Modelling the action of caloric stimulation of vestibule. III. Caloric nystagmus induced by osmotic pressure variation.

The properties of the membranous wall of the semi-circular canal and of the labyrinthine fluids give as a result the inflating pressure of this inflatable structure. The difference of osmotic pressure between perilymph and endolymph, which is involved in this problem, depends on temperature. Therefore, a caloric stimulation leads to a change in the inflating pressure. A numerical model, similar to the model used to study the effects of relative volume variations, gives a quantitative estimation of the transcupular pressure arising in a horizontal semi-circular canal (i.e. without gravity dependent effects) during a caloric stimulation, according to the inflating pressure change. As a consequence, it appears that rotational and caloric stimulations are not quite similar. The caloric stimulation leads not only to a transcupular pressure difference but also to a change in inflating pressure. As a result of the change in inflating pressure, the stiffness of the cupula varies. This modifies the gain and the dynamics of the vestibulo-ocular reflex, and may explain the asymmetry between hot and cold stimulations.

Modelling the action of caloric stimulation of the vestibule. IV. The global mechanical model.

Caloric stimulation acts on the bio-accelerometer (the semi-circular canal), as on engineered ones, through second order type multiple pathways. Three temperature induced peripheral actions have been described in our previous reports. The hydrostatic mechanism induces in the endolymph a gravity dependent transcupular stationary pressure difference. The differential expansion of the membranous duct and its content creates a local volume variation, while the modification of the transmembranous exchanges causes a local pressure variation. These two last mechanisms are gravity independent. They depend on parameters of the membrane, and induce a transcupular transient pressure difference and a stationary variation of the inflating pressure. It seems reasonable to assume the independency of these three mechanisms. If this assumption is true, than the global effect of caloric stimulation should be the sum of the effects of the three partial mechanisms. It is shown here that, for the physical model, this assumption holds. For humans, in the more general frame of the caloric vestibulo-ocular reflex experiments reported in the first paper, qualitatively and quantitatively this assumption holds, too. The model predicts a percentage of gravidity dependent effects of about 75%. It is shown that the reported human experiments lead to compatible estimates of this percentage. For humans in the earth gravity field, enduring the caloric stimulation it is not necessary to include neither otolithic interactions, nor significant modifications of the mecano-neural transduction, in the limits of precision of today's experimentation.

Modelling the action of caloric stimulation of the vestibule. II. The mechanical model of the semi-circular canal considered as an inflatable structure.

In order to explain the mechanical effects that arise when a semi-circular canal is thermally stimulated in the horizontal position (i.e. in the absence of gravity effects) a physical model was used. The duct (corresponding to the canal) is deformable, the pressure transducer (corresponding to the ampulla) is not deformable. There is no thermal similarity but a dynamical similarity has been respected, so the mechanical phenomena occurring in the semi-circular canal and in the model are identical. The time scale is close to one. The physical model showed that the relative volume variations (fluid/duct) due to caloric stimulation lead to a pressure variation measured by the pressure transducer at the place of the ampulla and the cupula. The time history and the value of this pressure depend on the mechanical and thermal properties of the duct and the fluid. The qualitative responses of the physical model and of the vestibulo-ocular reflex after caloric stimulation were coherent. A numerical model simulating the same mechanisms yielded a quantitative estimation of the transcupular pressure arising in a horizontal semi-circular canal (i.e. without gravity dependent effects) during caloric stimulation. The physical model and the numerical simulation take no account of the inflating pressure variation.

Modelling the action of caloric stimulation of the vestibule. I. The hydrostatic model.

In this first article of four the problem is displayed using experiments on humans for two kinds of gravity related positions. In each case the nystagmus depends sinusoidally on a particular orientation of the canal to the vertical. In each case, too, a dissymmetry of the response occurs. This kind of behavior confirms that the caloric stimulation induces both a gravity dependent and a gravity independent effect. A simple mechanical model gives account of the gravity dependent effect. It does not imply the otolithic system. Since the cupula adheres to the ampullar wall and to the crista, this is a hydrostatic model in contrast to Bárány's model, which is of hydrodynamic type.

Local and serum IgE in vasomotor rhinitis.

Total and specific IgE in serum and nasal secretions were measured in twenty five subjects with vasomotor rhinitis without asthma (21 perennial vasomotor allergic rhinitis and 4 seasonal vasomotor allergic rhinitis) after Carbacholine nasal challenge-test. The level of total and specific IgE was lower in the pure, non diluted nasal secretions than in the serum. The diagnostic usefullness of these measurements and the concept of "localized allergy" are discussed.

[Captopril potentiation of the hypotension induced by halothane]. / Potentialisation par le captopril de l'hypotension induite par l'halothane.

In a double-blind study, twenty-four ASA 1 and II patients scheduled for otosclerosis surgery were randomized in two groups according to the premedication given orally 1 h before anaesthesia: placebo (group P; n = 12) or 25 mg captopril (group C; n = 12). Anaesthesia was induced with thiopentone, fentanyl and vecuronium and was maintained, after oral tracheal intubation, with N2O/O2 (50/50); 5 min after intubation, the inspired halothane concentration (FIH) was set at 1.8-2% in order to obtain a mean arterial pressure (Pa) of 45-55 mmHg; thereafter, FIH was increased or decreased (+/- 0.5% every 3 min) in order to maintain this Pa value. Ventilation was controlled in order to assure normocapnia (35-40 mmHg). Inspired and expired (FEH) halothane concentrations were monitored by an halothane analyser. The plasma renin (ARP) and conversion enzyme activities (AEC) were measured before anaesthesia (ARP1, AEC1), 5 min (ARP2) and 55 min (ARP3, AEC2) after the start of anaesthesia. In group C, AEC1 and AEC2 were reduced by half, confirming the efficiency of captopril in inhibiting the conversion enzyme. ARP1 and ARP2 were increased in group C (5.42 +/- 4.2 and 9.92 +/- 7.35 micrograms.l-1.h-1. ARP3 increased in both groups (20.75 +/- 8.42 micrograms.l-1.h-1 in group C, and 24.60 +/- 15.40 in group P). Pa decreased to 55 mmHg more rapidly in group C (9 min in group C; 18 min in group P; p less than 0.05) and FEH could be reduced by a third (1.38 +/- 0.29% in group P; 0.90 +/- 0.17% in group C; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

[Electronystagmograhy in disseminated sclerosis. Uses and limits (author's transl)]. / L'électronystagmographie au cours de la sclérose en plaques. Intérêt et limites.

A review of the literature shows the extreme frequency of nystagmus and changes in vestibular reflexes in disseminated sclerosis. During the course of this disease, it is possible to detect nystagmus in at least two-thirds of cases and in a similar proportion there are changes in vestibular reflexes, usually a hyperreflexia, especially in the early phases of disseminated sclerosis. Subjectively the patients rarely complain of vertigo and such symptoms are in any case part of the early form of the disease. On the other hand, disorders of balance are much more frequent but the factors involved are numerous, and the role of the vestibular system is often debatable. Electronystagmography and oculography demonstrate the extreme frequency of spontaneous or fixed gaze nystagmus in this disease, as well as the extreme frequency of changes in conjugated eye movements; changes in reflex, voluntary and automatic conjugated eye movements. As a matter of fact, there are many kinds of nystagmus which are not related to any changes in the vestibular system, but which are rather more part of the overal changes of conjugated eye movements. Seen in this light, electronystagmography and oculography, by exploring the different kinds of conjugated eye movement, can help decisively in the diagnosis of disseminated sclerosis by revealing changes which reflect damage to the brain stem, lesions which are clinically very often silent. In this way the diagnosis of disseminated sclerosis may be confirmed. Furthermore, electronystagmography can easily suggest another diagnosis, other than the early form of disseminated sclerosis of the vestibular type.

[Technic and value of the carbachol nasal test in vasomotor rhinopathies]. / Technique et intérêt du test nasal à la carbacholine dans les rhinopathies vasomotrices.

The carbacholine nasal test assesses "nasal hyperreactivity", particularly its parasympathetic component, in vasomotor rhinopathies. This simple, reproducible test has been applied to two groups of subjects: a group of 26 healthy subjects without any rhinopharyngeal and/or allergic affections, and 10 patients with aperiodic non-allergic (6 cases) or allergic (4 cases) vasomotor rhinopathy, the 4 cases with allergy including 3 allergic to house dust mite and one to house dust mite and grass pollen. Nasal reactivity to carbacholine was evaluated by measuring the amount of rhinorrhea following variable concentrations (1/1000, 1/100, 1/25) and volumes (0,10 to 0,50 ml) of carbacholine solution. Nasal secretion was markedly increased in patients with a vasomotor rhinopathy (1.80 +/- 0.65 ml) when compared with control subjects (0.64 +/- 0.17 ml). The main conclusions to be drawn from this study, and possible applications of this test in rhinology are discussed.

[Polyposis of the nasal sinuses. Epidemiology and clinical aspects of 350 cases. Treatment and results with a follow-up over 5 years on 93 cases]. / La polypose nasosinusienne. Epidémiologie et clinique sur 350 cas. Traitement et résultats avec un recul supérieur à 5 ans sur 93 cas.

The authors report a series of 350 patients referred for clinical investigation of nasal polyps between 1980 and 1990. 93 patients were followed for more than 5 years. Allergy to inhalants was rarely found (2.8%). Detailed study of past rhinosinusal and bronchial symptoms often revealed a history of vasomotor rhinitis (nasal hyperreactivity HRN) preceding the nasal polyposis by a mean interval of 8 years. The ratio non-allergic vasomotor rhinitis/nasal polyps was 4.31 in women (41.4% of the patients) and 1.74 in men (58.6% of the patients). Treatment is usually based on the use of local corticosteroids. However, because of the variable clinical pattern of nasal polyposis treatment may be medical alone or both medical and surgical, and always requires a long clinical follow-up. Intolerance to aspirin is a factor of poor prognosis. A 15% failure rate was noted among patients intolerant to aspirin.

[Objective audiometry by recording of early and middle-latency auditory evoked potentials using an external method]. / Audiométrie objective par enregistrement des potentiels évoqués auditifs précoces et semi-précoces par voie externe.

The bio-electric potentials induced by a stimulus in the cochlea and the various structures of the auditory pathways of the brain stem and the primary auditory cortex may be collected using an external method. The authors frequently emply in clinical practice early components, which correspond to the cochlea response in the cochlear nucleus of the medulla, in the olive of the pons and the posterior quadrigeminal tubercle, and middle latency components, sub-cortico-cortical potentials generated in the thalamus and the primary auditory cortex. Combined use of early and middle latency components makes it possible, without preparation and with simple sedation in the child, to obtain an objective determination of threshold. In oto-neurology, this examination provides appraciable information concerning lesions in the auditory pathways: acoustic neuroma, brain stem tumour, multiple sclerosis, central deafness in patients with cerebral motor insufficiency.

[Vertebral-basilar artery insufficiency nystagmus (author's transl)]. / Le nystagmus de privation vertébro-basilaire.

The vertebral-basilar artery insufficiency nystagmus is the nystagmus induced by torsion and extension of the neck, continued for more than three minutes, after nystagmus of other origin has been excluded. It stands particularly in opposition with the nystagmus of cervical origin, which is proprioceptive. On the contrary, vertebral-basilar artery insufficiency nystagmus is of vascular origin. It enables the detection of an infra-clinical vertebral-basilar insufficiency. It deserves to be elicited before subjecting patients to any operation requiring prolonged cervical rotation.

[Nasosinusal aspergillosis. Apropos of 35 cases]. / Les aspergilloses naso-sinusiennes. A propos de 35 cas.

Principal characteristics of clinical and paraclinical pictures of nasosinusal aspergillosis (NSA) in 35 patients are analyzed and allow distinction of three main types of this nasosinusal fungal lesion. Localized, non-invasive nasosinusal aspergillosis (NINSA) is frequently of dental origin and presents as a chronic maxillary sinusitis resistant to conventional treatment. Serology is negative or non-significant for Aspergillus and recovery is complete after surgery. Invasive nasosinusal aspergillosis (INSA) affects debilitated patients (diabetes, immunodepression, malignant blood disease...), and presents with bone destruction, extension to orbit, base of skull and intracranial region, following an acute or subacute course with positive serology for Aspergillus. Early, wide surgical eradication is combined with local and general antifungal therapy but prognosis is poor. Allergic nasosinusal aspergillosis (ANSA), of more recent description, combines chronic sinusitis with severe nasosinusal polyposis, and specific histologic and immunologic features. Its course is favorable with corticoid therapy but long-term results are unknown.

[Extensive cervical hematoma complicating multinodular goiter. Apropos of a case]. / Hématome cervical extensif compliquant un goitre multinodulaire. A propos d'une observation.

The massive hemorrhagic accidents of multinodular goiter are very rare, implicating the vital prognosis through an airway obstruction by tracheal compression. To illustrate this situation, the authors present an original case with a large cervico-thoracic hematoma without any respiratory's difficulties. The serious evolutive potential of that situation in spite the unworrying aspect of the patient, bring them to operate in delayed emergency.

[Use of madreporic material in ear surgery. An initial study]. / Utilisation de matériaux madréporaires en chirurgie otologique. Etude préliminaire.

Numerous surgical techniques now call for biomaterials. Included in this term is material foreign to the receiver, of natural or artificial origin, which is implanted in a living organism in order to repair the impaired function of the organ. By using a recent material, coral, the authors here by relate their experience within the scope of ear surgery. The analysis of the preliminary results encourages the further use of this material, bio-compatible, easily-used and giving excellent functional results.

[Mucormycosis-actinomycosis and caseous dental sinusitis associated with sinusal foreign body]. / Mucormycose-actinomycose et sinusite caséeuse dentaire avec corps étranger intra-sinusien.

The authors report an uncommon case of caseous dental sinusitis with infection or superinfection by mocorales and actinomycetes. The patient was healthy, without diabetes mellitus, but was treated for lymphoma 18 years before. This observation leads to a discussion of nosologic, diagnostic and therapeutic features of caseous sinusitis, dental or not, fungal or not, which are often or too often called aspergillosis sinusitis. The recovery of the patient was complete after surgery, amphotericin B and hyperbaric oxygen.

[Cholesteatoma in children. Apropos of 110 cases]. / Le cholestéatome de l'enfant: a propos de 110 cas.

This retrospective study of 110 middle ear cholesteatomas, concerning children up to 15 years old which have been treated between 1982 and 1992 in the ENT department of the university hospital of Strasbourg, analyzes the particularities of this disease and the therapeutic strategy adopted. The evolution of middle ear cholesteatoma is more rapid in childhood than in adulthood, due to greater growth potential of tissue in childhood, persistence of Eustachian tube dysfunction and aggressive extension in middle ear. The surgical removal is said to be difficult with numerous postoperative recurrences. Closed technique tympanoplasty was used for 47 cholesteatomas (43%), with a postoperative recurrence rate of 54%. An open technique was used for 63% cholesteatomas (57%), with a recurrence rate of 29%. The postoperative follow up has to be continued as long as possible, whatever the technique used may be.

[Rhabdomyosarcoma of the nasopharynx occurring with immunosuppressive treatment with cyclosporin A. Apropos of a case]. / Rhabdomyosarcome du cavum apparu sous traitement immunosuppresseur à la ciclosporine A. A propos d'un cas.

The authors report the case of a 15 year old adolescent who presents a rhabdomyosarcoma of the rhinopharynx. This young patient underwent 23 months before a kidney transplantation and was since under immunosuppressing treatment including corticoids, azathioprine and cyclosporin A. The characteristics of this tumor make it probably induced by the therapeutic based on cyclosporin.

[Cancer of the maxillary sinus. A retrospective study of 29 cases]. / Cancers du maxillaire supérieur. Etude rétrospective à partir de 29 cas.

Representing 2% of malignant tumors and 6% of head and neck cancer, almost always diagnosed at a late stage, maxillary sinus cancer still remains a rather rare pathology but fearsome prognosis. From the 29 cases, over 10 years of follow up at the clinic and Paul Strauss cancer treatment center, this study focuses mainly on two criteria: diagnosis, in the study of the presenting symptoms in order to treat this pathology as soon as possible; therapeutic, by analysing our results, and by focusing on the current treatment.

[Static and dynamic posturography. Application to a population of young athletes]. / Posturographie statique et dynamique. Application à une population de jeunes sportifs.

The authors used a vertical force platform fitted with 4 pressure gauges (Societe Toennies). The static regime provides the statokinesigram, the lateral and sagittal stabilograms and their Fourier transformations. Information is collected with the eyes open and closed, thereby allowing the Romberg quotient to be determined. In the dynamic regime, the platform unexpectedly tilts to a toes-up position (4 degrees at a rate of 50 degrees/s). The activity of the tibialis anterior and soleus muscles is recorded by integrated electromyography. The early soleal response, provoked by the myostatic reflex, is followed by later responses due to the vestibulo-spinal reflex. These various parameters were recorded in young athletes and the obtained tracings are commented on.

[A new approach to the mechanism of vestibular response to caloric stimulation]. / Nouvelle approche du mécanisme de la réponse vestibulaire à la stimulation calorique.

Barany's classical hydrodynamic theory has been called into question by the zero-gravity Spacelab experiments, and several new hypotheses are put forth to explain the vestibular response to caloric stimulation. We have developed a mathematic model based on the analysis of an experimental model of the semicircular canal, incorporating observations done with zero-gravity and with gravity. Two purely mechanical phenomena are involved: one one hand, the modification of the hydrostatic pressure on both sides of the cupula due to a temperature variation if the semicircular canal is not in the horizontal plane in normal gravity conditions; on the other hand, local changes in endolymph pressure and volume due to the mechanical and osmotic properties of the canal, which are independent from gravity and from the position of the canal. These mechanical processes, though not exclusive, are predominant and therefore sufficient to explain the caloric response of the vestibulum in all cases.