Systematic Review of Normative Data for the vHIT Using the EyeSeeCam System in Adults With Normal Vestibular Function

This systematic review aimed to establish normative vestibulo-ocular reflex (VOR) gain parameters for the Video Head Impulse Test (vHIT) using the EyeSeeCam system in healthy adults. Measurement variability highlights the need for standardization. To identify and synthesize studies reporting normative EyeSeeCam vHIT data in individuals aged 18 and older, focusing on horizontal, LARP (Left Anterior-Right Posterior), and RALP (Right Anterior-Left Posterior) canal gains. We searched PubMed, Scopus, and SciELO for papers published in the past decade. We excluded studies lacking predefined thresholds, involving vestibular pathologies, or using non-EyeSeeCam systems. We assessed the risk of bias using the QUADAS-2 tool and conducted a narrative synthesis. Nine out of 227 screened papers met the inclusion criteria (N=404). The normative VOR gain ranged from (based on minimum and maximum mean or cutoff values reported across studies) 0.76 to 1.25 (horizontal), 0.70 to 1.42 (LARP), and 0.70 to 1.3 (RALP). Two studies were assessed as high risk, 3 as moderate, and 4 as low risk, primarily due to incomplete demographic data or selective canal evaluation, which limits generalizability. This is the first review focusing exclusively on EyeSeeCam-based normative values. Despite methodological differences, horizontal canal gains consistently cluster around 0.80. Our synthesis and expert consensus propose 0.70 as a clinically acceptable lower cutoff for VOR gain across all semicircular canals. This threshold strikes a balance between sensitivity and specificity. Our findings highlight the need for standardized vHIT protocols and support the development of system-specific normative criteria.