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Biomedical subjects

M Portmann

Publications and source records attributed to M Portmann.

At least 55 records · Page 3Linked to original sources
PubMed1988

Clinical significance of the summating potential in Menière's disease.

Transtympanic (TT) electrocochleography (ECochG) data recorded with click stimuli and tone bursts (1, 2, 4, and 8 kHz) were evaluated in 50 patients with Meniere's disease and compared with the data from control groups of 10 sensorineural hearing impaired patients and 5 subjects with normal hearing. The mean summating potential (SP) amplitude was larger in the Meniere's disease group for 1, 2, and 8 kHz. The low frequency (1 or 2 kHz) SP decreased in 59% of the Meniere's disease patients during a glycerol dehydration test, whereas subjective hearing improved in only 29%. The use of ECochG with the monitoring of SP thus improves the sensitivity of the glycerol test for the detection of endolymphatic hydrops. There appeared no clear relation between clinical observations and the ECochG data either before or after glycerol. However, the Meniere's disease patients with a large negative SP at low frequencies also had larger action potential (AP) and often had short-term symptoms. The present report confirms the usefulness of measuring the SP in the diagnosis of Meniere's disease.

Action Potentials↗
PubMed1987

Stapedius reflex and cerebellopontine angle tumours.

The stapedius reflex was investigated in 61 patients with cerebellopontine angle tumours, in order to evaluate the reliability of the reflex-decay test in VIIIth nerve disorders. The reflex was completely normal in 11% of the patients. The 2 most frequently observed abnormalities were (1) an absence of the reflex when stimulating the ear on the side of the tumour, and (2) the conjunction of pathological reflex-decay at 0.5 kHz with a unilateral threshold elevation and/or absence of the reflex at other frequencies. The decay test was normal in one-third of the patients with a preserved reflex.

Acoustic Impedance Tests↗
PubMed1987

Electrophysiological prognosis in facial paralysis.

Electrical prognosis was evaluated in 79 patients with facial paralysis, of spontaneous (n = 43) or post-traumatic origin (n = 36). Three electrophysiological tests were employed jointly: detection, stimulation and stimulodetection. The patients were reviewed at least 1 year later, in order to appreciate the agreement between the electrical prognosis and the clinical outcome (satisfactory or not). Those patients with a favourable prognosis on electrical testing had in the majority of cases a satisfactory outcome. The accuracy of the prognosis was also better in cases of early examination (within 15 days) and partial paralysis.

Adolescent↗
PubMed1987

The Portmann procedure after sixty years.

This article recalls the technique described by Georges Portmann in 1926 for the opening of the endolymphatic sac in cases of Meniere's disease. Criteria of indication used at the time are critically analyzed. Modifications of the original operation proposed by various authors, particularly those of T. Naito, W. House, A.W. Morrison, and I.K. Arenberg, are then described. Finally, the current technique and indication criteria implemented in Bordeaux are analyzed, with stress on electrocochleographic determination of the summation potential and its disappearance under the effect of glycerol. According to the author, these latest examination techniques contribute to improving results by providing a better selection of cases likely to be treated by the opening of the endolymphatic sac.

Ear, Inner↗
PubMed1986

Ceravital in ossiculoplasty: experimental studies and early clinical results.

The biocompatibility of the bioactive glass-ceramic Ceravital was investigated experimentally both in vivo and in vitro. In the former, ceramic discs were interposed in 30 rat middle ears for periods ranging from 6 weeks to 12 months. In the latter, Ceravital otological prosthesis were placed in human fibroblast culture. Reactions to the biomaterial were assessed by means of scanning electron microscopy (SEM) with chemical analysis facilities (EDAX, WDAX) and light microscopy. The interface reactions were similar in both in vivo and in vitro studies and confirmed the findings of other authors regarding the implants' biocompatibility and bioactivity. The technique of ion etching, however, enabled clear demonstration of this bioactivity on the implant surface, exposed merely to the middle-ear secretions, thus questioning the necessity of placing bone pâté on the implant head at surgery, in order to encourage bioactive bonding with the overlying drum. A clinical trial of Ceravital in 128 patients with an average follow-up period of 2 years is reported. Forty per cent of these patients underwent a type II tympanoplasty, 60 per cent a type III. Though relatively short-term, the results to date have been encouraging: 88 per cent of the implants have been well-tolerated; 70 per cent of the cases have yielded a satisfactory hearing result; and only 3 per cent of the implanted prostheses have been extruded.

Animals↗