The Problem of Central Compensation of Peripheral Vestibular Dysfunctions

Abstract

The present study is based upon the results of repeated vestibular examinations under nystagmographic control, performed in a group of patients with strictly unilateral peripheral vestibular lesions. Central compensation of peripheral vestibular dysfunctions is based upon two entirely different mechanisms: the first one is a specific vestibular phenomenon, depending on the integrity of the efferent vestibular system. It is termed “accommodation”, i.e. by means of the efferent fibres the responses from the remaining intact labyrinth are modulated, adjusting them to be functional deficiency (inhibition and facilitation). Accommodation is generally completed within a short time unless there is a lesion of the elements of the vestibular ganglion or an impairment of conductivity of the peripheral neuron. Functional disorders at the level of the vestibular ganglion or of the first neuron will implicate uncomplete and delayed accommodation. The second mechanism is a non-specific central phenomenon, substituting the deficient vestibular functions by optic and somatosensory regulation. Hence the term central compensation should strictly speaking be used only for this particular phenomenon. It depends upon the functional integrity of the central nervous system. For this reason traumatic and vascular lesions of the brain will delay the achievement of this compensatory mechanism according to the severity of the central disorder.