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Biomedical subjects

G Eden

Publications and source records attributed to G Eden.

9 recordsLinked to original sources
PubMed1983

Physiological evidence for central modulation of voice tremor.

The present report presents an attempt to define the physiological parameter used to describe "voice tremor" in psychological stress evaluating machines, and to find its sources. This parameter was found to be a low frequency (5-20 Hz) random process which frequency modulates the vocal cord waveform and (independently) affects the frequency range of the third speech formant. The frequency variations in unstressed speakers were found to be the result of forced muscular undulations driven by central nervous signals and not of a passive resonant phenomenon. In this paper various physiological and clinical experiments which lead to the above conclusions are discussed. a) It is shown that induced muscular activity in the vocal tract and vocal cord regions can generate tremor in the voice. b) It is shown that relaxed subjects exhibit significant tremor correlation between spontaneously generated speech and EMG, with the EMG leading the speech tremor. c) Tremor in the electrical activity recorded from muscles overlapping vocal tract area was correlated with third formant demodulated signal and vocal cord demodulated pitch tremor was correlated with first formant demodulated tremor. d) Enhanced tremor was found in Parkinson patients and diminished tremor in patients with some traumatic brain injuries.

Electromyography↗
PubMed1979

Two-dimensional fast transforms applied to memory limited disk operating computers.

Two-dimensional transform algorithms are usually impractical to small machines which cannot handle N2 real (or complex) data points in core when N is large. Storing the input data in N disk records and computing two sequential one-dimensional transforms requires N(N + 3) disk access and 2 N applications of the one-dimensional procedure. Expanding the fast one-dimensional algorithm it is suggested that only 2 N log2N disk accesses are needed whereas the one-dimensional procedure is activated only N times.

Computers↗
PubMed1978

Physiological model analysis of involuntary human-voice tremor.

Frequency variations in the human voice result from voluntary and involuntary changes in the parameters of the vocal system. The present work deals with involuntary frequency perturbations from two theoretical aspects: 1) the influence of pitch period variations on frequency changes in the band-limited signal which results from the resonant characteristics of the vocal tract; 2) the physiological parameters of the vocal system which are potentially able to govern involuntary frequency changes. It is shown that the modulation function of the vocal-cord wave can theoretically be derived from its harmonics using FM demodulation techniques, and that higher distortion may appear at higher harmonics. It is also shown that involuntary geometirical changes of the vocal tract and its terminal impedance as well as tension and initial-area changes of the vocal cord--changes well within the physiological range--can influence frequency changes in the human voice. The present results are correlated with our reported experimental findings on involuntary voice tremor, used in psychological stress evaluation. The role of the central nervous system, and possible mechanisms for these phenomena, are discussed.

Humans↗
PubMedDate not supplied

Steady state investigation of possible pharmacokinetic interactions of moxonidine and glibenclamide.

The aim of the study presented here was to determine possible pharmacokinetic interactions of moxonidine and glibenclamide at steady state in 18 healthy male volunteers. Multiple oral doses of 0.2 mg of moxonidine b.i.d. (q. 12 h) and of 2.5 mg of glibenclamide o.i.d. (q. 24 h) were administered alone and in combination in an open, non-randomized, three-treatment design. The preparations were given for 5 days in each of the 3 periods. The results of this multiple dose study did not indicate substantial pharmacokinetic interactions of the drugs. Regarding the influence of glibenclamide on the pharmacokinetics of moxonidine, no significant changes were seen at all. In the presence of moxonidine, a minor decrease of bioavailability of glibenclamide was detectable, as could be derived from the AUC and clearance data. The actual differences were small and not considered to be of clinical significance.

Administration, Oral↗