carotid body tumor. Two of the four patients with glomus jugulare failures were salvaged, one with stereotactic radiosurgery and one with surgery and postoperative RT at another institution. Two of the five recurrences had been treated previously at other institutions with RT and/or surgery. Treatment for a third recurrence was discontinued, against medical advice, before receiving the prescribed dose. There were, therefore, only 2 failures in 65 previously untreated lesions receiving the prescribed course of RT. The overall crude local control rate for all 80 lesions was 94%, with an ultimate local control rate of 96% after salvage treatment. The incidence of treatment-related complications was low. CONCLUSIONS: Irradiation offers a high probability of tumor control with relatively minimal risks for patients with chemodectomas of the temporal bone and neck. There were no severe treatment complications.

Insecticidal activity of common reagents for insect foreign bodies of the ear.

OBJECTIVE: Insects commonly present as painful and distressing foreign bodies of the external ear canal. Removing live insects can be challenging, especially for primary care physicians who have limited equipment. The purpose of this study is to compare the insecticidal activity of commonly available preparations for insects that are most frequently recovered from ear canals: cockroaches (German and American), ticks, beetles, and honeybees. STUDY DESIGN: Prospective, blinded. METHODS: One hundred seventy insects of each species were placed in test tubes and submerged in 17 test preparations (10 tubes per preparation, 1 insect per test tube). Insect activity was stimulated by agitation of the test tube. Responses were monitored, and the time until death was measured. RESULTS: Most test preparations exhibited some insecticidal activity against most insect species. Ticks were completely resistant to all of the test reagents. Ethanol killed the American cockroaches (mean time, 32.6 s), German cockroaches (mean time, 29.6 s), and honeybees (mean time, 19.6 s) the most rapidly. CONCLUSION: Many commonly available reagents may be used to kill or immobilize insect foreign bodies of the ear.

Pneumococcal antibiotic resistance and rates of meningitis in children.

OBJECTIVES/HYPOTHESIS: Recent studies have shown alarmingly high rates of antibiotic resistance in Streptococcus pneumoniae isolates from patients with otitis media. A recent study has implicated resistant S pneumoniae for rising rates of acute mastoiditis. The purpose of this study was to determine whether S pneumoniae antibiotic resistance has similarly affected the rate of pediatric community-acquired meningitis, the most common intracranial complication of otitis media. STUDY DESIGN: Retrospective chart review. METHODS: All cases of pediatric community-acquired meningitis treated at an academic tertiary care hospital during a 10-year period were reviewed, and meningitis rates were calculated as a proportion of yearly admissions. RESULTS: The overall rate of meningitis decreased linearly during the study period (P = .001). This was largely because of a drop in the rate of Haemophilus influenzae meningitis (P = .001), corresponding with the introduction of H influenzae type B vaccine. Annual rates of S pneumoniae meningitis did not change. Only one case of S pneumoniae meningitis was due to a highly penicillin-resistant strain and isolates from four cases had intermediate sensitivity. Twenty-four of 83 cases were associated with antecedent acute otitis media and 63% of these had been treated with antibiotics before admission. Otitis media, as a cause of meningitis, did not increase during the study period. CONCLUSION: S pneumoniae is responsible for a greater proportion of cases of pediatric community-acquired meningitis. However, this is because of a decline in the rate of H influenzae cases, not the rise in S pneumoniae antibiotic resistance.

Hearing preservation with labyrinthine ablation in otitis media.

OBJECTIVES: Iatrogenic fenestration of the inner ear in the presence of otitis media is commonly associated with permanent hearing loss. Hearing can generally be preserved when the vestibular labyrinth is ablated in a controlled manner in noninflamed ears. The purpose of this study was to examine the feasibility of hearing preservation with violation of the inner ear in the presence of middle ear inflammation. STUDY DESIGN: Prospective and controlled animal model. METHODS: Otitis media was induced bilaterally in pigmented guinea pigs with transtympanic injection of Streptococcus pneumoniae, nontypeable Haemophilus influenzae, or formalin-killed nontypeable H influenzae. Two to 4 days after injection, the horizontal canal of one ear was transected and sealed. Hearing was tested before and after labyrinthine ablation. RESULTS: Otitis media was induced in all ears. Bacterial cultures were positive in 19 of 20 S pneumoniae-injected ears, and in 10 of 16 nontypeable H influenzae-injected ears. One week after surgery, elevation of click thresholds (> 15 dB) was encountered in none of the fenestrated or unfenestrated S pneumoniae-infected ears, in two of six unfenestrated and three of six fenestrated nontypeable H influenzae-infected ears, and in one of five killed-nontypeable H influenzae-injected ears both with and without fenestration. CONCLUSIONS: These data suggest that ablation of a semicircular canal in the presence of middle ear inflammation or infection does not necessarily lead to profound sensorineural hearing loss. Hearing loss associated with iatrogenic violation of the semicircular canals may be more dependent on factors other than the presence of nonspecific middle ear inflammation.

Inner ear barotrauma after stapedectomy in the guinea pig.

OBJECTIVE: The safety of scuba diving after stapedectomy is controversial. Stapedectomy is thought to predispose to inner ear barotrauma (e.g., perilymph fistula); however, many individuals continue to scuba dive following stapedectomy without ill effects. The purpose of this study was to evaluate the cochlear effects of barotrauma, similar to that experienced with scuba diving, on inner ears previously treated with stapedectomy. STUDY DESIGN: Prospective, controlled. METHODS: Sixteen Hartley albino guinea pigs underwent unilateral total stapedectomy followed by hyperbaric dives on 5 consecutive days, beginning 3 weeks after stapedectomy. Cochlear effects were determined using click and tone-pip evoked electrocochleographic thresholds and cochlear hair cell counts. RESULTS: Mean auditory thresholds increased by 29 dB after stapedectomy (P < .001), then remained stable thereafter. Mean thresholds in both the operated and control ears did not change with hyperbaric dives. Evidence of middle ear barotrauma (e.g., hemorrhage or tympanic membrane perforation) was observed in eight poststapedectomy ears and five control ears, but none demonstrated significant threshold elevation greater than or equal to 10 dB. Hair cell counts were not different between operated and control ears. CONCLUSIONS: Stapedectomy does not appear to predispose to cochlear sequelae in the guinea pig model of diving-related barotrauma.

Stapedectomy in the guinea pig.

Stapedectomy has traditionally been studied in the feline model. Ethical considerations and costs have made this model less feasible for ongoing research. The purpose of this study was to examine the guinea pig as a model for research on stapedectomy. Technical difficulties included limited exposure and small dimensions of the ossicles. The surgical technique with and without the use of a CO(2) laser and the relevant anatomy of the guinea pig middle ear are described.

Diagnostic yield of high-resolution computed tomography for pediatric sensorineural hearing loss.

OBJECTIVES/HYPOTHESIS: In recent years, relatively subtle inner ear anomalies have become apparent using high-resolution computed tomography (CT). The purpose of this study was to determine the diagnostic yield of high-resolution CT for pediatric sensorineural hearing loss (HL) (SNHL). METHODS: A review was performed on the records of all children (<18 y of age) who had undergone CT of the temporal bones over a 5-year period, since the introduction of current CT techniques. RESULTS: Three hundred eighty-three studies were performed in 351 subjects. The indication for the CT was SNHL or mixed HL in 157 children. Forty-nine (31%) of these studies revealed significant inner ear findings. Large vestibular aqueducts (LVAs) were reported in 15%, commonly in association with cochlear modiolar deficiencies. Modiolar deficiencies (11%) and other cochlear dysplasias (12%) followed LVA in frequency. The incidence of inner ear dysplasia in children with perinatal or postnatal risk factors was only slightly lower than those without (22% vs. 32%, P > .05). The rate of dysplasias did not correlate with SNHL severity, pattern of HL, or type of HL (mixed vs. sensorineural). CONCLUSIONS: These findings suggest that radiographic imaging has a relatively high diagnostic yield in children with SNHL. These findings may be of value in counseling patients and guiding the management of their SNHL.

Central nervous system metabolic activity after cochlear implantation in the feline neonatal model.

OBJECTIVE: To determine the effects of deafening and cochlear implant stimulation on central nervous system (CNS) metabolic activity in the feline neonate model. BACKGROUND: Deafening of fetal animals has been shown to result in acute, profound depression of CNS glucose metabolism, in both auditory structures and the cerebral hemispheres. Preliminary studies have suggested that electrical stimulation of the auditory system may increase central nervous metabolic activity after deafening. The purpose of this study was to investigate this possibility. METHODS: This was a prospective, randomized, blinded, and controlled animal study of 13 random-source newborn kittens. It was set in an animal research facility for otologic disorders. OUTCOME: Deoxyglucose metabolism (assessed with autoradiograph densitometry) of brain cross-sections of normal, deafened, and deafened and cochlear-implanted animals after 6 weeks of auditory stimulation or deprivation. RESULTS: Chronic deafening did not result in a profound reduction in CNS metabolic activity. Cochlear implantation and electrical stimulation did not significantly raise the level of CNS metabolic activity within either auditory pathways or the cerebral hemispheres. CONCLUSIONS: Deafening is not associated with significant chronic reduction in CNS metabolic activity. Other parameters of CNS activity and maturation may be necessary to assess the effects of cochlear implantation and stimulation in animal models.

Impact of resistant pneumococcus on rates of acute mastoiditis.

OBJECTIVE: To determine whether the rate of acute mastoiditis is rising, specifically as a result of antibiotic-resistant strains of Streptococcus pneumoniae. METHODS: A retrospective chart review of all patients with a discharge diagnosis of acute mastoiditis between July 1, 1987, and June 30, 1997, was performed at our academic, tertiary-care medical center. There were no interventions, and the main outcome measures included the number of cases of acute or coalescent mastoiditis, stratified by pathogen, per year. RESULTS: The rate of acute mastoiditis as a proportion of yearly otorhinolaryngology admissions increased linearly over time (P = 0. 024). Pneumococcal-related rates of acute mastoiditis, expressed as a proportion of yearly hospital and otorhinolaryngology admissions, increased linearly over time (P = 0.002, P = 0.002). All but 1 case of pneumococcal mastoiditis during the past 3 years were caused by penicillin-resistant strains. CONCLUSIONS: The emergence of antibiotic-resistant S pneumoniae may be responsible for an increasing rate of acute mastoiditis.

Sensorineural hearing loss after occlusion of the enlarged vestibular aqueduct.

OBJECTIVE: This study aimed to report the hearing results of endolymphatic sac occlusion in patients with enlarged vestibular aqueduct syndrome. STUDY DESIGN: The study design was a multiinstitutional retrospective case series. SETTING: The study was conducted at tertiary otologic referral centers. PATIENTS: The study included 10 previously unreported patients with progressive sensorineural hearing loss and vestibular aqueducts greater than 1.5 mm in diameter on computerized tomography. INTERVENTION: Occlusion of the enlarged vestibular aqueduct was performed by means of a transmastoid surgical approach. Either intraluminal endolymphatic sac obliteration (five patients) or extraluminal extradural endolymphatic sac obliteration (five patients) was accomplished with temporalis fascia. MAIN OUTCOME MEASURES: The postoperative pure tone average (PTA) and speech discrimination scores were compared with the preoperative levels using conventional audiometry. RESULTS: Nine of 10 patients experienced some degree of sensorineural hearing loss. The median change in PTA was a loss of 21 decibels (dB), and 50% of the patients experienced a sensorineural hearing loss greater than 25 dB. Postoperative change in PTA ranged from +10 dB to -59 dB. The median change in speech discrimination score was a loss of 27.5%. Only one patient had an improvement in both speech discrimination score and pure tone averages after surgery. Patients who underwent extraluminal occlusion had a median PTA loss of 12 dB, and patients who underwent open sac occlusion had a median PTA loss of 34 dB. These were not statistically different. CONCLUSION: In this series of 10 patients, 5 had a greater than 25 dB decrease in hearing after occlusion of the enlarged vestibular aqueduct. Surgical occlusion of the enlarged vestibular aqueduct showed no significant benefit in hearing preservation. The otologic surgeon is alerted to the potential for severe sensiorineural hearing loss after occlusion of the enlarged vestibular aqueduct.

The effects of kanamycin injection into the fetal lamb cochlea.

Mammalian auditory hair cells have minimal capacity for repair or regeneration after a variety of insults, including acoustic trauma and aminoglycoside exposure. Although fetal tissues have a greater potential for repair and regeneration than adult tissues, there have been no reported studies on fetal hair cell response to injury in mammals. The purpose of this research was to investigate the effects of local application of kanamycin on fetal lamb cochlear hair cells. Eleven fetal lambs in the early third trimester underwent kanamycin injection through the left round-window membrane. The right ear served as a control. Click-evoked compound action potentials (CAPs) were serially recorded in 8 fetuses. CAPs were observed in all control ears. None of the 8 kanamycin-injected ears had measurable CAPs on postoperative day 1. One kanamycin-injected ear demonstrated definite CAPs, beginning on postoperative day 6. Hair cells were found to be intact in 6 of 9 kanamycin-treated ears. Hair cells were missing only in animals that went into premature labor. The presence of intact hair cells despite the loss of measurable CAPs in kanamycin-perfused lamb cochleae was striking. This finding may indicate that the fetal auditory epithelium is relatively resistant to aminoglycoside injury or may be capable of prompt repair or regeneration. Further studies on the effects of aminoglycoside injury in the fetal cochleae seem to be warranted.

Computed tomography and the diagnosis of coalescent mastoiditis.

OBJECTIVE: To evaluate the sensitivity and accuracy of temporal bone CT findings for the diagnosis of acute coalescent mastoiditis. DESIGN: CT scans were blindly scored for mastoid bone integrity (air cell septae, sigmoid cortical plate, and lateral cortical wall) by an otologist and 2 neuroradiologists. Scores were analyzed to determine their sensitivity and specificity for acute coalescent mastoiditis. SUBJECTS: Twenty-one patients with acute coalescent mastoiditis or acute noncoalescent mastoiditis and 12 patients with chronic mastoiditis. SETTING: Academic tertiary care facility. RESULTS: Pair-wise interobserver agreement was good to excellent (kappa = 0.4 to 0.83) for the sigmoid plate, the lateral cortex, and the septae. Scores for the sigmoid plate were significantly greater (indicative of greater bone destruction) in the coalescent group than in either the noncoalescent group or the chronic group (P < 0.05). Within the coalescent group, scores were highest for the sigmoid plate, followed by the septae and the lateral wall. Sensitivity and specificity for coalescent mastoiditis were both highest for the sigmoid plate (67% and 90%, respectively). CONCLUSIONS: Erosion of the cortical plate overlying the sigmoid sinus is the most sensitive and specific CT finding for distinguishing coalescent from noncoalescent acute mastoiditis.