Biomedical subjects

Ross Tonini

Publications and source records attributed to Ross Tonini.

5 recordsLinked to original sources

PubMed2006

Endoscopically guided placement of prefabricated cochlear implant electrodes in a common cavity malformation.

OBJECTIVE: To devise a safe and effective method of optimal customized electrode placement in the common cavity of children with cochleovestibular malformations. METHODS: Specialized electrodes were manufactured on the basis of three-dimensional data obtained from the high resolution computed tomography (HRCT) scans of the temporal bones of these two children. Electrode positioning was achieved with direct endoscopic view of the cavity utilizing a three-hole common cavity technique. RESULTS: Optimal electrode positioning in apposition to the medial neuroepithelium in the common cavity was verified visually intraoperatively. Postoperatively, minimal stable electrical current levels were found to be required. CONCLUSIONS: Custom-designed electrodes have the potential to offer improved results in children with common cavity malformations. Intraoperative direct positioning may further improve these results.

Cochlea↗

PubMed2006

Dyslipidemia and auditory function.

The relationship between dyslipidemia and hearing is unclear. This study was conducted to investigate whether elevated serum lipid levels impact auditory function in humans and in guinea pigs. In the human study, a cross-sectional study of 40 volunteers with dyslipidemia was conducted. Pure tone thresholds, distortion product otoacoustic emissions, and lipid profiles were analyzed. When controlled for patient age and sex, we found that elevated triglycerides were associated with reduced hearing. In the guinea pig study, a prospective study of animals fed a high-fat diet for 14 weeks was conducted. Although the high-fat diet led to a dramatic elevation in the average weight and total cholesterol in all animals (from 61 to 589 mg/dl), there were no meaningful changes in distortion product otoacoustic emission magnitudes. These results suggest that whereas chronic dyslipidemia associated with elevated triglycerides may reduce auditory function, short-term dietary changes may not.

Adult↗

PubMed2005

Steady-state response audiometry in a group of patients with steeply sloping sensorineural hearing loss.

OBJECTIVES: The purpose of this study was to examine the predictive value of auditory steady-state response (ASSR) evoked potential thresholds and predicted behavioral thresholds in a group of children with steeply sloping sensorineural hearing loss (HL). STUDY DESIGN: Case series. METHODS: Twenty-nine children with sloping sensorineural HL underwent behavioral audiometric evaluation, impedance testing, distortion product otoacoustic emissions, and steady-state response testing. A t test was performed to compare the means of ASSR predicted behavioral thresholds and behavioral responses. Pearson correlation coefficients were calculated at each tested frequency, 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz, using the same data. RESULTS: Bracketed thresholds were obtained at 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz. Nineteen ears were used in this evaluation. A comparison of threshold difference as a function of bracketing revealed that the means were statistically different (P < .05). The mean threshold differences were calculated, and Pearson r values were determined between the behavioral thresholds and the predicted thresholds using the Rance 95 algorithm. The results revealed no difference of means at 500 Hz between predicted and measured behavioral thresholds. Linear regression analysis revealed strong correlation at 500 Hz, 1,000 Hz, and 2,000 Hz. CONCLUSIONS: The GSI Audera appears to predict the configuration of HL in children with steeply sloping sensorineural HLs and over-predicts the severity of the loss by 15 to 20 dB above 500 Hz at each test frequency (1,000, 2,000, and 4,000 Hz). Correlation coefficients display a strong correlation at 500 Hz, 1,000 Hz, and 2,000 Hz.

Acoustic Impedance Tests↗

PubMed2005

Auditory steady-state response audiometry in profound SNHL: the impact of abnormal middle ear function.

Auditory steady-state response (ASSR) audiometry is a commercially available tool that is used to predict behavioral auditory threshold levels. Its particular value stems from the technology's ability to measure frequency-specific responses in the background electroencephalogram to auditory stimuli presented across a broad range of frequencies and sound pressure levels. It is clearly of benefit when used to assess threshold levels in infants and children with severe-to-profound hearing impairment (i.e., cochlear implant candidates). Although numerous authors have provided evidence of the usefulness of ASSR testing, their reports have concerned patients whose middle ear impedance measures were normal. We report the cases of 2 patients who, following improvement of abnormal middle ear impedance values, experienced a marked improvement in measurable thresholds by ASSR testing.

Acoustic Impedance Tests↗

PubMed2002

Neonatal hearing loss in the indigent.

OBJECTIVE: To compare the risk factor profile for neonatal hearing loss (HL), and the follow-up rate of those identified with HL in an indigent population with those in an insured population. STUDY DESIGN: Retrospective review. METHODS: We studied 4526 neonates from the high-risk nursery or neonatal intensive care unit from two adjacent hospitals in Houston, Texas. Ben Taub General Hospital (BTGH) is a county public hospital that serves mainly the indigent. Texas Children's Hospital (TCH) is a private tertiary care center that serves patients with private insurance and Medicaid. RESULTS: Overall, 133 infants failed the screening test. Follow-up diagnostic testing identified 48 patients with definite HL. Although nearly twice as many patients at BTGH failed screening compared with TCH (88 vs. 45), four times as many patients at BTGH did not return for diagnostic testing (43 vs. 10). When a hearing aid was needed, there was a delay in getting one at BTGH (P <.05). There was a higher prevalence of dysmorphic facial features and central nervous system disease and a lower prevalence of long-term ventilatory support at BTGH (P <.05). There were no differences between BTGH and TCH in the prevalence of low birth weight, neonatal asphyxia, syndromic stigmata, neonatal infection, family history of HL, or neonatal transfusion (P >.1). CONCLUSIONS: Significant differences in the risk factor profile for neonatal HL exist between the indigent and the general population. A worrisome problem exists with the timely intervention in hearing-impaired indigent neonates.

Audiometry↗