[Reference ranges and test-retest reliability of subject visual horizontal from different head-tilt angles in young healthy adults].

<b>Objective:</b>To establish the normal values of subjective visual horizontal（SVH） under different head tilt angles, analyze the test-retest reliability, and provide a normal value reference for the refined diagnosis and functional assessment of SVH in clinical vestibular disorders. <b>Methods:</b>Thirty-one healthy young people were selected to wear visual reality glasses to test SVH data in five different head tilt angles: upright head position 0°, head tilted 45°to the left（L45°）, head tilted 45° to the right（R45°）, head tilted 90° to the left（L90°）, and head tilted 90° to the right（R90°）, and were re-tested 2 weeks later. <b>Results:</b>①The normal values of SVH at 0°, L45°, R45°, L90°, and R90°were 0.30±1.32, 5.94±5.54, -11.44±5.32, -0.87±8.63, -2.70±8.02, respectively. ②The 95% confidence intervals of SVH at 0°, L45°, R45°, L90°, and R90° were: （-2.34,2.94）,（-5.14,17.02）,（-22.08,-0.80）,（-18.13,16.39）,（-18.74，13.34）, respectively. The ratio of asymmetry in the absolute value of bilateral 45° deviation was 26.4% and the ratio of asymmetry in the absolute value of bilateral 90° deviation was 1.3%. ③The intra-class correlation coefficient（ICC） for 0°, L45°, R45°, L90° and R90° was 0.625, 0.641, 0.564, 0.769, 0.656, respectively. <b>Conclusion:</b>SVH has good test-retest reliability and high clinical test stability and stability. The data on normal values of SVH at different head tilt angles established in this study can provide clinical references for the refined diagnosis and functional assessment of vestibular system disorders.