The just-noticeable difference in speech-to-noise ratio

Just-noticeable differences (JNDs) have been measured for various features of sounds, but despite its importance to communication, there is no benchmark for what is a just-noticeable—and possibly meaningful—difference in speech-to-noise ratio (SNR). SNR plays a crucial role in speech communication for normal-hearing and hearing-impaired listeners. Difficulty hearing speech in background noise—a poor SNR—often leads to dissatisfaction with hearing-assistance devices. While such devices attempt through various strategies to address this problem, it is not currently known how much improvement in SNR is needed to provide a noticeable benefit. To investigate what is a noticeable benefit, we measured the JND in SNR for both normal-hearing and hearing-impaired listeners. Here, we report the SNR JNDs of 69 participants of varying hearing ability, estimated using either an adaptive or fixed-level procedure. The task was to judge which of the two intervals containing a sentence in speech-spectrum noise presented over headphones was clearer. The level of each interval was roved to reduce the influence of absolute level cues. The results of both procedures showed an average SNR JND of 3 dB that was independent of hearing ability. Further experiments using a subset of normal-hearing listeners showed that level roving does elevate threshold. These results suggest that noise reduction schemes may need to achieve a benefit greater than 3 dB to be reliably discriminable

The just meaningful difference in speech-to-noise ratio

The speech-to-noise ratio (SNR) in an environment plays a vital role in speech communication for both normal-hearing (NH) and hearing-impaired (HI) listeners. While hearing-assistance devices attempt to deliver as favorable an SNR as possible, there may be discrepancies between noticeable and meaningful improvements in SNR. Furthermore, it is not clear how much of an SNR improvement is necessary to induce intervention-seeking behavior. Here we report on a series of experiments examining the just-meaningful difference (JMD) in SNR. All experiments used sentences in same-spectrum noise, with two intervals on each trial mimicking examples of pre- and post-benefit situations. Different groups of NH and HI adults were asked (a) to rate how much better or worse the change in SNR was in a number of paired examples, (b) if they would swap the worse for the better SNR (e.g., their current device for another) or (c) if they would be willing to go to the clinic for the given increase in SNR. The mean SNR JMD based on better/worse ratings (one arbitrary unit) was similar to the just-noticeable difference, approximately 3 dB. However, the mean SNR JMD for the more clinically relevant tasks -- willingness (at least 50% of the time) to swap devices or attend the clinic for a change in SNR -- was 6-8 dB regardless of hearing ability. This SNR JMD of the order of 6 dB provides a new benchmark, indicating the SNR improvement necessary to immediately motivate participants to seek intervention

Survey of highly non-Keplerian orbits with low-thrust propulsion

Celestial mechanics has traditionally been concerned with orbital motion under the action of a conservative gravitational potential. In particular, the inverse square gravitational force due to the potential of a uniform, spherical mass leads to a family of conic section orbits, as determined by Isaac Newton, who showed that Kepler‟s laws were derivable from his theory of gravitation. While orbital motion under the action of a conservative gravitational potential leads to an array of problems with often complex and interesting solutions, the addition of non-conservative forces offers new avenues of investigation. In particular, non-conservative forces lead to a rich diversity of problems associated with the existence, stability and control of families of highly non-Keplerian orbits generated by a gravitational potential and a non-conservative force. Highly non-Keplerian orbits can potentially have a broad range of practical applications across a number of different disciplines. This review aims to summarize the combined wealth of literature concerned with the dynamics, stability and control of highly non-Keplerian orbits for various low thrust propulsion devices, and to demonstrate some of these potential applications

Use of interphase cytogenetics in demonstrating specific chromosomal aberrations in solid tumors new insights in the pathogenesis of malignant melanoma and head and neck squamous cell carcinoma

The detection of structural and numerical chromosomal aberrations is an important part of the characterization of tumors and genetic diseases. The direct demonstration of DNA sequences in interphase nuclei and metaphases by fluorescence in situ hybridization (FISH) has been termed interphase cytogenetics. It has been proven as a powerful technique to detect specific aberrations in a wide variety of cell types, including paraffin-embedded tissue. Nowadays a standard method in leukemia and lymphoma, interphase cytogenetics contributes mainly to the diagnosis in these tumors and helps to classify soft tissue tumors. Therefore FISH is mandatory for the choice of therapy in these tumors. In contrast to the aforementioned, up to now, the value of FISH in solid tumors is mostly limited to pure research and contributes in this way to our understanding of tumor biology. But with the use of paraffin-embedded tissue and the first results obtained, it seems very likely that a direct correlation between histological classification and cytogenetic characteristics of solid tumors can be achieved in the near future. This information might not only provide insights into tumor biology, but could also contribute to a different tumor classification, a sort of risk estimation, where we might predict the possible biological behavior of solid tumors. This could greatly influence further therapeutic decisions thus establishing the FISH technique as an indisputable part in the diagnosis of solid tumors

Bewertung epithelialer Veränderungen des Kehlkopfes mittels konfokaler Laserendomikroskopie

Hintergrund: Die Confocale Laser Endomikroskopie (CLE) ermöglicht eine "Echtzeit-Biopsie" des Epithels im oberen Aerodigestivtrakt. Durch die 1.000-fache Vergrößerung entsprechen die gewonnenen Bilder konventionellen histologischen Schnittbildern. Der Unterschied besteht darin, dass bei der CLE keine Gewebsverletzung entsteht. Es ist bekannt, dass an den Stimmlippen schon geringste invasive Maßnahmen das Risiko einer dauerhaften Schädigung der Stimmqualität bergen können. Die CLE scheint besonders geeignet, non-invasiv eine strukturelle Untersuchung des Epithels des Kehlkopfes vorzunehmen. Ziel dieser Studie war der Nachweis, dass mittels CLE Neubildungen der Larynxschleimhaut von gesundem Epithel differenziert werden können.Material und Methoden: Bei 10 Mikrolaryngoendoskopien wurden mit der "GastroFlex UHD Sonde" (Cellvizio, Mauna Kea Technologies, Paris) Aufnahmen des Larynxepithels durchgeführt. Benigne und maligne Veränderungen der Stimmlippen sowie klinisch gesunde Schleimhaut wurden aufgezeichnet. Zur Verifizierung der Befunde wurden von den Raumforderungen Biopsien entnommen. Die Auswertung der CLE-Aufnahmen erfolgte verblindet durch einen mit der Methode vertrauten HNO-Arzt und einen erfahrenen Pathologen, sowie durch methodisch unerfahrene HNO-Ärzte.Ergebnisse: Ihm Rahmen der Bewertung der CLE-Sequenzen waren alle Untersucher in der Lage, an Hand der Regularität des epithelialen Stomas und der Form der Epithelzellen mit einer hohen Ratewahrscheinlichkeit gesundes Epithel von den Raumforderungen zu unterscheiden. Der erfahrene HNO-Arzt und der Pathologe waren zudem in der Lage, in einem hohen Maß die bösartigen Veränderungen von den gutartigen Läsionen zu unterscheiden.Fazit: Die CLE ist ein geeignetes nicht-invasives Verfahren zur "echtzeit" Diagnostik von Erkrankungen des Stimmlippenepithels. Die Bewertung ist subjektiv und abhängig von der Erfahrung des Untersuchers. Die Bewertungskriterien entsprechen denen der Beurteilung von nativen histologischen Präparaten

Erste Erfahrungen mit dem NBI-System an der HNO-Klinik Erlangen

Einleitung: Das narrow band imaging (NBI) ist ein neues innovatives klinisches bildgebendes Verfahren, welches schmalbandiges Licht mit zwei Wellenlängen (415nm und 540nm) einsetzt. Es wird von Gefäßen absorbiert und von Schleimhaut reflektiert. Der dadurch entstandene Gefäßkontrast ermöglicht eine dezidierte Beurteilung pathologischer Gefäßanomalien, die sich bei malignen Läsionen charakteristisch zeigen. Methode: Ziel der vorliegenden Untersuchung war die routinetaugliche Evaluation von Schleimhautveränderungen, welche unter NBI besser zu erkennen sind als unter Weißlicht. Bei 10 Patienten wurde das NBI-System sowohl mittels flexibler Optik zur gröberen Orientierung als auch eine Kombinationsanwendung mit einem Kontaktendoskop zur genaueren Gefäßdarstellung durchgeführt und mit regulärer Weißlichtendoskopie verglichen.Ergebnisse: Im Vergleich zur Weißlichtendoskopie konnten bei malignen Läsionen Gefäßanomalien mittels NBI besser kontrastiert werden. Durch die zusätzliche Anwendung eines Kontaktendoskopes wurde die Darstellung von Gefäßanomalien (z.B. Loops, Gefäßabbrüche) sehr deutlich. Rückschlüsse auf die Dignität von Gewebsveränderungen lassen sich so vermuten.Schlussfolgerung: Das NBI schafft eine Möglichkeit die klinische Aussagekraft der Endoskopie zu erhöhen und dabei die Biopsieentnahme zu optimieren bzw. die Biopsie-Notwendigkeit besser zu beurteilen. Weitere Studien mit höherer Patientenanzahl und histologischer Korrelation sind nötig um die Ergebnisse zu validieren.Der Erstautor gibt keinen Interessenkonflikt an

Expression of Skp2 and p27KIP1 in naevi and malignant melanoma of the skin and its relation to clinical outcome

Skp2 (S-phase kinase associated protein 2) controls progression from G- to S-phase by promoting the proteolysis of the cyclin dependent kinase inhibitor p27KIP1. Despite the fact that a p27KIP1 decrease has been documented in melanoma progression, the role of Skp2 in these tumours is unknown. We therefore examined by immunohistochemistry the expression of Skp2, p27KIP1 and Ki-67 in 10 naevi (Ns), 15 superficial spreading melanomas (SSMs), 10 nodular melanomas (NMs) and 14 melanoma metastases (Ms). Nuclear Skp2 expression augmented with increasing malignancy (Ns: 1.4%, SSMs: 5.6%, NMs: 17.3%, Ms: 19.1%). In all tumours nuclear Skp2 expression correlated with Ki-67 (p=0.024) and inversely with p27KIP1 (p=0.007). A cytoplasmic reaction for Skp2 was also observed in most tumours and its expression decreased from Ns (12.3%) to SSMs (7.9%) and NMs (4.5%). In contrast, Ms showed an increase of cytoplasmic Skp2 (11.9%) that correlated with its nuclear expression (p=0.016). While nuclear Skp2 expression correlated with the pT-level (p=0.023), Clarklevel (p=0.023) and Breslow index (p=0.019), the cytoplasmic Skp2 expression might be of biological significance only in NMs since it correlated with tumour depth (p=0.02) and pT-level (p=0.025). Our data suggests that Skp2 could contribute to melanoma progression. This is further highlighted by the fact that vertical growth phase (VGP) melanomas show significant higher nuclear Skp2 expressions when compared with the harmless radial growth phase (RGP) (p=0.047). Also nuclear Skp2 expression correlates with a reduced survival time (p=0.025) in melanoma