Układ równowagi - Nowe odkrycia w dziedzinie otoneurologiii
Prof. Nakiela J.: Vertigo. The vestibulo-cerebellar system according to the latest investigations and interpretation of the author

The theoretical foundations of Bechterew's phenomenon

 

In 1883 Bechterew was the first to observe that after the destruction of one labyrinth and waiting for a suitable period of time, i.e. until the regression of paralytic nystagmus, we will ruin the other labyrinth, then we will observe the appearance of nystagmus which is this time directed towards the side of the originally damaged labyrinth. The researcher claimed that the mechanisms decisive about compensation were outside the labyrinth and were located in the vestibular nuclei. Other authors, on the basis of their experimental studies, showed that the destruction of the vestibular nuclei were responsible for the entire compensation process. At the moment of the destruction of the second labyrinth there appears a similar picture image like in the originally damaged labyrinth. The vestibulo-cerebellospinal reflexes are directed towards the side of the recently ruined labyrinth and nystagmus towards the earlier ruined labyrinth. As I have already indicated, Bechterew’s phenomenon, in order to arise, requires an appropriated time interval between one and another destruction of the labyrinth. In frogs it takes 5 minutes, in rabbits - 5 days. In 1925 Spiegel and Demetriades showed quotation according to (1) that cutting off connections with the cerebellum or destructing the vestibular nuclei on the side of the later damaged labyrinth does not eliminate Bechterew’s phenomenon. Only the destruction of the vestibular nuclei complex on the side of the originally damaged labyrinth eliminates this phenomenon completely. It is worth mentioning the following quotation according to (1), connected with Bechterew’s phenomenon: quotation: "Bechterew’s phenomenon is also indirectly associated with the phenomenon of overcompensation and the so-called recovery nystagmus (Erholungsnystagmus) which consists in the appearance of nystagmus or (in a more subtle form) the directional predominance of reactions induced towards the damaged labyrinth, after the period of partial compensation of the arisen damage. Nowadays there is a consensus of opinions with the position of Stenger (56), who claims that this process results from partial or entire restoration of functioning in the damaged vestibular receptor. Summing up of the returning activity of the receptor with the activity of the vestibular nuclei complex on that side, increased during compensation, results in the functional predominance of the side on which the destruction occurred. However, as it is difficult to produce an experimental model of such a damage, there is no detailed research into this form of vestibular disturbances".

The quoted Bechterew's phenomenon is connected with the phenomenon of habituation and not compensation. The described overcompensation is nothing else than the directional predominance of the nystagmus reaction towards the damaged labyrinth and appears in most cases at the asymmetric activity of labyrinths. So that arise Bechterew’s phenomenon after the destruction of the right labyrinth in the first instance the right cerebellar hemisphere must surrender to bringing to a stop and the left cerebellar hemisphere to the stimulation. Thanks to the activity of the cerebellar hemispheres, retuned in this way, habituation can result in a return of the activity of the right vestibular nuclei complex. So, Bechterew’s phenomenon can be caused already if there is a reaction to a cold stimulus on the side of the healthy labyrinth. In order for such a reaction to arise, the hemisphere associated with the healthy labyrinth, as a result of habituation must be inhibited and the opposite hemisphere, connected with the damaged labyrinth, must be stimulated. Without earlier properly retuned activity of the cerebellar hemispheres in the course of habituation after the unilateral destruction of the labyrinth it would be impossible to cause the tension equalization in both vestibular nuclei complexes in the brain stem and, as a consequence, to cause Bechterew’s phenomenon. Therefore, it is justified to accept the earlier observations that only the destruction of the vestibular nuclei complex on the side of the damaged labyrinth eliminates completely Bechterew’s phenomenon.

Science teaches those dealing with it how to remain humble. A countless number of explorers who in their scientific career dealt with research into vestibular compensation, have been obtaining professorial titles based on these research, and now unexpectedly after all these years another scientist proves that the phenomenon of compensation in otoneurology does not appear at all.

 

REFERENCES

1. Bień S.:  Vestibular compensation. In: Clinical Otoneurology edited by G. Janczewski. Warsaw 1986. PZWL

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