[Seven principles in the treatment of vestibular vertigo and results of the study of VIRTUOSO]. / Sem' printsipov lecheniia vestibuliarnogo golovokruzheniia i rezul'taty issledovaniia.

This article reports the results of the international post-marketing observational program VIRTUOSO aimed at the evaluation of the efficacy of betahistine dihydrochloride at the dose of 48 mg/day for 1-2 months in patients with paroxysmal vertigo of various origins. The clinical response was rated as good, very good or excellent in 74.1% of the patients (p<0.001). Monthly vertigo attack frequency with betahistine decreased in average from 8.0 to 3.0 (p<0.001). Vertigo attack frequency further decreased during the 2-month follow-up after the end of betahistine treatment. No serious adverse effects of betahistine have been reported.

[MODERN INSTRUMENTS FOR EAR, NOSE AND THROAT RENDERING AND EVALUATION IN RESEARCHES ON RUSSIAN SEGMENT OF THE INTERNATIONAL SPACE STATION].

The paper reports the results of testing some diagnostic video systems enabling digital rendering of TNT teeth and jaws. The authors substantiate the criteria of choosing and integration of imaging systems in future on Russian segment of the International space station kit LOR developed for examination and download of high-quality images of cosmonauts' TNT, parodentium and teeth.

[The complete elimination of the episodes of benign positional paroxysmal vertigo in a patient with the involvement of the posterior semicircular canal following the eccentric rotation test].

The objective of the present study was the clinical and neurophysiological analysis of the observations of a 42 year-old female patient suffering from benign paroxysmalpositional dizziness (BPPD) associated with the lesion of the posterior semicircular canal. The dynamic evaluation of the utricular function was performed during eccentric rotation of the patient in the vestibulometric chair at a speed of 300 degrees. The chair together with the patients was atomatically displaced during the rotation 3.5--4.0 cm to the right or left off the vertical axis, and the error in subjective perception of the deviation from the vertical was estimated. The saccular function was evaluated by recording cervical vestibular evoked myogenic potentials. The symptoms of BPPD were found to completely disappear after the eccentric rotation. Not a single spell of benign paroxysmalpositional dizziness was documented within 6 months after the eccentric rotation. The mechanisms underlying the elimination of these symptoms as a result of eccentric rotation are discussed.

[Prospects for the use of histaminergic preparations for the purpose of noise otoprotection].

The objective of the present study was to experimentally evaluate the otoprotective effect of the histaminergic preparation betagistin dihydrochloride given at a dose of 32 mg to 10 healthy male volunteers aged from 18 to 22 (mean 19.4) years who were exposed to 85 dB "white" nose for 1 hour. The functional state of their auditory system was estimated from the results of investigations including determination of the tonal auditory threshold, delayed evoked otoacoustic emission and distortion-product frequency otoacoustic emission, short-latency evoked auditory potentials, and extratympanic electrocochleography. It was shown that betagistin dihydrochloride produced a well-apparent otoprotective effect over the entire range of tests comprehensively characterizing the functional state of the cochlea. It is concluded that betagistin dihydrochloride has good prospects for the application in a variety of production activities (to treat occupational noise-induced pathology) including aerospace medicine.

[Otoprotective effect of argon in exposure to noise].

The trial with participation of 10 healthy volunteers aged 18-25 years was made to assess an otoprotective effect of inert gas argon (Ar) in 1-hour exposure to 85 dB white noise. The condition of the acoustic system was evaluated by findings of pure-tone audiometry, TEOAE, DPOAE, BERA and electrocochleography (EcohG). Breathing with oxygen-nitrogen-argon gas mixture (02 - 16%, N2 - 60%, Ar - 24%) in normobaric pressure provides cochlear defense from noise hazard. The authors believe that argon has otoprotective and neuroprotective effects in all types of existing models of cochlear hair cell affection related to hypoxia, oxidative stress, activation of peroxide radicals, toxic effect of glutamate. The detected defensive effect of argon in experimental human hypoxia and in exposure to noise opens a perspective of a new therapeutic strategy in noise damage to the organ of hearing, ototoxic processes in the cochlea and of a novel trend in the treatment of neurosensory hypoacusis and noise in the ear.

Efficacy of histaminergic drugs in experimental motion sickness.

The purpose of this investigation was to evaluate the efficacy of the histaminergic drug "Betahistine dihydrochloride" in experimental motion sickness in 10 healthy volunteers (mean age 19.4 y.o.) with high susceptibility to motion sickness. Motion sickness was modeled using Coriolis (precession) accelerations (cumulative Coriolis stimulation test--CCST). Each subject took 32 mg of "Betahistine dihydrochloride" or placebo under "double-blind" conditions 1 hour before testing. The duration and slow phase velocity of the post-rotational nystagmus, the pursuit eye tracking test, and the latency, velocity and accuracy of saccades were estimated. The tolerability level of the CCST in volunteers in the betahistine series was shown to be significantly (p<0.001) higher, as compared to placebo and baseline. The mean illusory sensations score for the experimental series was significantly lower than that in the placebo and baseline series (p < 0.01). It was found that "Betahistine" demonstrated antimotion sickness efficacy and improved oculomotor activity (increased gain during pursuit movements, faster and more accurate saccades).

[Use of auditory brain stem implant in a patient with bilateral vestibular schwannoma (type 2 neurofibromatosis]. / Ispol'zovanie slukhovogo implanta stvola golovnogo mozga u bol'nogo s bilateral'noi vestibuliarnoi shvannomoi (neirofibromatoz 2-go tipa).

Surgical technique and functional results of implantation of the acoustic implant of the brain stem (BS) are described for a 16-year-old patient with bilateral vestibular shvannoma (neurofibromatosis of type 2). Initially, a large (IV degree) tumor was removed from the left cerebellopontile angle using the translabyrinthine-transcochlear approach. The function of the facial nerve recovered completely. The BS implant was implanted a year later in the course of removing shvannoma from the right cerebellopontile angle using the above approach. The patient received 22-channel implant Nucleus-CI22M. Speech intelligibility improved by 90-100%. BS implantation is today the only effective method of reestablishment of acoustic sensations in patients with bilateral destruction of the acoustic nerves due to bilateral vestibular shvannoma.

[Role of external respiration in the formation of the autonomic component in motion sickness]. / O roli vneshnego dykhaniia v formirovanii vegetativnogo komponenta bolezni dvizheniia.

Time course variations in the ventilation and gas exchange functions of the lungs, gas composition and acid-base equilibrium of blood were investigated in 22 male test subjects, aged 27-49 years, who were kept in the head-down position (-8 degrees) and rocked in parallel swings. The subjects susceptible to motion sickness developed lung hyperventilation and concomitant alveolar-arterial hypocapnia and respiratory alkalosis which may potentiate a symptom-complex of vestibular disorders. To control hypocapnia, the subjects used a hypercapnic breathing mixture (4% CO2, 96% air). This eliminated the above changes in the gas composition and acid-base equilibrium of blood, and in 7 out of 10 subjects alleviated vestibular symptoms and elongated the time of motion tolerance. In addition, the prophylactic effect of hypercapnic exposure showed individual variations which seem to be associated with individual sensitivity of the respiratory center to hypercapnic stimulation.

[Otosurgery in the professional rehabilitation of divers]. / Ispol'zovanie otokhirurgii v professional'noi reabilitatsii vodolazov.

Factors responsible for barotraumas of the middle and internal ear of divers are discussed. A rapid, uncontrollable change in the intratympanic pressure upon diving may cause tympanum perforation, injury and displacement of auditory ossicles which, in turn, may lead to excitation of vestibular receptors. Barotraumas of the middle ear may also be produced by exostoses of the auditory meatus. The present work describes follow-up data of two divers who were grounded due to external and middle ear problems. One of them was operated on to remove bone exostoses that obturated the auditory meatus. The other diver underwent surgery to close the tympanic "barometric" perforation. After reconstructive surgery both divers resumed their professional activities. Both cases were followed-up for over three years.

[Characteristics of motion sickness during prolonged otolith stimulation in anti-orthostatic position]. / Osobennosti techeniia bolezni dvizheniia pri dlitel'noi otolitovoi stimuliatsii v antiortostaticheskom polozhenii.

Thirty healthy volunteers were tested for an extended period of time (up to 4 hours) on modified parallel swings during a head-down tilt (-8 degrees) study. The pattern of motion sickness that developed in this situation was evaluated in terms of physiological parameters (electrocardiography, rheoencephalography, arterial pressure, respiration rate electrooculography, etc.), hormonal status, fluid-electrolyte balance, sensory function. The test subjects developed a vestibulo-hemodynamic syndrome that included vestibular disorders, spatial illusions, fluid displacement in the cranial direction, excitation of the hypothalamic-pituitary-adrenal system, changes in fluid-electrolyte balance. The resulting data may help better understand mechanisms underlying motion sickness.

Comparative assessment of vestibular, optokinetic, and optovestibular stimulation in the development of experimental motion sickness.

The contribution of vestibular, optokinetic, and optovestibular stimulation to experimental motion sickness was evaluated in 29 volunteer subjects. Vestibular stimulation (Coriolis effect) was found to induce the most significant vestibular-autonomic disorders. Optokinetic stimulation (pseudo-Coriolis effect) and optovestibular stimulation could provoke such disorders only in susceptible subjects. In quantitative terms, optokinetic and optovestibular stimulation were less effective than vestibular Coriolis stress. Nystagmic reactions of susceptible subjects to the three types of stimulation differed significantly from those of tolerant subjects. This may be important from the theoretical point of view because susceptibility to motion sickness and responses to vestibular and optokinetic stimulation may be universal and associated with the general CNS mechanism, i.e. inhibition mechanism. The identified correlation between the duration of postoptokinetic illusion and motion sickness susceptibility may be used to differentiate susceptible and tolerant subjects.

Experimental assessment of selected antimotion drugs.

Space motion sickness (SMS) has been a perplexing problem in both the Soviet and U.S. manned space programs. Both the sensory conflict theory (neuronal signal mismatch) and the cephalad fluid shift concept explain the mechanism. This paper reviews the mechanism of action of various drugs that primarily affect brain blood flow or brain metabolism. In particular, Cavinton (apovincamic acid ethyl ester) has been used successfully in offsetting SMS in experimental test subjects.