Covert anti-compensatory quick eye movements during head impulses.

Maria Heuberger,Murat Sağlam,Klaus Jahn,Erich Schneider,Nicholas S Todd,Nadine Lehnen

doi:10.1371/journal.pone.0093086

Maria Heuberger, Murat Sağlam + Show 4 more

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https://doi.org/10.1371/journal.pone.0093086

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Abstract

BackgroundCatch-up saccades during passive head movements, which compensate for a deficient vestibulo-ocular reflex (VOR), are a well-known phenomenon. These quick eye movements are directed toward the target in the opposite direction of the head movement. Recently, quick eye movements in the direction of the head movement (covert anti-compensatory quick eye movements, CAQEM) were observed in older individuals. Here, we characterize these quick eye movements, their pathophysiology, and clinical relevance during head impulse testing (HIT).MethodsVideo head impulse test data from 266 patients of a tertiary vertigo center were retrospectively analyzed. Forty-three of these patients had been diagnosed with vestibular migraine, and 35 with Menière’s disease.ResultsCAQEM occurred in 38% of the patients. The mean CAQEM occurrence rate (per HIT trial) was 11±10% (mean±SD). Latency was 83±30 ms. CAQEM followed the saccade main sequence characteristics and were compensated by catch-up saccades in the opposite direction. Compensatory saccades did not lead to more false pathological clinical head impulse test assessments (specificity with CAQEM: 87%, and without: 85%). CAQEM on one side were associated with a lower VOR gain on the contralateral side (p<0.004) and helped distinguish Menière’s disease from vestibular migraine (p = 0.01).ConclusionCAQEM are a common phenomenon, most likely caused by a saccadic/quick phase mechanism due to gain asymmetries. They could help differentiate two of the most common causes of recurrent vertigo: vestibular migraine and Menière’s disease.

Highlights

Patients with a deficient vestibulo-ocular reflex (VOR) cannot stabilize their gaze during head impulse testing
Covert saccades, which occur during the head movement, require search-coil or video head impulse testing to be observed
On the basis of our clinical observation, we hypothesized that 1) a compensatory saccade that returns the eyes to the target after compensatory quick eye movement (CAQEM) could be mistaken for a peripheral vestibular sign during clinical examination; 2) CAQEM are associated with a peripheral vestibular deficit contralaterally and could be used to differentiate peripheral vestibular diseases, e.g., Meniere’s disease, from vestibular migraine

Summary

Introduction

Patients with a deficient vestibulo-ocular reflex (VOR) cannot stabilize their gaze during head impulse testing They re-fixate the target with compensatory saccades, i.e., quick eye movements in the opposite direction of those of the head [1]. Covert saccades, which occur during the head movement, require search-coil or video head impulse testing (vHIT [3]) to be observed In addition to these well-known compensatory saccades in VOR-deficient patients, covert anti-compensatory quick eye movements during the head movement (CAQEM, Fig. 1A) were recently observed in older individuals during vHIT [4]. Quick eye movements in the direction of the head movement (covert anti-compensatory quick eye movements, CAQEM) were observed in older individuals We characterize these quick eye movements, their pathophysiology, and clinical relevance during head impulse testing (HIT)

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Results

Conclusion