A Survey on Application Specific Processor Architectures for Digital Hearing Aids

On the one hand, processors for hearing aids are highly specialized for audio processing, on the other hand they have to meet challenging hardware restrictions. This paper aims to provide an overview of the requirements, architectures, and implementations of these processors. Special attention is given to the increasingly common application-specific instruction-set processors (ASIPs). The main focus of this paper lies on hardware-related aspects such as the processor architecture, the interfaces, the application specific integrated circuit (ASIC) technology, and the operating conditions. The different hearing aid implementations are compared in terms of power consumption, silicon area, and computing performance for the algorithms used. Challenges for the design of future hearing aid processors are discussed based on current trends and developments

Ergebnisse der kombinierten bilateralen Medialisrücklagerung mit Fadenoperation bei kindlichem Innenschielen

1. Hintergrund Schielen, insbesondere das frühkindliche Innenschielen, ist eine relativ häufige Störung des Sehens, die unter Umständen – besonders bei großem Schielwinkel – erhebliche Auswirkungen für den betroffenen Patienten haben kann. Die operative Behandlung der frühkindlichen Esotropie ist nicht einheitlich. Es werden vor allem die beidseitige Medialis- Rücklagerung (BMR), die kombinierte Konvergenzoperation, zum Teil kombiniert mit kontralateraler Medialis-Rücklagerung oder auch mit anderen Verfahren angewendet. Außerdem ist die beidseitige Medialis- Rücklagerung mit Myopexie (BMRF) eine Möglichkeit der operativen Versorgung. In der vorliegenden Studie werden die Ergebnisse der BMRF evaluiert und mit anderen Studien verglichen. 2. Patienten und Methoden Es erfolgte eine retrospektive Auswertung der Akten von Patienten, die von 1997 bis 2011 in der Universitätsaugenklinik Gießen als Ersteingriff eine BMRF mit oder ohne zusätzliche Obliquus-Chirurgie wegen frühkindlicher Esotropie erhielten. Erfasst wurden die präoperativen, sowie die 1 Woche und 3 Monate postoperativen Schielwinkel im simultanen (manifester Schielwinkel) und alternierenden (maximaler Schielwinkel) Prismenabdecktest bei Geradeausblick in Ferne und Nähe. Außerdem wurde das Alter zum Zeitpunkt der Operation, das Geschlecht, die in Zykloplegie mittels Skiaskopie oder Refraktometrie ermittelte Refraktion, der bestkorrigierte postoperative Visus, bestimmt mit Landolt-Ringen und bei Kleinkindern mit Lea-Symbolen, die postoperative Binokularfunktion im Bagolini, Titmus-, Lang-, oder TNO-Test, die Operationsstrecken (Faden und Medialisrücklagerung) und die axiale Bulbuslänge der operierten Augen erfasst. 3. Ergebnisse 161 (76 männlich, 85 weiblich) Kinder wurden von 1997-2011 in Giessen erstmalig einer BMRF unterzogen und hatten kein Orbitatrauma in der Vorgeschichte, erfüllten also kein Ausschlusskriterium. Es wurden nur die Daten der 142 Kinder (69 männlich, 73 weiblich) ausgewertet, die zur Kontrolle nach 3 Monaten erschienen waren. Im Folgenden sind die Mediane und in Klammern die 10%- und 90%- Quantile angegeben: Die Kinder waren 58,52 Monate (22,11; 86,63) alt, das sphärische Äquivalent (Refraktion in Zykloplegie) betrug 2,75dpt (0,5; 5,50), der Visus beider Augen präoperativ 0,8 (0,32; 1,00), 3 Monate postoperativ 0,8 (0,32; 1,00). Der präoperative maximale Schielwinkel betrug in der Nähe 28° (20,0; 44,9), in der Ferne 18° (12,0; 36,0), der manifeste in der Nähe 28° (18,0; 44,9), in der Ferne 18° (5,0; 36,0). 1 Woche postoperativ betrug der maximale Schielwinkel in der Nähe 4,0° (-3,1; 10,0), in der Ferne 1,00° (-6,0; 6,0), der manifeste Winkel in der Nähe 2,0° (-3,0; 10,0) und in der Ferne 0,0° (-5,0; 6,0), wobei 94 (66,2%) in der Nähe auf kleiner gleich ±5° korrigiert waren, in der Ferne 117 (82,4%), beim manifesten Nahschielwinkel 105 (73,9%), beim manifesten Fernschielwinkel 121 (85,2%). Nach 3 Monaten lag der maximale Schielwinkel in der Nähe bei 3,0° (-5,0; 10,0), in der Ferne bei 0,00° (-10,0; 7,9), der manifeste Schielwinkel in der Nähe bei 1,0° (-5,0; 10,0) und in der Ferne bei 0,0° (-8,0; 5,0). Hier waren 101 (71,1%) Kinder in der Nähe und 120 (84,5%) in der Ferne auf Maximalschielwinkel im Betrag von kleiner gleich ±5° korrigiert. Manifeste Restschielwinkel im Betrag von kleiner gleich ±5° wurden in der Nähe bei 113 (79,6%), in der Ferne bei 127 (89,4%) Kindern erreicht. 3 Monate postoperativ zeigten 18 Kinder (12,7%) einseitige Exklusion bzw. Suppression, 87 (61,3%) hatten Simultansehen im Bagolini-Lichtschweiftest, 10 (7,0%) Titmus-Fliege-Test positiv, 13 (9,2%) Titmus-Ringe oder -Tiere positiv und 4 Kinder (2,8%) erkannten die Random-Dot- Stereogramme im Lang- oder TNO-Stereotest. Die axiale Bulbuslänge betrug 21,30mm (20,0; 22,6). Die Myopexieabstände vom Hornhautrand betrugen 18,5mm (18,5; 19,0), die Strecke der Rücklagerung betrug 4,0mm (3,0; 5,0). 4. Schlussfolgerung Bei frühkindlichem Innenschielen mit großen Schielwinkeln konnte der Schielwinkel durch eine beidseitige Medialis-Rücklagerung mit Myopexie in ca. drei Viertel der Fälle in einem Schritt auf einen Betrag von kleiner gleich 5° korrigiert werden, ca. zwei Drittel gewinnen so zumindest ein binokulares Simultansehen, teilweise auch Stereosehen. Allerdings erfordert der Eingriff einen erfahrenen Operateur. Auch eventuelle Revisionseingriffe sind technisch anspruchsvoller, als nach einer großstreckigen beidseitigen Medialisrücklagerung ohne Myopexie.1. Background Strabismus, particularly esotropia in childhood, is a wide spread disorder which can have, under circumstances huge effects on affected patients, especially those with large angles of strabismus. Surgical methods are not uniform. Bilateral medial rectus muscle recession (BMR), combined recess and resect surgery, also combined with contralateral medial rectus recession or with other procedures are used. Alternatively, bilateral medial rectus recession with posterior fixation suture (BMRF) can be used. In this study the results of the BMRF should be evaluated and compared to other studies. 2. Patients and Methods We performed a retrospective analysis of the records of patients who received BMRF for infantile esotropia as a first surgery, at the University hospital Gießen between 1997 and 2011, casting with or without additional obliquus surgery. The following data were recorded: Patients´ age and gender, preoperative as well as 1 week and 3 months postoperative angles of strabismus measured in the simultaneous (manifest angle) and alternating (maximum angle) prism cover test in the primary gaze direction at 5m (distance) and 0.3m (near), cycloplegic refractive error as measured by retinoscopy or auto-refractometry, the best corrected postoperative visual acuity using the Landolt-C or with small children Lea symbols, postoperative binocular vision (Bagolini-, Titmus-, Lang- and TNO-tests), the amount of bimedial rectus recession and retro-equatorial myopexy, and the axial length of the eyes. 3. Results 161 (76 male, 85 female) children received a BMRF as a first surgery and didn´t have an anamnestic ocular trauma. Only those 142 children (69 male, 73 female) with available 3-month followup data were evaluated. The children were 58.52 months (22.11; 86.63) old. The spherical equivalent was 2.75dpt (0.5, 5.50). Visual acuity of both eyes was 0.8 (0.32; 1.00) both before and 3 months after surgery. The preoperative maximum squint angle was 28° (20.0; 44.9) at near and 18° (12.0; 36.0) at distance. Manifest angles were 28° (18.0; 44.9) at near and 18° (5.0; 36.0) at distance. 1 week postoperatively the maximum squint angles were 4.0° (-3.1, 10.0) and 1.0° (-6.0; 6.0) and the manifest squint angles were 2.0° (-3.0, 10.0) and 0.0° (-5.0; 6.0), respectively. A residual absolute squint angle less than or equal to ±5° was noted in 94 children (66.2%) at near and 117 children (82.4%) at distance. The absolute manifest squint angle was less than or equal to ±5° in 105 children (73.9%) at near and 121 children (85.2%) at distance. After 3 months, the absolute maximum squint angles were 3.0° (-5.0, 10.0) and 0.0° (-10.0, 7.9) and the absolute manifest squint angles were 1.0° (-5.0, 10.0) and 0.0° (-8.0; 5.0), respectively. 101 (71.1%) children had an absolute maximum angle less than or equal to ±5° at near and 120 (84.5%) at distance. Absolute manifest residual squint angles less than or equal to ±5° were achieved in 113 (79. 6%) and 127 (89.4%) children, respectively. 3 months postoperatively 18 children (12.7%) had monocular exclusion or suppression, 87 (61.3%) showed simultaneous binocular vision in the Bagolini striated glasses test. Ten children (7.0%) gained stereopsis in the Titmus-fly test, 13 (9.2 %) for Titmus-rings or -pets and 4 children (2.8%) recognized the random dot stereograms of the Lang- or TNO-stereo tests. The axial bulbus length was 21.3mm (20.0; 22.6). The myopexy was placed at 18.5mm (18.5; 19.0) from the corneal limbus, the amount of recession was 4.0mm (3.0; 5.0). 4. Conclusion In this study of large infantile esotropia about three quarters of the cases could be corrected by bimedial rectus recession with retroequatorial myopexy and about two-thirds of them achieved at least simultaneous vision, some of them even stereopsis. However, the method requires an experienced surgeon. Following procedures are also technically more demanding than a bilateral medial rectus recession

Numerical investigation of transient, low-power metal vapour discharges occurring in near limit ignitions of flammable gas

This article presents an investigation of a transient (30 {\mu}s - 5 ms) electrical discharge in metal vapour with low voltage (< 50 V) and current (< 1 A), drawn between two separating electrodes. Discharges of this type are rarely studied, but are important in electrical explosion safety, as they can ignite flammable gasses. An empirical model is developed based on transient recordings of discharge voltages and currents and high speed broadband image data. The model is used for predicting the electrical waveforms and spatial power distribution of the discharge. The predicted electrical waveforms show good accuracy under various scenarios. To further investigate the underlying physics, the model is then incorporated into a simplified 3-D gas dynamics simulation including molecular diffusion, heat transfer and evaporation of metal from the electrode surface. The local thermodynamic equilibrium (LTE) assumption is next used to calculate electrical conductivity from the simulated temperature fields, which in turn is integrated to produce electrical resistance over time. This resistance is then compared to that implied by the voltage and current waveforms predicted by the empirical model. The comparison shows a significant discrepancy, yielding the important insight that the studied discharge very likely deviates strongly from LTE

KAVUAKA : Chip Design für digitale Hörhilfen

Am Institut für Mikroelektronische Systeme (IMS) wird im Rahmen des Exzellenzclusters Hearing4all erforscht, wie Signalverarbeitung-Chips für digitale Hörgerätesystemen anhand von komplexen Hörgerätealgorithmen konzipiert und optimiert werden können. Ziel der Forschung ist es, neuartige Prozessorarchitekturen zu entwickeln, die die geforderte hohe Rechenleistung bereitstellen, gleichzeitig einen sehr geringen Stromverbrauch aufweisen und in kleine Hörgerätegehäuse integriert werden können

Use of IFNγ/IL10 Ratio for Stratification of Hydrocortisone Therapy in Patients With Septic Shock

Large clinical trials testing hydrocortisone therapy in septic shock have produced conflicting results. Subgroups may benefit of hydrocortisone treatment depending on their individual immune response. We performed an exploratory analysis of the database from the international randomized controlled clinical trial Corticosteroid Therapy of Septic Shock (CORTICUS) employing machine learning to a panel of 137 variables collected from the Berlin subcohort comprising 83 patients including demographic and clinical measures, organ failure scores, leukocyte counts and levels of circulating cytokines. The identified theranostic marker was validated against data from a cohort of the Hellenic Sepsis Study Group (HSSG) (n = 246), patients enrolled in the clinical trial of Sodium Selenite and Procalcitonin Guided Antimicrobial Therapy in Severe Sepsis (SISPCT, n = 118), and another, smaller clinical trial (Crossover study, n = 20). In addition, in vitro blood culture experiments and in vivo experiments in mouse models were performed to assess biological plausibility. A low serum IFNγ/IL10 ratio predicted increased survival in the hydrocortisone group whereas a high ratio predicted better survival in the placebo group. Using this marker for a decision rule, we applied it to three validation sets and observed the same trend. Experimental studies in vitro revealed that IFNγ/IL10 was negatively associated with the load of (heat inactivated) pathogens in spiked human blood and in septic mouse models. Accordingly, an in silico analysis of published IFNγ and IL10 values in bacteremic and non-bacteremic patients with the Systemic Inflammatory Response Syndrome supported this association between the ratio and pathogen burden. We propose IFNγ/IL10 as a molecular marker supporting the decision to administer hydrocortisone to patients in septic shock. Prospective clinical studies are necessary and standard operating procedures need to be implemented, particularly to define a generic threshold. If confirmed, IFNγ/IL10 may become a suitable theranostic marker for an urging clinical need

Use of IFNγ/IL10 Ratio for Stratification of Hydrocortisone Therapy in Patients With Septic Shock

Large clinical trials testing hydrocortisone therapy in septic shock have produced conflicting results. Subgroups may benefit of hydrocortisone treatment depending on their individual immune response. We performed an exploratory analysis of the database from the international randomized controlled clinical trial Corticosteroid Therapy of Septic Shock (CORTICUS) employing machine learning to a panel of 137 variables collected from the Berlin subcohort comprising 83 patients including demographic and clinical measures, organ failure scores, leukocyte counts and levels of circulating cytokines. The identified theranostic marker was validated against data from a cohort of the Hellenic Sepsis Study Group (HSSG) (n = 246), patients enrolled in the clinical trial of Sodium Selenite and Procalcitonin Guided Antimicrobial Therapy in Severe Sepsis (SISPCT, n = 118), and another, smaller clinical trial (Crossover study, n = 20). In addition, in vitro blood culture experiments and in vivo experiments in mouse models were performed to assess biological plausibility. A low serum IFNg/IL10 ratio predicted increased survival in the hydrocortisone group whereas a high ratio predicted better survival in the placebo group. Using this marker for a decision rule, we applied it to three validation sets and observed the same trend. Experimental studies in vitro revealed that IFNg/IL10 was negatively associated with the load of (heat inactivated) pathogens in spiked human blood and in septic mouse models. Accordingly, an in silico analysis of published IFNg and IL10 values in bacteremic and non-bacteremic patients with the Systemic Inflammatory Response Syndrome supported this association between the ratio and pathogen burden. We propose IFNg/IL10 as a molecular marker supporting the decision to administer hydrocortisone to patients in septic shock. Prospective clinical studies are necessary and standard operating procedures need to be implemented, particularly to define a generic threshold. If confirmed, IFNg/IL10 may become a suitable theranostic marker for an urging clinical need

Bmp4 Is Essential for the Formation of the Vestibular Apparatus that Detects Angular Head Movements

Angular head movements in vertebrates are detected by the three semicircular canals of the inner ear and their associated sensory tissues, the cristae. Bone morphogenetic protein 4 (Bmp4), a member of the Transforming growth factor family (TGF-β), is conservatively expressed in the developing cristae in several species, including zebrafish, frog, chicken, and mouse. Using mouse models in which Bmp4 is conditionally deleted within the inner ear, as well as chicken models in which Bmp signaling is knocked down specifically in the cristae, we show that Bmp4 is essential for the formation of all three cristae and their associated canals. Our results indicate that Bmp4 does not mediate the formation of sensory hair and supporting cells within the cristae by directly regulating genes required for prosensory development in the inner ear such as Serrate1 (Jagged1 in mouse), Fgf10, and Sox2. Instead, Bmp4 most likely mediates crista formation by regulating Lmo4 and Msx1 in the sensory region and Gata3, p75Ngfr, and Lmo4 in the non-sensory region of the crista, the septum cruciatum. In the canals, Bmp2 and Dlx5 are regulated by Bmp4, either directly or indirectly. Mechanisms involved in the formation of sensory organs of the vertebrate inner ear are thought to be analogous to those regulating sensory bristle formation in Drosophila. Our results suggest that, in comparison to sensory bristles, crista formation within the inner ear requires an additional step of sensory and non-sensory fate specification