Self-Assessment of Cochlear Health by New Cochlear Implant Recipients: Daily Impedance, Electrically Evoked Compound Action Potential and Electrocochleography Measurements Over the First Three Postoperative Months.

Hypotheses: In newly implanted cochlear implant (CI) users, electrically evoked compound action (eCAPs) and electrocochleography (ECochGs) will remain stable over time. Electrode impedances will increase immediately postimplantation due to the initial inflammatory response, before decreasing after CI switch-on and stabilizing thereafter.

Background: The study of cochlear health (CH) has several applications, including explaining variation in CI outcomes, informing CI programming strategies, and evaluating the safety and efficacy of novel biological treatments for hearing loss.

Classification of Acoustic Hearing Preservation After Cochlear Implantation Using Electrocochleography.

The objective to preserve residual hearing during cochlear implantation has recently led to the use of intracochlear electrocochleography (ECochG) as an intraoperative monitoring tool. Currently, a decrease in the amplitude of the difference between responses to alternating-polarity stimuli (DIF response), predominantly reflecting the hair cell response, is used for providing feedback. Including other ECochG response components, such as phase changes and harmonic distortions, could improve the accuracy of surgical feedback.

Self-assessment of cochlear health by cochlear implant recipients.

Recent technological advances in cochlear implant (CI) telemetry have enabled, for the first time, CI users to perform cochlear health (CH) measurements through self-assessment for prolonged periods of time. This is important to better understand the influence of CH on CI outcomes, and to assess the safety and efficacy of future novel treatments for deafness that will be administered as adjunctive therapies to cochlear implantation. We evaluated the feasibility of using a CI to assess CH and examined patterns of electrode impedances, electrically-evoked compound action potentials (eCAPs) and electrocochleography (ECochGs), over time, in a group of adult CI recipients.

The development and clinical use of the Guy's and St Thomas' quality of life questionnaire (GAST) for adult cochlear implant patients.

Objectives: To Review the benefit of the GAST questionnaire (Tilston, S. 2003. Assessing the quality of life in adult cochlear implant users.

Establishing Reproducibility and Correlation of Cochlear Microphonic Amplitude to Implant Electrode Position Using Intraoperative Electrocochleography and Postoperative Cone Beam Computed Tomography.

Objectives: The primary objective of this study was to establish the reproducibility of cochlear microphonic (CM) recordings obtained from a cochlear implant (CI) electrode contact during and immediately after insertion. This was achieved by evaluating the insertion angle and calculating the position of the apical electrode contact during insertion, using postoperative cone beam computed tomography (CBCT). The secondary objective was to create individualized patient maps of electrode contacts located within acoustically sensitive regions by correlating the CM amplitude to the electrode position determined using CBCT.

The Influence of Hearing Aids on Balance Control: A Systematic Review.

Aim: To assess the current opinion on the effects of hearing loss treatment by hearing aids (HAs) and the benefits of HA use on imbalance.

Methods: PRISMA-compliant systematic review was done, including observational studies in patients affected by mild to severe sensorineural hearing loss with HAs, investigating the benefits of HAs on balance. Electronic searches were performed through Medline, Cochrane, Embase, Web of Science, and Scopus.

Longitudinal economic analysis of Bonebridge 601 versus percutaneous bone-anchored hearing devices over a 5-year follow-up period.

Objectives: Percutaneous bone-anchored hearing devices (pBAHDs) are the most commonly used bone conduction implants (BCI). Concerns surround the long-term complications, notably skin-related, in patients with percutaneous abutments. The active transcutaneous BCI Bonebridge system can help avoid some of these pitfalls but is often considered a second-line option due to various factors including perceived increased overall costs.

2D FT-ICR MS of Calmodulin: A Top-Down and Bottom-Up Approach.

Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry (2D FT-ICR MS) allows data-independent fragmentation of all ions in a sample and correlation of fragment ions to their precursors through the modulation of precursor ion cyclotron radii prior to fragmentation. Previous results show that implementation of 2D FT-ICR MS with infrared multi-photon dissociation (IRMPD) and electron capture dissociation (ECD) has turned this method into a useful analytical tool. In this work, IRMPD tandem mass spectrometry of calmodulin (CaM) has been performed both in one-dimensional and two-dimensional FT-ICR MS using a top-down and bottom-up approach.

Two-Dimensional Mass Spectrometry for Proteomics, a Comparative Study with Cytochrome c.

Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry (2D FT-ICR MS) allows the correlation between precursor and fragment ions in tandem mass spectrometry without the need to isolate the precursor ion beforehand. 2D FT-ICR MS has been optimized as a data-independent method for the structural analysis of compounds in complex samples. Data processing methods and denoising algorithms have been developed to use it as an analytical tool.

Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry is a data-independent analytical method that records the fragmentation patterns of all the compounds in a sample. This study shows the implementation of atmospheric pressure photoionization with two-dimensional (2D) Fourier transform ion cyclotron resonance mass spectrometry. In the resulting 2D mass spectrum, the fragmentation patterns of the radical and protonated species from cholesterol are differentiated.

Does deamidation cause protein unfolding? A top-down tandem mass spectrometry study.

Deamidation is a nonenzymatic post-translational modification of asparagine to aspartic acid or glutamine to glutamic acid, converting an uncharged amino acid to a negatively charged residue. It is plausible that deamidation of asparagine and glutamine residues would result in disruption of a proteins' hydrogen bonding network and thus lead to protein unfolding. To test this hypothesis Calmodulin and B2M were deamidated and analyzed using tandem mass spectrometry on a Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS).

Unexpected crosslinking and diglycation as advanced glycation end-products from glyoxal.

Glyoxal-derived advanced glycation end-products (AGEs) are formed in physiological systems affecting protein/peptide function and structure. These AGEs are generated during aging and chronic diseases such as diabetes and are considered arginine glycating agents. Thus, the study of glyoxal-derived AGEs in lysine residues and amino acid competition is addressed here using acetylated and non-acetylated undecapeptides, with one arginine and one lysine residue available for glycation.

Improved optimization of the Fourier transform ion cyclotron resonance mass spectrometry phase correction function using a genetic algorithm.

Rationale: Fourier Transform Ion Cyclotron Resonance mass spectra exhibit improved resolving power, mass accuracy and signal-to-noise ratio when presented in absorption mode; a process which requires calculation of a phase correction function. Mass spectrometric images can contain many thousands of pixels; hence methods of decreasing the time required to solve for a phase correction function will result in significant improvements in this application.

Methods: A genetic algorithm approach for optimizing the phase correction function has been developed and compared with a previously described convergent iteration technique.

The occurrence of a deficit in contextual fear extinction in adult amyloid-over-expressing TASTPM mice is independent of the strength of conditioning but can be prevented by mild novel cage stress.

In the amyloid over-expressing TASTPM mouse model of Alzheimer's disease, impaired contextual fear memory occurs early, and is preceded, at 4 months of age, by a deficit in extinction of contextual fear that is resistant to improvement by repeated mild novel cage stress. The first aim of this study was thus to establish whether the extinction deficit could be prevented if the novel cage procedure was applied prior to its onset. The second aim was to establish whether the occurrence of the extinction deficit was dependent on the robustness of the conditioning protocol.

Levels of [(3)H]pirenzepine binding in Brodmann's area 6 from subjects with schizophrenia is not associated with changes in the transcription factor SP1 or BACE1.

Decreased muscarinic M1 receptor (CHRM1) mRNA has been reported in Brodmann's area (BA) 6 from subjects with schizophrenia. We have extended this study by measuring levels of CHRM1 ([(3)H]pirenzepine binding), CHRM3 ([(3)H]4-DAMP binding), the transcription factor SP1 and the CHRM1 downstream target beta-site APP-cleaving enzyme 1 (BACE1) in BA 6 from 19 subjects with schizophrenia and 19 control subjects. Radioligand binding was quantified using either in situ radioligand binding with autoradiography or, in cohorts of 10 control subjects and 10 subjects with schizophrenia, membrane enriched fraction (MEF) CNS ([(3)H]pirenzepine binding only).