Are test results from Subjective Visual Vertical and Ocular Vestibular Evoked Potentials correlated in a Danish Cohort of Patients admitted to a tertiary Dizziness Clinic?

Abstract

Formål: At undersøge hvorvidt der er overensstemmelse mellem oVEMP og SVV målinger i en heterogen gruppe af patienter, henvist med debuterende monosymptomatisk vertigo. Metode: Et retrospektivt klinisk studie bestående af 103 patienter henvist til svimmelhedsambulatoriet på grund af debuterende monosymptomatisk vertigo. Samtlige patienter blev undersøgt med både SVV og oVEMP. De to tests blev sammenlignet ved hjælp af stratificering og Receiver Operation Characteristics (ROC) kurver, samt udregning af arealet under kurven (AUC). Resultater: Når oVEMP antages at være referencepunkt for patologiske fund, viste et AUC [95%CI] på 0.83 for patienter med symptomvarighed på < 1 måned. ROC-kurver for den samlede studiepopulation, samt patienter med symptomvarighed > 1 måned, viste et AUC [95% CI] på < 0.5 indikerende dårligere overensstemmelse mellem SVV og oVEMP end den der kunne opnås ved ren tilfældighed. Patienter med Mb. Ménière, Neuritis Vestibularis eller BPPV blev stratificeret på baggrund af hvilken side den undersøgende læge angav som værende afficeret i patientjournalen. Resultaterne viste en overensstemmelse mellem lægelig vurdering og klinisk test på henholdsvis 27.5 % og 24 % for oVEMP og SVV. For patienter alene diagnosticeret med BPPV var der 20% overensstemmelse mellem lægelig vurdering og oVEMP såvel som SVV. Patienter der kun havde unilateral målbar oVEMP blev stratificeret i forhold til deres korresponderende SVV resultater. Dette viste en enighed på 34% mellem de to tests, samt at 59% af patienterne med normal SVV havde patologisk oVEMP. Konklusion: Dette studie viste overensstemmelse mellem målinger fra oVEMP og SVV hos patienter med monosymptomatisk vertigo karakteriseret ved en symptomvarighed på under 1 måned. Til trods for at både oVEMP og SVV er en del af det vestibulære testbatteri og bidrager til det samlede billede bør man som klinikeer være meget bevidst om de relativt mange potentielle fejlkilder som disse undersøgelser besidder således de i fremtiden kan undgås eller minimeres.

Objectives: To investigate if any concordance exists between oVEMP and SVV results in a heterogeneous group of patients admitted with first time monosymptomatic vertigo. Methods: The retrospective clinical study included 103 patients referred to a tertiary dizziness clinic due to first time monosymptomatic vertigo. All patients were examined with SVV and oVEMP. The tests were compared by means of stratification as well as Receiver Operation Characteristics (ROC) curves with area under the curve (AUC) computed. Results: ROC curves comparing SVV and oVEMP results, with the oVEMP system as the benchmark for pathological findings, showed an AUC [95%CI] of 0.83 for patients with symptom duration of less than one month. The entire study population as well as the patients with symptom duration more than one month showed ROC curves with AUC [95%CI] of < 0.5 indicating less accuracy than random outcome. Patients with Ménière, Vestibular Neuritis or BPPV were stratified based on which side the examining doctor noted as being pathological. Pooled together, the three diagnoses demonstrated an agreement between the examining doctor and oVEMP or SVV of respectively 27.5% and 24%. An agreement of 20% was found for BPPV in regard to both tests. Patients with only one measurable oVEMP, stratified on SVV classification showed a 34% agreement between the two tests, as well as 59% of patients with normal SVV, but pathological oVEMP. Conclusion: Among patients experiencing monosymptomatic vertigo the present study showed a correlation between oVEMP and SVV results in patients with a symptom duration of less than one month. Despite oVEMP and SVV both being part of the extensive test battery in vestibular diagnostics, clinicians should be conscious of avoiding the potential errors discussed in this study; both during testing and interpretation.

A master thesis from Aalborg University

Are test results from Subjective Visual Vertical and Ocular Vestibular Evoked Potentials correlated in a Danish Cohort of Patients admitted to a tertiary Dizziness Clinic?