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Biomedical subjects

P Bonfils

Publications and source records attributed to P Bonfils.

At least 145 records · Page 8Linked to original sources
PubMed1988

Evoked otoacoustic emissions in patients with acoustic neuromas.

Click-evoked otoacoustic emissions were recorded in 28 patients with surgically proven acoustic neuromas and 22 patients with brain stem pathologic disorders. Data collected in acoustic tumor ears were compared with those obtained in 30 nontumor ears demonstrating sensorineural hearing losses. Acoustic emissions were altered (increased detection-threshold or no detectable emissions) in all ears with eighth nerve tumors and were not affected in those with brain stem pathologic conditions that do not involve cochlear function. The properties of acoustic emissions were similar in both tumor and nontumor ears with hearing loss, which suggests that acoustic tumors usually produce a cochlear hearing loss.

Adult↗
PubMed1988

[Alterations of speech audiometry in presbycusis brought about by cochlear acoustic emissions].

Click-evoked oto-acoustic emissions (EOEs) and speech audiometry were recorded in a group of normally hearing subjects (n = 56 ears), and a group of patients demonstrating sensorineural hearing loss due to presbycusis (n = 39 ears). Correlations were made between detection-threshold of EOEs, speech reception threshold (i.e., lowest hearing level at which the subject can repeat 50% of a message), and discrimination score (i.e., discrimination score determined 35 dB above the speech reception threshold). EOEs have never been observed when speech reception threshold was equal to or greater than 35 dB HL. EOEs were always found when speech reception threshold was equal to or lower than 25 dB HL. Moreover, the detection-threshold of EOEs increased when increasing speech reception threshold. On the other side, there was not a good correlation between the discrimination score and the detection-threshold of EOEs. Thus, complementary information on outer hair cell degenerative changes in presbycusis could be deduced from these data.

Adolescent↗
PubMed1988

[Contribution of cochlear acoustic emissions in pediatric audiology].

A new method is described for pediatric otologic exploration : cochlear acoustic emissions (CAE), and results reported of CAE recordings in 15 children with normal hearing and 31 infants at otoneurologic risk, suspected of having moderate or severe hypoacusia on conventional audiometry. Results were compared with those obtained by study of V wave threshold of AEP. The incidence of CAE in children and infants with normal hearing was 100%, the absence of CAE being related to a V ware threshold of AEP of 30 dB nHL or more. The CAE threshold is closely related to that of the V wave of AEP. The use of CAE, a rapid, non-invasive, objective audiometric method, could be a first line screening technic allowing separation, within several minutes, of a normal hearing population from one with a lesion of transmission or endocochlear apparatus with CAE V wave threshold of over 30 dB nHL. In addition, in children with a flat AEP the CAE allows study of the cochlear independently of auditory pathways.

Adolescent↗
PubMed1988

[Esophagectomy and pharyngectomy in cancers of the upper respiratory and digestive tracts and the esophagus. Results apropos of 16 cases].

A series of 16 squamous cell carcinomas of the pharynx with an extension to the cervical esophagus, or multiple primaries of the pharynx and esophagus is presented. The surgical procedure consisted of an oesophagectomy associated with either total pharyngolaryngectomy, or partial pharyngectomy, or transmandibular resection. 13 patients received neo-adjuvant chemotherapy: CDDP-5-FU. Postoperative complications occurred in less than 20% without any postoperative death. One-year and five-year actuarial survival rates were respectively 20% and 13.3%. The mean survival was 9.5 +/- 3.7 months. 75% of the deaths were due to local or cervical lymph node recurrences. Neo-adjuvant chemotherapy could improve the prognosis of these pharyngo-oesophageal carcinomas.

Adult↗
PubMed1988

[Olfactory meningioma with ethmoido-orbital extension. Diagnostic and therapeutic problems. Apropos of a case].

Our purpose is to present a case of olfactory meningioma with extensive invasion of the orbit and the ethmoid sinuses revealed by an exophthalmia. Diagnosis discussions with others tumors of the ethmoid sinuses are presented. Meningioma resection was realized simultaneously by ENT surgeons and neurosurgeons through a bifrontal coronal skin flap and orbital roof remaining. Anterior skull base reconstruction was performed with a madreporic coral graft, which is a simple, fast and reliable technique, permitting a complete skull base closure.

Ethmoid Sinus↗
PubMed1987

Modulation of the masking phenomenon by the crossed part of the medial olivocochlear bundle.

The masking phenomenon is used in clinical investigation of the inner ear to determine the frequency selectivity properties of the auditory system. Sectioning of the crossed part of the medial efferent bundle in a guinea pig model decreases the simultaneous masking phenomenon. The efferent effect seen in the forward masking varied with the masking paradigm used. When the masker onset precedes the maskee onset by more than 40 ms, masking diminishes after sectioning the crossed part of the medial efferent bundle. When this duration was shortest (30 ms), no effect was observed. This phenomenon could be explained by the time necessary to stimulate the medial efferent loop. Our results could explain some differences observed in the compound action potential masking curves with different masking paradigms.

Acoustic Stimulation↗
PubMed1987

The ultra-thin bronchoscope in management of the difficult paediatric airway.

The use of an ultra-thin flexible fiberoptic bronchoscope with a single lumen diameter of 2.7 mm at the distal tip to assist intubation of paediatric patients with a difficult airway is reported. Two patients (ages 30 months and 18 months) with mandibular hypoplasia and one patient (three months) with the Pierre-Robin syndrome are reported. In each case two fiberoptic bronchoscopes were used. The first allowed introduction of topical local anaesthetic while the second and smaller one was used for tube placement.

Anesthesia, Local↗
PubMed1987

Functional properties of the crossed part of the medial olivo-cochlear bundle.

The efferent innervation of guinea pig cochleas was sectioned medially, at the level of the floor of the fourth ventricle, to study the effects of the crossed part of the medial efferent pathway on the compound action potential (CAP) masking phenomenon. Sectioning reduced CAP masking for a masker level varying with the frequency of the masker and the time elapsed between the masker onset and the probe onset. Functional properties of the crossed part of the medial efferent tracts: latency, thresholds and frequency selectivity, could be deduced from these data.

Action Potentials↗
PubMed1987

Variations of cochlear microphonic potential after sectioning efferent fibers to the cochlea.

Cochlear microphonic (CM) potentials were recorded, in guinea pig, with differential electrodes before and after sectioning the medial efferent innervation at the level of the brainstem. Sectioning the crossed part of the medial efferent innervation did not change the CM whatever the frequency or level of stimulation used. Sectioning the medial--crossed and uncrossed--efferent fibers diminished CM amplitude at frequencies above 2 kHz. Thus, the ipsilateral medial efferent tract seems to be involved, through a tonic action, in controlling outer hair cell micromechanics.

Acoustic Stimulation↗
PubMed1987

[Latency, threshold and frequency selectivity of the crossed medial cochlear efferent pathways].

The efferent innervation of guinea pig cochleas was sectioned medially, at the level of the floor of the fourth ventricle, to study the effects of the crossed part of the medial efferent pathway on the compound action potential (CAP) masking phenomenon. Sectioning reduced CAP masking for a masker level varying with the frequency of the masker and the time elapsed between the masker onset and the probe onset. Functional properties of the crossed part of the medial efferent tracts: latency, thresholds and frequency selectivity, could be deduced from these data. This intensification of the masking phenomenon permitting the improvement of the signal to noise ratio, may thus be attributed to the crossed part of the medial efferent bundle which innervates the outer hair cells.

Animals↗
PubMed1987

[Recruitment and diplacusis. Current physiopathological concept].

The actual conception of cochlear physiology can explain the semiology of endocochlear hearing losses: mainly recruitment and diplacousis. Recruitment and diplacousis reflect lesions of outer hair cells in the cochlea. Actually, an early detection of these outer hair cells lesions may be a diagnostic priority: this seems possible with recordings of oto-acoustic emissions.

Cochlea↗
PubMed1987

[Gelatinous tear substitutes and nonspecific eye ointments in the critical care unit and in perioperative use].

The effect of Vidisic (a new jelly artificial tear solution) and an ointment basing on Dexpanthenol on the tear production and the tear film stability was studied both on patients in the intensive care units (ICU) and during operations. In 10 relaxed and ventilated patients of the ICU there was no significant change in the tear production after application of either therapy. In 30 patients, undergoing surgery in endotracheal anaesthesia, the break-up-time and the test according to Schirmer were measured pre- and postoperatively. Like in the ICU-patients no difference in tear production could be found. Regarding the stability of the precorneal tear film however Vidisic was more effective than ointment basing on Dexpanthenol. Especially this clear jelly artificial tear solution allowed in contrast to the ointment a permanent and reliable judgement of the pupillary reaction. In addition the patients felt more comfortable with Vidisic.

Acrylates↗
PubMed1987

[Oto-acoustic emissions. I. Evoked oto-emissions: a new technic of functional study of the cochlea].

Otoacoustic emissions (OAE) are sounds emitted by the cochlea and recordable in the external ear canal by a miniature microphone. These OAE reflect the existence of an active mechanism within the cochlea, probably based upon outer hair cells (OHC). Recordings of OAE are easy, noninvasive, objective and permit the exploration of an essential property of the cochlea which was impossible to study by the usual electrophysiological techniques. Clinical applications are discussed in this paper.

Adolescent↗
PubMed1986

Efferent tracts and cochlear frequency selectivity.

The cochlear innervation of guinea pigs was sectioned medially in a rostrocaudal direction at the level of the floor of the fourth ventricle, to study the effects of efferent pathways on cochlear microphonic (CM) suppression, the compound action potential (CAP) masking phenomenon, the input-output CAP function, and cochlear frequency selectivity estimated with tuning curves of single auditory nerve fibers. Sectioning reduced CM suppression without having any effect on absolute CM amplitude; it also reduced CAP masking. The input-output CAP function was not changed at intensities below 75 dB, and the single-unit tuning curves recorded before and after nerve sectioning were unaffected. Thus, the crossed efferent tracts (i.e., mainly the medial system) seems to be involved in the masking function itself, rather than one of the mechanisms responsible for high frequency cochlear selectivity.

Acoustic Stimulation↗
PubMed1986

Effects of section of the medial efferent tracts (crossed and uncrossed) on cochlear frequency selectivity.

The cochlear innervation of guinea pigs was sectioned midway between the midline and the external side of the cochlear nucleus, in a rostrocaudal direction at the level of the floor of the fourth ventricle, to study the effects of medial efferent pathways on cochlear frequency selectivity estimated with tuning curves of single auditory nerve fibers. Single-unit tuning curves were affected by this type of efferent sectioning. Thus, the ipsi-lateral efferent system seems to be involved, through a tonic action, in the mechanisms responsible for high frequency cochlea selectivity.

Acoustic Stimulation↗
PubMed1986

Severe adult hypersomnia--sleep apnea syndrome in craniofacial dysostosis.

Polysomnography and blood gas measurements during sleep in a young man with craniofacial dysostosis, who presented with an extremely severe sleep apnea syndrome, are reported. Tracheostomy relieved all his complaints permanently, namely hypersomnia, deteriorated intellectual performance, automatic behaviour with hypnagogic hallucinations and snoring. Laboratory results also returned to normal. The polygraphic data of night sleep (and daytime naps) before and after surgery suggest that hypersomnia was primarily caused by severe nighttime oxygen desaturations and that the hypnagogic hallucinations were caused by apnea-induced chronic REM sleep deprivation. Furthermore, the periodic variation of central respiratory drive, which was also abolished after surgery, is interpreted as the cause of apnea-induced fluctuations between sleep stages in this case.

Adult↗