Utility of Suppression Head Impulse Paradigm in Identifying Various Peripheral Vestibular Disorders: A Systematic Review

Abstract

Introduction: The vestibulo-ocular reflex (VOR) is a gaze stabilization reflex which ensures ocular stability by making fovea focus on the object of interest. The VOR is often affected in patients with various peripheral vestibular disorders. The video head impulse test (vHIT) is a widely used clinical tool for assessing the functional integrity of semicircular canals and their projections in various vestibular pathologies. vHIT has two paradigms: Head impulse paradigm (HIMP) and Suppression head impulse paradigm (SHIMP). Aim: To systematically review the articles related to Suppression Head Impulse Paradigm (SHIMP) findings in patients with various peripheral vestibular pathologies. Method: A review search was carried out initially in different databases. Searches across different databases resulted in 109 topic-related articles, of which 13 met the inclusion and exclusion criteria to meet the objectives of the study. The quality and potential risk associated with each article were evaluated using the QUADAS-2 risk of bias assessment tool. Results: The results of all the studies indicate that the VOR gain is reduced on the side with the lesion. On the contra-lesional side (healthy side), the VOR gain is observed to be normal. This was consistent among peripheral pathologies such as vestibular neuritis, unilateral and bilateral hypofunction, and vestibular schwannoma. The VOR gain aids in ruling out the extent of vestibular damage, course of the disease, central compensation, recovery process, and prognosis of vestibular rehabilitation. Across studies, it was consistent that there is no or significantly limited occurrence of anti-compensatory saccades in patients with various peripheral vestibular pathologies. The aspects of anti-compensatory saccade measures such as frequency of occurrence, peak-saccadic velocities, and the ratio of saccadic velocity to head velocity of the anti-compensatory saccades are demonstrated across various studies that have affirmed the utility of this measure in arriving at a clinical diagnosis in patients with peripheral vestibular disorders. Conclusion: The Suppression Head Impulse Paradigm (SHIMP) is valuable in providing insight into various peripheral vestibular pathologies. When administered along with the HIMP and other significant test tools, SHIMP offers useful information that aids in arriving at a clinical diagnosis. It is always recommended to administer both SHIMP and HIMP as they complement each other. The SHIMP VOR gain and the anti-compensatory saccades are the most crucial parameters that help diagnose various peripheral vestibular pathologies.