Effects of single-channel phonemic compression schemes on the understanding of speech by hearing-impaired listeners.

The effect of digital processing on speech intelligibility was studied in hearing-impaired listeners with moderate to severe high-frequency losses. The amount of smoothed phonemic compression in a high-frequency channel was varied using wide-band control. Two alternative systems were tested to compensate for upward spread of masking (USOM) and to reduce modulations in the high-frequency channel effectively. Consonant-vowel-consonant tests were conducted in a group of 14 subjects using eight different speech-processing settings. Speech intelligibility improved significantly with compression, mainly due to positive effects on the initial-consonant score. Surprisingly, listeners with a smaller residual dynamic range tended to profit less from compression. Compensation for USOM gave an additional improvement of vowel intelligibility. In background noise, consistently negative effects of speech processing were found. The combined use of phonemic compression and USOM compensation is promising in conditions without background noise.

[Ultra-small superparamagnetic iron oxide particles: the signal behavior and relaxation times of the bone marrow after repeated i.v. application in the pig model at 1.5 tesla]. / Ultrakleine superparamagnetische Eisenoxidpartikel: Signalverhalten und Relaxationszeiten des Knochenmarks nach wiederholter i.v. Applikation im Schweinemodell bei 1,5 Tesla.

PURPOSE: Evaluation of the influence of an iron-containing MR contrast agent on the signal behaviour and the relaxation time of the bone marrow at 1.5 tesla after repeated doses. ANIMALS AND METHODS: 14 pigs received i.v. on days 1, 9, and 15 ultra-small (core diameter 6-8 nm) superparamagnetic iron oxide particles at doses of 20 (low dose = LD) or 200 mumol/kg body weight (high dose = HD). RESULTS: Following the first administration a dose-independent reduction in the bone-marrow signal intensity in the T2-weighted gradient-echo sequence (FFE) was observed together with a reduction in the T1 and T2 relaxation times. Following the second application there were no further signal-reductions in the HD-group; in contrast, there was a signal reduction in the LD-group, made possible by a signal recovery in the meantime. On the other hand, the relaxation times T1 and T2 were shortened after each administration of contrast medium. CONCLUSION: Nano-SIPS result at both doses in a signal reduction in the bone marrow. Only in the LD-group may repeated examinations with new contrast agent offer diagnostically sufficient images. Relaxometry shows a shortening of T1 as well as T2. This effect could be summed up after repeated doses. Almost no iron remained in the medullary space three weeks after i.v. administration of the contrast agent, which suggests mobilization and metabolization.

[Stimulant current diagnosis and therapy with pulsed currents]. / Reizstromdiagnostik und Therapie mit Impulsströmen.

Thanks to its efficiency and versatility, and the fact that it has none of the frequently negative side-effects of drugs, stimulant-current therapy has become rapidly more important. The use of defined stimulant-current pulses also enables the condition of neuromuscular system to be described accurately in terms of measurements--a valuable diagnostic aid and therapeutic monitoring facility. The method, procedure and criteria for its use, and some special therapies, are described.