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Biomedical subjects

F L Wuyts

Publications and source records attributed to F L Wuyts.

47 records · Page 3Linked to original sources

Selective vestibular neurectomy in Menière's disease: a review.

A review of the literature on selective vestibular neurectomy for Meniere's disease is presented. The procedure is placed in historical context and current refinements of the technique are highlighted. In particular, the different methods of evaluating results on vertigo, hearing, tinnitus, aural pressure and imbalance are summarised. The controversy over the indication, timing and outcome measures for selective vestibular neurectomy is discussed. In experienced hands there appears to be a low complication rate, emphasising the value of this procedure in relieving intractable vertigo when a destructive procedure is indicated.

Humans↗

The perceptual evaluation of voice disorders.

The consent about the necessity of perceptual evaluation in the assessment of patients with voice disorders is almost unanimous. This is not the case with regard to the method or scale. This article gives an outline of historical backgrounds and presents a survey of contemporary perceptual rating scales. Reliability and influencing factors are discussed and recommendations are made with respect to clinical use.

Adolescent↗

Phonetography in voice diagnoses.

Phonetography has been defined by SCHUTTE and SEIDNER in 1983. Nevertheless publications on phonetography go back to the thirties. Due to publications in the last decade and the development of computer phonetography this testing method has been used for various purposes in voice evaluation. This article gives a historical background, with the different ways of phonetogram recording and describes variables who have their effect on phonetogram results and interpretation. Secondly the range of application with normative and reference phonetograms is discussed.

Adult↗

Elastic properties of human aortas in relation to age and atherosclerosis: a structural model.

A new structural model is described for the tension-radius relationship of blood vessels, taking into account their mechanically important constituents: collagen, elastin and smooth muscle. The model has four characteristic parameters: EC, the Young's modulus of the collagen fibres; ESE, the Young's modulus of the combined smooth-muscle/elastin network; epsilon mu, the amount of strain at which the high stiffness region on the tension-radius curve is reached, and eta an indicator for the degree of collagen fibre stretching. The structural stiffness of the wall constituents is reflected by EC and ESE whereas the global stiffness of the entire blood vessel is described by epsilon mu and eta. All these elasticity parameters are pressure independent, in contrast to generally quoted values for the incremental modulus or vascular compliance which are strongly pressure dependent. Hence, an objective comparison of the mechanical properties for various types of blood vessel, based on the present model parameters, has been made possible. The model was successfully fitted to tension-radius data of 65 human aortas, age range 30-88 years, with moderate or severe atherosclerosis. The structural as well as the global stiffness changes with age, e.g. collagen stiffness shows a ninefold increase over 60 years. Global stiffness depends on atherosclerosis.

Adult↗

Founder effect in a Belgian-Dutch fragile X population.

For many years, the high prevalence of the fragile X syndrome was thought to be caused by a high mutation frequency. The recent isolation of the FMR1 gene and identification of the most prevalent mutation enable a more precise study of the fragile X mutation. As the vast majority of fragile X patients show amplification of an unstable trinucleotide repeat, DNA studies can now trace back the origin of the fragile X mutation. To date, de novo mutations leading to amplification of the CGG repeat have not yet been detected. Recently, linkage disequilibrium was found in the Australian and US populations between the fragile X mutation and adjacent polymorphic markers, suggesting a founder effect of the fragile X mutation. We present here a molecular study of Belgian and Dutch fragile X families. No de novo mutations could be found in 54 of these families. Moreover, we found significant (P < 0.0001) linkage disequilibrium in 68 unrelated fragile X patients between the fragile X mutation and an adjacent polymorphic microsatellite at DXS548. This suggests that a founder effect of the fragile X mutation also exists in the Belgian and Dutch populations. Both the absence of new mutations and the presence of linkage disequilibrium suggest that a few ancestral mutations are responsible for most of the patients with fragile X syndrome.

Alleles↗

Longitudinally oriented smooth muscle cells in rabbit arteries.

Intima formation in vessels, spontaneous or experimentally induced, is generally characterized by the presence of longitudinally oriented smooth muscle cells (LSMC). During an experiment of neo-intima induction in carotid arteries in rabbits, by application of a non-constrictive silastic cuff, a study was performed to investigate the presence of LSMC in the systemic and pulmonary circulations, in both elastic and muscular arteries. Three patterns could be distinguished: intimal cushions in muscular arteries, single or small groups of LSMC in the intima in elastic and larger muscular arteries, and intra-medially located layers or columns of LSMC in the aorta, the pulmonary artery, at the bifurcation of the aorta and around orifices of branches. In order to understand this peculiar orientation a biomechanical approach was used: this showed that near the lumen the circumferential stress is 4.5 times higher than the longitudinal. Because the cell surface of the smooth muscle cells exposed to this stress per unit vessel length is much less in the longitudinal than in the circular direction we conclude that the LSMC align in the direction which allows them to cope most effectively with the mechanical stresses.

Animals↗

Effect of cleft type on overall speech intelligibility and resonance.

The main purpose of this study was to measure and compare the effect of an unilateral cleft lip and palate (UCLP) and a bilateral cleft lip and palate (BCLP) on overall speech intelligibility, nasalance and nasality. An additional objective was to compare the nasalance and nasality patterns of cleft palate children with the available normative data for normal children. The subjects were 37 children with an UCLP (19/37) or a BCLP (18/37) with normal cognitive and motor functions and normal hearing levels. All subjects had a non-syndromic cleft, followed the same surgical protocol and did not undergo secondary pharyngeal surgery. To measure and compare the effect of cleft type, objective and subjective assessment techniques were used. For the objective assessment of nasal resonance the nasometer and the mirror-fogging test were used. Nasalance scores were obtained, while patients produced sounds, read three standard passages or repeated sentences focusing on specific consonants. A perceptual evaluation of speech, the Gutzmann (1913) test and the tests of Bzoch (1989) were used as subjective assessment techniques. The perceptual assessment of the overall speech intelligibility was based on the spontaneous speech and reading or repeating of the nasometric sentences. These samples were judged by three speech pathologists using a 4-category nominal scale. A subjective test (Morley, 1945) was used to evaluate the velopharyngeal mechanism. The findings of the present study show no statistically significant differences for nasalance values, nasality and overall speech intelligibility between the UCLP and BCLP children. Significant differences were found between the data of the normal group and the cleft palate children. These differences included nasalance values as well as nasality data and overall speech intelligibility.

Adolescent↗

A psychological cascade model for persisting voice problems in teachers.

In 76 teachers with persisting voice problems, the maintaining factors and coping strategies were examined. Physical, functional, psychological and socioeconomic factors were assessed. A parallel was drawn to a psychological cascade model designed for patients with chronic back pain. The majority of the patients were found to be in a deadlocked situation (phase 1 of the cascade model), for which the combination of externalization and unawareness of the situation is the main risk factor. Subjective rating of the voice problem was assessed by the Voice Handicap Index (VHI) and a visual analogue scale (VAS). Patients in phase 1 of the cascade model showed higher VHI and VAS scores compared with the other patients. For a high VHI score, the combination of socioeconomic factors and being in phase 1 was the most important risk factor. Socioeconomic factors were the most important risk factors for a high VAS score. We introduce the term 'chronicity', which means that the problems are maintained, the patient finds himself in a deadlocked situation, and is sliding down into a chronic disease. 'Chronicity' is essentially different from 'chronic', which refers only to the duration of the disease. We consider maintaining factors and (inadequate) coping factors, which consist of emotional/psychological, physical and socioeconomic aspects, as indicators for chronicity.

Adaptation, Psychological↗