The Influence of Cognitive Factors on Outcomes with Frequency Lowering

 IntroductionSince frequency lowering technology has become commercially available in modern digital hearing aids, researchers have set out to determine what benefits this technology could provide hearing-impaired patients. There is an abundance

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Understanding and Treating Severe and Profound Hearing Loss

Oticon has a history of creating excellent solutions for patients with severe-to-profound hearing loss. With the release of Oticon Dynamo, Sensei Super Power, and the Plus Power products in our performance line categories, we have again raised the ba

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Beyond what the eye can see.

Beyond what the eye can see.

Surv Ophthalmol. 2016 Feb 24;

Authors: Ahmad KE, Fraser CL, Sue CM, Barton JJ

Abstract
A 45 year old woman presented with acute sequential optic neuropathy resulting in bilateral complete blindness. No significant visual recovery occurred. Past medical history was relevant for severe pre-eclampsia with resultant renal failure, diabetes mellitus, and sudden bilateral hearing loss when she was. There was a family history of diabetes mellitus in her mother. Testing for common causes of bilateral optic neuropathy did not reveal a diagnosis for her illness. The maternal history of diabetes, and personal history of diabetes and deafness prompted testing for mitochondrial disease. The three primary mitochondrial DNA mutations responsible for Leber Hereditary Optic Neuropathy (LHON), but the patient was subsequently found to have a disease causing mitochondrial DNA mutation, m.13513G>A. The case illustrates the importance of early testing for mitochondrial disease, and demonstrates that LHON like presentations may be missed if testing is limited to the three primary mutations.

PMID: 26921807 [PubMed - as supplied by publisher]

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Validity and repeatability of three in-shoe pressure measurement systems

Publication date: Available online 28 February 2016
Source:Gait & Posture
Author(s): Carina Price, Daniel Parker, Christopher Nester
In-shoe pressure measurement devices are used in research and clinic to quantify plantar foot pressures. Various devices are available, differing in size, sensor number and type; therefore accuracy and repeatability. Three devices (Medilogic, Tekscan and Pedar) were examined in a 2 day x 3 trial design, quantifying insole response to regional and whole insole loading. The whole insole protocol applied an even pressure (50-600kPa) to the insole surface for 0-30seconds in the Novel TruBlue™ device. The regional protocol utilised cylinders with contact surfaces of 3.14 and 15.9cm² to apply pressures of 50 and 200kPa. The validity (% difference and Root Mean Square Error: RMSE) and repeatability (Intra-Class Correlation Coefficient: ICC) of the applied pressures (whole insole) and contact area (regional) were outcome variables. Validity of the Pedar system was highest (RMSE 2.6kPa; difference 3.9%), with the Medilogic (RMSE 27.0kPa; difference 13.4%) and Tekscan (RMSE 27.0kPa; difference 5.9%) systems displaying reduced validity. The average and peak pressures demonstrated high between-day repeatability for all three systems and each insole size (ICC≥0.859). The regional contact area % difference ranged from -97 to +249%, but the ICC demonstrated medium to high between-day repeatability (ICC≥0.797). Due to the varying responses of the systems, the choice of an appropriate pressure measurement device must be based on the loading characteristics and the outcome variables sought. Medilogic and Tekscan were most effective between 200-300kPa; Pedar performed well across all pressures. Contact area was less precise, but relatively repeatable for all systems.



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HEI-OC1 Cells as a Model for Investigating Drug Cytotoxicity

Publication date: Available online 27 February 2016
Source:Hearing Research
Author(s): Gilda Kalinec, Pru Thein, Channy Park, Federico Kalinec
The House Ear Institute–Organ of Corti 1 (HEI-OC1) is one of the few, and arguable the most used, mouse auditory cell line available for research purposes. Originally proposed as an in vitro system for screening of ototoxic drugs, it has been used to investigate, among other topics, apoptotic pathways, autophagy and senescence, mechanism of cell protection, inflammatory responses, cell differentiation, effects of hypoxia, oxidative and endoplasmic reticulum stress, and expression of molecular channels and receptors. However, the use of different techniques with different goals resulted in apparent contradictions on the actual response of these cells to some specific treatments. We have now performed studies to characterize the actual response of HEI-OC1 cells to a battery of commonly used pharmacological drugs. We evaluated cell toxicity, apoptosis, viability, proliferation, senescence and autophagy in response to APAP (acetaminophen), cisplatin, dexamethasone, gentamicin, penicillin, neomycin, streptomycin, and tobramycin, at five different doses and two time-points (24 and 48 hours), by flow cytometry techniques and caspase 3/7, MTT, Cytotoxicity, BrdU, Beclin1, LC3 and SA-β-galactosidase assays. We also used HEK-293 and HeLa cells to compare some of the responses of these cells with those of HEI-OC1. Our results indicate that every cell line responds to the each drug in a different way, with HEI-OC1 cells showing a distinctive sensitivity to at least one of the mechanisms under study. Altogether, our results suggest that the HEI-OC1 might be a useful model to investigate biological responses associated with auditory cells, including auditory sensory cells, but a careful approach would be necessary at the time of evaluating drug effects.



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Human Audiometric Thresholds do not Predict Specific Cellular Damage in the Inner Ear

Publication date: Available online 27 February 2016
Source:Hearing Research
Author(s): Lukas D. Landegger, Demetri Psaltis, Konstantina M. Stankovic
IntroductionAs otology enters the field of gene therapy and human studies commence, the question arises whether audiograms – the current gold standard for the evaluation of hearing function – can consistently predict cellular damage within the human inner ear and thus should be used to define inclusion criteria for trials. Current assumptions rely on the analysis of small groups of human temporal bones post mortem or from psychophysical identification of cochlear “dead regions” in vivo, but a comprehensive study assessing the correlation between audiometric thresholds and cellular damage within the cochlea is lacking.MethodsA total of 131 human temporal bones from 85 adult individuals (ages 19-92 years, median 69 years) with sensorineural hearing loss due to various etiologies were analyzed. Cytocochleograms – which quantify loss of hair cells, neurons, and strial atrophy along the length of the cochlea – were compared with subjects’ latest available audiometric tests prior to death (time range 5 hours to 22 years, median 24 months). The Greenwood function and the equivalent rectangular bandwidth were used to infer, from cytocochleograms, cochlear locations corresponding to frequencies tested in clinical audiograms. Correlation between audiometric thresholds at clinically tested frequencies and cell type-specific damage in those frequency regions was examined by calculating Spearman’s correlation coefficients.ResultsSimilar audiometric profiles reflected widely different cellular damage in the cochlea. In our diverse group of patients, audiometric thresholds tended to be more influenced by hair cell loss than by neuronal loss or strial atrophy. Spearman’s correlation coefficient across frequencies was at most 0.7 and often below 0.5, with 1.0 indicating perfect correlation.ConclusionsAudiometric thresholds do not predict specific cellular damage in the human inner ear. Our study highlights the need for better non- or minimally-invasive tools, such as cochlear endoscopy, to establish cellular-level diagnosis and thereby guide therapy and monitor response to treatment.



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