FUNDAMENTAL PRINCIPLES OF FUNCTIONAL HEARING TESTS: WITH RECENT DEVELOPMENTS IN TUNING FORKS AND SOUNDING RODS

1933 ◽  
Vol 18 (5) ◽  
pp. 599-613 ◽  
Author(s):  
R. SONNENSCHEIN
1929 ◽  
Vol 22 (3) ◽  
pp. 361-376
Author(s):  
T. A. Clarke

Necessity for consideration of present hearing tests.—Testing of tonal limits considered; present tests accepted as satisfactory. Anomalous results of comparison of perception of the monochord by air and bone conduction.—The Rinne, Schwabach, Weber and Bing tests destructively criticized.—The Gellé and galvanic cochlear tests; Fraser's modification of Gellé's test.—Suggestions for the improvement of testing.—The “absolute bone conduction” test affords an absolute index of the perceptive component of hearing (nerve function).—Mechanism of transmission of sound waves through the skull (bone “conduction”).—Quantitative determination of hearing power; results expressed on a distance basis are to be preferred; use of tuning forks in obtaining such results.—The mathematics underlying this use of tuning forks.—Accurate quantitative estimation of nerve function (the perceptive component of hearing).


2020 ◽  
Vol 161 (46) ◽  
pp. 1944-1952
Author(s):  
Péter Kalinics ◽  
Imre Gerlinger ◽  
Péter Révész ◽  
Péter Bakó ◽  
Ildikó Végh ◽  
...  

Összefoglaló. Halláspanasszal számos beteg fordul orvoshoz. A rutinszerűen elvégzett súgottbeszéd-, hangvilla- és tisztahangküszöb-audiometriai vizsgálat alapján vezetéses, sensorineuralis, illetve a kettő együttes fennállása esetén kevert típusú halláscsökkenést különböztetünk meg. Vezetéses halláscsökkenés létrejöhet mind a külső, mind a közép- vagy a belső fül veleszületett vagy szerzett rendellenességei esetén. Amennyiben a stapediusreflex kiváltható, ugyanakkor a betegnél nincs jelen a külső fület, valamint a középfület érintő kórfolyamat, felmerül a harmadikablak-szindróma lehetősége. A kórkép okaként egy, a belső fül csontos tokján „harmadik ablakként” funkcionáló laesio van jelen, amely az ovális ablakon keresztül beérkező hangenergia egy részét elvezeti, mielőtt az a kerek ablakon át kivezetődik a középfülbe. A diagnózis felállítása gyakran nehéz feladat elé állítja a klinikust, melyhez a megfelelő audiológiai, illetve képalkotó vizsgálatok elvégzése elengedhetetlen. Tekintettel arra, hogy a panaszok megszüntetésére számos műtéti módszer került leírásra, közleményünkben átfogó képet adunk a kórkép etiológiájáról, diagnosztikájáról, terápiájáról, valamint bemutatjuk saját kezdeti tapasztalatainkat is 2 eset prezentálásával. Orv Hetil. 2020; 161(46): 1944–1952. Summary. Patients frequently present to the physician with hearing loss. Routine hearing tests include speech field (whisper test), tuning forks and pure tone threshold audiometry, which can identify the presence of sensorineural hearing loss, conductive hearing loss or a combination of both (mixed type). Conductive hearing loss can be a symptom of many different conditions. These include congenital or acquired malformations of the outer, middle and inner ear. If a conductive hearing loss with intact stapedial reflexes are recorded and in the absence of outer or middle ear pathology, then the third window syndrome should be considered. The cause is a bony defect on the otic capsule that acts as a ’third window’, dissipating the incoming sound energy. Without the appropriate audiological and imaging tests, the diagnosis of the condition is challenging in clinical setting. Several surgical techniques have been described to treat the condition. The authors give a comprehensive review of the etiology, diagnosis and treatment of the disease presenting their initial experiences with 2 cases. Orv Hetil. 2020; 161(46): 1944–1952.


Author(s):  
C. Colliex ◽  
P. Trebbia

The physical foundations for the use of electron energy loss spectroscopy towards analytical purposes, seem now rather well established and have been extensively discussed through recent publications. In this brief review we intend only to mention most recent developments in this field, which became available to our knowledge. We derive also some lines of discussion to define more clearly the limits of this analytical technique in materials science problems.The spectral information carried in both low ( 0<ΔE<100eV ) and high ( >100eV ) energy regions of the loss spectrum, is capable to provide quantitative results. Spectrometers have therefore been designed to work with all kinds of electron microscopes and to cover large energy ranges for the detection of inelastically scattered electrons (for instance the L-edge of molybdenum at 2500eV has been measured by van Zuylen with primary electrons of 80 kV). It is rather easy to fix a post-specimen magnetic optics on a STEM, but Crewe has recently underlined that great care should be devoted to optimize the collecting power and the energy resolution of the whole system.


Author(s):  
Kent McDonald

At the light microscope level the recent developments and interest in antibody technology have permitted the localization of certain non-microtubule proteins within the mitotic spindle, e.g., calmodulin, actin, intermediate filaments, protein kinases and various microtubule associated proteins. Also, the use of fluorescent probes like chlorotetracycline suggest the presence of membranes in the spindle. Localization of non-microtubule structures in the spindle at the EM level has been less rewarding. Some mitosis researchers, e.g., Rarer, have maintained that actin is involved in mitosis movements though the bulk of evidence argues against this interpretation. Others suggest that a microtrabecular network such as found in chromatophore granule movement might be a possible force generator but there is little evidence for or against this view. At the level of regulation of spindle function, Harris and more recently Hepler have argued for the importance of studying spindle membranes. Hepler also believes that membranes might play a structural or mechanical role in moving chromosomes.


Author(s):  
G.Y. Fan ◽  
J.M. Cowley

In recent developments, the ASU HB5 has been modified so that the timing, positioning, and scanning of the finely focused electron probe can be entirely controlled by a host computer. This made the asynchronized handshake possible between the HB5 STEM and the image processing system which consists of host computer (PDP 11/34), DeAnza image processor (IP 5000) which is interfaced with a low-light level TV camera, array processor (AP 400) and various peripheral devices. This greatly facilitates the pattern recognition technique initiated by Monosmith and Cowley. Software called NANHB5 is under development which, instead of employing a set of photo-diodes to detect strong spots on a TV screen, uses various software techniques including on-line fast Fourier transform (FFT) to recognize patterns of greater complexity, taking advantage of the sophistication of our image processing system and the flexibility of computer software.


Author(s):  
William Krakow ◽  
David A. Smith

Recent developments in specimen preparation, imaging and image analysis together permit the experimental determination of the atomic structure of certain, simple grain boundaries in metals such as gold. Single crystal, ∼125Å thick, (110) oriented gold films are vapor deposited onto ∼3000Å of epitaxial silver on (110) oriented cut and polished rock salt substrates. Bicrystal gold films are then made by first removing the silver coated substrate and placing in contact two suitably misoriented pieces of the gold film on a gold grid. Controlled heating in a hot stage first produces twist boundaries which then migrate, so reducing the grain boundary area, to give mixed boundaries and finally tilt boundaries perpendicular to the foil. These specimens are well suited to investigation by high resolution transmission electron microscopy.


Author(s):  
W.J. de Ruijter ◽  
P. Rez ◽  
David J. Smith

There is growing interest in the on-line use of computers in high-resolution electron n which should reduce the demands on highly skilled operators and thereby extend the r of the technique. An on-line computer could obviously perform routine procedures hand, or else facilitate automation of various restoration, reconstruction and enhan These techniques are slow and cumbersome at present because of the need for cai micrographs and off-line processing. In low resolution microscopy (most biologic; primary incentive for automation and computer image analysis is to create a instrument, with standard programmed procedures. In HREM (materials researc computer image analysis should lead to better utilization of the microscope. Instru (improved lens design and higher accelerating voltages) have improved the interpretab the level of atomic dimensions (approximately 1.6 Å) and instrumental resolutior should become feasible in the near future.


Author(s):  
S.J. Krause ◽  
W.W. Adams

Over the past decade low voltage scanning electron microscopy (LVSEM) of polymers has evolved from an interesting curiosity to a powerful analytical technique. This development has been driven by improved instrumentation and in particular, reliable field emission gun (FEG) SEMs. The usefulness of LVSEM has also grown because of an improved theoretical and experimental understanding of sample-beam interactions and by advances in sample preparation and operating techniques. This paper will review progress in polymer LVSEM and present recent results and developments in the field.In the early 1980s a new generation of SEMs produced beam currents that were sufficient to allow imaging at low voltages from 5keV to 0.5 keV. Thus, for the first time, it became possible to routinely image uncoated polymers at voltages below their negative charging threshold, the "second crossover", E2 (Fig. 1). LVSEM also improved contrast and reduced beam damage in sputter metal coated polymers. Unfortunately, resolution was limited to a few tenths of a micron due to the low brightness and chromatic aberration of thermal electron emission sources.


Author(s):  
S. Yegnasubramanian ◽  
V.C. Kannan ◽  
R. Dutto ◽  
P.J. Sakach

Recent developments in the fabrication of high performance GaAs devices impose crucial requirements of low resistance ohmic contacts with excellent contact properties such as, thermal stability, contact resistivity, contact depth, Schottky barrier height etc. The nature of the interface plays an important role in the stability of the contacts due to problems associated with interdiffusion and compound formation at the interface during device fabrication. Contacts of pure metal thin films on GaAs are not desirable due to the presence of the native oxide and surface defects at the interface. Nickel has been used as a contact metal on GaAs and has been found to be reactive at low temperatures. Formation Of Ni2 GaAs at 200 - 350C is reported and is found to grow epitaxially on (001) and on (111) GaAs, but is shown to be unstable at 450C. This paper reports the investigations carried out to understand the microstructure, nature of the interface and composition of sputter deposited and annealed (at different temperatures) Ni-Sb ohmic contacts on GaAs by TEM. Attempts were made to correlate the electrical properties of the films such as the sheet resistance and contact resistance, with the microstructure. The observations are corroborated by Scanning Auger Microprobe (SAM) investigations.


Author(s):  
Philippe Pradère ◽  
Edwin L. Thomas

High Resolution Electron Microscopy (HREM) is a very powerful technique for the study of crystal defects at the molecular level. Unfortunately polymer crystals are beam sensitive and are destroyed almost instantly under the typical HREM imaging conditions used for inorganic materials. Recent developments of low dose imaging at low magnification have nevertheless permitted the attainment of lattice images of very radiation sensitive polymers such as poly-4-methylpentene-1 and enabled molecular level studies of crystal defects in somewhat more resistant ones such as polyparaxylylene (PPX) [2].With low dose conditions the images obtained are very noisy. Noise arises from the support film, photographic emulsion granularity and in particular, the statistical distribution of electrons at the typical doses of only few electrons per unit resolution area. Figure 1 shows the shapes of electron distribution, according to the Poisson formula :


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