Models to predict positive and negative effects of cochlear implantation on tinnitus

Objectives: The effect of cochlear implantation on tinnitus is heterogeneous: implantation does not always reduce tinnitus and may even worsen tinnitus. Therefore, it is important to know which factors influence the consequences of cochlear implantation for tinnitus. To date, no consensus has been reached regarding the factors that influence tinnitus. This study aimed to create prognostic models, using binary logistic regression analyses to predict positive or negative changes in tinnitus after cochlear implantation. Methods: For this study we retrospectively sent two questionnaire packages to 117 cochlear implant patients. Results: In the binary logistic regression analyses of the responses to the questionnaires, it was not possible to create a significant model to predict a positive effect of cochlear implantation on tinnitus. However, a negative effect of cochlear implantation on tinnitus was predictable, using a backward stepwise selection method in a model including the Abbreviated Profile of Hearing Aid Benefit (APHAB) and Tinnitus Handicap Questionnaire (THQ) (P < .001, Nagelkerke R2 = 0.529). Conclusions: Our results suggest that the lower the preoperative tinnitus handicap and the preoperative hearing handicap, the higher the chance that cochlear implantation will worsen tinnitus. More research needs to be done, preferable in a big prospective study, to make this model instrumental for clinical decision making and preoperative patient counselling. However, our results might suggest that preoperative THQ and APHAB screening could be meaningful. Especially in patients who are afraid to develop tinnitus or tinnitus worsening as complication of cochlear implantation. Level of Evidence: 4

NetIbis: An Efficient and Dynamic Communication System for Heterogeneous Grids

Grids are more heterogeneous and dynamic than traditional parallel or distributed systems, both in terms of processors and of interconnects. A grid communication system must handle many issues: first, it must run on networks that are not yet determined when the application is launched, including user-space interconnects; second, it must transparently run on different networks at the same time; third, it should yield performance close to that of specialized communication systems. In this paper, we present NetIbis, a new Java communication system that provides a uniform interface for any underlying intercluster or intracluster network. NetIbis solves the heterogeneity issues posed by Grid computing by dynamically constructing network protocol stacks out of drivers, self-contained building blocks for flexible configuration, with limited functionality per driver. We describe the design and implementation of the major NetIbis drivers for serialization, multicast, reliability, and various underlying networks. We also describe various optimizations for performance, like layer collapsing for the GM driver. We evaluate the performance of NetIbis on several platforms, including a European grid

Changes in Tinnitus by Cochlear Implantation:A Parametric Study of the Effect of Single-Electrode Stimulation

Introduction: While cochlear implantation may have a positive effect on tinnitus, it is not effective in reducing tinnitus in all patients. This may be due to different patients requiring different strategies of electrical stimulation in order to obtain a positive effect on tinnitus. It is, therefore, important to identify the most effective stimulation strategies to reduce tinnitus. The simplest possible strategy is stimulation by only one electrode. In this study, we investigated tinnitus suppression by electrical stimulation via a single electrode of the cochlear implant. Methods: We performed a listening experiment in 19 adult participants, who had received a unilateral cochlear implant (CI) because of severe bilateral hearing loss. All of these patients had indicated that they suffered from tinnitus. During a 300-s interval, patients listened to blocks of single-electrode stimulation and rated the loudness of the stimulus and any effects on their tinnitus. The 300-s interval included a block of single-electrode stimulation (duration 120 s). In consecutive intervals, the stimulus differed in its cochlear location (basal or apical), its pulse rate (720 or 725 Hz, 1,200 Hz, and 2,400 or 2,320 Hz), and amplitude (just above threshold or equivalent to moderate loudness). Thus, 2 × 3 × 2 = 12 stimulus conditions were tested in each participant, and each condition was presented only once. During the experiment, the participants promptly rated the loudness of the stimuli and the loudness of their tinnitus on a Visual Analogue Scale (10-point VAS). Results: Significantly more tinnitus reduction was observed with stimuli at a moderate intensity level (30%) compared to stimuli at near-threshold level (18%) ([1, N = 222] = 14.115, p < 0.01). No significant differences in tinnitus levels resulted from the different pulse rates and stimulation sites. Eight participants reported an increase of tinnitus loudness under at least one stimulus condition. Changes in tinnitus loudness were generally minor, and never exceeded 3 points on the VAS. The overall effect of cochlear implantation on tinnitus, that is, the effect with full-array stimulation, was not correlated with the effectiveness of the single-electrode stimulation on tinnitus. Conclusion: In conclusion, the effect of single-electrode stimulation on tinnitus is relatively insignificant in comparison to the effect of full-array stimulation. However, in some individual cases, sustained single-electrode stimulation may be beneficial for tinnitus management

A Prospective Study of the Effect of Cochlear Implantation on Tinnitus

Previous studies have shown diverse and sometimes even contrary results concerning the effect of cochlear implantation on tinnitus and the factors that can influence this effect. The aim of this prospective questionnaire study was to determine the effects of cochlear implantation on tinnitus and explore which factors can influence the effect of cochlear implantation on tinnitus. Forty-four of the patients implanted in our hospital returned 2 questionnaire packages, i.e., one before the cochlear implantation and one 6 months after implantation. Before implantation, 66% of the patients experienced tinnitus. This study shows that cochlear implantation could help to reduce tinnitus and the tinnitus handicap in at least 28% of the patients with preoperative tinnitus. In 72% of the patients the tinnitus remained after implantation. None of the patients developed tinnitus after implantation. A shorter duration of tinnitus prior to implantation, a more fluctuating type of tinnitus, a higher tinnitus handicap prior to implantation, and a round-window surgical approach might have a positive influence on the effect of cochlear implantation on tinnitus, but further research is necessary to confirm these findings. (C) 2019 The Author(s) Published by S. Karger AG, Basel</p

A Bast-like valve in the pigeon?

The first description of the presence of a utriculo-endolymphatic valve in human fetuses was given by Bast in 1928. Since then this valve-like structure is called Bast’s valve. Its exact function has not yet been established. The general opinion is that it has a protective function by having the possibility to separate the superior endolymphatic compartments of the labyrinth from the inferior compartment. Phylogenetically seen birds are the first vertebrates with a cochlear duct and a distinct inferior and superior part of the labyrinth. A structure in the pigeon inner ear, resembling Bast’s valve in mammals, is described

The Relation Between Tinnitus and a Neurovascular Conflict of the Cochleovestibular Nerve on Magnetic Resonance Imaging

Introduction:Magnetic resonance (MR) imaging is often used in diagnostic evaluation of tinnitus patients. Incidental findings like a neurovascular conflict (NVC) in the cerebellopontine angle are often found; however, the diagnostic value of this finding remains unclear. The aim of this study is to investigate whether the type or degree of compression of the vestibulocochlear nerve is of diagnostic value in patients with a NVC.Methods:A retrospective study was performed in 111 tinnitus patients with available MR imaging between 2013 and 2015. Clinical and audiometric variables were gathered and MR imaging was reevaluated by two neuroradiologists. NVCs were analyzed using a grading system based on previous research by Sirikci et al.Results:In total, 220 ears were available for assessment. In patients with unilateral tinnitus a loop compression and an indentation of the cochleovestibular nerve were more frequent than in patients with bilateral tinnitus. However, there was no significant difference in distribution of the type of compression between tinnitus and nontinnitus ears. Patient with unilateral tinnitus had a significantly higher degree of hearing loss in the symptomatic ear, compared with the asymptomatic ear and with the bilateral tinnitus group. Also, it was found that the degree of hearing loss did not differ between the various types of compression.Conclusion:This study did not find a diagnostic value of specific types of compression in patients with a NVC. Although the distribution of NVC classification was different in patients with unilateral and bilateral tinnitus, there was no definite relation between the type of NVC and the presence of ipsilateral tinnitus. Also, the degree of hearing loss was not related to specific types of NVC