[Utricular function. Correlation of three investigations carried out in routine practice]

Abstract

Background: For vestibular disorders competence in otorhinolaryngology (ENT) is required to diagnose disorders in the complete vestibular system. It seems difficult, however, to evaluate otolithic functions although the influence and importance regarding vestibular dysfunction could be relevant. Currently it is possible to unilaterally diagnose different functions of the saccule by recording cervically registered vestibular evoked myogenic potentials (c-VEMP). Partial functions of the utricle can be checked through the so-called turn-over manoeuvre during thermal examination, a gravitation-dependant caloric examination. Ocular recorded VEMPs and registration of the subjective visual vertical (SVV) are further tools for the discrimination of utricular function. This paper evaluates whether the results using these diagnostic tools are in agreement for distinct ENT-relevant vestibular disorders.

Patients and methods: In this study 100 unselected patients attending the vestibular outpatient department of the tinnitus clinic Dr. Hesse in Bad Arolsen and who were suffering from various forms of dizziness were consecutively and prospectively examined. In addition to standard diagnostic examinations (i.e. caloric testing, rotary chair, optocinetics and posturography) the turnover manoeuvre during caloric testing, o-VEMP recording and registration of the SVV were also performed.

Results: For 62 % of the patients all 3 methods that measure partial functions of the utricle concurred. For an additional 6 % the results of the turnover manoeuvre and o-VEMP matched. The most conformity, with respect to sufficient utricular function was found for patients with non-vestibular dizziness, psychogenic vertigo and for the majority of patients with Menière's disease.

Conclusions: In the context of specific vestibular examinations it is possible to test utricular function through o-VEMO recordings and the turnover manoeuvre during caloric (cold) testing which allow clear conclusions especially with sufficient (positive) function. With 68% conformity between o-VEMP and the turnover manoeuvre it is obvious that both tests give strong indications for possible utricular dysfunction but do not give complete proof alone. The SVV is easy to register but is discriminating for utricular function only in cases of acute disorders.