EVOKED VESTIBULAR POTENTIALS- ASSESSMENT OF VESTIBULAR FUNCTION IN RELAPSING PAROXISMAL POSITIONAL VERTIGO THROUGH EVOKED VESTIBULAR POTENTIALS
Abstract
ABSTRACT
Objective. Vestibular evoked myogenic potentials (VEMPs) are now being used worldwide as a reproducible screening test of the otholitic function, particularly to assess the saccular function. They have been employed in patients affected by Paroxysmal Positional Vertigo (PPV), especially in the relapsing form (RPV). Recently, a new test to study otolithic evoked potentials – electro-vestibulo-graphy (EVG) has been introduced to study vestibular function during head tilts and bendings. It is a specific single neuron reflex test by the use of an extratympanic electrode. Aim of the work was to investigate EVG and VEMPs responses in peripheral vertigo. Methods. Ipsilateral and contralateral VEMP and EVG were determined in 52 patients suffering from RPV by assessing them in the intermittent phase, after a successful repositioning manoeuvre, when otoconia are no longer in the semicircular canals, in order to detect residual vestibular involvement. Results. Both kind of vestibular potentials showed abnormalities in the largest part (90.24%-97.5%, in VEMPs and EVG, respectively) of patients still complaining symptoms after positional vertigo resolution. EVG showed that abnormalities regarded vestibular responses both to lateral tilts and antero-posterior bendings Conclusions. Both tests well agreed with the clinical condition and were useful in the assessment of balance disorder. EVG gave specific information regarding also the status of the vertical canal-utricle coupling allowing interesting speculation upon inter-labirinthic interaction in patients.