Publications by authors named "Roland J"

Objectives: X-linked deafness is a potential etiology of sensorineural hearing loss characterized by bulbous dilatation of the fundus of the internal auditory canal (IAC) and the absence of the bony plates separating the basal turn of the cochlea and IAC. These malformations predispose patients to IAC insertion during cochlear implantation (CI). Our objective is to describe the surgical technique, audiometric and speech performance outcomes in a group of patients with this unique cochlear malformation.

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Objectives/hypothesis: To evaluate the safety and efficacy of acoustic and electric sound processing for individuals with significant residual low-frequency hearing and severe-to-profound high-frequency sensorineural hearing loss.

Study Design: Prospective, single-arm repeated measures, single-subject design.

Methods: Fifty individuals, ≥ 18 years old, with low-frequency hearing and severe high-frequency loss were implanted with the Cochlear Nucleus Hybrid L24 implant at 10 investigational sites.

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Perforating arteries rarely project from the fundus of an aneurysm. We present the case of a 35-year-old woman who was found to have a right posterior communicating artery (PCOM) aneurysm via catheter angiography. Superselective microcatheter angiography revealed that perforating arteries arose from the aneurysm fundus that supplied the anterolateral thalamus.

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Although the preponderance of cerebellopontine angle lesions are schwannomas, focused attention to patient clinical history, imaging studies, and tissue biopsies when indicated will aid in detection of less common lesions that might otherwise be misdiagnosed. This is most critical for pathologies that dictate different management paradigms be undertaken.

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Objective And Importance: Preoperative chronic otitis media (COM) is a risk factor for postoperative infection after cochlear implantation (CI), but its management varies by surgeon. Our case highlights a strategy for implant preservation in a patient with a history of recurrent cochlear implant infection.

Clinical Presentation: A 70-year-old woman with a history of chronic lymphocytic leukemia presented in 2005 with bilateral COM and sensorineural hearing loss meeting CI candidacy.

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Objectives: To examine the variables affecting outcomes for sequential bilateral cochlear implantation patients in the adolescent population.

Study Design: Retrospective chart review at tertiary care center.

Methods: Main outcome measures were open set speech recognition tests at the word (Consonant-Nucleus-Consonant/Phonetically Balanced Kindergarten List Test [CNC/PBK]) and sentence levels in noise (Hearing in Noise Test-Noise [HINT-N]) in different test conditions with respect to the age at first and sequential implantation, as well as the interval between implants.

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Objective: Preservation of residual low-frequency hearing has become a priority in cochlear implantation. The purpose of this study was to compare rates of hearing preservation and effects on performance of loss of low-frequency acoustic hearing with two different length electrodes.

Study Design: Retrospective chart review.

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Objectives: Commercially available cochlear implant systems attempt to deliver frequency information going down to a few hundred Hertz, but the electrode arrays are not designed to reach the most apical regions of the cochlea, which correspond to these low frequencies. This may cause a mismatch between the frequencies presented by a cochlear implant electrode array and the frequencies represented at the corresponding location in a normal-hearing cochlea. In the following study, the mismatch between the frequency presented at a given cochlear angle and the frequency expected by an acoustic hearing ear at the corresponding angle is examined for the cochlear implant systems that are most commonly used in the United States.

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Objective: The aim of this study was to develop a multidimensional metric for assessing quality of life (QoL) in patients with neurofibromatosis type 2 (NF2).

Study Design: Electronically distributed questionnaire.

Setting: University tertiary care hospital, NF2 support groups.

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Objective: To assess whether recombinant growth factor (hGH) therapy has an effect on cochlear implant (CI) performance.

Patients: Two pediatric CI recipients (S1, S2) who underwent treatment with hGH for short stature were identified for review. S1 has bilateral labyrinthine dysplasia and received implants at ages 10 months (right) and 4 years 3 months (left).

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Rab11a is a key component of the apical recycling endosome that aids in the trafficking of proteins to the luminal surface in polarized epithelial cells. Utilizing conditional Rab11a-knockout specific to intestinal epithelial cells, and human colonic epithelial CaCo2-BBE cells with stable Rab11a knockdown, we examined the molecular and pathological impact of Rab11a deficiency on the establishment of apical cell polarity and microvillus morphogenesis. We demonstrate that loss of Rab11a induced alterations in enterocyte polarity, shortened microvillar length and affected the formation of microvilli along the lateral membranes.

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Background: Cochlear implants are the treatment of choice for individuals with severe to profound sensorineural hearing loss. In most cases, the anatomy is normal and the insertion of the electrode-array is straightforward, complete and in the correct position. In the presence of inner-ear malformations, the risk of an intra or extra-cochlear malpositioned electrode-array increases.

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Acoustic startle response (ASR) is a defensive reflex that is largely ignored unless greatly exaggerated. ASR is suppressed after moderate and severe traumatic brain injury (TBI), but the effect of mild TBI (mTBI) on ASR has not been investigated. Because the neural circuitry for ASR resides in the pons in all mammals, ASR may be a good measure of brainstem function after mTBI.

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Objectives/hypothesis: Trauma to intracochlear structures during cochlear implant insertion is associated with poorer hearing outcomes. One way surgeons can influence insertion trauma is by choosing the surgical approach. We seek to compare cochleostomy (CO), peri-round window (PRW), and round window (RW) approaches using a fresh frozen temporal bone model.

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Both landscape structure and population size fluctuations influence population genetics. While independent effects of these factors on genetic patterns and processes are well studied, a key challenge is to understand their interaction, as populations are simultaneously exposed to habitat fragmentation and climatic changes that increase variability in population size. In a population network of an alpine butterfly, abundance declined 60-100% in 2003 because of low over-winter survival.

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Objective: The preferential delayed enhancement of the perilymphatic space enables detection of the non-enhancing endolymphatic hydrops present in patients with Ménière's disease. The aim of this study was to evaluate the diagnostic utility of delayed postcontrast 3D FLAIR images and a color map of fused postcontrast FLAIR and constructive interference steady state (CISS) images in the identification of endolymphatic hydrops in patients with clinically diagnosed Ménière's disease.

Study Design: Case control, blinded study.

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Objective: Is conscious sedation an effective, safe, and efficient anesthetic choice in patients undergoing select neurotologic and otologic procedures?

Study Design: Retrospective case review.

Setting: Tertiary referral center.

Patients: Six patients underwent eight neurotologic procedures including cerebrospinal fluid leak and encephalocele repair, and primary and revision cochlear implant surgery.

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Imidazopyridine 1 was identified from a phenotypic screen against P. falciparum (Pf) blood stages and subsequently optimized for activity on liver-stage schizonts of the rodent parasite P. yoelii (Py) as well as hypnozoites of the simian parasite P.

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Purpose Of Review: To summarize the recent medical literature related to the feasibility of hearing preservation after cochlear implantation and to identify variables that may influence hearing preservation in the implanted ear as well as the hearing perception outcomes.

Recent Findings: The published data provide evidence that hearing preservation in the implanted ear yields significantly higher levels of speech recognition in complex listening environments than having just monaural acoustic hearing. There is ample evidence that hearing preservation is feasible and the reported rate is 50-89% in the low frequencies.

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The medial septum and diagonal band of Broca (MSDB) influence hippocampal function through cholinergic, GABAergic, and glutamatergic septohippocampal neurons. Non-selective damage of the MSDB or intraseptal scopolamine impairs classical conditioning of the eyeblink response (CCER). Scopolamine preferentially inhibits GABAergic MSDB neurons suggesting that these neurons may be an important modulator of delay CCER, a form of CCER not dependent on the hippocampus.

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Microvillus inclusion disease (MVID) is a severe form of congenital diarrhea that arises from inactivating mutations in the gene encoding myosin Vb (MYO5B). We have examined the association of mutations in MYO5B and disruption of microvillar assembly and polarity in enterocytes. Stable MYO5B knockdown (MYO5B-KD) in CaCo2-BBE cells elicited loss of microvilli, alterations in junctional claudins, and disruption of apical and basolateral trafficking; however, no microvillus inclusions were observed in MYO5B-KD cells.

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