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At least 577 records · Page 32Linked to original sources
PubMed2004

Mandarin speech perception in nucleus CI 24 implantees using MAPs based on neural response telemetry.

The purpose of this study is to compare speech perception performance in Mandarin-speaking Nucleus CI24 implantee using standard behavior MAPs and NRT-based MAPs. Eight Nucleus CI24 users (5 years and older) participated in the study. They all fulfilled the following criteria: (1) behavioral MAP and NRT thresholds can be reliably obtained; (2) had more than 18 functioning electrodes; (3) had at least 6 months experience using CI. All subjects received speech evaluation under three different MAPs: a traditional behavioral MAP, a MAP predicted from the NRT thresholds of the E22 (electrode 22), E19, E15, E11, E8, E5, E1 and a combined MAP based on the information of NRT thresholds and behavioral threshold/comfortable levels of the E11. The speech evaluation package included word recognition test in quiet, in noise, and a Mandarin sentence test in quiet. Results showed that three MAPs are similar in some subjects, but different in other subjects. Compared to the NRT MAPs, the combined MAPs are more similar to the behavioral MAPs. There was no significant difference in the mean score of the word recognition test in quiet, in noise and sentence test under these three MAP conditions. In conclusion, although the behavioral MAPs and the NRT-based MAPs are not identical, the speech performance of Mandarin-speaking CI24 implantee using MAPs predicted from NRT thresholds appeared to be no worse than the traditional behavioral MAPs. Therefore, in certain cases that behavioral MAPs are difficult to obtain (such as in very young or multiple handicapped children), NRT-based MAPs may serve reliably as an initial estimation.

Action Potentials↗
PubMed1995

Modeling hemodynamic profiles by telemetry in the rat. A study with A1 and A2a adenosine agonists.

The newly developed radiotelemetry system offers a number of advantages for the measurement of blood pressure and heart rate in laboratory animals. However, no available statistical methods permit valid use of the many data gathered with this continuous recording of hemodynamic parameters. This study describes elaboration and testing of mathematical functions as applied to the measurement of the effects of drugs on blood pressure and heart rate in spontaneously hypertensive rats. We used parametric functions analogous to those for pharmacokinetic studies. Curve fitting is in fact the only approach that provides reasonable estimates of hemodynamic kinetic constants. Nonlinear functions were assessed by analyzing telemetric hemodynamic effects induced by three adenosine receptor agonists with different selectivity for the A1 or A2a receptor. After acute administration in conscious rats, the A1 agonist 2-chloro-N6-cyclopentyladenosine induced dose-related hypotension (eg, 0.03 mg/kg; peak, -70 mm Hg; time to peak, 0.34 hour) and bradycardia (eg, 0.03 mg/kg; peak, -186 beats per minute [bpm]; time to peak, 0.38 hour). The A2a agonist 2-hexynyl-5'-N-ethylcarboxamidoadenosine induced dose-related hypotension (eg, 0.003 mg/kg; peak, -36 mm Hg; time to peak, 0.32 hour) with reflex tachycardia (eg, 0.003 mg/kg; peak, 152 bpm; time to peak, 0.35 hour). The nonselective adenosine agonist 5'-N-ethylcarboxamidoadenosine (0.1 mg/kg) induced hypotension (peak, -75 mm Hg; time to peak, 2.2 hours) and bradycardia followed by tachycardia (first peak, -131 bpm; time to peak, 1.26 hours; second peak, 123 bpm; time to peak, 13.9 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed2002

Individually coded telemetry: a tool for studying heart rate and behaviour in reindeer calves.

The aim of the study was to test the performance of a silver wire modified version of the coded telemetric heart rate monitor Polar Vantage NV (PVNV) and to measure heart rate (HR) in a group of captive reindeer calves during different behaviour. The technical performance of PVNV HR monitors was tested in cold conditions (-30 degrees C) using a pulse generator and the correlation between generated pulse and PVNV values was high (r=0.9957). The accuracy was tested by comparing the HR obtained with the PVNV monitor with the standard ECG, and the correlation was significant (r=0.9965). Both circadian HR and HR related to behavioural pattern were recorded. A circadian rhythm was observed in the HR in reindeer with a minimum during night and early morning hours and maximum at noon and during the afternoon, the average HR of the reindeer calves studied being 42.5 beats/min in February. The behaviour was recorded by focal individual observations and the data was synchronized with the output of the HR monitors. Running differed from all other behavioural categories in HR. Inter-individual differences were seen expressing individual responses to external and internal stimuli. The silver wire modified Polar Vantage NV provides a suitable and reliable tool for measuring heart rate in reindeer, also in natural conditions.

Animals↗
PubMed2005

Miniaturization (0.2 g) and evaluation of attachment techniques of telemetry transmitters.

We have developed a miniaturized very high frequency (VHF) transmitter design for radio-tagging small animals. The average mass of the circuitry is 0.084 g (range 0.081-0.087), hence, with the smallest power cell, complete tags weigh 0.2 g and have a life of 18-22 days. We further demonstrate that with such small tags the technique of attaching the device to the animal's body strongly affects the effective radiated power, and thus transmission ranges. Ideally the attachment couples the electronics to the animal's body as a ground plane for improved radiation. The transmitter allows the application of radio-tracking to be expanded to new taxa whose spatial behaviour and population dynamics are largely unknown, for example arthropods, reptiles or amphibians. The new design is also suitable for miniature implants and signal modulation with sensors.

Electronics↗
PubMed1996

Low-power radio telemetry: the potential for remote patient monitoring.

Radio-based signalling devices will play an important role in future generations of remote patient monitoring equipment, both at home and in hospital. Ultimately, it will be possible to sample vital signs from patients, whatever their location and without them necessarily being aware that a measurement is being taken. This paper reviews current methods for the transmission by radio of physiological parameters over ranges of 0.3, 3 and 30 m, and describes the radiofrequency hardware required and the carrier frequencies commonly used. Future developments, including full duplex systems and the use of more advanced modulation schemes, are described. The paper concludes with a case study of a human temperature telemeter built to indicate ovulation. Clinical results clearly show the advantage to be had in adopting radio biotelemetry in this instance.

Body Temperature↗
PubMed2002

Quantitative analysis of cardiac data from rats monitored by telemetry: reducing within- and between-animal variability.

Few studies have examined the sources of variability in cardiac function measurements in unrestrained animals and the impact of this variability on detection of treatment effects. The heart rate was monitored with implanted ECG transmitters in two groups of male rats, age 7 and 23 mo. Animals were monitored in their cages to determine optimal heart rate sampling frequency and sources of variability in heart rate, including whether there were persistent animal-to-animal differences. Ambient temperature was transiently increased to test whether correction for animal-to-animal differences improved sensitivity for detection of treatment effects. Animal-to-animal differences were statistically significant and accounted for about 18.3% and 11.5% of the total variance for old and young rats, respectively. In both the old and young rats, the heart rate decreased during the heat challenges relative to the control group, but the noncorrected differences were not statistically significant. When pre-exposure baseline values for each rat (average of 72 h prior to the first temperature challenge) were subtracted, the decrease in heart rate was statistically significant during all three challenges for both old and young rats. Subtraction of preexposure heart rate data to correct for baseline differences between animals is important for measuring treatment effects.

Age Factors↗