Feasibility of vestibulo-occular reflex gain measurement during large amplitude gaze shifts in acute unilateral vestibular dysfunction – a case series.





Vestibular assessment, large gaze shift, eyes saccades, vestibular hypofunction


Background: Head and eye movements orientate gaze during daily activities. In the case of vestibular disorders, these movements can lead to oscillopsia, avoidance behaviours or catch-up saccades. No specific test currently exists to assess large amplitude gaze shifts in clinical practice.

Objective: The aim of the study was to determine the clinical feasibility of measuring the vestibulo-ocular reflex gain and the amplitude and velocity of the head during large amplitude gaze shifts in people with acute unilateral vestibular dysfunction.

Methods: We retrospectively analysed recordings from a Frami-VCOR device in 4 individuals with acute unilateral vestibular dysfunction. Participants were asked to fix an illuminated diode and as soon as it switched off, to rotate their head as quickly as possible to fix a second illuminated diode.

Results: The vestibular ocular reflex gain was smaller when the head turned towards the impaired side but head amplitude and velocity did not differ significantly between the impaired and healthy sides. Post-hoc analysis showed that the amplitude and the velocity of the first saccade (i.e. in the same direction as the head) differed significantly between the impaired and healthy sides.

Conclusions: Evaluation of head and eye movements during a large gaze shift is feasible with a device available in clinical practice: this tool could be useful for clinicians who treat vestibular disorders.






Case Report