Biomedical subjects
Publications and source records attributed to P Bonfils.
Hearing impairment should be detected in early childhood. Among available screening techniques, acoustic oto-emission testing is a rapid, reliable, noninvasive method which specifically investigates peripheral hearing but does not provide data on auditory nerve centers. This functional test should be carried out within a few days of birth in infants with risk factors for hearing impairment.
Serous otitis media is an extremely commonplace condition in pediatric patients and tends to resolve spontaneously. Only some forms warrant treatment. Indications for treatment include frequent superinfections, lasting hearing impairment with adverse consequences on socialization, or debilitation of the tympanic membrane carrying a risk for the ear. Tympanostomy tubes are a palliative treatment for serous otitis which restores hearing within a few hours and eliminates unfixated retractions of the tympanic membrane within a few weeks. Tympanostomy tubes may lead to complications including otorrhea and perforation of the tympanic membrane and should therefore be used only in patients with severe otitis media. Etiologic treatment of serous otitis rests on restoration of satisfactory nasal ventilation (education to improve nose-blowing, adenoidectomy), improvement of eustachian tube patency (corticosteroids), and modification of the characteristics of middle ear secretions (mucolytic agents and mucomodifying agents).
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The aim of this study was to measure distortion-product otoacoustic emissions (DPOEs) in a clinical setting. First, DPOE input-output functions were automatically realized to determine the ratio of the pure tones (primaries) f2 and f1 that would elicit the most significant DPOE input-output function. The DPOE input-output functions presented two separate portions for the f2/f1 ratio, ranging from 1.18 to 1.26: (1) below 60-dB sound pressure level (SPL), a saturating portion with a DPOE detection threshold at 36-dB SPL; and (2) above 66-dB SPL, a linear portion. For other f2/f1 ratios, DPOE input-output functions had a more linear behavior. The DPOEs generated by primary intensities below 60-dB SPL, which show saturating behavior, probably have their origin in the properties of outer hair cells. This indicates that DPOE measurements in a clinical setting must be realized with precise stimulus values: (1) f2/f1 ratio near 1.22, and (2) primary intensities below 60-dB SPL. Second, DPOE input-output functions were realized for DPOEs varying from 707.5 to 342 Hz. No more saturating plateau could be observed with DPOEs below 512.5 Hz, suggesting that active mechanisms are absent below 725 Hz within the human cochlea. These data permit us to establish the bases of an objective low-frequency audiometric test.
The amplitudes of evoked otoacoustic emissions (EOE) and their detection threshold were measured in 44 normal young adults and 118 patients with two categories of cochlear dysfunction, acoustic trauma and presbycusis. A different method was used for each category: detection of click EOE or of stimulus frequency emissions. A partial correlation and multivariate analysis was performed for both groups of results to investigate the relations between EOE threshold one pure tone audiometric thresholds (250 to 8000 Hz). Only one significant correlation was found, linearly relating EOE threshold and hearing threshold at 2 kHz (P less than 0.001), independently of the origin of cochlear dysfunction. It suggests that EOE threshold is not frequency-specific since the frequency of EOE at threshold was nearly always close to 1 kHz. A simple model is proposed, based on the assumption that EOE amplitudes and threshold are proportional to the total number of residual active sites in the organ of Corti, i.e. to the total length of active basilar membrane. It is shown that this model accounts for the results disclosed by the statistical analysis and fits the experimental data. It can be used for quantitatively predicting the residual cochlear activity of a patient. However, the EOE threshold is only sensitive to already important cochlear alterations and this parameter does not seem to allow a follow-up of early stages of cochlear dysfunction.
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We report one case of pseudotumoral salivary location of the Rosai-Dorfman syndrome, with a favorable outcome, occurring in a 32-year-old man from Guadeloupe. The clinical, biological and clinicopathological features of this syndrome, as well as the pathogenetic hypotheses, are summed up. In this case, no bacterial, fungal, parasitic or viral agent was discovered. The subject presented with no immune abnormality likely to account for the persistence and intensity of the histiocytic infiltration with lymphophagocytosis associated to the lymphoplasmocytic infiltration. The rarity of ENT, and more specifically salivary, locations is emphasized. The importance of the detection of possible immune abnormalities in such patients is demonstrated by the outcome of the syndrome being more often unfavorable when such abnormalities are present.
The authors have studied the induced acoustic otoemissions in 53 children with tubal malfunction. Otoemissions were present in 29% of all ears. In cases of retraction of the eardrum, the otoemissions were present in 2 of 23 ears. Some ears had no induced oteomission, with hypoacousia ranging from 10 to 15 dB only. Conversely, there were induced otoemissions in some ears while hypoacousia was as high as 25 dB.
Distortion products are otoemissions produced when the cochlea is stimulated by two pure, continuous sounds f1 and f2. The most ample distortion product in Man corresponds to a frequency of 2f1-f2. The aim of our work is to appreciate the possibilities to study the distortion products for the exploration of low frequencies in Man. Three populations of subjects have been studied: young subjects have been studied: young subjects with a normal hearing, subjects with pathological otoscopic findings in spite of a normal hearing, subjects with pathological otoscopic findings in spite of a normal audiometric study, and subjects with endocochlear perceptive deafness. The major result of this study was to demonstrate that the lowest frequency that can be explored with distortion products is 750 Hertz.
This paper presents the first case of human genetic hearing loss due to predominant inner hair cell damage investigated by psychoacoustic audiometry, auditory brainstem responses (ABR), evoked acoustic emissions (EAEs), and distortion product otoacoustic emissions (DPOEs). The genetic transmission was an autosomal dominant inheritance. The audiogram pattern was a dominant high-frequency hearing loss. EAE and DPOE properties were normal. Bronx waltzer mutant mouse with genetically determined predominant inner hair cell defects provide an interesting model to study this congenital deafness. This rare congenital deafness with predominant damage to inner hair cells cannot be detected by neonatal screening techniques using EAEs or DPOEs.
Amplitudes and detection thresholds of evoked otacoustic emissions (EOE) were measured in various groups of subjects: 44 normal young adults, 80 patients with presbycusis and 38 patients with acoustic trauma. Relations between these EOE parameters and tonal audiogram were analyzed. Surprisingly, EOE detection threshold at 1 kHz was strongly correlated with auditory threshold at 2 kHz and no other one. This result demonstrates that some EOE parameters are not frequency-specific. A simple model is implemented in which it is assumed that EOE amplitudes are proportional to the global cochlear activity. This model fits very well experimental data and allows a quantitative evaluation of the residual cochlea. The domain of validity of EOE test in clinics has therefore been precised.
The aim of this paper is to review the properties of otoacoustic emissions from a clinical point of view and to discuss the perspective interest of this test. In adults, the clinical significance of evoked otoacoustic emissions seems to be limited either in endocochlear hearing losses or for detecting retrocochlear diseases. In infants, evoked otoacoustic emissions seem to be a reliable, simple, non-invasive, and precise method for estimating auditory sensitivity for midfrequencies (1-4 kHz). Then, EOEs could be considered as an interesting way for screening auditory dysfunction in infants.
Evoked otoacoustic emissions (EOEs) were recorded in a group of normally hearing neonates (n = 100 ears) to study the basic properties of EOEs and the parameters influencing them. The results obtained with EOE recordings were compared with those of behavioral screening investigations. The main properties of EOEs in neonates are: 1. EOEs can be recorded in 98% of the tested ears or neonates; 2. there were no statistically significant variations in EOE detection thresholds of neonates between the ages of 1 and 4 days; 3. no statistical difference in the EOE threshold was found between males and females; 4. all EOEs exhibited a broadband spectrum with high-component frequencies; 5. EOEs demonstrating narrowband frequency peaks super-imposed on the broadband component had detection thresholds lower than EOEs without narrowband frequency peaks. EOEs can be used as a screening test. The main clinical interest of this test is to detect the presence (i.e., normal auditory peripheral function) or the absence (i.e., pathological peripheral auditory function) of EOEs in response to a 30-dBHL click stimulation. The results of this study have important applications concerning the possible clinical use of EOEs for screening peripheral auditory dysfunction in neonates.
Acoustic distorsion products are sounds emitted by the cochlea, in relation with the outer hair cell properties and the micromechanical properties of the Organ of Corti, in response to an acoustic stimulation by two primairies F1 and F2. Acoustic distorsion product 2F1-F2 have been recorded in two populations: 10 normally-hearing subjects and 10 subjects with pure sensorineural hearing losses. Three points are discussed: (i) the test-retest reliability, (ii) the clinical tolerance and (iii) the clinical applications of this test.
Otoacoustic emissions are sounds emitted by the inner ear. Their genesis requires the outer hair cells of the organ of Corti to be intact. Analysis of these sounds provides a fine evaluation of cochlear function. Evoked otoacoustic emissions (in response to a sound) are constant in subjects with normal hearing, whereas they always have pathological characteristics in patients with endocochlear conduction or perceptive deafness. When the acoustic nerve or the central nervous system are affected, otoacoustic emissions are normal for as long as the pathological process has no repercussions on the inner ear. This new functional exploratory method is of particular interest, being simple, non-invasive, rapid and objective. One of its main uses in adults is early detection of a lesion of the organ of Corti by e.g. ototoxic drugs or acoustic trauma. In children, it might become a test for objective detection of deafness, being easier to perform than evoked potentials of the brain stem.
Evoked acoustic emissions (EAEs) and spontaneous acoustic emissions (SAEs) recordings hold some promise as a fast, objective and non-invasive audiological procedure, especially in children. However, accurate interpretation in the emission response must be based on the basic properties of the emissions present in a younger age group. In so doing, the properties of emissions were investigated in 49 ears from 26 children, whose ages varied between 2 days and 10 years. EAEs could be recorded in all normal ears, but the incidence of long-duration EAEs decreased with age. There were no statistically significant variations in recording the EAEs detection threshold with age. The incidence of SAEs also decreased with age.
Click-evoked otoacoustic emissions were recorded in a group of normally hearing subjects (n = 52 ears) and a group of patients demonstrating several common types of sensorineural hearing loss (n = 85 ears) in order to study the clinical applicability of acoustic emissions. In the normally hearing population, all ears demonstrated acoustic emissions that could be elicited at intensities below the normal subjective threshold for the sequence of clicks (mean, -5.2 dB hearing level [HL]). Sixty-seven percent of the normal ears showed long (greater than 20 ms) click-evoked emissions, and spectral analysis showed a broadband spectral component with several narrowband frequency peaks. In patients with sensorineural hearing loss, the incidence of acoustic emissions decreased and the detection threshold increased linearly with increasing threshold. No emissions were elicited from ears exhibiting subjective click thresholds greater than 35 dB HL. Hearing-impaired ears showed a significantly higher proportion of short duration emissions and a significant reduction in the mean number of narrowband frequency peaks in comparison to the controls. Therefore, acoustic emissions can be used as a reliable technique for objective study of normal micromechanical activity within the cochlea and for detection of subtle changes in cochlear disease. However, they have not been demonstrated to be useful in differentiating cochlear disease.
Spontaneous otoacoustic emissions (SOEs) were recorded in a group of normally hearing participants (n = 148 ears) and a group of patients demonstrating several common types of sensorineural hearing loss (n = 136 ears) in order to study the clinical interest of spontaneous otoacoustic emissions. In the normal population, the incidence of SOEs decreased from 68% in the group of infants less than 18 months old to 0% after the age of 70 years old. On the other hand, the SOE incidence and the spectrum content did not change with sex. In the group of participants with sensorineural hearing loss, the incidence of SOEs decreased linearly with increasing click threshold or the detection-threshold of evoked otoacoustic emission. No statistical difference in SOE incidence was found between participants with or without tinnitus. These results have several important applications concerning the possible clinical application of SOEs.