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Biomedical subjects

W L Creten

Publications and source records attributed to W L Creten.

At least 19 recordsLinked to original sources
PubMed1994

An analysis of spontaneous conversational speech fluency in children with acquired aphasia.

We report on an instrumental analysis of spontaneous conversational speech (SCS) fluency in acquired childhood aphasia (ACA). Tape-recorded SCS samples of 25 children with ACA (clinical judgment: 12 nonfluent and 13 fluent), and of 12 dysarthric and 12 nonaphasic and nondysarthric right hemisphere injured children were analysed in order to: (1) investigate whether a more refined analysis can objectively contribute to the differentiation of patients who were labelled as fluent or nonfluent on the basis of a clinical judgment: (2) verify whether an instrumental analysis of phonation duration does confirm the subjective estimation of verbal rate (i.e. the number of words produced in a unit of time) in groups of children with acquired neurogenic speech/language disorders frequently met in clinical practice. The results are: (1) phonation rate (i.e. the vocalization percentage) seems to represent an adequate variable to distinguish clinically diagnosed nonfluent aphasic children from speech/language impaired children belonging to other clinical groups of acquired neurogenic speech/language disorders; (2) the verbal rate is highly correlated to the phonation rate in all investigated groups except the dysarthric one. We suggest the instrumental method discussed here might contribute to the differential diagnosis between dysarthric and aphasic disturbances in the acute stage of the disease. Concerning the study of ACA, the main issue of the present investigation is that an objective fluency measurement has succeeded in identifying aphasic children who obviously do not fit in with the standard doctrine on ACA, which claims that ACA is invariably nonfluent irrespective of lesion location.

Adolescent↗
PubMed1985

Multifrequency tympanometry in normal ears.

Susceptance and conductance tympanograms were recorded from 10 normal subjects with probe frequencies ranging from 220 to 910 Hz. Tympanometric shapes progressed through an orderly sequence of patterns, becoming more complex with increasing probe frequency. When the direction of ear-canal air pressure change was from negative to positive values, more complicated tympanometric shapes occurred for all subjects, compared to the positive to negative direction. The results are discussed in relation to the Vanhuyse et al. [Scand. Audiol. 4:45-50, 1975] model of tympanometric shapes. In general, the model is a good first approximation to the distribution of tympanometric patterns from normal ears.

Acoustic Impedance Tests↗
PubMed1985

Immittance audiometry. Normative data at 220 and 660 Hz.

Normative immittance data for normal ears were collected at 220 and 660 Hz probe tone frequencies. The experimental set-up enabled conversion of simultaneously recorded susceptance and conductance data to resistance, reactance, admittance and phase angle tympanograms. Special attention was given to the subtraction of the ear canal admittance and to the pump speed. This paper demonstrates first the frequent occurrence (43.2%) of W-shaped tympanograms at 660 Hz probe tone in healthy ears. This percentage is not influenced by age, sex or pump direction. Normative data of the central extremum of the tympanogram are reported only for those immittance components in which W-notching does not occur. The wide variance of measurements in the population precludes the creation of subcategories. The intra-individual variation is much smaller and the authors advocate to use the value of the contralateral healthy ear as a reference.

Acoustic Impedance Tests↗
PubMed1984

Tympanometric middle-ear pressure determination with two-component admittance meters.

Exact tympanometric determination of the middle-ear pressure based on the location of the (central) extremum of susceptance, conductance, admittance, impedance, reactance or phase-angle tympanograms is not possible. None of these immittance components reaches its extremum exactly at middle-ear pressure neither at 220 nor at 660 Hz, due to the hysteresis caused by the viscoelastic behaviour of the soft biological tissue of the middle-ear structures. These effects cannot be avoided by lowering the rate of the pressure change during the recordings. The error on the middle-ear pressure determinations using a tympanometric method can be estimated to be of the order of 15 daPa.

Acoustic Impedance Tests↗
PubMed1983

A search for the most suitable imminent components and probe tone frequency in tympanometry.

The relative occurrence of bell-shaped and various types of W-shaped susceptance-conductance and admittance-phase tympanograms at a probe-tone frequency of 660 Hz was determined from registrations on normal ears. The diagnostic value of the susceptance-conductance versus the admittance-phase representation of tympanograms was studied on pathological middle-ear systems. Using probe-tone frequencies from 510 Hz up to 910 Hz, tympanograms for all four imminent components were recorded on 10 pathological ears and the diagnostic value compared. From the combination of these studies we conclude that the admittance-phase approach at a probe tone frequency between 500 and 700 Hz is a good choice.

Acoustic Impedance Tests↗
PubMed1983

Optimizing tympanometric variables for detecting middle ear traumas.

The combination of the results of different studies lead to the conclusion that the susceptance-conductance immittance audiometer at 660 Hz is not the only useful instrument for the detection of middle-ear traumas. Measurements at probe-tone frequencies from 510 up to 910 Hz prove that the admittance tympanogram combined with the electrical phase angle tympanogram recorded in the 500-700 Hz frequency range have definite advantages.

Acoustic Impedance Tests↗
PubMed1982

Incudo-stapedial joint pathology: a tympanometric approach.

Two-component tympanometry with a high probe-tone frequency enables a better distinction to be made between mobile but normal middle-ear systems and middle-ear systems suffering from necrosis, luxation, or disruption. Susceptance and conductance tympanograms obtained from 14 patients with confirmed pathological middle-ear lesions and 8 postmortem temporal bones, experimentally manipulated either surgically or with a 1 N HCl solution, were compared to tympanograms obtained from 80 normal subjects of an earlier study. With a 660-Hz probe tone, normal middle ears generate bell-shaped or normal sharp W-shaped patterns, whereas the pathologies of the middle ear give rise to irregular multi-extrema tympanograms. The differences between the two types of multi-extrema curves are discussed in detail. The use of phase-angle tympanometry is recommended to enable a quick and accurate distinction between normal and abnormal types of multi-extrema tympanograms. This study also points out clearly that 220-Hz tympanograms do not allow clear differentiation between pathological and normal middle ears.

Acoustic Impedance Tests↗
PubMed1981

The diagnostic value of phase-angle tympanograms.

The diagnostic value of susceptance, conductance, resistance, reactance, admittance and phase-angle tympanograms is compared. Phase-angle tympanograms seem to be best suited for the discrimination between normal W patterns and broad irregular curves obtained from ossicular disruptions, luxations and necroses. Several possibilities are proposed: phase-angle tympanograms at the drum, phase-angle tympanograms at the tip of the measuring probe and corresponding phasor curves. The best choice will depend on the kind of data processing and/or measuring equipment available.

Acoustic Impedance Tests↗
PubMed1980

Tympanometry-detection of middle ear pathologies.

Two component susceptance-conductance tympanometry at a probe tone frequency of 660 Hz is superior to admittance tympanometry at 220 Hz for the detection of an ossicular discontinuity, a luxation or a necrosis. It is, however, essential to understand well the difference between non-pathological W-patterns and pathological broad multi-extrema tympanograms. The systematics of normal W-patterns is reviewed and the influence of the sign and magnitude of the pumpspeed on the shape of both types of tympanograms is discussed.

Acoustic Impedance Tests↗
PubMed1979

On the asymmetry of susceptance tympanograms.

The origin of the tail asymmetry of susceptance tympanograms was investigated. A flow-measuring device enabled an accurate determination of ear-canal volume changes produced during tympanometry. From these measurements one finds that not only is the asymmetry due to the earcanal volume change but that finite drum susceptances exist at high transtympanic pressures. This residual susceptance was found to differ in the two tails of the tympanogram. Although no absolute values of those drum susceptances can be computed, it is possible to indicate which pressure side has the greater residual susceptance.

Acoustic Impedance Tests↗
PubMed1976

Two-component versus admittance tympanometry.

The probe tone frequency of electro-acoustic bridges has a direct effect on the shape of the tympanograms obtained. At higher frequencies (800 Hz) typical patterns are generated for eardrum abnormalities and ossicular discontinuities. The 625- and 660-Hz frequencies sometimes prove to be not quite high enough to obtain the expected 'W' or undulating admittance tympanograms. Our investigation proves that much more certainty is given even at 660-Hz probe tone when components B and G are both recorded. The same information for ossicular disruption is found in an admittance (Y) together with a new kind of tympanogram, namely the phase tympanogram.

Audiometry↗
PubMedDate not supplied

Some physical considerations in the choice of techniques for ossiculoplasty.

A comparative study between the monobloc tympano-ossicular implant and the classical columellar technique is made. Although both give satisfactory audiometric results, the follow-up of the columellar restoration showed some post-operative disadvantages, namely: invagination and perforation of the tympanic membrane, slipping of the columella, and fixation of the columella to the tympanic ring (bony annulus) or to the promontory. In view of the normal tympano-malleal fixation, the normal static pressure accomodation in the incudo-malleal joint and the normal topological situation, monobloc implant obviates the disadvantages inherent in the columellar technique. Two aspects of the monobloc implant need further examination; these are the restoration of the correct rotation axes and the incudo-stapedial connection.

Animals↗