Vestibular Reactions Research Articles

Posterior cingulate epilepsy: Seizure semiology and intracranial electrical stimulation using SEEG

PurposeThis study aimed to explore seizure semiology and the effects of intracerebral electrical stimulation on the human posterior cingulate cortex (PCC) using Stereoelectroencephalography (SEEG) to deepen our comprehension of posterior cingulate epilepsy (PCE). MethodsThis study examined the characteristics of seizures through video documentation, by assessing the outcomes of intracranial electrical stimulation (iES) during SEEG. We further identified the connection between the observed semiology and precise anatomical locations within the PCC subregions where seizure onset zones (SOZ) were identified. ResultsAnalysis was conducted on 59 seizures from 15 patients recorded via SEEG. Behavioural arrest emerged as the predominant manifestation across the PCC subregions. Where ictal activity extended to both the mesial and lateral temporal cortex, automatism was predominantly observed in seizures originating from the ventral PCC (vPCC). The retrosplenial cortex (RSC) is associated with complex motor behaviour, with seizure discharges spreading to the temporal lobe. Seizures originating from the PCC include axial tonic and autonomic seizures. Only one case of positive clinical seizures was documented. High frequencies of iES within the PCC induced various clinical responses, categorised as vestibular, visual, psychological, and autonomic, with vestibular reactions primarily occurring in the dorsal PCC (dPCC) and RSC, visual responses in the left RSC, and autonomic reactions in the vPCC and RSC. ConclusionThe manifestations of seizures in PCE vary according to the SOZ and the patterns of seizure propagation. The occurrence of seizures induced by iES is exceedingly rare, indicating that mapping of the PCC could pinpoint the primary sector of PCC.

Features of vestibular function in patients with sensorineural deafness of vascular origin

Objective: to study the features of vestibular dysfunction in patients with sensorineural hearing loss of vascular origin, depending on the degree of discirculation in the main vessels of the head. Metods. We examined 60 patients with various degrees of sensorineural hearing loss with circulatory disorders in the vertebrobasilar system (VBS), including 36 (60%) women and 24 (40%) men. The average age of the surveyed was 49.9±1.89 years. All patients underwent audiometry in an extended frequency range up to 20 kHz, the study of acoustic stem evoked potentials, acoustic reflexometry. A caloric test was used to study experimental vestibular reactions, and the results were recorded using computerized electronystagmography. Results. According to the otoneurological examination, the patients were divided into 3 subgroups. Peripheral cochleovestibular syndrome (PCVS) was diagnosed in 14 (23%) patients, central cochleovestibular syndrome (CCVS) in 19 (32%), and combined cochleovestibular syndrome (CVS) was diagnosed in 27 (45%) patients. In the analysis of complaints presented by patients with SHD of vascular origin, the combined complaints of hearing deafness, tinnitus and neurological symptoms (headaches, amnesia, paresthesia, fatigue, etc.), as well as dizziness and neurological symptoms, significantly prevailed compared with individual complaints of hearing loss or dizziness (p < 0.05). An analysis of the asymmetry of the pathological process on the right or left side did not reveal significant differences, however, the proportion of patients with bilateral lesions in the subgroup with CCVS was significantly higher. If vestibular nystagmus is an unconditioned stem reflex, then optokinetic nystagmus is a product of the activity of the cerebral cortex and occurs with the active participation of the patient himself in the process of research. Conclusion. The obtained data were compared with the structural changes and hemodynamic parameters in the blood of vertebral arteries (VA) and internal carotid arteries (ICA), as well as magnetic resonance imaging of the brain (MRI).

О некоторых ярких страницах в истории вестибулологии ХХ века (исторический обзор, дискуссионные вопросы) Часть IV. Нистагм и история его изучения. От визуальной оценки до электро- и видеонистагмографии

The article is devoted to the stages of studying nystagmus, the most valuable vestibular reaction in diagnostic terms. It tells about the development of methods for recording nystagmus, from visual assessment to objective methods: electro- and videonystagmography. The importance of excluding gaze fixation when assessing nystagmus is emphasized, which both of these methods provide. The author dwells separately on the works of remarkable scientists, vestibulologists, and researchers of nystagmus – the leader in the 1970s–1990s of the vestibular laboratory at the Leningrad Research Institute of Ear, Throat, Nose, and Speech, Professor Mikhail Levashov and the long-term head of the laboratory of clinical labyrinthology of the Belarusian Research Institute of Neurology, Professor Abram Sklyut.

О некоторых ярких страницах в истории вестибулологии ХХ века. Исторический обзор, дискуссионные вопросы. Часть 3. Постижение «неразгаданного сфинкса» (вестибулология и хирургия отосклероза)

The article, which consists of several parts, continues the discussion of some bright pages from the history of vestibulology in the 20th century. The third part deals with the impact of the global “otosclerotic boom” and the success of cophosurgery in the 1950s and 1960s on the development of vestibulology. The need to study the vestibular function in patients with otosclerosis was due to the task of determining the stage of the otosclerotic process, assessing the functional state of the inner ear depending on hypo- or hyperreflexia of the labyrinth, predicting the severity of the postoperative vestibular reaction and its objective assessment in the postoperative period. Vestibular studies have helped to comprehend important pathogenetic aspects of otosclerosis: understanding the impact of the otosclerotic process on the structures of the inner ear due to hydrops of intralabyrinthine fluids when the stapes is immobile, through the impact of metabolic products of active foci directly on prescription formations, and others. The article tells about the revival of interest in labyrinthology after the Second World War in the aspect of the study and surgery of otosclerosis. The great interest of Soviet otosurgeons in the pre-war work of Julius Lempert on the fenestration of the labyrinth (1938) and in the successes of world stapedial surgery in the 1950s is reported. The facts are given about the visit of the author of the stapes mobilization operation, Samuel Rosen, in 1958 to the USSR and his participation in the V All-Russian Congress of Otorhinolaryngologists. As a result of these global processes, in 1964, for the improvement and widespread introduction of surgical methods for restoring hearing in patients with otosclerosis, prominent Soviet scientists-otorhinolaryngologists – A. I. Kolomiichenko, K. L. Khilov, S. N. Khechinashvili, N. A. Preobrazhensky and V. F. Nikitina were awarded the Lenin Prize. Among the well-known researchers of otosclerosis are domestic scientists and at the same time successful otosurgeons, women, contemporaries – L. G. Svatko, O. F. Patyakin and N. I. Hrappo. Clinical-morphological-histochemical comparisons and studies of the activity of the otosclerotic process, carried out in the works of the professor of the Kazan Medical University Lyudmila Grigoryevna Svatko, a deep researcher of the pathogenesis of otosclerosis, are reported. It tells about the professor of the Moscow Research Institute of Ear, Throat and Nose Olga Fyodorovna Patyakina-Fyodorova and about the school of domestic otosurgeons she created. The article tells about the long-term studies of the vestibular function in otosclerosis and other diseases by the famous otoneurologist, professor of the Samara Medical University Nina Stepanovna Khrappo and about the audiology direction of the ENT department, for many years headed by Academician I. B. Soldatov. A conclusion is made about the stimulating and beneficial effect of the study of the “mysterious sphinx” (according to N. V. Belogolovy, 1933) and cophosurgery on the development and improvement of vestibulometry techniques, as well as functional ear function studies in general, and more broadly, otosurgery, as such.

On the Issue of Functional Vestibular Disorders and Methods of Their Correction in Foreign Students

Vestibular stimulations influence the somatic-vegetative functions of the organism, including the muscular system. The prevalence of a sedentary lifestyle among students and, especially foreign students, in combination with a prolonged fixed position of the head, promotes to the development of functional-vestibular disorders. This affects both the academic progress and health state of these students. The purpose of the work was to study the influence of vestibular disorders of the motor and visual analyzers, with the following correction of these disorders by using relax gymnastics with yoga elements. Materials and methods. The study was carried out during 4 months, and included 52 students from India, studying at the 2nd year of Kharkiv National Medical University. A block of anamnestic and diagnostic-instrumental research methods was used. Results and discussion. As a result of the observations, it was found that the initial level of body physical development and the degree of an adequacy of the mode of mental work and rest to the nature of the educational process play a large role in the degree of occurrence of vestibular reactions. Particular attention was paid to the assessment of vestibular stability, which was reduced in 21 out of 52 students, which was noted on the basis of the presence of 2 or more parameters defined during the study. These students were included in the experimental group (12 people) and the control group (9 people). All these students had either a reduced level of physical development or various deviations in the level of body physical development. For the students of experimental group three-months cycle of relax-training gymnastics with yoga elements was proposed. For all students, vestibular irritations reduced the accuracy of the performed movements, but for students with a reduced level of physical development, these indicators were worse and more stable. As a result, the students of the experimental group demonstrated positive dynamics of the correction for vestibular adaptation to the studying process in comparison with the students of the control group that did not demonstrate the same results. Conclusion. The results of the investigation which was carried out allow to formulate the following conclusions: 1) Vestibular reactions depend on the initial level of physical development of students and the nature of the educational process; 2) Regular stimulations of the vestibular apparatus on the background of relaxation and training exercises with yoga elements contribute to an increase in the motor functions of the body; 3) Vestibular irritations cause more frequent and expressed somatic reactions in comparison with vegetative ones

Vestibular and acoustic dysfunction in patients with early stages of vestibular schwannoma

Introduction: Vestibular schwannoma (VS) is known to be a benign tumor. It develops from the Schwann cells in the vestibular portion of the VIII nerve. The causes of tumor development are not fully defined. VS is diagnosed more often in people of active age (30-60 years), mostly in women. Aim: The aim is to study the state of vestibular and acoustic dysfunctions in patients with VS at an early stage. Materials and Methods: A total of 71 patients with MRI-verified VS at an early stage were analyzed. The 1st group consisted of 34 patients with intracanal VS, and the 2nd group included 37 patients with stage one VS. Vestibular dysfunction, including the registration of three pathological vestibular reactions vestibulo-somatic, vestibulo-sensory and vestibulo-vegetative, was studied. Acoustic dysfunction was studied using tonal, speech and suprathreshold speech audiometry, and auditory brainstem responses (ABR). Results: Unilateral or asymmetric bilateral vestibular dysfunctions have been established in all patients at the early stages of VS, which forms phantom phenomena of sensory and motor memory in the cortical structures of the brain in the form of pathological vestibulo-somatic, vestibulo-sensory and vestibulo-vegetative reactions, which are to be considered during rehabilitation. Acoustic dysfunction of different manifestations—from normal symmetrical hearing to socially adequate unilateral or asymmetric sensorineural hearing loss of degree I-II, and significant socially inadequate sensorineural hearing loss of degree III-IV, deafness, and also mixed hearing loss, was determined in these patients. ABR registration indicated unilateral or asymmetric delays of sound signals transferring in the brainstem structures at the early stages of VS with both normal hearing and socially adequately impaired hearing. Conclusion: Various manifestations of vestibular and acoustic dysfunctions with development of excitatory and inhibitory processes in the peripheral, brainstem, and cortical structures of the vestibular and acoustic systems were defined in all patients at the early stages of VS.

METHODS OF RESEARCH OF THE FUNCTIONAL CONDITION OF THE VESTIBULAR APPARATUS IN CHILDREN WITH SENSORINEURAL HEARING LOSS

The article considers research methods and features of the functional state of the vestibular apparatus and vestibular disorders in children with sensorineural hearing loss. We used the methods of analysis, generalization and systematization of data from domestic and foreign literature sources on methods of studying the vestibular apparatus in children with sensorineural hearing loss. It was determined that the function of balance and coordination of movements is one of the most complex, and consists of several analyzers - visual, vestibular, proprioceptive and tactile. When studying the physical development of children with this pathology, attention is paid to the formation of the main static-dynamic and coordination capabilities according to the age of the child. In children with congenital sensorineural deafness, and especially double deafness, there are signs of vestibular insufficiency and impaired translational control, movement and gait. This affects the development of gross motor functions, such as sitting and walking, to a lesser extent affects fine motor skills, if there are no layers of other pathologies of the central nervous system.
 The pathological process in the auditory analyzer changes the function of the vestibular apparatus, due to their close location in the labyrinth and innervation by one cranial nerve, and in turn changes in the vestibular apparatus contribute to the formation of motor disorders. Therefore, we can observe a certain general principle of operation of the auditory and vestibular systems. At children who have low vestibular stability any turns, inclinations, sharp change of a direction of movement causes imbalance of coordination and balance of movements. All these delays in physical development, according to many authors, are cumulative in character and are caused by the hearing defect itself, insufficient information from the environment, difficulty expressing thoughts and desires verbally, as well as the state of the motor analyzer and vestibular activity. Children with hearing impairment have an insufficient level of coordination development, physical development, static and dynamic balance, spatial orientation. Researches of the vestibular apparatus, namely the functions of coordination and balance are carried out in several categories: the research of tonic vestibular reactions, coordination of movements and static and dynamic balance. Researches of tonic vestibular reactions are performed on the following tests: the test with outstretched arms, Vodak-Fisher test, pointing test Barani, finger-nose test, Holmagi test. Researches of static and dynamic equilibrium are carried out on the samples of Romberg, Grahe, Oppenheim, walking in a straight line. When analyzing these samples, we can talk about the degree of violation of coordination and stato-dynamic balance.
 As a result of vestibular compensation, children with sensorineural deafness can catch up with their peers with normal hearing with the help of visual and somato-sensory systems, pyramidal and extra-pyramidal systems.

The Effect of Afferentation of Various Sensory Systems on the Otolith-Ocular Reflex in a Real and Simulated Weightlessness

Weightlessness can affect the vestibular function, primarily the otolith function, both directly due to the loss of gravitational influence and by eliminating the support and minimizing proprioceptive afferentation, influencing indirectly through the central integrative multisensory structures of the central nervous system (CNS), where the convergence of afferent signals of various sensory modality (primarily visual, vestibular, support and motor) occurs. All this prompted the study of the influence of various afferentations on the otolith-ocular reflex under the conditions of real and simulated weightlessness. Using the video oculography method, 58 Russian cosmonauts, members of long-term missions to the ISS (125–219 days, ~175 days on average), were examined by a static torsional otolith-cervical-ocular reflex (OCOR) with a head tilt to the shoulder at an angle of 30 deg, the otolith-ocular reflex (OOR) when the body is tilted at an angle of 30 deg, and the otolith-ocular reflex when exposed to centrifugal acceleration using a centrifuge (OORCF). Nine out of 58 cosmonauts were examined in microgravity (175 days) as part of the Virtual space experiment (Stage 1). The study of simulation of the spaceflight (SF) factors involved 30 subjects during five- or seven-day horizontal “dry” immersion (DI) and 12 subjects in 60-day head-down tilt (–8 deg) bed rest (BR). The procedure and the corresponding hardware and software used both in studies with the participation of cosmonauts and in model experiments were completely identical. In weightlessness, throughout the whole SF, all the cosmonauts surveyed had a significant OCOR decrease with the presence (from 11 to 55%, depending on the flight day) of the atypical (inversion or absence) otolith-ocular reflex. After SF, on days 1–4 of examination, 80% of the cosmonauts exhibited a significant OCOR/OOR decrease; 34% of the cosmonauts had atypical (inversion or absence of the otolith reflex) vestibular reactions, while no differences were found between OCOR and OOR. Statistically significant differences were found between the values ​of the OCOR/OOR and OORCF reflexes before and on days 4–5, 9–12 after SF. On days 2–3 after SF, no difference between OORCF and OCOR/OOR was observed. The return of the otolith reflex to the baseline took place only on day 9 after SF. The OCOR/OOR study on days 1–3 after DI showed that the otolith-ocular reflex in 47% of those examined was significantly reduced; in 13% of the subjects atypical reactions (absence or inversion of the reflex) were recorded. On days 4–6 after DI, OCOR/OOR returned to the baseline in all subjects. Analysis of OCOR/OOR after the BR experiment showed that only 14% of the surveyed had a significant decrease in OCOR/OOR on day 1 after the experiment. The atypical form of OCOR/OOR (inversion or complete absence of the otolith reflex) after BR was not revealed in contrast to the testers after DI. The results obtained demonstrated the influence of nonvestibular afferentation on the intensity of the otolith-ocular reflex and its dependence on other sensory inputs.

РОССИЙСКИЕ ВЕСТИБУЛЯРНЫЕ ИССЛЕДОВАНИЯ НА ОБЕЗЬЯНАХВ ПОЛЕТАХНА БИОСПУТНИКАХ

The BION program with primates included 2 vestibular studies one was focused on coordination of the eye and head movements and activities of the medial vestibular nuclei and cerebellum flocculus during angular head movements in the horizontal plane for gaze fixation and the other, on the central vestibular neurons and otolith-induced cardiac rhythm reaction during linear displacement about the body axis. Sensitivity of the central vestibular neurons to both angular and linear accelerations was found to increase at the beginning of microgravity and then normalized gradually, whereas the flocculus activity remained high throughout the mission.

Efficiency of Electrical Tranquilization of the Central Nervous System in Combination with Vestibular Training to Improve the Statokinetic Stability

Improvement of statokinetic stability is a pressing problem of aviation medicine in view of progress in aviation engineering. As the speed and maneuver capability of aircrafts grew, the conflict between a continuous increase in available power and constant psychophysiological abilities of the human body becomes inevitably harder. Statistics evidences that 49.0% of aviation accidents are due to erroneous actions of pilots. Today, tough mental activity is involved in an aviator’s labor, while the body is affected by a broad variety of flight-related factors. Information flow analysis, instant decision making, and control of aircraft strain the psychophysiological human abilities to their limit. All aircrew members must keep being professionally effective throughout the mission. This circumstance warrants the development of appropriate means and methods to improve the statokinetic stability in air and space crews. The objective of this work was to study the psychophysiological dynamics during statokinetic perturbations prior to and after a course of electrical tranquilization of the central nervous system (CNS) in combination with modified Yarotsky’s test (MYT). Statokinetic perturbations were modeled using a continuous Coriolis acceleration accumulation test (CAAT) in a rotating chair. The indices under study included the maximum CAAT tolerance time and the strengths of vestibular sensory, vestibular vegetative, and vestibular somatic reactions. Functional characteristics were tested using complex functional computer stabilography (CFCS). An analysis of the results led to the conclusion that a course of CNS electrical tranquilization in combination with MYT is highly efficient.

25-Influence of vestibular neurectomy on posture of the head and shoulder

Introduction The aim of this study was quantitative evaluation of vestibular head tilt in 3 D. Patients after vestibular neurectomy served as model of acute unilateral vestibular failure. Methods Real time measurement of head and shoulder posture was done in eleven patients who underwent vestibular neurectomy for vestibular Schwannoma. All patients were examined within two weeks. Angle deviations of the head in pitch, yaw and roll planes and deviation of the shoulders in yaw and roll planes were calculated. Results were compared with a control group of 130 healthy persons. Results There was significant head tilt in the roll plane towards operated ear. No correlation between head rotation in yaw and pitch planes was observed. Position of shoulders tended to compensate head rotation in six of eleven patients. Range of movements of head was increased. Conclusions Our study finds significant head tilt in roll towards weak labyrinth – part of vestibular ocular tilt reaction. Contrary to expectations, no systemic head rotation in yaw plane was found.

Vestibular stimulation improves insight into illness in schizophrenia spectrum disorders

Impaired insight into illness (IMP-INS) is common among individuals with schizophrenia spectrum disorders (SSD), contributing to medication nonadherence and poor clinical outcomes. Caloric vestibular simulation (CVS) is typically used to assess peripheral vestibular system function. Left cold CVS is also a transiently effective treatment for IMP-INS and hemineglect secondary to right brain hemisphere stroke, and possibly for IMP-INS and mood stabilization in patients with SSD. Participants with SSD and moderate-to-severe IMP-INS participated in an exploratory double blind, crossover, randomized controlled study of the effects of CVS on IMP-INS. Participants sequentially received all experimental conditions—left cold (4°C), right cold, and body temperature/sham CVS—in a random order. Repeated measures ANOVA were performed to compare changes in IMP-INS, mood and positive symptom severity pre and 30min post CVS. A significant interaction was found between CVS condition, time, and body temperature nystagmus peak slow phase velocity (PSPV) for IMP-INS, indicating that single session left cold CVS transiently improved IMP-INS while right cold CVS may have worsened IMP-INS, particularly in participants with greater vestibular reactivity (i.e. higher PSPV) to body temperature CVS. The procedure's effectiveness is attributed to stimulation of underactive right hemisphere circuits via vestibular nuclei projections to the contralateral hemisphere.

Effect of optokinetic stimulation on visual–manual tracking under the conditions of support-proprioceptive deprivation

The effects of additional dynamic visual stimuli (retinal optokinetic stimulation (ROKS)) on the visual–manual tracking (VMT) indicators in the absence of support afferentation and with a reduced level of proprioceptive afferentation were determined using a model of horizontal “dry” immersion. The accuracy of the VMT of jerky and smooth (linear, pendular, and circular) movements represented by visual dot stimuli was evaluated in all 18 participants aged 19–31 before, during and after their exposure to a five- to seven-day immersion bath. The eye movements were recorded by electrooculography, while the hand movements were recorded by a joystick with a biological visual feedback (the current angle of the joystick handle was imaged on the screen). Computerized visual stimulation tests were presented, through virtual reality glasses, to subjects in the absence and against the background ROKS. We analyzed the temporal and the amplitude- and velocity-related visual and manual tracking (VT and MT) characteristics, including the efficiency (e) and gain (g) coefficients as the ratios between the amplitudes and velocities of eye/hand movements and the amplitude of stimulus movements. The efficiency and gain coefficients of both VT and MT without ROKS were significantly decreased against the baseline during the entire period including three days of immersion and 3 post-immersion days. The most pronounced worsening was observed in the VT parameters. Whereas the VT and MT parameters remained unchanged against the threshold ROKS before the immersion, they were improved during and after the immersion (the improvement was significant on the fifth to seventh day of immersion and on the thirdthird post-immersion day, compared to the test indicators on the clean screen). The most pronounced impact of ROKS was observed in the VT parameters. The vestibular function (VF) was evaluated by videooculography before and after immersion. We analyzed the static torsional otolith-cervicalocular reflex (OCOR), dynamic vestibular-cervical-ocular reactions (VCOR), vestibular reactivity (VR), and spontaneous eye movements (SpEM). A significant decrease in OCOR (gOCOR was 0.1, compared to the background gOCOR value of 0.25) was detected alongside a simultaneous significant increase in the VCOR/VR parameters in 28% of subjects on day R + 1 after immersion. Correlational has been found between the parameters of VT and MT, as well as between those of VF and VT, but no correlation has been found between the VF and MT characteristics. The results have shown that the removal of support afferentation and the minimization of proprioceptive afferentation more affected the accuracy of VT rather than that of MT. The correlational links between the studied parameters against the background of ROKS were not only preserved, but also intensified. The obtained results confirm the development of sensory deprivation (and afferent deficit) under the exposure to an immersion bath and indicate the approach to correcting the sensory deprivation through additional ROKS.

Visual–manual tracking after long spaceflights

This study presents the results of the pre- and postflight clinical and physiological examination (CPE) and scientific experiment “Sensory Adaptation-2” at the Gagarin Research and Test Cosmonaut Training Center, which involved 14 Russian cosmonauts, crewmembers of long-term international spaceflights ISS-28/29 to ISS 36/37, who were in microgravity from 159 to 195 days. The cosmonauts were aged 35–50 years. The studies were conducted twice before the spaceflight (the background), as well as on days R+1(2), R+4(5), and R+8(9) after landing. In the study of visual–manual tracking (VMT), eye movements were recorded by the electrooculography method (EOG), and hand movements were recorded by a joystick (the screen represented the current tilt angle of a joystick handle). The examinations were conducted using stimulation computer programs, were presented to an examined subject on the screen of the Sensomotor hardware–software complex. The examinations took place in the dialog mode and included the EOG calibration; VMT within ±10° on the screen with blank background (the smooth linear and sinusoidal movement of a point target with a frequency of 0.16 Hz in the vertical and horizontal directions). The study estimated the time, amplitude, and velocity characteristics of visual and manual tracking (VT and MT), including the effectiveness (ec) and gain (gc) coefficients as the ratios of the amplitude and velocity of eye/hand movements to the amplitude and velocity of the visual stimulus. The study of the vestibular function (VF) was performed before and after the spaceflight using videooculography. The static torsion otolith–cervical–ocular reflex (OCOR), dynamic vestibular–cervical–ocular reactions (VCOR), vestibular reactivity, and spontaneous eye movements were assessed. The study of VF in the first postflight days has shown a sharp decrease (up to its complete absence) of static vestibular excitability accompanied by the increased dynamic reactivity of the vestibular system. The study of VTM in the first postflight days has shown a significant decrease in the ec and gc of VT as well as correlations between the parameters of VT and MT and between the parameters of VF and VT and has not found a correlation between the parameters of VF and MT. The conditions of the spaceflight have been revealed to affect the accuracy of VT more strongly than the accuracy of MT. A complete return of the characteristics of VMT and VF to the baseline was observed on R+8(9) days after the spaceflight.

The Treatment of Peripheral Vestibular Dysfunction Using Caloric Vestibular Stimulation in Patients with Cerebral Hypertensive Crisis

Background: To verify the efficacy of caloric vestibular stimulation in patients with peripheral vestibular dysfunction after cerebral hypertensive crisis. Methods: Enrolled in the study were 60 patients with peripheral vestibular dysfunction caused by a cerebral hypertensive crisis, docu-mented by vestibulometry. Thirty patients underwent standard treatment plus caloric vestibular stimulation, and 30 control group patients received standard treatment alone. Results: After the two-week treatment course, the sensation of vertigo was observed in 40.0% ± 8.9% of treatment group patients compared with 80.0% ± 7.3% of control group patients (t = 3.46; p < 0.001). Spontaneous vestibular somatic reactions were found in 46.7% ± 9.1% of the study treatment group in contrast to 86.7% ± 6.2% of the control group (t = 3.63; p < 0.001). Spontaneous nystagmus was seen in 40.0% ± 8.9% of treatment group patients compared with 93.3% ± 4.6% of control subjects (t = 5.31; p < 0.001). Spontaneous vestibular vegetative reactions were observed in 33.3% ± 8.6% of patients receiving study treatment in contrast to 93.3% ± 4.6% of control group patients (t = 6.16; p < 0.001). Also, 53.3% ± 9.1% of study treatment group patients showed asymmetry of labyrinths compared with 86.7% ± 6.2% of patients from the control group (t = 3.03; p < 0.001). Conclusion: Caloric vestibular stimulation was shown to be an effective treatment for peripheral vestibular dysfunction in patients with cerebral hypertensive crisis. During the 14-day treatment of cerebral hypertensive crisis, complete labyrinthine function recovery occurred in 46.7% of treatment group patients who underwent caloric vestibular stimulation as opposed to 13.3% of control group patients who received standard treatment alone.

Interocular nystagmus asymmetry and motion sickness

Binocular videonystagmography (VNG) was used to study the vestibulo-ocular response to a double rotation test as a pre-flight medical examination (PFME) for assessing an aircrew’s vestibulo-autonomic stability. The objective of our study was to identify the relationship between the degree of the nystagmus response to rotation and the severity of motion sickness (MS). The investigated cohort included 135 subjects selected from flight crews aged 23 to 47 years, who were qualified healthy according to the PFME criteria. The test used was based on the intermittent cumulation of Coriolis accelerations by Bryanov’s method. The post-testing vestibular reactivity was assessed using criteria for determining the level of autonomic reactivity and protection movements. Binocular videonystagmography (VNG) with a mask cover was performed during and after rotation. The degree of interocular asymmetry of nystagmus velocity was shown to be directly associated with the severity of MS. We suggested the following asymmetry coefficients: the asymmetry coefficient of unidirectional nystagmus during flexions (ACf) and extensions (ACe); and the duration of convergence rotatory nystagmus during flexions (DCNf) and extensions (DCNe). It has been found that ACf and DCNf are correlated with the severity of MS (p < 0.05). On the basis of our data, we formulated the idea of the mechanism for MS development due to double rotation, which was understood as the occurrence in these conditions of intravestibular interlabyrinth conflict.

Observaciones : Otorrinolaringológicas en las altiplanicies habitadas del Perú (4000 metros)

Con el propósito de prestar alguna contribución al estudio que lleva a cabo el Profesor Monge sobre la vida del hombre en las alturas andinas, emprendimos, en Julio de 1930, un viaje de 7 horas de ferrocarril al centro minero de Casapalca, lugar situado a 4146 metros (13621 pies) sobre el nivel del mar. Presion barométrica 460 m.m. Nuestro objeto era observar las modificaciones más saltantes en las vías respiratorias altas, en el oído y las reacciones vestibulares que pudiera experimentar el hombre aclimatado de los Andes o el que sufriese de Eritremia de las Alturas o Enfermedad de Monge. Además, intentamos estudiar estas modificaciones en el hombre que se traslada del nivel del mar a esas alturas, lo que no pudimos cumplir sino muy imperfectamente por haber sufrido del mal de montañas nuestros acompañantes.

Level of psychological and psychophysical readiness of students for professional labor on railway

Purpose. Railway transport specialties make high demands to the development of number of characteristics in psychological and psycho-physical spheres of the specialist person. For the purposeful work organization on effective forming of these spheres the students should have clear information about the existing trends. It is necessary to determine these trends. Methodology. Techniques of psychological diagnosis are used in the research. Namely: rating scale of the level of situational and personal anxiety (Ch. Spilberger); the questionnaire of subjective control level (Ye. F. Bazhin), developed on the basis of Dzh. Rotter’s locus of control scale; Munsterberg test, Bourdon correction task); special physical exercises to assess the sensorimotor characteristics (action speed, stability of the vestibular reactions). Findings. Existing trends concerning the development level of students: situational and personal anxiety, level of subjective control, attention selectiveness, concentration and attention fixation, speed of action, stability of the vestibular reactions were determined. Originality. Innovation in the research is the identification in the development level of railway students of some indicators of psychological and psychophysical readiness for professional work. Practical value. The data obtained during the research give the idea of the existing realities with regard to psychological and psychophysical readiness of railway students for the professional work. This is the basis for the focused effort organization concerning the formation of students' psychological and psychophysical readiness during training sessions.

Respuestas Vestibulares Al Estimulo Irritativo Termico En 100 Sujetos Normales

Con la finalidad de obtener factores cuantitativos normales de las reacciones vestibulares en individuos de nuestro medio, usando en parte el procedimiento descrito en el vestibulograma (cuadros Nos. 1, 2) que se emplea en la Cátedra de Otorrinolaringología de la Facultad de Medicina de San Fernando, se realizó el presente trabajo. Para el aspecto práctico de la especialidad hemos seleccionado el test térmico con algunas peculiaridades en su técnica, de tal manera que resulte cómodo en su realización y fácil en su interpretación final. El objetivo que se propone la presente tarea es determinar respuestas vestibulares ante el estímulo térmico en individuos normales, fijando valores de respuesta patrón. La presente investigación contó con la feliz colaboración de entusiastas discípulos del Profesor Dr. Reynaldo Salazar V., así como de enfermeras y empleados del Hospital Materno Infantil San Bartolomé, cuya contribución agradecemos muy sinceramente. Esperamos que esta pequeña tarea resultara de utilidad tanto entre especialistas como en médicos generales en uno de los aspectos más vastos e interesantes de la otología.

Hearing, vestibular reactivity and postural stability after 21-day period at high altitude

The exposure to high-altitude hypobaric hypoxic environment results in a lot of organic responses and adaptation mechanisms. Depending on the absolute altitude and the duration of exposure, some effects, named mountain sickness, are evident, including cardiovascular and pulmonary responses and cerebral dysfunctions. In this study we analyzed the hearing sense, vestibular reactivity and the postural stability of seven climbers before and after a 21-day period of exposition to hypobaric hypoxia (over 5,000 m). To obtain this goal we assayed: audiometric and bithermal caloric tests, and the postural stability by static stabilometry. Our data revealed that all subjects showed normal values in all tests. There was a slight, but not significant, neurosensorial hypoacusia in hearing capacity, even if at different frequency and ear. After the hypobaric hypoxia exposition, the caloric test did not reveal significant differences in pre vs. post analyses, even if two subjects reported a transitory positional vertigo at 12 and 13 days of expedition. Interestingly, the climbers significantly improved their stability not involving the visual perception. This experience suggests that the high altitude could transiently modulate the vestibular function without any pathological consequences, and it improved the stability probably integrating the proprioceptive stimuli and muscle strength also as a consequence of physical efforts.