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Biomedical subjects

P Bonfils

Publications and source records attributed to P Bonfils.

At least 91 records · Page 5Linked to original sources
PubMed1994

[Role of the basal cochlea in the genesis of evoked acoustic oto-emissions in the subject with normal hearing].

The aim of this study was to determine the role of the basal part of the cochlea (8-16 kHz) on the genesis of evoked otoacoustic emissions (EOEs) in normally hearing subjects (0.25-8 kHz thresholds below or equal to 20 dBHL). This study was realized on 43 subjects. The EOEs were generated by a linear click of 0 dB (ILO88 Ref.). The high-frequency (8-16 kHz) audiometric thresholds varied between 30 and 74 dBHL while conventional audiometric thresholds were below 20 dBHL. Correlation studies between EOE amplitude and audiometric thresholds were statistically significant only when the high frequency thresholds were considered. Those data are a new argument for the hypothesis that EOEs are generated by the global cochlear activity.

Adult↗
PubMed1994

[ORL surgery in Albucasis's treatise on surgery. A vision of cervicofacial surgical therapeutics in the year 1000].

The work of the famous Arab doctor, Albucasis, is not well known to head and neck surgeons. However, the thirtieth time of his treatise on medicine is essentially a surgical textbook and includes many. Facts concerning otorhinolaryngology. Albucasis's complete work is an exhaustive compilation of late tenth century medical knowhow which ensured the link between ancient medicine, essentially of Greek origin, and modern western medicine. The important work of Jewish and Arab physicians in the early and late Middle Ages was necessary for the transmission of knowledge from the ancient near last to the modern western world. Among Albucasis's descriptions of surgical techniques, tonsillectomy and trachestomy are particularly interesting. In order to accurately formulate indications for surgery, Albucasis endeavors to present the signs and symptoms of pathological conditions requiring surgical treatment. Finally, Albucasis reveals himself to be a humanist, as well as a physician and surgeon.

History, Medieval↗
PubMed1993

Temporal patterns of transient-evoked otoacoustic emissions in normal and impaired cochleae.

The spatial distribution of outer hair cells that participate in generating transient-EOE frequency-components has been investigated in man. According to several models (e.g. Wilson (1990) Hear. Res. 2, 527-532; Zwicker (1986) J. Acoust. Soc. Am. 80, 154-162; Wilson and Kemp (Eds.), Cochlear Mechanisms, Structures, Functions and Models, Plenum Press, NY), EOEs result from interferences between broadly distributed contributions, responsible for their long frequency-dependent delay. This work presents an analysis of the temporal patterns of click- and tone-burst-EOEs in human ears when contributions to EOEs are reduced by noise-induced lesions with audiometric notches centred around 4 kHz (N = 46). Although the auditory thresholds at the frequencies of the studied EOE-components were always normal, these components exhibited drastic and predictable changes compared to normal control ears (N = 40). (1) Their temporal pattern at the highest EOE frequency fmax just below the audiometric notch appeared to be determined by the cochlear state at high frequencies (6 to 8 kHz). Either it was normal and the EOE exhibited a complicated beat-structure, or it was impaired and the time envelope of the EOE was simple. In contrast, any type of time pattern could be observed in normal ears. (2) The temporal patterns of EOEs one octave below fmax always presented many beats and short delays. The proposed interpretation is that contributions to a transient-EOE component at frequency f can come from distant basal cochlear areas, i.e. more than 1 and sometimes 1.5 octaves from the place tuned to f. Therefore, the possible relationships between transient-EOEs and tuning mechanisms which presumably involve only a small number of OHC need further investigations.

Acoustic Stimulation↗
PubMed1993

Exploration of cochlear function by otoacoustic emissions: relationship to pure-tone audiometry.

The amplitudes, growth functions and detection thresholds of evoked otoacoustic emissions (EOE) were measured in 44 normally hearing subjects and 138 patients with two categories of cochlear dysfunctions: (a) acoustic trauma; and (b) presbycusis. Separate sets of experiments were also performed: (a) detection of stimulus frequency emissions; and (b) click EOE. EOE properties were studied around 2 kHz, 1 kHz and 0.75 kHz (+/- 0.1 kHz). A partial correlation and multivariate analysis was carried out to investigate the relationships between EOE properties and puretone auditory thresholds (from 0.25 to 8 kHz, half-octave steps). For each experiment and each frequency, only one highly significant correlation was found, linearly relating the n kHz EOE threshold with the hearing threshold at 2n kHz: there was a shift of about one octave between EOE amplitudes and audiometric data. This means that EOE thresholds give no direct information about the local cochlear state. A simplified model has been implemented, which assumes that EOE thresholds and amplitudes are proportional to the total number of residual active sites along the organ of Corti, i.e., to the total length of active basilar membrane towards the base of the cochlea. It is shown that this model accounts for the results revealed by the statistical analysis and closely fits the experimental data.

Acoustic Stimulation↗
PubMed1993

Internal architecture of the parotid gland at MR imaging: facial nerve or ductal system?

A radiologic-anatomic study was performed to determine the nature of the low-signal-intensity curvilinear structures currently seen in the normal parotid gland on axial T1-weighted magnetic resonance (MR) images. These structures are considered by some to represent the intraparotid facial nerve. After cannulation of the Stensen duct, the authors imaged the parotid gland of two cadavers in situ before and after intraductal injection of gadolinium tetrazacyclododecanetetraacetic acid. Retrograde filling was obtained in one gland. The same sections were used throughout a subsequent anatomic study, allowing correlation of the MR findings with the macroscopic and histologic appearance of the gland. Comparison of MR images and gross and histologic sections established that two intraparotid facial nerve segments, although identified from the histologic study, were not visible on corresponding MR images. Many areas of low signal intensity seen within the gland were found to represent the main duct and some afferent ductal branches.

Cadaver↗
PubMed1993

Audiological assessment of eleven congenital hypothyroid infants before and after treatment.

Eleven congenital hypothyroid newborns were consecutively referred for audiological evaluation before any treatment. Evoked otoacoustic emissions were present bilaterally in 9 newborns. These results suggest the normality outer hair cells and contrast with results obtained in experimental studies. The auditory brainstem responses in 6 newborns showed a prolonged wave I, as previously reported by other authors. At 9 to 12 months of age, all children treated had evoked otoacoustic emissions in at least one ear. In 9 cases, the auditory threshold was normal (equal to or below 20 dB) as determined by behavioural tests.

Auditory Threshold↗
PubMed1993

Frequency specificity of human distortion product otoacoustic emissions.

The amplitudes and growth functions of distortion product otoacoustic emissions (DPOE) at 2f1-f2, elicited by two primary tones f1 and f2 with a constant frequency ratio f2/f1 = 1.23 and varying geometric mean values 1, 1.5, 2, 4, 6 and 8 kHz, were measured for 25 normal subjects and 50 patients with sensorineural hearing loss. Partial correlations between DPOE amplitudes and auditory thresholds (0.25 to 8 kHz, half-octave steps) were examined. The amplitude of DPOE evoked by low-intensity primary tones (at or below 62 dB SPL) was strongly correlated only with the auditory threshold at their mean frequency, and DPOE disappeared for local hearing losses larger than about 30 dB. Moreover, DPOE amplitudes did not depend on the basal cochlear state. Confounding effects of middle ear transmission and aging were not significant in this set of experiments. When elicited by higher intensities of primary tones (72 dB SPL), DPOE exhibited a more complex and non-local behavior, and their sensitivity to hearing loss decreased. These results suggest that when low-intensity primaries are used, DPOE patterns provide frequency-specific information on the local cochlear state.

Acoustic Stimulation↗
PubMed1993

[Does the use of nasal vasoconstrictor agents change tomodensitometric images of nasosinusal polyposis?].

This study compared the results of the CT scan of the paranasal sinuses in nasal polyposis patients before and after a topical vasoconstrictor application on the nasal mucosa. No change have been observed either on the maxillary and ethmoidal sinuses, or the middle meatus. On the other hand, an important retraction was observed on the nasal mucosa, in particular on the inferior turbinate. Then, the application of a topical vasoconstrictor on the nasal mucosa does not seem necessary in order to explore the sinuses in patients with nasal polyposis.

Adult↗
PubMed1993

[Reoperation of tumors of the parotid gland. Technical approach and consequences for the 7th cranial nerve. Apropos of 22 cases].

Second or more surgical procedures on parotid are usually difficult and may induce injury on the facial nerve. The authors report their experience about 42 patients. The choice between a total parotidectomy or a surgical excision of a tumor depends of the number of surgical procedure, the type of initial procedure and the histological type of the tumor. Second surgical procedures for a wrong initial histological diagnosis (11 cases) were always a total parotidectomy with facial nerve preservation. The risk of a partial or total facial palsy is higher after several recurrences (3 of 8 cases). The facial nerve had to be resected in 3 of 9 cases of malignant tumors recurrences. The initial treatment of a tumor of the parotid must be radical so it can prevent for further surgical procedures and then avoid a facial nerve injury.

Adult↗
PubMed1993

[Screening of deafness in the young child. Value, techniques and initial results of products of acoustic distortion].

Distortion-product otoacoustic emissions are otoacoustic emissions evoked by two pure tones called primaries and proposed in order to provide a frequency specific investigation of the cochlea. This paper first reports complete input-output functions of distortion-product otoacoustic emissions for conventional audiometric frequencies in a population of 35 neonates without any risk for cochlear function. Distortion-product otoacoustic emissions could be useful, in association with evoked otoacoustic emissions and comportemental audiometry, to precisely evaluate the peripheral auditory system in infants and neonates.

Audiometry↗
PubMed1992

Distortion-product otoacoustic emissions. Values for clinical use.

Distortion-product otoacoustic emissions are otoacoustic emissions evoked by two pure tones. They are proposed as a frequency-specific test of the mechanical properties of the cochlea. The aim of this study was to measure distortion-product otoacoustic emissions in a clinical setting to establish the most interesting values suitable for clinical use and the clinical interest of the method. The statistical analysis of the data points out some clinically interesting values: (1) a screening limit value of 30 dB hearing level and when measuring distortion-product otoacoustic emissions in response to 52 dB sound pressure level for studying active frequency selective mechanisms; (2) a screening limit value of 50 dB hearing level and when measuring distortion-product otoacoustic emissions in response to 72 dB sound pressure level for studying passive cochlear mechanisms; and (3) the slope of the input-output function. All physiologic properties of the cochlea fit with these basic distortion-product otoacoustic emission properties. These criteria can be used whatever the population studied and the material used for distortion-product otoacoustic emissions recordings. Distortion-product otoacoustic emissions can be used as a screening test to separate (1) subjects with normal hearing and subjects with a hearing threshold above 30 dB hearing level (distortion-product otoacoustic emissions in response to a 52 dB sound pressure level "primaries" [ie, pure tones] stimulation intensity), and (2) patients with a hearing threshold above or below 50 dB hearing level (distortion-product otoacoustic emissions in response to a 72 dB sound pressure level primary stimulation intensity). Distortion-product otoacoustic emissions cannot be used as a more precise audiometric test.

Adolescent↗
PubMed1992

Analysis of possible interactions of an attentional task with cochlear micromechanics.

Several contradictory studies have been published regarding the effect of selective attention on cochlear mechanics, possibly modulated through efferent pathways. Click-evoked otoacoustic emissions have been proposed as a highly sensitive tool for testing the hypothesis of such a modulation. In this study, two other types of evoked otoacoustic emissions (i.e. distortion products and stimulus frequency emissions between 1 and 4 kHz) were measured on 20 normal subjects in absence and presence of a visual selective attention task. The duration of measurements at a given frequency was short enough to eliminate possible artefacts due to long-time averaging. No significant change was observed in these signals, considered as probes of cochlear micromechanics. It is concluded that in this set of experimental conditions, selective attention has a negligible effect on peripheral sensitivity.

Acoustics↗
PubMed1992

Spontaneous and evoked otoacoustic emissions in preterm neonates.

Spontaneous (SOEs) and evoked otoacoustic emissions (EOEs) were recorded in a group of preterm neonates (N = 134 ears) in order to study the basic properties of SOEs and EOEs as a function of gestational age. In the study, it was found that: 1. EOEs were recorded in 93% of the tested ears; 2. SOEs were recorded in 61% of the tested ears; 3. there were no statistically significant variations of EOE amplitude with gestational age; 4. EOE spectrum did not vary with age; and 5. the two main factors influencing EOE amplitude were the SOE presence and the fast Fourier transform spectrum, especially the lower limit of the spectrum. Thus, the maturation of outer hair cell properties appears to be complete at 32 weeks of gestational age. Because a number of infants at risk for hearing loss are preterm babies, screening for EOEs, an objective, rapid, and nontraumatic technique, may prove useful in evaluating peripheral auditory dysfunction in preterm neonates.

Cochlea↗
PubMed1992

Distortion-product otoacoustic emissions in neonates: normative data.

Distortion-product otoacoustic emissions (DPOEs) are otoacoustic emissions evoked by two pure tones and used in order to provide a frequency specific assessment of the mechanical properties of the cochlea. This paper first reports complete input-output DPOE functions for audiometric frequencies between 867 Hertz and 8 kHz in a normal neonate population (normative data). DPOE results were analyzed as a function of evoked otoacoustic emission (EOE) properties. Neonates having normal EOEs have large DPOEs. DPOE amplitudes in neonates are larger than in adults. Neonates with atypical EOE frequency spectrum without low frequency components had normal DPOE input-output functions only for high frequencies (above 2 kHz). DPOEs could be useful, in association with EOEs, to precisely evaluate the auditory peripheral function in neonates.

Humans↗
PubMed1992

[Is facial nerve visible on magnetic resonance imaging?].

The internal architecture of the parotid gland was studied by nuclear magnetic resonance (NMR) imaging, particular attention being paid to the intra-parotid portion of the facial nerve. Currently available apparatuses provide high resolution images of previously poorly elucidated anatomic details. Certain authors consider that images in the axial plane in T1 allow direct visualization of the facial nerve and its branches in the form of low frequency linear signals within the gland. The present study, based on radio-anatomic correlations and date determined in a healthy volunteer, demonstrated that these structures correspond in fact to segments of the excretory canal tree, the facial nerve and its branches being invisible on NMR imaging. It is not possible, therefore, to determine the location of a parotid tumor in relation to these nerve elements using this imaging technique.

Facial Nerve↗
PubMed1992

[Nasal and sinusal polyposis. Semiology and values of magnetic resonance imaging].

Twelve patients with nasal polyposis were examined with magnetic resonance imaging (MRI) prior to surgical ethmoidectomies (20 ethmoidectomies). MRI signal was analyzed in correlation with surgical findings in order to define the semiology of nasal and sinuses polyps. One of the most important point of this semiology is based on the analysis of sequences after administration of gadolinium. MRI seems an interesting method for analysing the extension of nasal polyposis and could be useful for ENT surgeons before an endoscopic nasal surgery.

Adolescent↗
PubMed1992

[Acoustic distorsion products. A systematic analysis of technical parameters. How to explain the results?].

The aim of this study was to define the most interesting parameters useful for a clinical application of acoustic distortion products (mainly, F1 and F2 primaries frequencies and levels). The most interesting F1 and F2 primaries level in order to separate subjects with a normally-hearing function and patients with a sensorineural hearing loss is 50 dBHL. This result can be explained by some physiological properties of cochlear mechanisms.

Acoustic Stimulation↗