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Biomedical subjects

Thomas J Balkany

Publications and source records attributed to Thomas J Balkany.

9 recordsLinked to original sources
PubMed2004

Evaluation of hearing and auditory nerve function by combining ABR, DPOAE and eABR tests into a single recording session.

In this article, we describe an efficient method for testing both auditory receptor and auditory nerve function in a single recording session. Auditory receptor function is tested in response to pure tone, tone burst and click acoustic stimuli (i.e. distortion products of otoacoustic emissions, DPOAE; and auditory-evoked brainstem responses, ABR). The function of the auditory neurons and nerve is measured in response to direct electric current stimulation (i.e. electrically evoked auditory brainstem responses, eABR). All measurements were obtained from anesthetized laboratory rats during single recording sessions using hardware and software stimulation and analysis programs developed by Intelligent Hearing Systems, Miami, FL.

Acoustic Stimulation↗
PubMed2004

Further prospective findings with compound action potentials from Nucleus 24 cochlear implants.

The purpose of this study was to gain greater understanding of compound action potential (CAP) specific characteristics including: slope of the growth function, P1-N1 amplitude, threshold and latencies of P1 and N1 measured in cochlear implant users. Experienced adult subjects underwent behavioral threshold (T) measurement and electrically elicited stapedial reflex (eSR) recording, followed by CAP measurements on six selected electrodes. Based on the electrically elicited stapedial reflex threshold (eSRT), maximum stimulation level for each measured electrode was set. Relationships among the three thresholds of the above measures and maximum CAP P1-N1 amplitude and slope of the growth function were statistically evaluated for each measured electrode. Threshold of the CAP response showed relationships of similar strength with eSRT and T (r=0.69 and 0.61, respectively). For both slope of the growth function and CAP P1-N1 amplitude, a statistically significant relationship with cochlear place was found. Both specific characteristics of CAP measurement for the most apical electrodes were roughly double those for the most basal electrode (alpha=0.05). This may be partially explained by cochlear anatomy and is consistent with prior mammalian and human studies showing increasing density and survival of spiral ganglion cells in the regions corresponding to intracochlear electrode placement from basal to apical electrodes (90-360 degrees ).

Action Potentials↗
PubMed2003

Pediatric tympanoplasty: effect of contralateral ear status on outcomes.

OBJECTIVE: To assess the prognostic value of different variables on the outcome of pediatric type I tympanoplasty. DESIGN: Retrospective review of medical records. SETTING: An otolaryngology department in a large urban tertiary care medical center. PATIENTS: We reviewed 72 ears in 60 patients who had undergone a type I tympanoplasty from 1987 to 2000. Patient ages ranged from 3 to 18 years. INTERVENTIONS: Type I tympanoplasty. MAIN OUTCOME MEASURES: We identified the following 3 criteria for success: (1) healing of the neotympanic graft; (2) healing of the graft with a postoperative air-bone gap of no greater than 20 dB; and (3) healing of the graft with aeration of the middle ear space. RESULTS: Healing occurred in 59 (82%) of the 72 neotympanic grafts; 39 (83%) of the 47 healed ears for which a postoperative audiogram was available had an air-bone gap of no greater than 20 dB; and 49 (83%) of the 59 healed ears had a normally aerated middle ear space. A statistically significant difference in the rate of graft healing was identified for large perforations (76%), as well as for creation of an aerated middle ear space, when there was evidence of ongoing contralateral eustachian tube dysfunction (ie, otitis media with effusion or negative middle ear pressure, but not a perforation). CONCLUSIONS: Pediatric type I tympanoplasty can offer reasonably good chances for postoperative graft healing, serviceable hearing, and creation of an air-containing middle ear space if performed in carefully selected patients. Caution should be exercised in performing tympanoplasty in children with evidence of ongoing eustachian tube dysfunction, as evidenced by otitis media with effusion and negative middle ear pressure, but not perforations, in the contralateral ear.

Adolescent↗
PubMed2003

Comparative study of cochlear damage with three perimodiolar electrode designs.

OBJECTIVE: To describe intracochlear insertion trauma caused by three perimodiolar cochlear implant electrodes. STUDY DESIGN: Descriptive histological study of 15 human cadaver temporal bones. METHODS: Fifteen cadaver temporal bones underwent surface preparation and were implanted with one of the following perimodiolar electrode arrays: Combi 40+PM (MedEl Corporation), HiFocus II (Advanced Bionics Corporation), or Contour (Cochlear Corporation). A cryosectioning technique was used to study horizontal sections at 200 microm intervals with the electrode in place. Image-enhanced videofluoroscopy and computer-assisted morphometrics were used to assess the mechanism of insertion trauma and to determine electrode position within the modiolus. RESULTS: Histological examination revealed varying degrees of damage to the spiral ligament, basilar membrane, and osseous spiral lamina. Using a novel grading system for electrode trauma, there was no statistically significant difference among the three electrodes. A literature search of histological studies of a commonly used "standard" electrode showed damage equal to or greater than that seen in the current study. CONCLUSIONS: Insertion trauma caused by periomodiolar electrodes occurs to an acceptable degree. Refinement of electrodes based on mechanisms of trauma may be able to further reduce damage.

Basilar Membrane↗
PubMed2003

Arrest of apoptosis in auditory neurons: implications for sensorineural preservation in cochlear implantation.

HYPOTHESIS: The JNK/c-Jun cell death pathway is a major pathway responsible for the loss of oxidative stress-damaged auditory neurons. BACKGROUND: Implantation of patients with residual hearing accentuates the need to preserve functioning sensorineural elements. Although some auditory function may survive electrode insertion, the probability of initiating an ongoing loss of auditory neurons and hair cells is unknown. Cochlear implantation can potentially generate oxidative stress, which can initiate the cell death of both auditory neurons and hair cells. METHODS: Dissociated cell cultures of P4 rat auditory neurons identified the apoptotic pathway initiated by oxidative stress insults (e.g., loss of trophic factor support) and characterized this pathway by arresting translation of pathway-specific mRNA with antisense oligonucleotide treatment and with the use of pathway specific inhibitors. The presence or absence of apoptosis-specific protein and changes in the level of neuronal survival measured the efficacy of these interventional strategies. RESULTS: These in vitro studies identified the JNK/c-Jun cascade as a major initiator of apoptosis of auditory neurons in response to oxidative stress. Neurons pretreated with c-jun antisense oligonucleotide and exposed to high levels of oxidative stress were rescued from apoptosis, whereas neurons in treatment control cultures died. Treatment of oxidative-stressed cultures with either curcumin, a MAPKKK pathway inhibitor, or PD-098059, a MEK1 inhibitor, blocked loss of neurons via the JNK/c-Jun apoptotic pathway. CONCLUSION: Blocking the JNK/c-Jun cell death pathway is a feasible approach to treating oxidative stress-induced apoptosis within the cochlea and may have application as an otoprotective strategy during cochlear implantation.

Animals↗
PubMed2002

Phase III clinical trial results with the Vibrant Soundbridge implantable middle ear hearing device: a prospective controlled multicenter study.

OBJECTIVES: The goal of the study was to evaluate the performance of a semi-implantable middle ear hearing device (Vibrant Soundbridge System [VSB]; Symphonix Devices, Inc). STUDY DESIGN: A prospective, single-subject, repeated-measures multicenter study was conducted to determine the safety and efficacy of the VSB using analog and digital external processors. Measures included residual hearing, functional gain, speech recognition, acoustic feedback, occlusion, and patient self-assessment to determine satisfaction, perceived performance, and device preference compared with an appropriately fit acoustic hearing aid. Fifty-three adult subjects with moderate to severe sensorineural hearing loss were evaluated at 4 or more intervals after implantation. RESULTS: Improvements in satisfaction, performance, and preference were statistically significant with the VSB, as was functional gain across all test frequencies (P < 0.001). Occlusion and feedback were virtually eliminated. Aided speech recognition was comparable between VSB and the hearing aid. Residual hearing was unchanged. CONCLUSION: The VSB is a safe and effective treatment option for adults with moderate to severe sensorineural hearing loss.

Adult↗
PubMed2002

Cochlear implants in children--a review.

Over the past two decades, cochlear implantation has become a widely accepted treatment of deafness in children. Over 20,000 children have received cochlear implants worldwide. Hearing, language and social development outcomes have been positive. We review current issues in cochlear implantation, candidacy, evaluation, surgery, habilitation, ethics and outcomes.

Child↗
PubMed2002

Modiolar proximity of three perimodiolar cochlear implant electrodes.

A new generation of cochlear implant electrodes has been designed to position the stimulating contacts close to the modiolus in order to reduce power consumption and increase stimulation selectivity. The purpose of this study was to assess electrode position in the cochlea for three recently designed electrodes. Fifteen cadaveric temporal bones were implanted with one of three perimodiolar electrode arrays: Nucleus Contour; Med-El Combi40+ PM (developmental version); and Clarion HiFocus II. Image-enhanced videofluoroscopy and computer morphometrics were used to assess stimulating contact position relative to the modiolus. The mean distance (+/- 1 standard deviation) to the modiolus for all electrode contacts was 0.33 (+/-0.24), 0.30 (+/-0.27) and 0.16 mm (+/-0.19) for the Contour, Combi40+ PM and HiFocus II arrays, respectively. In addition, dynamic videofluoroscopy was used to correlate device-specific insertion characteristics with contact-to-modiolus distance. All three devices were successful in terms of locating electrode contacts very close to the modiolar wall.

Adult↗