Microsaccades during video head impulse test in normal subjects

Abstract

Objective

This study aimed to quantitatively analyze the characteristics of saccades in normal subjects during video head impulse test (vHIT), to establish a reference for clinical practice.

Methods

A cohort of 20 healthy individuals (40 ears) was recruited and compared with a matched group of 20 patients (20 ears) suffering from vestibular neuritis (VN), utilizing vHIT to evaluate the functionality of all three semicircular canals (SCCs). This study analyzed the quantitative characteristics of saccades observed in healthy individuals and patients with VN.

Results

Significant differences were observed between both groups in terms of lateral saccade frequency, latency, peak velocity, and duration for both the first and second saccades (all p < 0.05, with age as a covariate). Similarly, significant differences were found in vertical SCCs between groups for the frequency, latency, peak velocity, and duration of the first saccade (all p < 0.05, with age as a covariate). However, no significant differences were found in Perez-Rey (PR) scores either in lateral (p = 0.259) or vertical (p = 0.102) SCCs. Within the healthy group, significant differences were observed in the frequency, peak velocity, and duration of the first saccade in lateral and vertical SCCs (all p < 0.05). However, the latency (p = 0.827) and PR scores (p = 0.552) exhibited no significant variation.

Conclusions

Microsaccades characterized by prolonged latency and reduced amplitude can occur in healthy individuals during vHIT and are distinct from the saccades seen in patients with VN due to vestibular impairment. This highlights the need to carefully identify and interpret relevant saccades during clinical assessments.