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Biomedical subjects

M Gioux

Publications and source records attributed to M Gioux.

26 records · Page 2Linked to original sources

Physical and aerodynamic features of the Bordeaux voice prosthesis.

Performance of a voice prosthesis, used to restore speech in patients following total laryngectomy, was evaluated by measuring in vitro, as well as in vivo, airflow resistances. The pressure-flow characteristics of the device were analyzed using the standard pressure-flow diagram (to calculate airway resistance) and a Moody plot (to determine the different flow patterns). The flow rate and the pressure drop were measured with a Fleisch pneumotachograph and a variable reluctance transducer, respectively. Total device resistances were found in the range of 34-50 cm H2O/L/s when the flow-rates ranged from 0.05 to 0.35 L/s. Comparison of these resistances with those of other commercially available devices showed that our voice prosthesis had the lowest resistance.

Airway Resistance↗

Associated postural adjustments in Parkinson's disease.

Postural activity in muscles of the back and legs associated with voluntary forward elevation of the arm at the shoulder with the subject standing was examined in 14 patients with Parkinson's disease and nine normal individuals. The time of onset of EMG activity in each of the postural muscles, relative to the onset of activity in the prime mover, was the same for both patient and normal groups and did not depend on load. The amplitude of the EMG bursts and their frequency of occurrence, was less in patients off drug treatment and immobile, than when mobile on therapy. We conclude that the timing of associated postural adjustments is normal in Parkinson's disease, although their size may be decreased.

Adult↗

[Emotional and attentive interferences and slow cerebral potentials (CNV-P 300) (author's transl)].

A study was conducted to establish possible correlations between electrophysiological indices and performance under neutral situations and those involving completing a double task of increasing complexity, by studying CNV and P 300 in young healthy men. The results demonstrated that: 1. After habituation, the CNV amplitudes were not related to performance. A significant correlation was noted only during the most complex tasks. 2. The CNV appears to depend mainly on endogenous factors, that is to say the aptitude and readiness of an individual to treat the information, rather than on the performance resulting from this treatment. 3. The amplitude of the P 300 is related to performance, as a function of detection rate and the complexity of the tasks. The functional duality of the CNV and the differences between it and the P 300 have been emphasized. The indices obtained from slow potentials appear to be of value for an evaluation of behaviour. Rather than analyzing the characteristics of the potentials in a supposedly "neutral" situation it would appear preferable to establish, from the indices, profiles of individual reactivity and adaptation to different experimental situations.

Action Potentials↗

[Visual evoked potentials in elderly subjects (author's transl)].

Study of visual evoked potentials by contrast stimuli (VEPL) and by luminance stimuli (VEPC) in 28 subjects aged between 65 and 95 years (mean age: 81.8 years). Changes related to aging in regard to VEP involve: an increase of latencies of VEPL affecting the early components and an increase in the maximum amplitude of VEPL. The course of EP as age progresses introduces a difference in topographical organisation with a deterioration of responses in the left occipital regions and a change in potentials recorded at the vertex. Aging would appear to cause more marked inter-individual differences which could have clinical implications by making it possible to demonstrate individual differences in the biological processes of aging.

Aged↗

Neurotoxicity of nonionic iodinated water-soluble contrast media in myelography: experimental study.

The neurotoxicity of four contrast media--iotrol, iopamidol, metrizamide, and ioglunide--was studied by subarachnoid injection in 14 rabbits implanted with four cerebral electrodes. Thirty-four recordings and quantitative analyses were carried out of spontaneous electrical brain activity, seizure activity, and visual- and somatosensory-evoked potentials. The quantitative study of the electroencephalograms showed differences among the four products. All four of the contrast media induced a general slowing of the electroencephalographic activity and, 30 min after injection, slow waves and a shift of the spectrum energy toward the slow frequencies (0.5-3.5 Hz). The slowing of the recording was the least marked with iotrol and recovery of a normal recording was also quickest with iotrol. The quantitative study of electrical seizures and paroxysms revealed higher seizure activity with ioglunide and iopamidol. The study of the evoked potentials does not permit any distinction among the four contrast agents. Metrizamide induced the fewest seizures, but, considering the slow waves and the seizures, iotrol appears to be the least neurotoxic.

Animals↗