Rodney C. Diaz

Location and frequency cues in auditory selective attention

The roles of frequency and location cues in auditory selective attention were investigated in a series of experiments in which target tones were distinguished from distractors by frequency, location, or the conjunction of frequency and location features. When frequency separations in high-rate tone sequences were greater than 1 octave, participants were fastest at identifying targets defined by frequency and were sometimes faster at identifying conjunction than location targets. Frequency salience diminished as filtering demands were reduced: At long interstimulus intervals (> 2.0 s), performance was superior in location conditions. The results suggest that frequency may play a role in auditory selective attention tasks analogous to the role of spatial position in visual attention.

Endoscopic Approach to Orbital Blowout Fracture Repair

OBJECTIVES: Transconjunctival and subciliary approaches to orbital floor blowout fractures (OBF) have known risks of postoperative eyelid malposition. This study evaluates the endoscopic transmaxillary repair of OBFs in a cadaveric model and clinical setting. METHODS: Sixteen cadaveric and 10 clinical OBFs were repaired endoscopically. A Caldwell-Luc approach and modified sinus surgery instrumentation were used to repair each fracture. Variations in fracture pattern, instrumentation, and surgical technique were evaluated. RESULTS: Endoscopic repair was achieved in all 16 cadaveric orbits and in 9 of 10 patients. Fracture patterns were classified as either medial or lateral to the infraorbital nerve. Average clinical operating time was 1:38. Of 9 postoperative CT scans, 5 were rated as excellent, 3 as good, and 1 as poor. CONCLUSIONS: The endoscopic transmaxillary approach is a safe, viable technique for OBF repair. It offers improved visualization, anatomic fracture repair, no risk of postoperative eyelid complications, and good clinical results. EBM rating: C.

Cochlear implantation in single-sided deafness for enhancement of sound localization and speech perception.

Purpose of reviewTo examine the current literature regarding application of cochlear implantation in patients with single-sided deafness for improvement in sound localization. Recent findingsAs familiarity of the technical and biological capabilities of cochlear implantation improves and criteria for use broaden, investigators have begun examining usage of cochlear implantation in patients with single-sided deafness as a viable solution in attempts to improve sound localization and speech perception. Although studies of such application are limited, from the available published literature, modest benefits have been described in both sound localization and speech perception. Patients consistently report improvement in quality of life after cochlear implantation for single-sided deafness. SummaryAlthough single-sided deafness is not a currently approved indication for cochlear implantation, limited investigational studies to date have demonstrated patient improvement in both sound localization and speech perception.

Tumors and Pseudotumors of the Endolymphatic Sac

This article reports on the presentation, diagnosis, management, and treatment outcomes of lesions of the endolymphatic sac in patients treated at a tertiary neurotology referral center. It summarizes survival results in the largest series groups and presents a new diagnostic entity of pseudotumor of the endolymphatic sac. The study includes retrospective review of all patients diagnosed with lesions of the endolymphatic sac within our practice between 1994 and 2005 as well as review of the literature. The primary outcome measure was survival, and the secondary outcome measure was disease-free survival following definitive resection. Postoperative complications were assessed. Survival characteristics of the largest reported case series groups were reviewed. Five cases of endolymphatic sac lesions were identified. Of these, three were true endolymphatic sac tumors and two were inflammatory pseudotumors of the endolymphatic sac. All three of the endolymphatic sac tumors patients survived (100%), and two of the three had disease-free survival (67%). Two of three patients maintained persistent facial paresis postoperatively. Both patients with benign pseudotumors survived (100%). Our study concluded that endolymphatic sac tumors are rare neoplasms of the temporal bone that, although locally aggressive and invasive, have excellent prognosis for survival with complete resection. We report a new entity of pseudotumor of the endolymphatic sac that mimics true sac tumors in every respect on presentation but which is non-neoplastic in origin.

Evolution in surgical management of superior canal dehiscence syndrome.

Purpose of reviewThis manuscript will review the progression of surgical techniques currently being used to repair a defect in the superior semicircular canal in symptomatic patients. Originally described via the middle cranial fossa route, larger series of patients have been demonstrated through less invasive approaches. These new innovative approaches will be discussed. Recent findingsRecently, the surgical indications for the repair of superior canal dehiscence have been broadened. As a result, several surgical techniques have been demonstrated to limit inherent risks to patients while still adequately treating the symptoms known to be associated with superior canal dehiscence. Transmastoid plugging, transmastoid resurfacing, endoscopic resurfacing and endaural approaches will be described and recent results discussed. SummaryAlthough the optimal surgical approach for superior canal dehiscence has yet to be determined, clearly a progression in techniques has been demonstrated. Surgical management of superior canal dehiscence syndrome began requiring a craniotomy but has now progressed to transmastoid and even endaural approaches.

Functional Consequences of Polyamine Synthesis Inhibition by l-α-Difluoromethylornithine (DFMO) CELLULAR MECHANISMS FOR DFMO-MEDIATED OTOTOXICITY

l-α-Difluoromethylornithine (DFMO) is a chemopreventive agent for colon cancer in clinical trials. Yet, the drug produces an across-frequency elevation of the hearing threshold, suggesting that DFMO may affect a common trait along the cochlear spiral. The mechanism for the ototoxic effects of DFMO remains uncertain. The cochlear duct is exclusively endowed with endocochlear potential (EP). EP is a requisite for normal sound transduction, as it provides the electromotive force that determines the magnitude of the receptor potential of hair cells. EP is generated by the high throughput of K+ across cells of the stria vascularis, conferred partly by the activity of Kir4.1 channels. Here, we show that the ototoxicity of DFMO may be mediated by alteration of the inward rectification of Kir4.1 channels, resulting in a marked reduction in EP. These findings are surprising given that the present model for EP generation asserts that Kir4.1 confers the outflow of K+ in the stria vascularis. We have proposed an alternative model. These findings should also enable the rational design of new pharmaceuticals devoid of the untoward effect of DFMO.

Assessing stapes piston position using computed tomography: a cadaveric study.

Hypothesis: Temporal bone computed tomographic (CT) scanning in the postoperative stapedotomy patient is inaccurate in assessing stapes piston position within the vestibule. Background: Poststapedotomy patients that have persistent vertigo may undergo CT scanning to assess the position of the stapes piston within the vestibule to rule out overly deep insertion. Vertigo is a recognized complication of the deep piston, and CT evaluation is often recommended. The accuracy of CT scan in this setting is unestablished. Methods: Stapedotomy was performed on 12 cadaver ears, and stainless steel McGee pistons were placed. The cadaver heads were then scanned using a fine-cut temporal bone protocol. Temporal bone dissection was performed with microscopic measurement of the piston depth in the vestibule. These values were compared with depth of intravestibular penetration measured on CT scan by 4 independent measurements. Results: The intravestibular penetration as assessed by computed tomography was consistently greater than the value found on cadaveric anatomic dissection. The radiographic bias was greater when piston location within the vestibule was shallower. The axial CT scan measurement was 0.53 mm greater, on average, than the anatomic measurement. On average, the coronal CT measurement was 0.68 mm greater than the anatomic measurement. The degree of overestimation of penetration, however, was highly inconsistent. Conclusion: Standard temporal bone CT scan is neither an accurate nor precise examination of stapes piston depth within the vestibule. We found that CT measurement consistently overstated intravestibular piston depth. Computed tomography is not a useful study in the evaluation of piston depth for poststapedectomy vertigo and is of limited value in this setting.

Otogenic lateral sinus thrombosis: Case series and controversies

OBJECTIVES The aim of this study is to (1) report the clinical presentation, treatment, and sequelae in a series of pediatric patients with otogenic lateral sinus thrombosis and (2) to review the most controversial aspects of management of this rare intracranial complication of otitis media. METHODS Retrospective chart review of inpatients treated for central venous thrombosis at a tertiary care facility between 1996 and 2012. RESULTS Five pediatric patients (four male, one female) were identified with otogenic lateral sinus thrombosis. Age at presentation ranged from 13 months to 15 years. All underwent a surgical procedure, ranging from a simple myringotomy with tympanostomy tube placement to tympanomastoidectomy and internal jugular vein ligation or craniotomy. Three were anticoagulated with unfractionated heparin with subsequent transition to low molecular weight heparin of variable duration. One patient developed a non-life-threatening intracranial hemorrhage while on long-term anticoagulation. Follow-up imaging, when available, did not directly correlate complete thrombus resolution with use of anticoagulation or with persistent symptoms. CONCLUSIONS Otogenic lateral sinus thrombosis is a rare intracranial complication of otitis media with significantly reduced morbidity and mortality in the modern era of antibiotic treatment, surgical intervention, and anticoagulation therapy. Due to the rarity of this condition today, the recommended extent of surgical intervention and need for routine anticoagulation are unclear, and requires further data to determine definitively.

Noise-induced hearing loss: A recreational noise perspective

Purpose of reviewThis review will discuss the real-world risk factors involved in noise-induced hearing loss as a result of common and popular recreational activities prone to mid and high levels of noise exposure. Although there are currently no interventional measures available to reverse or mitigate preexisting hearing loss from noise, we discuss the vital importance of hearing loss prevention from noise exposure avoidance and reduction. Recent findingsDespite a seeming understanding of the effects of noise exposure from various recreational activities and devices, a large percentage of the general public who is at risk of such noise-induced hearing loss still chooses to refrain from using hearing protection instruments. SummaryWhile occupational exposures pose the greatest traditional risk to hearing conservation in selected workers, recreational risk factors for noise-induced hearing loss may be more insidious in overall effect given the indifferent attitude of much of the general public and particularly our youths toward hearing protection during recreational activities. Active counseling regarding the consequences of excessive noise exposure and the potential benefits to hearing from usage of hearing protection instruments is critical to providing best possible care in the hearing health professions.

Novel techniques for the diagnosis of Ménière's disease

Purpose of reviewThis review will consider the newly developed and emerging diagnostic techniques with real or potential clinical application to the diagnosis of Ménières disease. Recent findingsSeveral new diagnostic modalities have been introduced, which have the potential to help diagnose endolymphatic hydrops. These include cervical and ocular vestibular evoked myogenic potentials, cochlear hydrops analysis masking procedures, and three-dimensional fluid-attenuated inversion recovery MRI following intratympanic instillation of gadolinium. SummaryDiagnosis of Ménières disease has classically been of a clinical rather than a procedural nature. Despite the many recent advances in diagnostic testing which show potential applicability for aiding in diagnosis of Ménières disease, each has limitations which prevent immediate utility. For now, Ménières disease remains best diagnosed through the standard American Academy of Otolaryngology – Head and Neck Surgery clinical inclusionary and exclusionary criteria.