20% of world population reports dizziness. It is managed by doctors, who neglect vestibular dysfunction. Diagnostic is based at tests of 30-40% sensitivity. Pathology spread makes it obvious that no one healthcare can manage the problem. Progress increases suffering people amount. Prognosis is pessimistic: dizziness initiates immune, endocrine diseases, tumors.
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Guidelines on dizziness and space orientation disorders
Trinus K.F., Claussen C.-F.
Neurootological and Equilibriometric Society Reg. (Germany), SSE “Scientific Practical Center for Prophylactical and Clinical Medicine” State Administration (Kyiv, Ukraine)
Experts attended 39 Congress of NES (20-22 April 2012, Bad Kissingen, Germany) and participated in the discussion or sent their oppinion and valuable contribution through Internet: Aguilar, L. (Guatemala City, Guatemala); Aoki S., Arai Y. (Tokyo, Japan); Aust G. (Berlin Germany); Bertora G. O., Bergmann J. M. (Buenos Aires, Argentina); Biswas A (Kalkotta, India); Boniver, R. (Verviers, Belgium); Dejonckere P. H., Coryn C., Lebacq J. (Brussels & Louvain, Belgium); Goldstein B., Shulman A. (New York, USA); Hahn A. (Prague, Czech Republic); Kazmierczak H. (Bydgoszcz, Poland); Kornilova LN (Moscow, Russia); Likhachev SA (Mensk, Belarus); Nagy E., Bencze G., Bencsik B. (Budapest, Hungary); Oliveira C. A., Holdeffer L., Venosa A. (Brasilia, Brazil); Rapponi G. (Milan, Italy); Said J., Izita A. (Mexico City, Mexico); Sakata H., Endo M. (Saitama, Japan); Seabra J. C. R. (Oporto, Portugal); Castillo R. (Lisbon, Portugal); Schneider D. (Würzburg, Germany); Szirmai A. (Budapest, Hungary); Tan U. (Adana, Turkey); Wada M. (Ichikawa, Japan).
Neurootology Newletter, 2012, Vol. 9, № 1, ISSN 1023-6422
The information is current as of 22.04.2012
The online version of this article, along with updated information and services, is located at World Wide Web at:
http://homofortunatus.com (in Russian and Ukrainian)
Resources used for Document preparation: Proceedings of the N.E.S. – contents. Neurotic. Newsletter. 1995  and later years, personal opinions and personal communications with NES – List of members by names. Neurootol. Newsletter. 1996  and later years, Rote Liste 2010 , the Merck Manual , Trinus F.P. Pharmaco-Therapeutical reference book , Goodman and Gilman’s The pharmacological basis of therapeutics , Transactions of the Regular Meetings of the Bárány Society and Abstracts of Society for Neuroscience Annual Meetings. Document is adjusted to International Statistical Classification of Diseases and Related Health Problems. Tenth Revision. Vol. 1-2. World Health Organization. Geneva, 1992.
Table of contents:
Magnitude and scope of the
Vertigo versus dizziness differentiation
Types of space orientation disorders (SOD)
A. Concept of vestibular system and space orientation
1. Vestibular peripheral sensors
2. Space orientation sensory tetrad
3. Vestibular brain projections
4. Symptoms of vestibular dysfunction
B. Methods for dizziness study comparison
- Stages of diagnostics
C. Management of dizziness and related disorders
1. Etiological therapy
2. Therapy, dependent from topography of pathology
3. Management of exact types of dizziness
4. Meniere’s disease (MD) and syndrome (MS)
D. State of arts
E. Steps to be started
Magnitude and scope of the problem
Dizziness is met in more then 20% of Global population. It appears to be the third reason of patient admittance to the doctor in USA . According to Cochran reports a nationally representative sample of 4869 adults living in Germany being screened for dizziness, and 1003 individuals with dizziness underwent validated neurootologic interviews to differentiate vertigo from dizziness according to explicit diagnostic criteria. Dizziness/vertigo have a prevalence of 22.9% in the last 12 months and an incidence (first episode of dizziness/vertigo) of 3.1%. For vertigo, the prevalence is 4.9% and the incidence is 1.4%. 1.8% of unselected adults consulted a physician in the last 12 months for dizziness/vertigo (0.9% for vertigo). Compared with dizziness, vertigo is more frequently followed by medical consultation (70% vs 54%; P<0,001), sick leave (41% vs 15%; P<0,001), interruption of daily activities (40% vs 12%; P<0,001), and avoidance of leaving the house (19% vs 10%; P=0,001). More than half of the participants with “vestibular vertigo” reported “nonvestibular diagnoses”. Age- and sex-adjusted health-related quality of life was lower in individuals with dizziness compared with dizziness-free control subjects .
Common causes of all types of dizziness include Meniere’s disease with prevalence of 5% in series of dizzy patients, BPPV – up to 81% of vertigo cases, CNS ischemia in 73% of patients with vertebro-basilar insufficiency, about 60% patients with posttraumatic syndrome, dizziness appears to be the initial sign in 5-15% of cases of multiple sclerosis, 19% of patients with temporal epilepsy are complaining of dizziness, it accompany degenerative diseases, intoxications, disorders of general circulation, cervical disorders, psychological and psychiatric diseases etc [cited after: 32, 151]. From the other side: vertebral artery obstructions find in 0,3% out of 6400 patient brains sections; statistics have proved the lack of correlation between vertebral artery flow alterations and the presence of dysfunction at the brainstem . Besides “classic” neurootological nosologies, there are some atypical forms, like Meniere Syndrome, which means certain clinical forms, related to Meniere’s triad. Epidemiological data indicate significant increase of MS morbidity. Preliminary data have shown MS prevalence increase from 3,5 per 100000 to 513 per 100000 population. In USA medical and pharmaceutical reports have been used with databases of more than 60 million persons. In the years from 2005 to 2007 time window prevalence appeared to be 190 per 100000 with female:male ratio being 1.89:1. It is increasing with age, starting with 9 per 100000 for age interval before 18 to 440 per 100000 for 65 years and older .
In the literature the dizziness definitions are not clear-cut: “every discomfort sensation in the head might be regarded as dizziness” . Poor definitions result in subjectivism in diagnostics, situation is reflected in Cochran reviews. They suggest that the evidence base for dizziness evaluation and management is weak. Meta-analyses and systematic reviews are particularly important for clinicians because these studies design minimize bias and summarize evidence in a manner useful to clinicians. Most studies of medical tests pertaining to dizziness evaluate vestibular tests. Only few guidelines give consensus support of the clinical utility of vestibular tests. The guidelines, however, do not summarize important measures of diagnostic accuracy (e.g., sensitivity, specificity, and likelihood ratios) – the information which is the most useful when making medical decisions. When the sensitivity and specificity of posturography was assessed by a meta-analysis design, both of these operating characteristics were only about 50% for identifying vestibular disorders – indicating that the test results do not influence the probability of the outcome. Imaging studies are increasingly used in dizziness evaluations, but no meta-analysis was found that measures the operating characteristics of these tests in dizziness presentations. No guidance is proposed to clinicians about who needs an imaging study. In fact, none of the guidelines were even intended to be a clinical practice guideline for dizziness. Other than BPPV and Meniere’s disease, meta-analyses and systematic reviews were only found on alternative interventions. The main purpose of the guideline on Meniere’s disease was to establish design and reporting criteria for research studies. The statement on acoustic neuroma stems from a National Institutes of Health Consensus Development Conference – which aim to present useful consensus information to health professionals, but is not intended to be clinical practice guidelines. The guideline on ischemic stroke only briefly addresses dizziness. Research should address questions such as, “Which dizziness patients are likely to benefit from having a brain image, vestibular test, audiogram, or blood analysis?” – since these tests are expensive, inconvenient and often bothersome to patients, and are generally of very low yield. Evidence for interventions – other than re-positioning for BPPV – is either insufficient or absent entirely. Thus, more empirical studies, systematic reviews and meta-analyses on relevant dizziness topics are needed so that evidence is established in a way that will inform clinicians and also research agendas. Guideline statements can then be developed to transform evidence into actual recommendations for clinical care. With these goals as priorities, future work could make an important contribution to the efforts to optimize patient care and healthcare utilization for one of the most common symptom presentations in all the medicine [cited 113]. That is why the Consensus Expert Document is decided to be created in the frame of Neurootological and Equilibriometric Society.
The Merk Manuel definition is more exact: “vertigo – a disturbance in which the individual has a subjective impression of movement in space (subjective vertigo) or objects moving around him (objective vertigo), usually with a loss of equilibrium. True vertigo is distinguished from faintness, light-headedness, or other forms of “dizziness”, results from disturbance somewhere in the equilibratory apparatus: vestibule, semicircular canals, 8th nerve, vestibular nuclei in the brainstem and their temporal lobe connections, or eyes” . But even it does not propose the criteria for dizziness differentiation, documentation methods or therapeutic principles. One of the differentiation exactness criteria is its adequacy in the foreign languages translation. From this point of view very equivocal seems to be the term “light-headedness”. It is perfectly translated into German as liftgefühl . But in French language the precise translation does not exist . Moreover, in Slavic countries patients are rather complaining of heavy head, concentrations difficulties and darkness in head . Imprecise are also “nonvestibular dizziness” , starting from “general brain” and finishing with cardio-vascular, metabolic etc., dizziness. From the other side there is a big bulk of data, proving that many types of dizziness, including visual one, are formed just in vestibular system . Differentiation of dizziness/vertigo into central and peripheral  also poses more questions, than provide answers, the first one being: why they use medications influencing CNS for peripheral vertigo treatment!? This differentiation means historic interest, when the doctor has to identify the tumor or vascular catastrophe location and identify who will do the surgery: ENT or neurosurgery department. Today neurovisualization progress allows to solve the problem of very precise tumor location  and the structure of unclear diagnoses is replaced into smashed functional disorders .
Last time in English literature there appeared the diagnosis of “psychogenic postural instability”. It is based at posturography studies (Romberg test). Authors use next criteria (two and more are enough to establish the diagnosis) :
1. High level of coordination disorder fluctuation.
2. Excessive slowness or insureness.
3. Excessive swaying in Romberg test decreasing in attention attraction.
4. Clumsy positions, resulting in increased muscle energy losses.
5. Excessive carefulness while walking (walking on ice).
6. Sudden bending of knees, usually without fall.
Even from the first glance at these criteria their subjective nature is evident. First they are based at the Romberg test, the sensitivity of which is close to 40% . Second, the authors do not indicate how to measure excessive slowness or insureness, excessive swaying in Romberg test, clumsy positions, resulting in increased muscle energy losses, excessive carefulness while walking (during Romberg test performance!) and evaluate suddenness of knees bending. Third, psychological condition of patient is evaluated according to vestibulo-motor reactions.
At the same time there exist a big bulk of literature indicating that vestibular disorders are related to precisely identified space orientation disorders (SOD). Dizziness is identified as space, motion  and time perception disturbance , height vertigo or acrophobia – as discomfort at height [50, 247], claustrophobia – as fear of closed spaces , vertigo as illusion of non-existent movement . These definitions appear to be clear-cut identified. Therefore, it seems more reasonable to use group identification as SOD, and precise identification for exact type of disorder. Moreover, it has appeared that they have specific anatomic and physiologic mechanisms underlying their formation. Let us start of identification of dizziness and vertigo initiation location.
Vertigo versus dizziness differentiation
Electrophysiological characteristics of dizziness and vertigo symptoms have been studied . The subjective sensations of them being carefully recorded during caloric test. Only 60.0% of the patients have reported vertigo or dizziness, other 40.0% have indicated warmth, wetness and other sensations not related to vestibular system. Exclusively dizziness is reported by 8.0%, vertigo – 20.0% patients. 28.0% patients have reported that during one procedure the have felt dizziness, but during the other – vertigo. Attention is driven to the fact that some patients have reported dizziness, which is considered to be of “non vestibular origin” , during vestibular stimulation. Additional symptoms: headache, nausea have reported 4.0% each. Frequency analysis has shown that in the cases related to dizziness it is 0.7±0.2 Hz, vertigo – 1.0±0.4 Hz. (the difference is statistically significant by the Fisher qualitative criterion, р=0.04). Nystagmus might be physiological and pathological. In healthy volunteers caloric nystagmus frequencies have been identified in the range of 0.8-1.4 Hz . Claussen has identified the frequencies of physiological nystagmus in the range of 0.67-1.67 Hz at big amount of patients. Pathological nystagmus of high frequency is related to hyperreflexy, and vice versa, low frequency –hyporeflexy .
Evaluation of the lateralization and temperature dependence of vertigo and dizziness has shown the next results. The data being obtained indicates that vertigo is more exaggerated during cold water irrigation. Vertigo sensation is more typical to left labyrinth stimulation. Last fact might indicate the specifics of the interhemispheral relationship. Taking into consideration the existence of several cortical vestibular representatives (at least two) it is easy to suppose the predominance of sensations described formation in the different nervous centers at different hemispheres: in the right one vertigo, and in the left – dizziness .
VestEP recording has shown the crucially increased latencies of all the peaks while the EP of the other modalities: i.e., VEP, SEP, AEP are normal – indicates central and peripheral vestibular dysfunction – it is typical for vertigo. Another version is some moderate increase of P1 and N1 of the VestEP indicate maximal dysfunction in the peripheral, brainstem and subcortical parts of the vestibular system. P2, characterizing cortical excitation, might be intact; the other modalities might be in the normal ranges – typical for dizziness (for example Chornobyl clean-uppers, 884 persons examined ). In the patients with diabetes polymodal EP reveal peripheral nerves dysfunction, especially pronounced in visual and vestibular peripheral organs . Evoked potentials (including vestibular) being used for differentiation of neurosis, encephalitis and epilepsy, dizziness has prevailed .
Types of space orientation disorders (SOD).
In 849 patients among other complaints more frequently then 10% appeared to be: dizziness, subjective vertigo, objective vertigo, giddiness (pseudovertigo), disequilibrium, orthostatics, kinetosis, acrophobia, agoraphobia, nyctophobia, claustrophobia, ascendophobia, descendophobia, optokinesis, nausea, vomiting, headache, black-outs, tinnitus and numbness. The entire ‘phobia’ named being at the level of mild discomfort and not the exaggerated psychiatric signs. No one patient has psychiatric diagnosis. In 35 patients the correlation coefficients (in brackets) of complaints named versus instrumental examination results have been studied. Correlation coefficients more then 0.40 have been estimated as significant. The next data have been obtained .
Dizziness – distortion of perception of space, movement and time [46, 111]. Vestibular evoked potentials: especially increased P1 and N1 peak latencies . Posturography: negative correlation with limit of stability to the left (-0.4172). Pendular test (vestibulo-ocular reflex, VOR) with visual fixation suppression (VFX) at 0.04 Hz frequency: negative correlation with phase shift (-0.4754), random saccades: negative correlation with accuracy (-0.4016), smooth pursuit: positive correlation with right eye gain at 0.2 Hz (0.4101), pupillometry – positive correlation with anisocoria during Takahashi test (0.5329).
Objective vertigo – sensation the subjects moving around the patient . Vestibular evoked potentials: all peak latencies increased . 20-point scale – negative correlation with the results of tracking test visual evaluation (-0.4039), posturography – negative correlation with stability limit backwards (-0.4661), VFX at 0.04 Hz – exaggerated positive correlation with asymmetry (0.74742) and phase shift (0.8570), rotatory test clockwise (CW) – asymmetrical correlation with time constant (TC) of postrotatory nystagmus (AN) (0.5495). ECG: negative correlation with duration of QRS (-0.4237).
Subjective vertigo – illusion of nonexistent movement, patient feels him moving . Vestibular evoked potentials: all peak latencies increased . VOR: positive correlation with gain at frequencies 0.08 (0.4042) and 0.16 Hz (0.4251), asymmetry of gain at counter clockwise (CCW) rotation (-0.4914).
Giddiness – vertigo which is not similar to subjective or objective ones, sometimes called pseudovertigo: very intensive, difficult to describe, patients often tell that something is rotating inside of the head . Negative correlation with height (-0.4522). Positive correlation with complaints of nausea while headache spell (0.6455). Vestibular evoked potentials: all peak latencies increased . Pendular test with gaze fixation at frequency of 0.04 Hz – negative correlation with asymmetry (-0.4760) and phase (-0.6848). Rotation test: positive correlation with time constant of nystagmus at CW rotation (0.5469). ECG: positive correlation with duration of QRS interval (0.5447).
Imbalance (movement coordination disturbance) – sometimes is met alone. Patients are complaining of swaying, staggering, momentary push…. It correlates with complaints of acrophobia (0.4328) and descendophobia (0.4995). Multisensory evoked potentials: all peak latencies might be intact . Positive correlation with the result of 20-point scale is present (0.4311). During VOR it positively correlates with gain asymmetry at 0.01 Hz (0.5862), and during VFX at 0.04 Hz has highly expressed correlation with gain asymmetry (0.7811) and especially with phase shift (0.9081). ECG: positive correlation with duration of P (0.69561) and negative with QRS complex – (-0.5375).
Orthostatics – discomfort sensations that appear after sudden standing up [85, 239]. It correlates also with complaining of nausea (0.4267). Positive correlation with rotatory nystagmus gain (0.4531) and per-rotatory nystagmus gain (0.5290), negative with gain asymmetry (-0.4536 and -0.6916 correspondingly) and TC during CCW rotation (-0.4697). Positive correlation exists with gain during stepwise rotation both CW (0.4531), and CCW (0.52909).
Kinetosis – a disorder caused by repetitive angular and linear acceleration and deceleration and characterized primarily by nausea and vomiting [83, 207]. It appeared to correlate with weight increase (0.4146) and photophobia in migraine attacks (0.4414). Posturography: positive correlation with limit of stability to the left test (0.5933). VOR: positive correlation with gain at 0.16 Hz (0.4549), with VFX at 0.04 Hz – positive correlation with gain (0.4474) and asymmetry (0.4028). During rotation test – negative correlation with gain CW (-0.4588) and TC CCW (-0.4893), positive correlation with asymmetry during CCW rotation (0.4221), and negative correlation with postrotational nystagmus gain CW (-0.4588).
Acrophobia (height vertigo, does not belong to true vertigo) – discomfort that appears at height [55, 247]. Has positive correlation with imbalance (0.4328). Posturography – positive correlation with visual perturbed unstable platform test data (0.4109). During rotation test positive correlation with gain CW (0.4304) and gain of post-rotatory nystagmus (0.4304) is recorded. ECG: underlined positive correlation with P interval (0.7258).
Agoraphobia – (αγωρα – Grecian, market) discomfort in open, public places or crowds . Correlates positively with ascendophobia (0.4588) and associated headaches (0.4588). During VOR positive correlation is found with asymmetry at 0.64 Hz (0.4038), and during VFX at 0.04 Hz – negative correlation with asymmetry (-0.7026) and phase shift (-0.5288). During rotation test positive correlation is noted with asymmetry CW (0.4243) and TC for rotatory (0.6366) and post-rotatory nystagmus (0.4736). Pupillometry: positive correlation with anisocoria in dyadochokinesis test (0.4385).
Nyctophobia – discomfort, insureness in darkness and twilights . VOR– positive correlation with phase shift at 0.32 Hz (0.5794) is found, during video vestibulo-ocular reflex (VVOR) positive correlation with asymmetry at 0.16 Hz (0.4048) being seen. While CCW rotation is negative correlation with gain it appears (-0.4144). Smooth pursuit: negative correlation with left eye gain at 0.1 (-0.4034) and 0.4 Hz (-0.4084) is noted and positive correlation with left eye asymmetry at 0.1 (0.4548) and 0.4 Hz (0.4521), and expressed positive correlation with right eye asymmetry at 0.1 (0.6678) and 0.4 Hz (0.5277) is seen. ECG is characterized with exaggerated positive correlation with QRS interval duration (0.8321) and negative correlations with intervals Р (-0.5185), PQ (-0.4623) and ST (-0.4082).
Claustrophobia – discomfort appearing in small, closed spaces . Posturography: negative correlation with body movement velocity at the stable platform with eyes opened is recorded (-0.4581). VOR: positive correlation with asymmetry of nystagmus gain (0.4094) and phase shift (-0.600) is noted at 0.01 Hz frequency, while VFX at 0.04 Hz – underlined positive correlation with asymmetry (0.7474) and phase shift (0.8570) is recorded. During stepwise velocity rotation test negative correlation with gain CCW (-0.4376), during CW rotation positive correlation with asymmetry (0.5947) and negative correlation with TC (-0.6785) are found. Pupillometry has revealed correlation with anisocoria in Takahashi test (-0.4825). ECG: negative correlation with ST interval duration is marked (-0.4082).
Ascendophobia – discomfort while moving upstairs, patients note the necessity for visual control. Among other complaints correlations with agoraphobia (0.4588) and descendophobia (0.5784) are reported. 20-point scale: positive correlation with writing Fukuda test (0.4071) and general score (0.4678) is found. VOR: positive correlation with asymmetry at 0.08 Hz (0.4308) is found, as well as positive correlation with TC (0.6320) in CW rotation. ECG: expressed positive correlations with Р (0.7259) and PQ intervals (0.6472) and negative correlation with ST interval duration (-0.4082) are documented .
Descendophobia – discomfort during walking down the hill or descending the staircase, patients note the necessity of visual control. Among other signs there is positive correlation with age (0.4037), imbalance (0.5000), ascendophobia (0.5784) and dyspnoe (0.4461). VOR: positive correlation with asymmetry at 0.01 (0.4638), 0.04 (0.4352) and 0.08 Hz (0.4920) is visible. Step velocity CW rotation test reveals positive correlation with TC (0.7105). Random saccades have shown negative correlation with right eye right side direction movement accuracy (-0.4865). ECG: expressed positive correlation with Р (0.7259) and PQ intervals duration (0.6472), as well as negative correlation with ST complex duration (-0.4082) .
Optokinesis – discomfort evoked by optokinetic stimuli, train or cars movement, sunrays blinking through the row of trees etc . It has positive correlation with increase of systolic (0.5202) and diastolic (0.5033) blood pressure. VOR: negative correlation with gain at 0.64 Hz frequency (-0.4002) and positive correlation with asymmetry at 0.04 (0.4223) and 0.08 Hz (0.6080). During rotation test positive correlation is found with TC CW rotation (0.4841).
Nausea is identified as urge to vomit. It has positive correlation with complaints of orthostatics (0.4267), vomiting episodes (0.4148), and dyspnoe attacks (0.4148). VOR: positive correlation with asymmetry at 0.01 Hz (0.4702), and negative at 0.08 Hz (-0.4141), as well as positive correlation with phase shift at 0.64 Hz (0.4115), during VFX test exaggerated negative correlation with asymmetry (-0.8788) and phase shift (-0.6550) at the frequency of 0.04 Hz are revealed. Rotation test envisages positive correlation with gain both CCW (0.4594), and CW (0.4815), and negative correlation with nystagmus gain asymmetry during CCW rotation (-0.6031). Negative correlation with the increase of systolic blood pressure is reported in these patients (-0.411), also negative correlation with QRS complex duration (-0.6472), in ECG recordings.
Vomiting – is forceful expulsion of gastric contents. It has positive correlation with nausea (0.4148). 20-point coordination scale: positive correlation with Uemura test results (0.4266). Pupillometry: negative correlation with anisocoria during calculation test (-0.5363). ECG: negative correlation with QRS complex duration (-0.6472).
Headache as a substitute of dizziness  is positively correlating with agoraphobia (0.4588). Posturography has revealed positive correlation with backward limit of stability test (0.4534). VOR: positive correlation of asymmetry at frequencies of 0.01 (0.4675) and 0.64 Hz (0.4786).
Blackout might appear during sudden movements of head, physical loadings or per se . During random saccades test positive correlation is revealed with velocity of the left eye movements leftward (0.5514). At ECG it has positive correlation with Р (0.5101) and PQ complexes durations (0.62017) and negative with ST duration (-0.5477).
Tinnitus as dizziness substitute has positive correlation with numbness (0.4462). Vestibular evoked potential peaks are increased . During CCW rotation negative correlation is found with nystagmus gain (-0.4397), and positive with asymmetry of this gain (0.5069), as well as with TC of CW rotation (0.4320). Random saccades demonstrate positive correlation with the accuracy of the left eye movements leftward (0.4838).
Numbness is unpleasant sensation of temporary loss of feeling and volunteer control of the parts of the body. Among other complaints it correlates with tinnitus (0.4462). VVOR has revealed positive correlation with phase shift (0.4245), while rotation test – correlation with TC of nystagmus adaptation during CW rotation (0.4502) .
Therefore, there are clear-cut defined subjective dizziness-related complaints, which are recommended to be used in the description of dizziness. The data presented underline the vestibular input into formation of the SOD named above, their different nature (difference between each other), being documented with the help of the world-wide recognized standard test procedures .
A. Concept of vestibular system and space orientation
Dizziness is considered not to be separate disease, but symptom, which might be met either alone or associated with certain disease or group of nosologies. It accompany seasickness, meteosensitivity, diabetes and other metabolic disorders, hepatic dysfunction, it is met in gynecology: 14-15 years old girls, first trimester of pregnancy, and during climax; in the cases if cardio-vascular diseases, in postoperative period, in oncology, especially during chemotherapy, and as a result of stress, head trauma, intoxication or infection . It may be of occupational origin in the form of vibration or monitor disease, the result of ionizing or electromagnetic fields irradiation .
In many cases it has functional and not organic character, among patients with dizziness complaints only in 29% the CT scans and in 40% MRI have shown abnormalities: atrophies, infarctions, demyelination . In general being widely spread dizziness is not enough studied, often resistant to therapy and may result in invalidity of patient . Wide scale studies of dizziness, being done from 1974 by Neurootological and Equilibriometric Society, as well as knowledge accumulated by Barany Society and Society for Neuroscience, have lead to the concept of vestibular system, which involves the vestibular peripheral sensors, space orientation tetrad, vestibular projections in the brain and vestibular presentations in the brain cortex.
1. Vestibular peripheral sensors
Each analyzer consists of peripheral sense organ and its pathways to specific cortical zone. Sense organ often consists of more than one sensor, providing high sensitivity to different stimuli of the same modality. For example in eye retina coni and baculi are met, which percept accordingly white and color lights, at least four types of sensors are described at the tongue, percepting salty, acidic, sweat and bitter tastes. The structures, modulating sensitivity of peripheral organs are also present. In the ear – outer hair cells, in the eye – pupilla diameter, which provides fine tuning of sensitivity, protection from overexcitement, etc.
From this point of view vestibular organ is unique because of several reasons. Its peripheral end organ is a series of closed spaces, in which receptor structures are placed. Maculae with otoliths are located in sacculus, utriculus and lagena, while in the ampoules of semicircular canals – cristae and cupulae. Macula consists of otolith and sensory epithelium. First is the mass of small crystals (otoconia), conglomerate, connected by otoconial membranes – thin protein ligatures. Cupula differs from macula by absence of inorganic components, it resembles the sail, closing most part of canal ampoule. Main principle of vestibular inertial function is in the fact that mass, fixed at this vivid spring, deflects proportionally to the acceleration applied. Mutual position of maculas and cupulas is such that they cover all the possible movement directions both angular and linear. Signal perceived is coded into pattern of spikes, action potentials, which in its turn is send to CNS. Besides this, the structures named, also evaluate the changes of gravitational field direction, hypo, hypergravitation and weightlessness . Gravitation sensor responds not only to the head position against gravitation field of the Earth. Changes, but also to microgravitation changes, occurring because of celestial bodies dislocations. These changes are enough to result in the displacements of giant ocean water masses. Many patients feel excitation, sleeplessness, headache spells, and anxiety during full moon days .
Microstructure of labyrinths has specific features. Among the others there are macular lacinia (macula neglecta), which have been first found in fishes . They appear to be small macules distributed in disorder in sacculus and lagena and differ from ordinary macules by absence of gelatinous substance and otoconia. Hair cell cilia in these structures are most variable in length. This feature gives the researchers possibility to estimate macula neglecta being morphological structure for perception of low frequency vibrations. Vibration perception as a separate modality is especially important for fishes and amphibians, for which these stimuli mean the approach of enemy or danger. In nature they are met during earthquake, storm, hurricane and mean danger approach. Today cities are full of vibrations from underground, lorries, ventilations, etc. Among mammals macula neglectae are described in cats’ family and in humans . So, all this provide evidence for vestibular perception of low-frequency vibrations .
It is shown that labyrinth is also percepting sounds . In patients with destroyed cochlear it is possible to record flat audiogram proceeding from infrasound to 16 kHz and sensitivity threshold of 30-40 dBA . Saccular hearing is also used now for, so called: “vestibular evoked myogenic potentials”. Fine parameters of sound: frequency composition, direction, melody are seemed to be percept by hearing organ, and emotional (especially dangerous meaning of abrupt sounds) – labyrinth.
They discuss the importance of the fact of magnetic particles in fish otoliths . These have been also found in labyrinths  and ethmoid sinuses of mammals. So, in the living organisms there are magnetic sensors; magnetic impulse percepting system is related to macula as it is dynamic system . Magnetic particles in ethmoid bones are supposed to have the function of magnetic compass indicating, the direction of the magnetic field of the Earth, this system is rigid . It is possible to make up conditioned reflexes to magnetic stimuli and memorize them [153, 246]. Evoked potential in response to electromagnetic field (EMF) stimulus have been recorded, thus proving the presence of pathway from periphery to cortex in the human brain . It appears that moderate magnetic loading impairs coordination in magnetic sensitive patients, the fact indicating close relation of magnetic and vestibular senses . The question arises, why don’t we perceive EMF like visual or auditory stimuli? The answer is possible after analysis of natural, non-technogenic magnetic impulses. These appear when clouds, usually negatively charged, are moving or thunderstorm discharges. In living nature the clouds appear before rain, which is resulting in being wet and energy loss. During the rain time it is better to hide somewhere – therefore the biological sense of EMF impulse specific sensor is not to provide spectral-phase or amplitude parameters, but storm prediction. This provide explanation of weather change reactions – somnability, fatigue. Tight connection of magnetic and vestibular sensors might also cause dizziness, disturbances in motor, vegetative, limbic vestibular projections are also possible. In this case becomes understandable the number of accidents in the days of solar storms or in geopathogenic zones. Modern people have changed the Earth, we live today in the condition of “magnetic smog”, which is covering all the Globe and acts constantly at all the living beings. In the weakest persons it cause not the fatigue, but pathologic reactions – dizziness and imbalance, headaches, palpitations, nausea and vomiting.
Important finding is that animals with enucleated labyrinths stop reacting to emetics . Moreover, analysis of literary data has shown that just vestibular system is mostly sensitive to both inorganic , and organic toxins . Many industrial poisons result in vestibular dysfunction in concentrations, which do not influence any other organism function. Chemical reductive agents are increasing the sensitivity, oxidative – reduce it .
Mechanism of this phenomenon is disclosed in the studies of vestibular organ of snails. Perfusion of its hair cell cilia with reductive agents increase the cilia rigidity, oxidants – decrease. In both cases the mode of mechano-electric transduction changes . Hair cell sensitivity to red.-ox. potential changes is 2-5 orders higher than that of all the other organism tissues [108, 204]! Data presented indicate that vestibular analyzer is additionally plays the role of metabolism (condition of oxidative-reductive processes) sensor in the organism. In this context the correlation between vestibular sensitivity and radiation tolerance becomes understandable . Ionizing irradiation cause the accumulation of peroxide products, changing vestibular function. The more sensitive perceptive structure is, the earlier it switches on the compensatory mechanisms. From the other side it explains the identity of symptoms of kinetosis and intoxication. Penetration of the toxin into the organism excite the sensor in the labyrinth, which initiates the evacuation of toxin from the organism. Kinetosis or motion sickness is also overscale vestibular irritation [83; 99]. It also explains the dizziness, appearing in patients with diabetes, kidney disease, chemotherapy etc.
Resuming the data presented it is possible to estimate that labyrinth consists of set of sensors, for which six modalities of stimuli are adequate :
3. low frequency vibration,
4. sound including infrasound,
5. magnetic impulse,
6. metabolic changes.
2. Space orientation sensory tetrad
Dizziness belongs to space orientation disorders, therefore it is important to highlight the mechanisms of brain space perception. Role of the analyzers is found out with electrophysiological methods. Even at the level of rhomboid fosse the information inputs have been shown from the other sensory organs. For example, 28% of vestibular neurons, responding to horizontal canal excitation, also react to hearing and somatosensory stimuli. Reaction is always being the increase of impulsation frequency. For somatosensory information its increase appeared to be greater, than for hearing (62-145% and 20% correspondingly). Latencies of these responses being in the time frame of from 5 to 40 ms, indicating both oligosynaptic and polysynaptic pathways . Vestibular nuclei neurons respond also to visual stimuli (65% of cells, responding to linear accelerations). This input has the signs of polisynaptic. Cooperative action of visual stimuli and linear accelerations results in phase shift in the direction of maximal accelerations . Moreover, in this zone there are neurons (about 24%), responding to passive eye movements, i.e. from proprioceptors of oculomotor muscles. Latencies for these responses are from 6 to 30 ms, thus indicating several pathways with different amount of synaptic transmissions . 14% of Deiters nucleus neurons react to cornea stimulation with enough short latencies (6-16 ms). It provides the reason to speak about special corneal connections with spinal motor system in the tight contact with vestibular. Such complex fulfill coordinatory role, being the basis of nociceptive reflex, protecting face and eyes . Studies of many other reflexes show their formation at the structures of rhomboid fosse .
Brainstem vestibular nuclei in reptiles are the highest brain level, like cortex in primates. Therefore, the data presented bring evidence that vestibular nuclei are the most ancient primary associative area of the brain in the meaning of space perception, orientation and movement coordination. Primary coordinating vestibular associative center of rhomboid fosse is localized at the connection of lateral portion of medial vestibular nucleus, medial portion of lateral vestibular nucleus and descending vestibular nucleus. Physiological data reveal among other pathways intimate connections of this area with closely located vegetative centers, controlling blood redistribution, heart rate etc., during bending, standing up, locomotion and especially moving head up and down . That is why big portion of orthostatic problems are related to the dysfunction of just this brain zone. In the space perception major role is played by upper brain structures: medial longitudinal fasciculus and lamina quadrigemina, where the direction estimation occurs . Next is caudate nucleus and hippocampus, vestibular dysfunction results in their degeneration, which is manifested with spatial memory impairment and cognitive deficit [31, 72, 190,]. Subjects recognition, praxis, gnosis, cognition belong to cortical functions . Total spatial disorientation is described, if cortex is the subject of lesion.
Analysis of the influence of different sensory inputs on the rhomboid fosse neuronal function has shown the major input of somatosensory and visual systems and less of hearing. This is depicted in the idea that space perception is formed by three sensory systems (triad): visual, somatosensory and vestibular . The idea of space perception triad is basic in the whole diagnostic branch – posturography . The other proposal is to regard hearing as important part of space orientation . Phonation of patients during dynamic posturography allows to reveal the topography of the acoustic dysfunction input into dizziness and imbalance. Usually it appears at the level of rhomboid fosse and medial longitudinal fasciculus (MLF). At both locations acoustic and vestibular nuclei are tightly close. Moreover, lateral longitudinal fasciculus (LLF) is considered to be the very place, where the direction of sound origin is determined. Destruction of either MLF, LLF or lamina quadrigemina results in the fail to determine sound direction. Thus, intersensory interaction might be useful for understanding of dizziness origin, hearing function providing information about sound, vestibular – integrating sound information into space orientation . From the other side visual-vestibular interaction studies, first initiated in space microgravity, provided much benefit to patients in the Earth conditions .
Next question is “non vestibular dizziness” , “appearing somewhere in the eyes” . Investigation of dizziness, appearing in the first hour of wearing of improper glasses, have shown the excitation of the vestibular nuclei at the level of MLF or lamina quadrigemina, no visual nuclei function impairment is found . These data provide evidence for the idea, that space orientation is formed at the vestibular nuclei as a result of integrative processing, first of all of the information from tetrad – four principal inputs: vestibular, visual, somatosensory and hearing .
There is a big bulk of literature proving that dizziness is related to vestibular dysfunction. Minor head trauma starts as a vestibular dysfunction . Tinnitus is related to vestibular disturbances . Low-frequency whole-body vibration cause vestibular damage [122, 211, 214]. In the patients with diabetes polymodal EP reveal peripheral nerves dysfunction, especially pronounced in visual and vestibular peripheral organs . Among arrhythmic patients 15-30% appeared to be vestibular-dependent . Low doses of radiation cause primary vestibular damage, which need vestibular function correction . The latter crucially improves the patient condition . Vestibular dysfunction is present in dizzy patients with neurosis, encephalitis and epilepsy . Early vestibular damage in Chornobyl clean-uppers (miners exposed also to vibrations) lead later to immune deficiency . Monitoring of long-lasting consequences of vestibular damage patients has shown that primary peripheral distortion in two-three years spreads to higher levels of brain step-by-step involving motor, vegetative and limbic systems, resulting in organic pathology: neurological, cardiovascular, internal organs damage, including glands of inner secretion, psychiatric disturbances . When the process reach brain cortex, the balance of cortical processes is disturbed, causing immune failure, which is finished with chronic, autoimmune and oncologic diseases . In the cases of severe damage (high doses irradiation) this process is running quickly , in moderate – it becomes chronic and long lasting, but its development is the same .
3. Vestibular brain projections
Labyrinth projections with CNS structures are multiple and rather complicated. They differ several groups of them united into projections :
1. vestibulo-cortical (sensory),
4. vestibulo-limbic .
According to the physiological findings it is composed at least of three pathways [1, 209]:
1. Three neuron shortest pathway to the contralateral hemisphere;
2. Five neuron pathway to the ipsilateral hemisphere;
3. Multineuron pathway to the contralateral hemisphere.
The first of them is initiated by the thick fibers, innervating big type I hair cells localized in the central part of the peripheral receptor . The first order neurons are presumably represent the crista-ampoular projections. The first transmission appears at the central part of the superior and partly in lateral vestibular nuclei . The great neurons at this area sending the axons to the ventral posterior area of thalamus, medial longitudinal fasciculus, Deiters nucleus and interstitial nucleus of Cajal. These second order neurons also send collaterals to the oculo-motor nuclei, being thus important nystagmus producer. Other electrophysiological data have revealed that vestibular responses might be found in the variety of somatic parietal areas (areas 2, 3a and 5). This input originates from great thalamic cells being localized in oral portion of ventro-postero-lateral nucleus and ventro-postero-inferior nucleus. These nuclei in turn receive axon terminals from contralateral lateral and medial vestibular nuclei . The latent time of this pathway is 3-5 ms if the vestibular nerve is stimulated directly in the electrophysiological experiment .
The second pathway seems to be initiated by mostly thin fibers innervating the II type small hair cells, dispersed at the peripheral parts of all the receptor structures . The first order neurons are dispersed in all the vestibular nuclei of the brainstem. The pathway seems to pass through medial longitudinal fasciculus, Deiters nucleus and interstitial nucleus of Cajal, archicerebellum and striopalidum subcortical system [2, 72]. The latent time of this pathway is about 8 ms if the vestibular nerve is stimulated directly in the electrophysiological experiment .
Multineuron pathway or pathways to the contralateral hemisphere has been revealed in the evoked potentials studies. Cortical peak P2 has usual latency of 120-150 ms; the pathway seems to pass through the reticular formation .
This projection represents the analyzer in its general physiologic understanding. In normal conditions the principal manifestations of its function are space perception, motion and time. Quantitative measure of its function is sensitivity threshold of the investigated subject . Subjective sensation studies at the threshold level revealed three types of sensations: undiscriminated, inverted and discriminated, which appear to be the fundamental feature of movement perception, no matter which is the direction of movement [17, 210]. Quantitative measure of gravitation perception is considered to be vertical estimation, which is to be performed in total darkness . Dizziness, vertigo, being in general space orientation disorders, are manifestations of sensory vestibular disorder.
It is characterized by vestibulo-spinal and vestibulo-ocular pathways . In norm it provides wonderful coordination we see in sportsmen, dancers, cascadeurs. In pathology it is manifested with coordination disturbances, distortions of balance, gait (static and dynamic ataxia), nystagmus and saccades .
This one influences cardio-vascular system and inner organs . In normal conditions provides vegetative reserve for normal function of the whole organism, in special conditions it enhances reconvalescence of postinfarctus patients , improve children physical development [115, 164]. In pathology it causes kinetosis and many other vegetative disorders .
Physiological vestibular stimulation results in improvement of life quality, in pathology it results in limbic disorders .
4. Symptoms of vestibular dysfunction
Taking into consideration the presented material about the projections of the vestibular system, now it is possible to identify the symptoms, which might manifest vestibular disorder.
Vestibulo-cortical projection – vestibular analyzer – is the very brain structure, where the movement, space orientation and time perception is formed. In pathology we separate dizziness, vertigo  and time perception disorders . Dizziness means the disturbance of the movement, space orientation and time perception. The subjects feel themselves to be unstable or moving, the ground disappears, something is wrong in the head, sometimes light, sometimes heavy, sometimes it is somewhere in the glass sphere or it is impossible to explain what happens with this head . Speaking about movement the patient, nevertheless, is unable to indicate the movement direction. This condition might be accompanied with general inhibition or irritation, excitation is rather rare, but also possible, like the feeling after big dose of coffee. The time might be either dragged out or running too fast . The example of the time perception changes might be in the situation, when the car after driving in the highway at the speed of 140 km/hour is entering the city and the speed is decreased to 40-50 km/hour. It seems to move so slowwwwly! Claustrophobia, agoraphobia, acrophobia, nyctophobia, orthostatics and optokinesis , discomfort while going up and down the staircase, ascendophobia and descendophobia, are also might be related to vestibular dysfunction, as spatial perception disorders .
Vertigo means the illusion of the non-existent movement . In most cases the movement is rotatory like after carousery, less frequent swinging or linear movement. It might be objective, subjective, giddiness  or kinetosis . Usually, it accompanies acute cases of pathology and is combined with excitation or irritation and other additional symptoms: disequilibria, nausea, retching, up to consciousness loss .
Vestibular cortical representations
In electrophysiological experiments the vestibular cortical area has been located in the anterior Sylvian sulcus posterior to the facial somatosensory zone and anterior to auditory cortex . According to Brodmann’s classification this is the area 2V. Neurons in the area 2V respond actively to caloric and electric direct stimulation of labyrinth. The pathway is bilateral, but contralateral features are strongly exaggerated. A second vestibular cortical projection area in humans is found in area 3 may represent the projection from the somatosensory arm field . Therefore, this part of the projection is supposed to represent the somatic afferents, involved into balance. Here, the integration of labyrinthine and somatic proprioceptive signals are providing the subject of awareness of body orientation. It is well known, however, that thalamic neurons transmitting vestibular information to parietal lobe also carry somatosensory signals, usually from proximal joints and muscles [173, 72].
Because many secondary vestibular neurons with canal input also receive visual information from the optokinetic system, this signal must be present. Thus, the vestibular system is unique among sensory systems, because of its integrative function. For example, head angular movements are based on information from a variety of sources including the labyrinth, the retina, the joint and the muscle receptors. Vestibular system, starting from rhomboid fosse level, is integrating sensory coordinator to produce effective movement of organism in space .
It has been shown that the orientation of visual cortical receptive fields might be changed by otolithic stimulation. In the other experiments the semicircular canals stimulation influences visual cortical background firing rates as well as the size of complex visual cortical receptive field. Vestibulo-cortical pathway is necessary for spatial orientation and vestibular memory . Humans and animals without labyrinths cannot remember a path through which they have been transported. Such orientation ability seems to be mediated via a pathway through the vestibular nuclei, the magnocellular medial geniculate body and the caudal caudate nucleus [71, 72].
Thus, the specifics of the vestibular analyzer means small cortical representation area and presence besides vestibular cortical area itself of also the vestibular projections in somatosensory, visual and auditory cortical zones. These projections seem to be based at the two parallel systems: type I hair cells-thick fibers-threesynaptic pathways and type II hair cells-thin fibers-multisynaptic pathways . They are the very substrate, where the sensations like numbness, black-outs, tinnitus of vestibular origin are formed [230, 234].
Vestibulo-motor projection is responsible for the coordination function and locomotion. In the formation of this function several systems take part, including vestibular, other sensory systems, vestibulo-motor pathways and motor effector system. The general coordination disorder terminology might be further detalized. In locomotion disorder swaying, staggering or stamped walk might dominate . Static ataxia might be characterized by instability, swaying, and spastic disorder . The patient might complain of momentary staggering, walking like drunkard, inability to fix the gaze, numbness, etc . Pathologic eye movements, nystagmus and saccades, belong to the vestibulo-motor disturbances . They are formed at paramedial pontine reticular formation. Such patients are complaining of visual disturbances, inability to concentrate, while reading and writing, poor contrast of the subjects even in normal visual conditions .
Different disorders might appear in vestibulo-vegetative projection. Most typical are the disorders following motion sickness or kinetosis . They are characterized by intensive nausea, retching and vomiting episodes ; usually they are accompanied by blood vessels spasms, palpitations, tachycardia, extrasystols [24, 159], sweating, spasms of esophagus, laryngospasms. Persons are complaining of dyspnoe, pain in epigastrium and bronchi .They depend on the exact vestibular pathway and level of the pathological process location . It might involve this or that internal organ, forming sometimes exotic versions of disease structure. An extraordinary example: patient complains that after about quarter an hour in city traffic the uncontrolled urination happens. The treatment proposed – dimenhydrinate before trip appeared to be successful – thus being one more support of vestibulo-vegetative projection existence .
Special attention has to be attracted to headache of vestibular origin, which sometimes is called vestibular migraine . Sometimes migraine is considered as a substitute of vertigo, sometimes as an additional symptom . It might be complicated with other symptoms: nausea and vomiting, convulsions and even consciousness losses . According to the WHO statistics 6% of male and 18% of female population of the Globe suffers from migraine attacks . Epidemiological data report that vestibular migraine affects more than 1% of the general population, about 10% of the patients with dizziness and 9% patients with migraine . These data disagree with the preliminary data of the same authors indicating that 22.3% of German population suffers from dizziness , thus providing at least 2.23% of population suffering from migraine. The disagreement might be explained by the fact of subjective estimation of diagnosis . This means that the criteria of migraine and vestibular migraine diagnostics have to be based at objective instrumental methods. Vestibular origin of migraine is established with the help of Vestibular EP, cranio-corpography and nystagmography, ECG and pupillometry with vestibular loading tests. It demonstrates good regression during therapy with the medications, correcting vestibular function, especially histamine blockers. Among the latter special attention attracts betahistine hydrochloride [225, 227].
Vestibulo-limbic connections are least studied and today the data about their disturbances looks like preliminary studies from the point of view of evident-based medicine. Nevertheless, pioneering physiological studies have attracted the researchers attention to this projection . The clinical experience with Chornobyl clean-uppers has shown that up to 40% persons are complaining of fears, nightmares and phobia [218, 226]. This experience expands also to the patients with head trauma (including whiplash), poisoning and limbic disturbances triggered by kinetosis (sopit-syndrome, for example). Sopit-syndrome has been described by American astronauts and is manifested with weakness, somnability, loss of initiative . The correction of the vestibular function crucially influences the limbic symptoms, thus once more indicating its vestibular origin. Besides phobia and sopit-syndrome, limbic symptoms also include: disturbances of alimentary, drinking, sexual behavior, attacks of irritation, emotional lability, aggressiveness etc . Sometimes so called asthenization and related signs chronic fatigue, weakness, loss of initiative – might be the symptoms, indicating vestibulo-limbic disturbances. In severe cases depression and anxious disorders might develop at the basis of vestibular dysfunction .
The experience of aviation and space medicine has shown that being closely related from one side, from the other side the vestibular projections might be enough autonomic. It means that clearly expressed disturbances in one projection, might not be necessarily followed by the same expression of the disturbances in the other projection . In the cases of chronic pathology it means that the situations are possible, when we have enough expressed dysfunctions in vegetative or limbic systems, with minor vestibular symptoms. These patients spend years visiting hospitals and ambulances, diagnostic centers, circulating between the doctors – all in wane, they need only the vestibular investigation and correction of the leading trigger of the disease. The situation might be more pessimistic, because of patient might not relate poisoning, head trauma, visit of radar station several years ago with today palpitation episode or other dysfunctions .
B. Methods for dizziness study comparison
Comparison of dizziness study methods are ruled out from the concept of the vestibular system positions, the most prominent components of which being the idea that the formation of all the dizziness types is related to the vestibular system, which is anatomo-physiologically organized into 4 principal projections: vestibulo-cortical (sensory), vestibulo-motor, vestibulo-vegetative and vestibulo-limbic. According to this vestibulo-cortical projection is to be investigated with the help of anamnesis, questionnaires and vestibular evoked potentials (vestibular EP, VestEP) (we don’t consider vestibular evoked myogenic potentials, VEMP, because it does not characterize vestibulo-cortical projection).
Vestibulo-cortical projection investigation methods
Though in scientific literature dizziness is described with three-four terms: vertigo, imbalance, faintness and light-headedness , in reality it is much more variable . Usually the disease initial phase is missed both by patient and the doctor. Everything starts from the dizziness attacks of little expression. During several months their duration is increasing and intensity is growing. It starts being accompanied with unbearable headaches, nausea, vomiting episodes, up to conscious losses. At this point the patient admits to doctor, but in the general structure of the disease, dizziness is often ignored both by patient and doctor, because of “more important symptoms”. Only the accentuation of patient attention at the dizziness, he remembers that the sickness started just with it. Dizziness description by patients is full of difficulties in searching appropriate words to characterize their condition. It is often subjectively percept as space or motion orientation disorders. They describe it as swimming, the ground is moving, the subjects are floating, or something wrong before eyes (eyes of glass, micropsia and macropsia) or in the head. Proposed to detailize clearly the floating direction or other its parameters, patients are not able to do this. Sometimes they describe their sensations as head being placed into glass sphere or helmet. Symptoms are provoked by head movements or during transportation in cars, underground or elevators. They are usually accompanied by negative emotional perception of situation: patients feel fear of death, they complaint of feeling ill, fear of closed (claustrophobia) or opened (agoraphobia) spaces. Many patients complain of intolerance of certain kinds of traffic (kinetosis). Other patients tell about discomfort at height (acrophobia) insureness in the twilights and darkness (nyctophobia). They cannot track or gaze moving subjects (optokinesis), complain of balance disturbances, difficulties while descending from the hill or staircase (descendophobia), momentary black-outs and pushing aside . Only 4-5% of them can clearly characterize vertigo, establish its direction, velocity and other parameters .
Among most popular questionnaires in the vestibulology branch is NOASC. Its use is mostly profitable in statistical studies of wide contingents. There are two different ways of result interpretation. First is the most simple, when they calculate the percentage of patients having this or that complaint . Second is Іe, expression index, which characterize the number of signs from this group (for example, headache types or dizziness parameters) in one patient. Expression index is calculated as ratio of certain group symptoms sum to the number of patients examined .
Vestibular evoked potentials (VestEP). VestEP mean responses, obtained from EEG with the help of synchronous summation. If one presents patient vestibular stimulus and record EEG the brain response is recorded in which the expected signal is be lost in spontaneous EEG. But if the researcher store several such records in the computer memory and summate them, spontaneous rhythms are decreasing and sensory system response is summated, becoming greater then noise. Industrial issue of the devices for VestEp recording (vestibular sensitivity analyzer – VSA) in 90th being developed by company “Galactica” at Kyiv Polytechnic University (Ukraine). Mostly the response to chair rotation of about 3° in 400-500 ms time window is recorded. Calculated average acceleration has been in the frame of 1-25°/s2. This acceleration range allow the head to reflect the chair movement profile with great accuracy . For long latency VestEP the 1-33 Hz frequency and amplification of 106.appeared to be the optimal recording conditions. 16-20 recordings with 10-15 s interval appear to be enough for obtaining the expected signal. Literary sources indicate that with the intervals named for long latency evoked potentials habituation and sensibilization phenomena are absent, these conditions are considered to be optimal for cortical evoked potentials recording . Diagnostically significant parameters are considered to be the latencies of principal extremums  in the frame of first 250 ms to 1 s from the stimulus initiation. Method being independently initiated in at least three countries (Ukraine, USA, Germany) [209, 109, 56], passed verification procedure [223, 225] and evaluated by independent NASA experts [NASA Contractor Report 3922, №№ 13 & 23. USSR Space Life Sciences Digest, 1987 & 1988]. The results coincident ratio being in the frame of 95%, thus making these data highly important from the point of view of evidence-based medicine. Sensitivity of method has been evaluated in comparison to the amount of persons complaining of dizziness (n=912 examinations, 672 patients) – 90.57%, specificity – 98.57% . They are identical both for linear and angular stimuli  It is similar to the findings of acoustic evoked potentials  EEG and BAEP sensitivity in the cases of vestibular disorders appeared to be 33% and 18% correspondingly , thus showing the high sensitivity and specificity of just vestibular EP to this exact modality. Normative data for VestEP: P1 – 20-40 ms, N1 – 60-80 ms, P2 – 120-150 ms, sensitivity threshold level at 4-15 cm/s2 and optimal diagnostic stimulus range – 15-20 cm/s2 .
Vestibulo-motor projection examination methods
These tests are divided into two groups: vestibulo-spinal and vestibulo-ocular reaction tests.
Vestibulo-spinal reaction methods are based at the tests of Romberg , Unterberger-Fukuda and Uemura. Among first methods group most popular has become posturography, which means center of gravity (mass) displacements recording. It is based at the weight evaluation with the help of tensosensors, same to those used in the flour weights. While posturography performing the patient is proposed to stand at the special platform, and three tensosensors are demonstrating dynamic patient weight redistribution between them .
Usually 6 test procedures are performed 20 s each: 1) standing with eyes opened at stable platform; 2) standing with eyes closed at stable platform; 3) standing with eyes opened at stable platform, vision perturbed with moving picture. Than the platform is descended, it appears to be hanged at the springs and the same test procedures are repeated. Results are reflected as the square of mass center movements, the percentage of increase in the particular test corresponds to the degree of exact disturbed sensory function decrease .
It is understandable that square increase while eyes closing corresponds to vestibular dysfunction, while eyes opened – to visual, at hanged platform – somatosensory, during moving picture demonstration – dependence from vision. The more difference between test results, the more expressed disturbance of particular function . The next step, phonation, also being proposed, based at the idea of sensory tetrad (four sense organs forming space orientation: vestibular, hearing, vision and proprioception) . Stereo headphones are put at the patient’s head with melody running from one ear to another and above mentioned procedure being repeated. Patient phonation might either enhance balance performance or impair it .
Proposing many positive features posturography does not consider strategy of patient body and extremities movements while balancing, such as bending head, neck or knees, throwing hands forward or stepping. The unique point is evaluated – mass center displacement. Therefore, the amount of information is limited, thus decreasing its diagnostic value. According to the literary data its sensitivity is between 35 and 54% and specificity up to 90% . Our preliminary data coincide with the opinion of the author: sensitivity related to the amount of patients complaining of dizziness is 37.04% (n=54). The sensitivity of Uemura and Fukuda tests for the same patient group appeared to be 98.15% . Equipment for posturography is enough expensive – prices exceed the amount of 200 thousand $ . Today, scientific progress propose the possibility to obtain even more information with the help of simple and cheap technical support. To understand the idea let us first analyze cranio-corpo-graphy method. The latter means that markers (light emitting diodes or ultrasound markers) are fixed at the head and shoulders of the patient and then they perform Romberg and Unterberger tests. Zebris is the company producing these devices at market. The measuring procedure is based on the provocation test in the Romberg stance test and the Unterberger/Fukuda stepping test. The spatial positions of four ultrasonic transmitters (markers) are measured, two of which define the position of the head and the other two the position of the shoulders. The resulting movement patterns of the head and body are recorded and allow the findings to be evaluated directly during or after the measurement. Additional Zebris system for equilibrium analysis is the FDM-S measuring platform. Due to the large variety of extension possibilities, this system can be used as a complete measuring unit for stance and roll-off analysis. Unterberger stepping test means marching at a spot with eyes closed (100 steps or 1 min.) . The interpretation is based at the measuring of amplitudes for head and shoulders sways (separately), linear and angular displacement and rotation . Sensitivity of this test is 82.89%, and specificity – 99.78% (n=912) .
Prof. Uemura once has proposed the test of standing on one foot with eyes closed, as an express-test for vestibular function evaluation . Its sensitivity appeared to be of 98.90% (n=912) . The shortcoming of it is that it is not informative alone in the cases of low extremities diseases. To overcome the obstacle 20-point test battery has been proposed for express-diagnostics of coordination function .
20-point test battery for express-diagnostics of coordination function [after 218].
Complaints quantification. Dizziness attacks are considered to be significant when their duration is more than one minute and frequency is more than once per month. They also take into consideration additional symptoms: headache, black-outs, night mares, tinnitus, memory problems, depressions and consciousness losses, as well as weakness, fatigue, loss of initiative, time perception changes, etc., related to dizziness attacks. Out of vegetative symptoms nausea, retching, vomiting, diarrhea, sweating, palpitations are most common [46, 236]. Standardized results are described as following: 0 points – complaints are absent; 1 point – complaints of dizziness (or vertigo) which duration exceeds 1 minute; 1 – complaints of dizziness (or vertigo) which frequency exceeds once per month; 1 point – complaints of accompanying symptoms. Possible signs combination might be expressed in figures from 0 to 3.
Uemura test is performed in 4 steps: 1) standing at two feet with eyes opened; 2) standing at two feet with eyes closed; 3) standing at one foot with eyes opened; 4) standing at one foot with eyes closed. It is recommended to perform the test at each foot separately, the best performance is taken into account. If the patient is stable at one foot with eyes closed more than 10 s he is considered to be healthy. Uemura test is evaluated in 5 point score: 0 points – patient is stable 10 s with eyes closed at one foot; 1 – undulating moderately, but keeping balance; 2 – hands are need to keep balance (hand is reaching shoulder level); 3 – cannot stand at a spot or stands 3-10 s; 4 – cannot stand at one foot even 3 s; 5 – cannot stand even at two feet. Lateralization of displacements and falls are sometimes important.
Stepping (walking) Fukuda test. At the flour three concentric circles are painted with diameters of 0.5 m, 1 m and 1.5 m. In these circles they direct four perpendicular lines. Patient is proposed to stand in the very center and align himself with one of the lines. Then he is asked to make 100 steps at spot with eyes closed . Three principal parameters are considered during test performance: 1) displacement distance; 2) displacement angle; 3) spin (rotation) angle. Normal is forward linear displacement at the distance of 0.2-1.0 m, angle up to 300 and rotation up to 300. Displacement absence or backward displacement, especially with large sway is regarded as disturbance. Displacement direction might indicate lateralization of the lesion. Test evaluation is proceeded with three score system: 0 – points forward displacement at distance of 0.2-1,0 m, displacement and spin to the angle up to 300; 1 – displacement less than 0.2 m or more than 1,0 m; 1 – displacement at the angle more than 300; 1 – spinning at the angle more than 300. Note: sometimes it is useful to make correction of normative, according to the height and step length of the patient.
Fukuda writing test. Patient is proposed to write “33” in column with eyes closed . For healthy individuals it is easy going. Standardization of the results looks as following: 0 – column is strait; 1 – column is undulating; 2 – column decline more than 300; 3 points – dismetria.
Tracking means that patient is proposed to track small bright subject, moving horizontally and vertically. Subject is placed at the eyes level. Quantification of test results is the next: 0 – tracking is smooth in all the eyes positions; 1 – non-smooth in lateral positions; 2 – non-smooth not only in lateral positions; 3 points – spontaneous eye movements (nystagmus, saccades). Note: welders and persons, spending much time at monitors might demonstrate large amplitude spontaneous eye movements, which disappear after several gaze maneuvers to lateral eye positions. Test is better to be performed with nystagmography either electro or video version.
Indicating (past pointing) test – patient is proposed to point with pen or pencil the target with eyes closed at the distance of stretched hand. Results might be fixed at the sheet of paper, monitor screen, etc. Quantification means: 0 point – point in the diameter 25 mm; 1 – pointing diameter 50 mm; 2 – pointing diameter 75 mm; 3 – pointing outside diameter 75 mm. Direction of mispointing is fixed separately.
According to the result of all the tests vestibular function is evaluated from 0 to 20 points. Figures from 0 to 4 are characterizing norm, 5-9 points indicate small degree of vestibular dysfunction, 10-14 – moderate pathology, and 15-20 – severe lesion, mostly organic. According to our data (n=912) sensitivity of such test battery reaches 93.64%. Time necessary for one patient examination does not exceed 5 minutes. Use of digital camera with video function or even mobile phone provide the possibility to document patient test performance. Adding laser pointer, fixed to the head of the patient, doctor has the possibility to evaluate in figures the sways of patient in all the tests. Comparing sway amplitudes in Romberg test with eyes opened and closed, at soft support etc., it is de facto possible to obtain all the information same as using of posturographic platform and also additional data with phonation and more sensitive Unterberger-Fukuda and Uemura tests .
Vestibulo-ocular reflex (VOR) evaluation tests
Examinations are based at two inventions being made by Robert Barany, i.e., both rotation of healthy persons and patients and calorization of labyrinths result in systematic eye movements, nystagmus . Nystagmus eye beatings consist of quick and slow phases, the direction of nystagmus corresponds to the quick phase direction. Caloric test is recognized to be “Gold Standard” in the diagnostics of vestibular function and is usually performed according to the protocol of Dix-Hallpike (calorization during 30 s of left and right external acoustic meati with water or air of 30оС and 44оС). Unique feature of the caloric test is the possibility to analyze the result of stimulation of only one labyrinth . They use to study slow phase velocity (SPV)  or nystagmus frequency . To establish canal paresis (CP) the difference between right and left labyrinth reactions is estimated :