Habilitation

In order to thoroughly recognize the operational rules of the equilibrium system, I considered that the next stage of my research should concern the role of the cerebellar hemispheres in this complex system. According to Hennebert (39), the peripheral organ (the receptors of the labyrinth), is only a "vestibular entrance" to the uniquely complex equilibrium system, although undoubtedly the vestibular organs fulfill here the dominant role. The cerebellum fulfils a very important function in the complex mechanism of the equilibrium system, being a multineuronal organ, included into the branches of numerous nervous tracts. However, the role of this important organ has not been thoroughly recognized and explained yet. The findings of the experiments are sometimes contradictory, and the clinical observations of people in the course of different cerebellar diseases, and also after surgeries, are not always compatible. I decided that the following stage of my research should concern among other things assessments of spontaneous vestibulo-cerebellospinal reflexes in persons with injuries of the cerebellar hemispheres. In the thorough recognition of these reflexes I saw a key for explanation of the secret of formation of vestibulo-cerebellospinal reflexes and the rules of cooperation of the labyrinth and the cerebellum. It is still an unsolved problem of the contemporary otoneurology, a field which has been practiced for several centuries. Sensing the approaching thaw in the country in 1989 I prepared a habilitation thesis entitled: "Research into the efficiency of the equilibrium system after destruction of the cerebellar hemispheres (a clinical study)". The thesis originates from the Laboratory of the Research into the Equilibrium System of The Health Care Center in Tomaszów Mazowiecki, whose head I was.

THE AIM OF THE THESIS

The aim of the thesis was to assess changes in reactions of oculomotor, vestibulo-cerebello-ophthalmic and vestibulo-cerebellospinal reflexes resulting as a consequence of injuries of the cerebellar hemispheres. The assumption of the thesis was also to determine which from the well-known vestibular tests used in the otoneurology, after considering the habituation phenomena, have a diagnostic significance in injuries of the central part of the equilibrium system, i.e. the cerebellum.

THE SUBJECT OF STUDY AND METHODS

The subject of study was a group of 50 healthy persons and a group 58 persons with injuries of the cerebellar hemispheres. The control group consisted of 50 healthy persons aged from 17 to 50 (the arithmetic average: 30,6 years ± 11), including 26 women and 24 men. The participation in the control group of healthy persons was based on reactions obtained in static-dynamic tests, symmetrical and correct reactions in caloric tests by Fitzgerald-Hallpike and Torok and in the kinetic test of pendular stimulations. Additionally, another condition of being included in the control group was lack of spontaneous and positional nystagmus with eyes closed in the electronystagmographic recording. The other group consisted of 58 ill persons after surgeries of tumors of the cerebellar hemispheres, aged from 10 to 64 (the arithmetic average: 32,9 years ± 11,5), including 33 men and 25 women. In all the persons the tumor was removed entirely. As complications of the treatment 3 persons developed a destruction of the static-auditory nerve on the side of the operated tumor, confirmed with caloric tests and the audiometric research. Histopathologic examination revealed 42 cases of astrocytoma, 5 cases of hemangioblastoma, 5 cases of neurilemmoma, 2 cases of meningioma and 4 cases of cysts of the cerebellum. In 23 persons the tumor was located in the right cerebellar hemisphere, in 35 persons it was in the left cerebellar hemisphere.  The period of time which elapsed from the treatment to the moment of the examination was from 3 months to 25 years (average time 11,8 ±7,1). The research/study was carried out in the Studio of the Research into the Equilibrium System of the Otolaryngological Clinic of the Military Medical Academy in Lodz and in the Studio of the Research into the Equilibrium System of the Health Care Center in Tomaszów Mazowiecki. Apart from a detailed interview and an otolaryngological examination in all the persons underwent the following tests:

1. static-dynamic tests: the Romberg test, the Mann test, the past-pointing test, the deviation test, the diadochokinesis test, the finger-to-nose test.

2. dynamic tests: the Unterberger test and the author's dynamic test. 

3. audiological examination.

4. radiological examination.

5. otoneurological examination with electronystagmographic recording:

a. eye movement recording during calibration.

b. spontaneous nystagmus recording with eyes closed and open in a sitting position.

c. positional nystagmus examination with eyes closed in four positions, according to  recommendations by Nylen (83) and Cawthorn (10).

d. pendular eye movement examination or the smooth tracking test

e. optokinetic nystagmus examination in the horizontal plane by means of a semi-circular screen and a projector (a stimulation lamp).

f. registration of rotatory nystagmus in the kinetic test with the pendular stimulation.

g.  the Fitzgerald-Hallpike bi-thermal caloric test was performed in the manner provided by the authors (29), with eyes closed and the electronystagmographic recording.

h. the Torok monothermal differential test (58).

FINDINGS AND DISCUSSION

Static-dynamic tests:

The positive Romberg test was found in 13 persons, in 4 cases at the damaged right hemisphere and in 9 cases at the damaged left cerebellar hemisphere. The positive sensitized Romberg test (the Mann test) was found more frequently with statistically high significance. It was found in 46 persons altogether, in 20 cases at the damaged right and in 26 cases at the damaged left cerebellar hemisphere. Both these tests revealed staggering or falling down towards the side of the damaged cerebellar hemisphere and also towards the side of the healthy hemisphere. The positive past-pointing test was found in 3 persons with the destruction of the right and in 6 persons with the destruction of the left cerebellar hemisphere. One person with the destruction of the left cerebellar hemisphere showed a deviation of both upper limbs towards the side of the damaged cerebellar hemisphere, other persons showed a deviation of the opposite limb to the side of the destruction towards the healthy hemisphere (outside). This reaction is statistically significant. The positive deviation test was recorded in 7 persons altogether, in two cases with the destruction of the right cerebellar hemisphere and in five cases with the destruction of the left cerebellar hemisphere. One person with the destruction of the left cerebellar hemisphere showed a deviation of both upper limbs to the left side, other persons showed a deviation of the limb on the healthy side outside. This last reaction type Together in the past-pointing test and in the deviation test is highly statistically significant. Trembling and falling of the upper limb on the side of the damaged hemisphere were also observed. The positive finger-to-nose test was found in 23 persons altogether, the positive adiadochokinesis test - in 31 persons. In the Unterberger test 47 persons showed rotation around the long axis of the body above 90° towards the side of the healthy cerebellar hemisphere and 45 persons showed a shift of the body in the horizontal plane forward above 50 cm. The author's dynamic test revealed a rotation around the long axis of the body towards the side of the healthy hemisphere with the moved forward lower limb opposite to the destruction and lack of rotation with the moved forward lower limb on the side destruction - fig. 1

1

No rotation from the left lower limb moved forward	Rotation to the right from the right lower limb moved forward

Fig 1 Destruction of the left cerebellar hemisphere

Such a reaction model was found in 18 cases with the destruction of the right hemisphere and in 26 cases at the destruction of the left cerebellar hemisphere. The shift of the body in the horizontal plane above 50 cm was observed most frequently in the forward direction. The results illustrating this reaction model are highly statistically significant. The rotation towards the side of the damaged hemisphere during the performance of the test with the right and then with the left lower limb moved forward was observed in 2 cases of the destruction of the right and in 3 cases of the destruction of the left cerebellar hemisphere. Rotation towards the side of the healthy hemisphere with the right and then the left lower limb moved forward was observed in 1 case of the destruction of the right hemisphere and in 2 cases of the destruction of the left cerebellar hemisphere. The lack of rotation with the left and then the right lower limb moved forward was found in 1 case of the destruction of right and in 3 cases of the destruction of the left cerebellar hemisphere. The rotary motion to the left around one's own long axis of the body with the right lower limb moved forward and rotation to the right with the left lower limb moved forward were observed in 1 case of the destruction of the right and in 1 case of the destruction of the left cerebellar hemisphere. The described reaction models are not statistically significant for injuries of the cerebellar hemispheres.

 Oculomotor reactions recorded electronystagmographically

The recording of the calibration in all the ill persons was readable. The dysmetria of eye movements was found in 87,9 % of the entire population. These results are highly statistically significant. The recorded phenomena were movements of overdoing eye movement as well as underdoing eye movement to the bulbs which are switched on one by one.  Spontaneous nystagmus with eyes closed was found in 26 persons, with eyes open in 8 persons. In injuries of the cerebellar hemispheres, spontaneous nystagmus prevailed altogether towards the damaged hemisphere. In 2 cases square waves were recorded. The lack of nystagmus with eyes closed was found in 51,7 %, however, with eyes open in 82,8 % of the entire population. These differences are highly statistically significant. The span of the top angular speed of the free phase of spontaneous nystagmus with eyes closed was very large, from 4,5°/s to 56,3°/s. It was observed that the higher the angular speed of the free phase, the bigger the regularity of the course of the free phase of nystagmus. The study did not confirm any close relationship between the frequency of the occurrence of spontaneous nystagmus and the time which elapsed from the carried out neurosurgical treatment. Positional nystagmus in 2 positions at least was recorded in 32 persons. In 2 persons, in all positions, square waves were recorded. Positional nystagmus in all positions was present in 26 subjects. The type 1 of positional nystagmus according to Nylen was found in 9 persons with the destruction of the right and in 11 persons with the destruction of the left cerebellar hemisphere. Positional nystagmus type 2 according to Nylen was recorded in 4 persons with injuries of the right and in 8 persons with injuries of the left cerebellar hemisphere. So, the prevailing nystagmus type was type 1 according to Nylen. As a rule, in nystagmus type 1 no superiority of nystagmus towards one of sides was recorded. Positional nystagmus type 3 was not observed. In positional nystagmus with variable directions one did not observe any occurrence of nystagmus the direction opposite to the side on which the head was laid. Putting the head on the side compatible with the direction of spontaneous nystagmus caused nystagmus intensification but this was not a rule. Positional nystagmus was not accompanied by vertigo, only most of the subjects complained of dysphoria in the Rose's position. Positional nystagmus with variable directions prevailed in four positions to one of sides, only when the head was put in the opposite direction to the found superiority did it change its own direction. Positional nystagmus appearing in the direction opposite to the existing superiority was not so strong as when the head was put on the side compatible with the direction of the superiority of positional nystagmus. Among 3 persons who additionally had damaged the static-auditory nerve, none showed positional nystagmus in all positions. Optokinetic nystagmus was found in 25 ill persons altogether. In injuries of the cerebellar hemispheres on the right side, optokinetic nystagmus was recorded in 1 case only to the right side, in 3 cases only to the left side and in 9 cases to both sides simultaneously. In injuries of the hemispheres on the left side optokinetic nystagmus was found in 1 case only to the right side, in 4 cases only to the left side and in 7 cases to both sides.

Recording of the horizontal optokinetic nystagmus allows separating two main patterns of the optokinetic reaction. The first was characterized with a tendency to small amplitudes and high-frequency nystagmus, and the second to a small frequency and a large amplitude of nystagmus. The asymmetry of optokinetic nystagmus was found in 44 ill persons. These data are highly statistically significant. In injuries of the right cerebellar hemisphere symmetrical responses were obtained in 6 cases and the asymmetry in 17 cases. Inhibition of the optokinetic reaction in 10 cases was found with the usage of a stimulus to the side of the damaged cerebellar hemisphere and in 7 cases to the side of the healthy cerebellar hemisphere. At ill with the destruction of the left cerebellar hemisphere symmetrical reactions were found in 8 cases, asymmetric in 27 cases. Inhibition of the optokinetic reaction with the use of the stimulus to the side of the damaged cerebellar hemisphere was found in 15 cases and to the side of the healthy hemisphere in 12 cases. Generally, inhibition of the reaction during the use of a stimulus to the side of the damaged hemisphere was obtained in 25 ill persons, to the healthy side in 19 ill persons. These differences are not statistically significant. None of the subjects showed an entire abolition of the optokinetic reaction to one or both sides. The encountered disturbances in the recording of optokinetic nystagmus consisted in a large variability of amplitudes, prolongation of the free phase or the occurrence of the quick phase of nystagmus. On the arms of the free phase of nystagmus additional small saccades were observed. Whenever asymmetry was found, already in progress of the performance of the test the subjects reported difficulties in tracing the strips moving towards the damaged or the healthy cerebellar hemisphere. It was found that in the cases of the existence of spontaneous nystagmus and positional nystagmus with a constant direction or with a variable direction with a predominance to one of the sides, the phenomenon which was more frequently recorded was the asymmetry of optokinetic nystagmus with inhibition of the optokinetic reaction to the side opposite to the direction of spontaneous nystagmus. For instance, if spontaneous nystagmus was directed to the side of the damaged hemisphere, the inhibition of the optokinetic reaction was found with the use of a stimulus to the side of the damaged hemisphere. However, if spontaneous nystagmus was directed to the side of the healthy hemisphere, then the inhibition of the optokinetic reaction was recorded with the use of the stimulus to the side of the healthy hemisphere. No characteristic recordings of the optokinetic reaction underlining the “cerebellar" character of the destruction were found.

 The smooth tracking test was carried out by means of two tests:

a) a typical pendulum test,

b) by means of gonioscope.

In the research, when the ill persons were observing the pendular ball movement, the pathological recording of the curve was found in 49 cases. These results are highly statistically characteristic. Differences in injuries of the right and left hemisphere are not statistically significant. In 46 cases the recording of the curve type 2 was obtained, in 3 cases - type 3. In the smooth tracking test, a pathological recording was obtained by means of gonioscope in 55 persons.  These results are highly statistically significant. In 52 cases a recording of the curve type 2 was obtained, so, additional saccades overlapped on the arms of the sinusoid with relatively correct outlines. These were most frequently symmetrical inclinations, on the ascending and descending arm. The curve of the smooth tracking test showed then the characteristic recording of cogwheeling. Recordings with asymmetric saccades on the curve of tracking were also recorded. They were observed in the cases when the ball tracking movement or the light point was taking place towards the quick phase of spontaneous nystagmus. This was not a rule and this phenomenon did not have any significant relationship with the side of the damaged hemisphere. The observation of recordings of the curve of the smooth tracking test in injuries of the right and left hemisphere did not show any essential differences. The biggest changes of the recording of the curves in the pendulum test were recorded with inclinations of the ball by the angle of 30°. When the inclinations of the ball were gradually diminishing, minor disturbances in the recording of the curves of tracking were recorded. With inclinations of the ball by the angle of 10° and smaller, already correct curves were recorded in 15 persons. In both tests the curves clearly distorted or "broken up" were found in 3 persons from among the 58 subjects.

The Fitzgerald-Hallpike bi-thermal caloric test

In 46 persons symmetrical nystagmus reactions (a high statistical significance) were obtained.  The canal paralysis was found in 3 cases. They were persons with a post-surgical destruction of static-auditory nerves on the side of the operated cerebellar hemisphere. The symmetrical directional predominance was recorded in 4 persons, in 3 cases it was directed to the side of the damaged hemisphere and in 1 case to the side of the healthy hemisphere. In all persons with the symmetrical directional predominance spontaneous nystagmus with closed eyes was recorded. In the remaining 5 persons reactions were obtained connecting in themselves the canal paresis and a real directional predominance. In two cases the canal paresis was found on the side of the damaged hemisphere and the real directional predominance to the healthy side. In the next three cases the canal paresis was found on the side of the healthy hemisphere and the directional predominance to the side of the damaged hemisphere. In these reactions there were no responses on one side to the caloric stimulus with hot water (44° C), with symmetrical reactions to cold (30° C) water. Quite frequently there were nystagmus reactions with a variable amplitude of saccadic eye movements. Persons who were additionally exposed to radiation showed a more frequent occurrence of pauses in nystagmus reactions. The author carried out a comparative analysis of selected parameters of nystagmus reactions obtained in the Fitzgerald-Hallpike test in the control group and in the group of ill persons with injuries of the cerebellar hemispheres. The analysis of the parameter of the duration of nystagmus after caloric stimulation did not show any statistically significant differences between the presented groups. The author received slightly lower average values of the latency time in the group of ill persons compared with the control group. However, there were higher values of the average maximum amplitude and the average maximum angular speed of the free phase of nystagmus in the group of ill persons. There are interesting results of almost identical average values of the maximum angular speed of the free phase of nystagmus after the cold and the warm stimulus in the group of ill persons.

 The Torok caloric test

Test results of the Torok caloric test in the group of ill persons were processed based on the occurrence of the "vestibular decruitment" symptom. In 32 persons the occurrence of this symptom was found in one ear and in 8 persons in both ears. In total, the "vestibular decruitment" type 1 was found in 34 examined ears and type 2 in 14 examined ears. No "vestibular decruitment" symptom type 3 according to Torok was observed. In 27 cases this symptom appeared on the side of the healthy hemisphere and in 21 cases on the side of the damaged hemisphere. It was noticed that the side on which the "vestibular decruitment" appears, is dependent on the direction of the spontaneous and positional nystagmus. For example, if the spontaneous or positional nystagmus appears to the right side, then the "vestibular decruitment" occurs in the caloric reaction from the left ear. Areflexia of vestibules was recorded in 3 ill persons who had their static-auditory nerve damaged during the neurosurgical treatment. No hyperactivity responses were found, which means that in no person, in the culmination phase of nystagmus, the total number of saccadic eye movements in two subsequent five-second lengths of time was no higher than 30 after the use of a weak stimulus (10 ml, 20° C) and higher than 40 after the use of a stronger stimulus (100 ml, 20° C).

The pendular stimulation test

Symmetrical reactions were obtained in 45 persons (a high statistical significance), including in 10 ill persons they were symmetrical reactions with a lowered excitability. The curves of the reaction graph ran on the Greiner's network below the bottom line appointing the scope of the norm. In 35 persons the curve illustrating vestibular reactions ran within the range of the norm. In 11 subjects there were asymmetric reactions with a distinct predominance of nystagmus, compatible with the direction of recorded spontaneous nystagmus.

The predominance of reactions in these cases was visible throughout the entire test, only in 4 persons symmetrical reactions were found in the first period of deflections of the chair. In ill persons with recorded spontaneous nystagmus the number of nystagmus deflections in semi-periods compatible with the direction of spontaneous nystagmus was high and the curves of the graph of vestibular reactions ran beyond on the Greiner's network outside the upper line marking the scope of the norm. However, the number of saccadic eye movements in semi-periods in the opposite direction was considerably smaller and the curves of the graph of the reaction ran below the lower limit of the norm. In one case nystagmus unresponsiveness was found. This concerned a person with the destruction of the static-auditory nerve after surgery of the right cerebellar hemisphere. In one person in whom the tumor was situated in the right cerebellar hemisphere and the region of the bottom of the fourth ventricle, an atypical reaction was obtained. In the initial inclinations of the chair there were a predominance of nystagmus to the left, symmetrical reactions in central semi-periods and in final inclinations of the chair there was a distinct predominance of nystagmus to the right. It must be mentioned that in this person spontaneous nystagmus to the left was found with eyes closed and open, and the positional nystagmus with a variable direction Nylen I, with the dominant direction to the left. In the Fitzgerald-Hallpike bi-thermal caloric test symmetrical nystagmus reactions and secondary nystagmus (11) were recorded. While assessing qualitatively the recorded reactions it can be found that different recording patterns were found. One recorded correct and readable vestibular reactions with a marked latency period (75,8 % reactions) as well as reactions with difficult interpretation and calculation of saccadic eye movements (24,2 % reactions). From among qualitative changes of recording the most frequent phenomena were the variability of amplitudes, dysmetria, the presence of small recording, the lack of latency time. That last change is also called nystagmus silence or an interrotational interval. The lack of this nystagmus silence was found in ill persons with spontaneous nystagmus whose angular top speed exceeded 20°/s. In the pendular stimulation test a directional predominance was then recorded. Nystagmus with the direction opposite to the found directional predominance appeared directly after the previous nystagmus, without any latency period. The number of nystagmus strokes was in these semi-periods clearly smaller and the reaction time was shorter.  The nystagmus reaction appeared when the chair reached the greatest angular acceleration. As soon as the braking phase started, there appeared direct nystagmus compatible with the direction of spontaneous nystagmus. However, persons with recorded spontaneous nystagmus who showed symmetrical vestibular reactions in the pendular swivel chair test was found, typical nystagmus silence was recorded the moment the chair was approaching to the position of the maximum deflection.

Audiometric research

In audiometric research the lack of perception in the right ear was found in 2 persons and in the left ear in one person. In one case a bilateral, symmetrical destruction of hearing of the receiving type was found. At remaining persons the hearing stayed within the ancient norm.

DISCUSSION

As previously stated, first of all, the research into vestibulo-cerebellospinal reflexes is essential for correct assessment of the efficiency of the equilibrium system. The thorough knowledge of the caused reactions allows defining the pathology, differentiating the circumferential or the central character of the damage, though very often it is not an easy matter. The possibility of using electronystagmographic registration in the assessment of the research into these reactions influences the fact that most explorers focus mainly on recording vestibulo-cerebello-ophthalmic reflexes, which takes place very frequently in the published papers (37, 48, 49, 58, 99). However, the results of basic static-dynamic tests are more seldom presented. In the assessment of vestibulo-cerebellospinal reflexes, observations of spontaneous symptoms (40, 53, 60, 76, 103) are especially precious. In the presented studies, during the performance of the Romberg test and the Mann test ill persons more frequently staggered or fell down towards the side of the damaged cerebellar hemisphere. These observations are compatible with the descriptions included in the otoneurological literature (40, 57). However, Dow (23) found that after the unilateral destruction of the "vestibular" part of the cerebellum in animals (soon after treatment), they fell down in the opposite direction. The findings of the author's research concerning reflexes in the deviation test and in the past pointing test are different than the data presented in certain studies (40, 57, 63). These studies stressed that in injuries of the cerebellar hemispheres, the upper limb on the side of the damaged hemisphere deviates towards the focus. In his own research the author found abduction outside the upper limb on the side of the healthy cerebellar hemisphere and there was no deviation of the upper limb on the side of the damaged hemisphere. Such reactions were observed especially often during the performance of the Unterberger test and the author's dynamic test with upper limbs raised forward. The upper limb behaved in these cases as if it indicated the direction of the rotation which is to occur. These observations are compatible with the reactions obtained in the previous studies (11, 78, 92) and the results in experimental research by Walsh (103). In dogs whose entire cerebellum was removed, the prevailing movements are those of abduction and extension of limbs - Fig. 2

2

Fig. 2. Results of the destruction of the entire cerebellum (top) and only the vermis (below) - (Andre-Thomas, according to Walsh).

Such an image of abduction of upper limbs can be caused in healthy people by applying a strong asymmetric stimulus with cold water in the Ruttin test (the habilitation lecture - fig. 1). Inhibiting the cerebellar hemisphere by means of a stimulus caused by the endolymph flow towards the canal (ampulofugal movement) causes a similar situation as in the destruction of the cerebellar hemisphere. The cerebellum is the main central organ of the equilibrium system (the habilitation colloquium and the habilitation lecture). As I already mentioned, I could not disclose earlier my discovery concerning the vestibulo-cerebellar system because if I had done it I would not have been allowed to take the habilitation colloquium. I could only use knowledge which was included in the otoneurological literature. My own observations of ill suffering from tumors of the cerebellar hemispheres, verified by CT examination, confirm this model of spontaneous reactions concerning upper limbs, obtained in the Unterberger test and in the author's dynamic test. This reaction model can be caused in ill persons after removing a tumor of the cerebellar hemisphere, applying the symmetrical Ruttin test with cold water. One obtains then a nystagmus reaction towards the damaged cerebellar hemisphere and abduction of the upper limb on the side of the healthy cerebellar hemisphere (the habilitation lecture - fig. 14a). It must be remembered that the habilitation thesis, the habilitation colloquium and the habilitation lecture are one entirety of my habilitation. This was the only possibility and the privilege in my scientific activity to present all my discoveries to the Medical Faculty Council of the Military Medical Academy in Lodz in order to obtain the degree of habilitated doctor of medical science. The results of these reactions also confirm Wartenberg's earlier information (cited according to 40) that the cerebellum helps movements of abduction and bending of limbs. However, the researcher did not present the theoretical foundations of these observations. I introduce an explanation of this phenomenon also for the first time in the habilitation lecture. The destruction of the right cerebellar hemisphere increases abduction of the left upper limb. The description of pigeons' walking after the destruction of the cerebellar hemisphere - Małecki et al. (68), as well as the postures of bodies of people while walking - Best etc.(11), can confirm these observations. Relatively few cases of the described spontaneous reactions from upper limbs obtained in the presented research can indicate the occurrence of the habituation processes in vestibulo-cerebellospinal reflexes. Falling down of the upper limb on the side of the operated cerebellar hemisphere can be associated with the decrease of the muscular power as a consequence of injuries of the cerebellum (40, 103). From among the performed coordinative tests, the adiadochokinesis test was clearly more often found in comparison with the test finger-to-nose. The occurrence of positive coordinative tests in a few or a dozen years from the date of the undergone treatment can be a proof of the permanent character of the damage. This phenomenon one ought to be explained probably by the destruction of deep nuclei of the cerebellum (31). Therefore, both these tests, as shown by the literature and the author's research, have a large value in diagnostics of injuries of the cerebellar hemispheres, and the pathobiology of these reflexes has been discussed in every respect in numerous studies (11, 40, 103). The Unterberger test, in over 80% cases, showed a rotation around the long axis of the body towards the healthy cerebellar hemisphere, the lack of rotation in about 9% and a rotation towards the damaged hemisphere in about 10% subjects. This means that the first reaction model is dominant and proves abduction towards the healthy cerebellar hemisphere. In the author's dynamic test, like in the Unterberger test one reaction model prevailed. One observed mainly a rotation of the body towards the healthy cerebellar hemisphere during the performance of the test with the lower limb moved forward on the side of the healthy cerebellar hemisphere and lack of rotation during the performance of the test with the lower limb moved forward on the side of the damaged cerebellar hemisphere. Therefore, the obtained reactions were similar as in the past pointing test and the deviation test. The rules of formation of vestibulo-cerebellospinal reactions will also be thoroughly explained in my habilitation lecture. When abducting the upper limb and the lower one towards the healthy side, bending the trunk towards the side of the damage, and rotating his/her head with his/her chin directed at the healthy side, the subject resembled an image of the discus thrower position. The earlier physiological research shows (11) that a twist of the head of the animal (a rotation in the frontal plane of the skull) causes an increase in the tension of extensors of a posterior limb and an anterior limb on the side of the trunk towards which the jaw is rotated ("mandibular limbs") and reduces tensions of extensors in the opposite limbs ("cranial limbs"). Magnus (cited according to 11) introduced the name "mandibular limbs" to define the limbs on the side to which the human chin or the animal jaw are twisted or bent. The opposite limbs, i.e. the limbs towards which the top of the skull rotates, were then named "cranial limbs" by him. Wartenberg maintains (cited according to 40) that the cerebellum helps in adducting and bending limbs, however, the pyramid system collaborates actively in abducting and extending. Both these systems act antagonistically, if one of them is damaged, then the other one prevails functionally in a given range. Hence, in injuries of the cerebellar hemispheres adduction and bending of limbs is inhibited, however, abduction and extending dominates. Małecki et al. (68), observing the behavior of the pigeons walk  with an unilateral destruction of the cerebellum found that they deviated towards the healthy hemisphere. It's a well-known fact that the activities of the cerebellum and labyrinths are in a very close relationship with each other and both these organs exert influence on preservation of the musculature of the body (11, 103). It was as early as in 1892 that Ewald (27), after an experimental destruction of one labyrinth, found the lack of tension of abductor muscles of the limb on the damaged side, and observed an increase in tension of flexors and adductors on the other side. In the author's dynamic test of pendular marking time one observes a decided rotation of the body towards the damaged side during the performance of the test with the lower limb moved forward on the side of the healthy labyrinth and the lack of rotation during the performance of the test with the lower limb moved forward on the side of the destruction (76). In injuries of the cerebellar hemispheres and the labyrinth on the same side, opposed reactions were received in the author's dynamic test. This observation allowed deciphering the rules of operation of the vestibulocerebellar system. The tendency to abduct the limbs on the side of the healthy hemisphere in injuries of the cerebellar hemispheres makes ill persons walk on a wide base. This phenomenon is not observed in injuries of the labyrinth. The research shows that the author's dynamic test, the pendular marking time test is a sensitive test, which can not only define the symmetry or the asymmetry of vestibulo-cerebellospinal reflexes, but also evaluate the efficiency of the entire equilibrium system. The classical Unterberger test can be compared with the Weber test used in audiology, however, the author's dynamic test can be compared to the Rinne test, also used in audiology. The Rinne test allows one to differentiate conductive hearing injuries and receptive hearing injuries. The author's dynamic test allows one to differentiate peripheral injuries of the labyrinth from central injuries. The entire equilibrium system is too complex and difficult to assess only by means one selected vestibular test and the construction and function of the labyrinth are still too little known. Oculometric dysmetria is one of the symptoms of disturbances of functioning of the cerebellum. In 1954 Cogan (18) described for the first time changes in the symmetry of saccadic eye movements while shifting the sight from one object to another. When examining six persons with injuries of the cerebellum he found dysmetria of saccadic eye movements in each of them. According to his opinion, this symptom appears exclusively in diseases of the cerebellum or the cerebellar tracts. These observations were confirmed later by Zee et al. (113) presenting findings in 5 ill persons with the congenital cerebellar ataxia. All the persons showed both overshoots and undershoots of eyeballs during their saccadic movements both in the vertical and the horizontal plane. In later studies Haring and Simons (37) confirmed a frequent occurrence of eyeballs dysmetria during the electronystagmographic calibration. In 40 subjects changes in calibration were found, in 33 injuries of the cerebellum were detected. Similar results were presented by Wenmo et al. (104). Examining 12 ill persons with injuries of the cerebellum and mixed injuries of the cerebellum and the trunk, 9 showed the dysmetria of saccadic eye movements. Katsarkas and Younge (48), on the basis of clinical observations of 38 ill persons with oculometric dysmetria, suppose that if this pathology connected is also with other vestibular symptoms, then the dysfunction of the flocculonodular lobe or its neuronal connections are primarily responsible for it. These observations have never been confirmed by Kumar et al. (59). In 30 ill persons with injuries to the archicerebellum, overshoots in calibration were found only in 2 cases. Animal research shows that the back part of the worm and the nucleus of the top are responsible for controlling the amplitude of saccadic movements (111). Damages of the above mentioned structures cause permanent hypermetric disturbances of the amplitude of saccadic movements, however, without eyeballs flowing after the postsaccadic drift. Clinical observations also confirm that injuries to the cerebellum in the center line cause dysmetria of saccadic eye movements (111). The analysis of reactions during calibration in the author's research showed that the "inaccuracy" of saccadic eye movements was found in 87,9% cases. Both overshoots and undershoots of eyeballs were observed. The horizontal spontaneous nystagmus with eyes closed was recorded in 44,8% of the whole of the subjects with injuries to the cerebellar hemispheres. Similar results were obtained by Brzeziński and Latkowski (14). Tumors of the cerebellar hemispheres spontaneous nystagmus was recorded in 9 in 13 cases.

The diagnostic meaning of spontaneous nystagmus is especially stressed by most researchers (59, 80, 91). According to Hare et al. (36) the statement of spontaneous nystagmus draws a suspicion of the destruction of the cerebellum or its neuronal connections, because the influence of this organ on oculomotor activity is very significant. Although reasons of the occurrence of spontaneous nystagmus in subtentorial injuries are still inaccurately recognized, however, it is considered that it arises probably as a result of compression on structures of the stem and the archicerebellum - Fernandez et al. (28) and Grandt et al. (34). In the presented research ill persons were already after neurosurgery, on average 11,8 years from the date of the surgery. All of them had had their tumors removed entirely, so it can be thought that there did not appear any compression on the brain stem. It should be supposed that the recorded nystagmus was of the cerebellar origin. These observations are compatible with observations provided by Kumar et al. (59) and Duke-Elder and Scott (24). With the eyes open this nystagmus was recorded only in 13,7% of all the subjects. In all persons spontaneous nystagmus appearing with their eyes open had a smaller amplitude, a smaller angular speed of the free phase and a smaller frequency compared with spontaneous nystagmus, appearing with the eyes closed. Ukleja and Malukiewicz (99), in 18 tumors of the cerebellum, observed spontaneous nystagmus with the eyes open straight ahead in two cases, which is about 11%. The influence of the visual fixation mechanisms on nystagmus of the labyrinthine origin had already been documented (1). The labyrinthine spontaneous nystagmus is more distinct with eyes closed than with eyes open. Also, postcaloric nystagmus or post-rotary nystagmus is more distinct in the darkness than in the light (1, 89). This regularity appears in healthy people and in ill persons in whom changes are located on the periphery. However, in ill persons with central changes a different phenomenon can be observed, i.e. opening the eyes does not affect the intensity of nystagmus or clearly intensifies it (21, 75, 84). The author's observations based on the analysis of spontaneous nystagmus in injuries to the cerebellar hemispheres do not confirm these observations. Opening the eyes caused elimination of spontaneous nystagmus, recorded with eyes closed or clearly inhibited it. These observations seem to be significant in diagnosing central injuries. Takemori and Cohen (90) showed that the bilateral destruction of the cerebellar flocculus in monkeys completely eliminates the animals' capability of visual inhibition of nystagmus induced with a caloric stimulus. Contrary to these authors, Keller and Precht (50) observed the remaining influence of the sight on vestibular reactions after the entire removal of the cerebellum in cats. As it is visible even in experimental conditions, the obtained results are extremely various. An attempt to explain such contradictory results presented above is made by Godoux and Vanderkellen (32), who try to explain it. Investigating healthy cats, which had had their cerebellum removed, the authors found that the inhibitory influence of the sight on vestibular reactions induced with the caloric stimulus depends on the angular speed of the free phase of nystagmus. In cats with the removed cerebellum the suppressing influence of the sight remains whereas the angular speed of the free phase of nystagmus does not exceed 20°/s, disappears above these values. Therefore the relationship between the loss of visual inhibition of nystagmus and the removal of the cerebellum in cats is at least partly indirect. The removal of the cerebellum causes an increase in the angular speed of the free phase of caloric nystagmus and the ability of visual inhibiting is usually less effective at higher values of the angular speed of the free phase of nystagmus. The authors' research show that the cerebellum is not the place of the vestibulo-optical interaction and that the cerebellum only "improves" the quality of these interactions. In the author's research the range of the maximum value of the angular speed of the free phase of spontaneous nystagmus with eyes closed was very large and ranged from 4,5°/s to 56,3°/s. The inhibitory influence of the visual fixation was recorded also at these highest speeds of the free phase of nystagmus. At values of the speed of the free phase below 20°/s and eyes closed, spontaneous nystagmus with open eyes was not recorder. The lack of spontaneous nystagmus with eyes open was also found when the maximum values of the free phase of spontaneous  nystagmus with eyes closed exceeded 35°/s. The author is in possession of the documentation of a study of nystagmus in a 8-year-old girl who, in three subsequent neurosurgeries, had a substantial part of the worm and the cerebellar hemispheres removed. With eyes closed spontaneous nystagmus to the left was recorded in her, however, with eyes open no spontaneous nystagmus occurred. Therefore, Keller and Precht (50) seem to be right in their observations about the remaining influence of the sight on vestibular reactions after the entire removal of the cerebellum in cats. Analyzing the frequency of the occurrence of spontaneous nystagmus with eyes closed depending on the time which elapsed from the carried out neurosurgery it can be stated that there is no statistically significant effect of the central compensation on the disappearance of spontaneous nystagmus resultant as a consequence of the destruction of the cerebellar hemispheres (80). The results of this research seem to confirm the observations that damaging the cerebellar nuclei causes changes of permanent character (31). The presence of spontaneous nystagmus can be sometimes, after many years, an only and objective proof of past destruction of the cerebellar hemispheres. It was found that the regularity of the course of the free phase of nystagmus depended on its speed. With small angular speeds of the free phase one observed a smaller regularity of the course of the free phase than at higher values. The study by Latkowski et al. (65) concerning the assessment of the regularity of the course of the free phase of nystagmus in peripheral and central (subtentorial) injuries showed a statistically significant regularity of its course only in peripheral injuries.

Optokinetic nystagmus was found statistically more often in persons with injuries of the right cerebellar hemisphere. Also, it was recorded on the same side more often than spontaneous nystagmus with closed eyes. However, an inverse phenomenon was observed in injuries of the hemispheres on the left side. Robinson (86) recorded optokinetic nystagmus in cats after the entire removal of the cerebellum. The author maintains that this nystagmus results from the loss of the possibility of supporting the eyeballs during the abduction sideways, which results in floating of eyeballs to the neutral point. In order to maintain the image on the retina, additional adjustable eye movements must be performed (86, 111). Finding gaze nystagmus after the exclusion of the influence of medicines, indicates disturbances in the integration of the cerebellum and the brainstem, because for the maintenance of eyeballs in the suitable position responsible are centers in the brainstem (4). The position of eyes is counted by the integrator situated the reticulate creature of the bridge (86). According to Robinson (47) the role of the cerebellum consists in perfecting and the stabilization of reflexes swimming from the brainstem. The destruction of the cerebellum causes that the system of the integrator becomes "leaky". This means that the cerebellum improves the function of the integrator through an increase in the constant time to over 20s, with 1,3s which is the integrator's own time (47). Gaze nystagmus is a frequent symptom in isolated injuries of the cerebellum and in mixed injuries of the brain stem and the cerebellum (104). It is therefore often found in cases of acute ischemia of the area which is part of the vascularity of the posterior inferior cerebelllar artery (PICA), (25). It seems right to adopt the suggestions put forward by Daroff et al. (20) to use the term the "cerebellar system" instead of the "cerebellum" in clinical considerations. The authors unanimously prove that it is impossible to differentiate when the revealed symptoms of the destruction of the cerebellum belong only to this organ and when they are connected with its links with other centers of the Central Nervous System.

Positional nystagmus is one of the objective phenomena of the disorders of the equilibrium system and is assessed by the most explorers as a pathological symptom (15, 66, 83). The clinical interpretation of positional nystagmus is sometimes difficult because this symptom appears both in peripheral injuries as and central of the equilibrium system and does not selectively involve the features of every destruction separately. In injuries of the cerebellum it has a character of variable nystagmus or constant (direction) nystagmus (59, 68,99). Assessing in the presented thesis such a homogeneous group of ill persons with subtentorial injuries there was an attempt to take into account a great number of details in the positional nystagmus reactions, which can be useful in the diagnostics of injuries of the cerebellar hemispheres. The fact itself that this nystagmus was found in above 50% cases undoubtledly deserves attention and the presented results concerning the frequencies of the occurrence of positional nystagmus are coincident with the results obtained by Tanczew (91) and Ukleja et al. (99). In the statistical analysis of positional nystagmus in the author’s own research the absolutely prevailing type is type 1 according to Nylen. However, positional nystagmus type 3 according to Nylen was not observed. The lack of this nystagmus may have practical meaning in the diagnostics of injuries of the cerebellar hemispheres. Finding square waves in 2 cases proves that this is a very rare type of pathology in injuries of the cerebellar hemispheres. Brzeziński et al. (14), in 13 tumors of the cerebellar hemispheres, found square waves in one person in the kinetic reaction. Tanczew's observations (91) about the frequent occurrence of positional nystagmus towards the healthy side, were confirmed in the presented material only in injuries located in the right cerebellar hemisphere. In injuries of the hemispheres on the left side, positional nystagmus towards the damaged side occurred more often. The lack of positional nystagmus in 3 persons with the entire unilateral destruction of the static-auditory nerve can confirm earlier observations by Małecki et al. (68), carried out in research on pigeons, that in order for positional nystagmus to appear in cases of injuries of the cerebellum, it is necessary to maintain the function of the peripheral vestibular organ because the lack of the information flow from the periphery will automatically extinguish the positional nystagmus. However, when the peripheral activity is kept but there was an obstacle in the transmission or the reception of the peripheral signals (as it takes place in cases of injuries of the cerebellar hemispheres), then the overloads resulting from the determined positions of otoliths can be significant enough to cause the positional nystagmus (68).

The asymmetry of optokinetic nystagmus was found in 75,9% of the whole of the ill persons. The inhibition of the optokinetic reaction was found more often while using stimuli towards the side of the damaged hemisphere. These observations are close to the results obtained of other authors (14, 96, 98). In cases of injuries of the cerebellar hemispheres and spontaneous nystagmus which arose as a result of the damage, optokinetic nystagmus overlaps with spontaneous nystagmus and decreases or increases its intensity depending on the direction of spontaneous nystagmus and optokinetic nystagmus. The resultant depends also on the intensity of spontaneous nystagmus (98). Spontaneous nystagmus seems to clear the way in the brainstem reticular formation, for the optokinetic predominance (96). The optokinetic asymmetry connected with other disorders is a valuable symptom indicating the location and the side of the destruction in the central nervous system (59). The locational value of the optokinetic asymmetry in subtentorial lesions is being discussed. Coats (17) suggests that when the optokinetic asymmetry is connected with the eye-tracking nystagmus, this destruction is located in the bridge or the mesencephalon. The presented research also involved cases with a simultaneous optokinetic asymmetry and with the gaze nystagmus, the destruction being located not in the bridge but in one of the cerebellar hemispheres. According to Hart (38) the brainstem is often the location of the destruction with a considerable asymmetry of optokinetic nystagmus, especially in cases of the absence of spontaneous nystagmus with closed eyes. Such cases were also encountered in the examined persons, and the injuries were located not in the brainstem but in the cerebellar hemispheres. And here it seem that Daroff et al. (20) were correct claiming that it is not possible to clinically distinguish when the symptoms of the destruction of the cerebellum belong exclusively to this organ and when it is also a result of the connections with the brainstem. Hence the assessment and the interpretation of optokinetic disturbances in subtentorial injuries encounter understandable difficulties and the results of the optokinetic reaction must be considered with the entire clinical image. Honrubia et al. (41), while examining a group of 51 healthy persons with the optokinetic test, obtained two different patterns of the nystagmus reaction. The first pattern, characterized with a small amplitude and a large frequency, is connected with subcortical centers and does not require focusing one's attention to the moving objects. This nystagmus is also called passive nystagmus or staring nystagmus, being a result of "staring" (41). This type of nystagmus is found in animals (41). The second type of the optokinetic reaction - the "cortical" one, requires a conscious fixation of one's look on moving objects and tracking them as far sideways as  possible without turning away one's head (41). This is the response of the cerebral cortex to the impulse from the retina, which is also called a look nystagmus. Hood (41), on the basis of the electronystagmographic research of optokinetic nystagmus, distinguished two different and separate mechanisms of formation of this nystagmus. One requires peripheral vision, the other requires the macular vision (42). Instead of using the terms: subcortical and cortical, this author suggests using the term: peripheral and macular. So, the subjects who are recommended to look straight ahead at the center of the screen can actively track the strips moving in front of them, or simply look subconsciously, "stare" at them.

The disturbances of smooth tracking are a frequent symptom in injuries of the cerebellar hemispheres. The presented research found them in 84,5% in the typical pendulum test and in 94,8% in the smooth tracking test by means of the gonioscope. Harea et al. (36) seem to be correct claiming that the representation of eyes in the cerebellum exceeds all the other anatomical structures. Therefore, the disturbances of smooth tracking appear not only after damaging the  vestibulocerebellum (111), but also after damaging the cerebellar hemispheres. So, the destruction of different structures in the cerebellum can cause similar oculomotor disturbances (59). In the pendulum test, when the subject observes the inclinations of the ball, the size of the angular inclination of the observed object is a very important element - Katsarkas (49). The disturbances of smooth tracking were most often recorded at inclinations of the sphere from 30° to 10°. With inclinations of the ball of about 10° and smaller, correct curves were recorded in certain cases - Nakiela (79).  These observations are compatible with observations by other authors (49, 85). The biggest number of pathological recordings were found in the smooth tracking test by means of gonioscope. Tracking a light point, moving with a constant speed of 10°/s requires from the subject a constant macular fixation (10, 42, 79) and constant concentration. So, this test can be used to detect discreet disturbances in the oculomotor system, which could not be revealed by means of the typical pendulum test (104). In injuries of the cerebellar hemispheres the ill person is not able to incessantly maintain the light point on the macula of the retina for several seconds - Hood (42). Eyeballs perform additional inclinations towards the moving object. These are movements to overtake a given object, which results in arising of a characteristic "cog-wheel" recording. It must be mentioned that the speed of the displacement of the light point is more than two times smaller than the speed of the ball in its pendulum movement. Simultaneously, the destruction of the cerebellum causes disturbances in the work of the integrator, which results in irregular oculomotor phenomena of smooth tracking and the like. These two tests: tracking of the pendulum movement of the ball and tracking of the light point on the gonioscope, can be compared to the finger-to-nose test which is performed at first quickly and then slowly. In the positive finger-to-nose test a more intense intentional tremor of an upper limb is observed during the slow performance of this test. As shown by the author’s own research and the data from the literature (79, 87, 100), one can sometimes obtain a correct recording of the pendulum test in central injuries. Sakata et al. (87) claim that discreet disturbances in the oculomotor system can be undetected by means of a typical pendulum test. These authors proposed to use a test called the caloric-pendulum-interference-test (CPIT) for investigation of smooth tracking. According to them, the pathological recording of the caloric pendulum test appears in 94% of central injuries. It is underlined that in injuries of the oculomotor system, when the inhibitory mechanism still works efficiently and the destruction is not of a high degree, the pendulum test can be correct (87). In the situation when a caloric stimulus will cause vestibular asymmetry, the subclinically damaged oculomotor system will no longer be able to keep the visual aference over the vestibular one in the motor activity of the look, which will be revealed by means of pathological recording in the caloric pendulum test. The analysis of both of the presented tests shows that the research into smooth tracking by means of the gonioscope is a more sensitive examination and should be commonly used in the otoneurologic diagnostics.

One of the most often applied caloric tests in the otoneurologic diagnostics is the Fitzgerald-Hallpike test. Thanks to this caloric method we can detect two main abnormalities, the canal paresis and the directional predominance. Simultaneously, it is underlined that the symmetrical directional predominance is an expression of the domination of one of the vestibular systems, or it results from the increased or decreased peripheral inhibition. The cerebellum inhibits the activity of the vestibular system, receiving unilateral stimuli from the periphery through the system of vestibular nuclei (16, 70, 88, 111). In injuries of the cerebellum one should expect increased vestibular reactions on the side of the damaged cerebellar hemisphere. The author’s own research does not confirm such opinions. In 79,3% of the whole of the investigated cases symmetrical reactions were recorded, and these results are compatible with earlier studies (12, 44, 67, 78, 81, 103). The symmetrical directional predominance was found only in 6,9% cases. Ukleja et al. (99) observed the directional predominance towards the side of the damaged hemisphere more frequently. Reactions combining the canal paresis and the real directional predominance in the author's study occurred in 8,6% cases. As shown by the literature (58, 82), this type of answer does not have any established diagnostic values. The irregularity of amplitudes which occurs in the caloric reaction must be associated with the loss of the stabilizing activity of the cerebellum over the  vestibulo-ophthalmic reflexes. The carried out analysis of some parameters of the Fitzgerald-Hallpike test in healthy persons and in persons with injuries of the cerebellar hemispheres showed some characteristic differences. One found namely significantly higher values of the average maximum amplitude of saccadic eye movements and the average maximum angular speed of the free phase in the group of ill persons. One also received almost identical values of the maximum angular speed of the free phase of nystagmus with a cold and warm stimulus in the group of ill persons. As mentioned before, the cerebellum stabilizes vestibulo-ophthalmic reflexes and oversees the adequacy of vestibulo-ophthalmic responses depending on the applied stimulus (111). It "perfects", as it were, the work of the brain stem, the main integrator of oculomotor reflexes and vestibulo-ophthalmic reflexes. In healthy people, a stronger stimulus causes a bigger vestibulo-ophthalmic reaction than a weaker stimulus - Nakiela (78). The destruction of the cerebellum causes, among other things, formation of irregular reactions when a weaker stimulus causes a greater vestibulo-ophthalmic reaction from a stronger stimulus - Kumar et al. (59). Torok (94) used this phenomenon in his own caloric test for diagnosing central injuries. "Vestibular decruitment" in the Torok test was found in 68,9% of all the subjects. These results clearly prove a large significance of the Torok test in detecting damages located in the cerebellar hemispheres. Kumar et al. (59) on 31 cases of injuries of the cerebellum, including mainly the cerebellar hemispheres, "vestibular decruitment" found in 17 cases. These authors also found hyperactive reactions in 5 cases. The author did not observe such reactions in his research. These differences may originate from a little different research material. In my study ill persons had already had surgeries. In the study by Kumar et al. (59) the subjects had not been operated on and it should be supposed that in these cases there occurred compression on the neighboring central structures. The comparative analysis of the Fitzgerald-Hallpike caloric tests and the Torok test proves that whenever one suspects the destruction of the cerebellum, and the Fitzgerald-Hallpike test yields symmetrical reactions, additionally the Torok monothermal differential caloric test must be performed. Simultaneously, it is necessary to pay attention that the lack of the "vestibular decruitment" symptom does not exclude the destruction of the cerebellar hemisphere, as shown by the carried out research.

The analysis of the reactions in the pendulum chair test showed that in 77,6% of cases symmetrical vestibular reactions were obtained. These data are similar to the results obtained in the Fitzgerald-Hallpike test and prove that symmetrical vestibular reactions prevail in injuries of the cerebellar hemispheres. Walsh (103) claims that there are no changes in nystagmus arising during the rotary motion and originating from semi-circular canals in ill persons with injuries of the cerebellum. In persons with recorded spontaneous nystagmus with eyes closed or open, symmetrical reactions and the distinct asymmetry of the response was found in the pendulum chair test. Asymmetric reactions were recorded more often in persons in whom the angular speed of the free phase of spontaneous nystagmus exceeded 20°/s. It is difficult to answer the question why such various reactions are obtained with the existing spontaneous nystagmus. It is not known which factors are responsible for this phenomenon. Possibly, the compensatory processes in the central nervous system play the leading role here. No convincing evidence on it in was not obtained in this thesis. No close relationship between the type of the obtained reaction and the time which elapsed from the performed surgery. For example, symmetrical vestibular responses were observed in ill persons after 3 years from the performed surgery and asymmetric vestibular reactions in ill persons 6 years after the past operation.

It can be supposed that these changes can be dependent on the extensiveness of the destruction of the hemispheres, including injuries of deep nuclei of the cerebellum. Also, one cannot determine the uniform model of the nystagmus reaction which would be characteristic for injuries of the cerebellar hemispheres. No symmetrical reactions with the hyperexcitability of the vestibules were found, either. Audiometric research shows that injuries of the cerebellar hemispheres do not cause any disturbances of hearing (88). These observations should be considered as fairly essential in the differential diagnostics of injuries of the equilibrium system (58). Summing up the discussion on the results obtained in individual tests it must be underlined that the use of the author's dynamic test creates new possibilities of the diagnostics of the cerebellar hemispheres. I consider introducing this test to the otoneurologic diagnostics as my modest contribution to finding about the complex vestibulo-cerebellospinal reflexes. The thorough understanding of these reflexes in cases of injuries of the cerebellar hemispheres allows defining more sensitively which role they fulfil in the equilibrium system. It is known that a considerable number of the described cerebellar symptoms (often contradictory) in cases of injuries of the cerebellar hemispheres arises anxieties regarding a fair and objective judgement about their value. Obtaining a statistically high significant repeatability of the described models of reflexes in the Unterberger test and the author's dynamic test, the pendulum marking time test local in ill persons with injuries of the cerebellar hemispheres, allows defining the role of these hemispheres in the formation of vestibulo-cerebellospinal reflexes. Using the Torok monothermal differential test, unusual in the Polish literature by now, for this research should be considered as further possibilities of enrichment of the otoneurologic diagnostics in injuries of the cerebellar hemispheres.

CONCLUSIONS

•     From among static-dynamic tests used for assessment of injuries of the cerebellar hemispheres the test of the greatest value seems to be the Unterberger test and the author's dynamic test. In both tests a statistically significant reaction model (p< 0,01) was obtained.
•     In the Unterberger test one recorded a rotation around the long axis of the body towards the side of the healthy cerebellar hemisphere and a shift of the body forward.
•     In the author's dynamic test the most often found phenomenon was a rotation of the body towards the healthy hemisphere (during the performance of the test with the lower limb moved forward on the healthy side) and the lack of rotation (during the performance of the test with the lower limb moved forward on the side of the damaged hemisphere).
•     In ill persons with injuries of the cerebellar hemispheres one found a statistically significant (p< 0,01), more frequent occurrence of oculomotor disturbances such as: the dysmetria of saccadic eye movements in the calibration test, the disturbance of smooth tracking, the asymmetry of optokinetic nystagmus.
•     The horizontal spontaneous nystagmus with eyes closed was recorded statistically more often than with open eyes (p< 0,01).
•     In the Fitzgerald-Hallpike caloric test and in the kinetic test of pendular stimulations one obtained in most cases symmetrical vestibular reactions (p< 0,01).
•     From among the vestibular tests applied in this research, the Torok caloric test seems to have the greatest value in the diagnostics of injuries of the cerebellar hemispheres. The phenomenon of "vestibular decruitment" was found in 68,9% cases of the whole of the subjects.

The thesis contains 142 pages, 114 tables, 114 items of references.

The reviewers of the habilitation thesis were:

1) Prof. Janusza Kubiczkowa, M.D., Ph.D., the Head of the Laryngological Clinic of the Military Institute Of Aeromedicine in Warsaw.

2) Prof. Stanisław Betlejewski, M.D., Ph.D., the Head of the Laryngological Clinic of the Medical Academy in Bydgoszcz.

3) Prof. Andrzej Radek, M.D., Ph.D., the Head of the Neurosurgical Clinic of the Military Medical Academy in Lodz.

All reviews were positive. As I already I mentioned before, I carried out the research by means of the experimental model in healthy people in parallel with clinical research of ill persons with injuries of the cerebellar hemispheres. My scientific discoveries undermine the current knowledge on the subject of the basic problems connected with the physiology and the pathology of the labyrinth and the cerebellum, and this is why I could not disclose them earlier because I would certainly not have been allowed to sit the habilitation colloquium. The Medical Faculty Council of the Military Medical Academy appointed the habilitation colloquium for 20 November 1990. After the habilitation colloquium, the candidate must deliver a habilitation lecture which as a separate part of the habilitation is also assessed by voting. I proposed three lecture topics to the Medical Faculty Council. One of them was to be chosen in voting of the Members of the Medical Faculty Council after passing the habilitation colloquium. I was not afraid of the defense of the thesis in the Military Medical Academy (WAM), but I was worried what will become with it in the Central Commission, therefore I decided to go out of the scientific underground and disclose the value of my own discoveries in my habilitation lecture so that nobody could think of rejecting my scientific achievements. On three days before my habilitation colloquium I presented to my thesis supervisor Prof. Bożydar Latkowski three lecture topics which I prepared for delivering at the Faculty Board after the habilitation colloquium. Since Prof. Latkowski is the author of the chapter "Rotary Tests" in the handbook "Clinical otoneurology" edited by Prof. Grzegorz Janczewski, I decided to present this problem to my tutor based on my discoveries, the functioning of the vestibulocerebellar system. By now, in kinetic stimulations the binding theory is LeDoux's theory which maintains that the organ responsible for the development of the rotatory reaction is one labyrinth, the one towards which the rotation occurs. I proved that both labyrinths are equally responsible for the development of the rotational and the post-rotary reaction in the physiological conditions. When I explained to Prof. Latkowski the principles of operation of the vestibulocerebellar system, suddenly Prof. Latkowski became pale in his face, stood up from the chair, threw the documents on the table and said: "Please, do not deliver these things and do not publish them because they will ruin you and will eat you up". I answered calmly, "Dear Professor, I am going to defend myself". Prof. Latkowski replied, "Do as you want", but he was immensely irritated. At that moment I did not realize that there was a "mafia" in the scientific world, a group "holding the power", and that it had its own influences and privileges and nobody else, not any of independent scientists, can threaten it. An epochal discovery in science destroys their existence and reveals the true value of their scientific achievements. On 20 November 1990 there was the habilitation colloquium which was evaluated very well by the Medical Faculty Council of the Military Medical Academy in Lodz in voting by secret ballot. Before the colloquium all the Members of The Medical Faculty Council received copies of the summary of the habilitation thesis and the information on the new discoveries. During the habilitation colloquium Prof. Hieronim Bartel, M.D., Ph.D., putting up the hand-outs distributed to the Members of The Medical Faculty Council, asked me why those materials are not included in the habilitation thesis. Strongly irritated, I finally answered that my discoveries were too revolutionary and could provide a certain degree of difficulty in writing a review.

The Medical Faculty Council of the Military Medical Academy chose the lecture entitled: "The vestibulo-cerebellar system according to the latest research and the author's interpretations". Also, the lecture in voting by secret ballot was assessed very well. In the habilitation lecture I presented also an experimental model where, by means of asymmetric stimulus with warm and cold water, one can simulate in healthy people the destruction of the labyrinth and the cerebellar hemisphere. Experiences with asymmetric stimuli confirm the reliability of vestibulo-cerebellospinal reflexes in clinical, isolated injuries of the labyrinth and the cerebellar hemisphere and also confirm the value of the author's dynamic test in the diagnostics of these injuries. Wanting to protect myself against the possibility of further lies, in the scientific documentation department of the Military Medical Academy I ordered a film recording from the course of the entire habilitation qualification. In the course of the habilitation colloquium, while replying to questions concerning the problem of habituation or the phenomenon of the directional predominance, I used my new theories based on the knowledge of the functioning of the vestibulocerebellar system, which had not been published anywhere by that time and unknown in the otoneurologic literature. After finishing the entire process connected with the habilitation qualification The Medical Faculty Council almost unanimously conferred the degree of habilitated doctor on me. Based on the habilitation lecture I will present and explain many problems connected with functioning of the vestibulocerebellar system.