Subjective Visual Vertical
What the patient calls vertical, and what that tells you about the otolith–graviceptive pathway from utricle to cortex.
Try it
The Subjective Visual Vertical (SVV) is the angle a person perceives as upright in the absence of a visible frame of reference. Healthy adults set the line within ±2° of true earth-vertical[4]. Larger tilts localise to the graviceptive pathway from utricle to cortex[2].
Drag the line below until it looks vertical to you, then reveal the angle. Switch the preset to see typical tilt magnitudes seen in disease.
Healthy adult, within ±2°.
Click or tap and drag the line until you perceive it as vertical. Arrow keys nudge by 0.5°; shift+arrow nudges by 5°. Select a disease preset to see typical tilt magnitudes from the literature.
What this atlas covers
How to use this atlas
A five-minute orientation to the features.
Anatomy & physiology
Utricle, vestibular nuclei, INC, parieto-insular cortex.
Technique
Bucket test, hemispheric dome, computerised SVV.
Dynamic SVV
Centrifugation, OVAR, galvanic — unmasking compensated asymmetries.
Normal findings
Tilt limits, age effects, test–retest reliability.
Ocular tilt reaction
Brainstem localisation in the roll plane.
Clinical cases
Fifteen hand-authored vignettes with SBA questions.
Interactive simulator
Draggable luminous line with disease presets.
Self-assessment
Browse, spaced review, and timed mode.
Why SVV matters
SVV is one of the few bedside tools that probes otolith function directly. Unlike the horizontal head impulse test or caloric irrigation — both of which interrogate the semicircular canals — SVV depends on the utricle and its central pathways[2]. That makes it especially valuable in localisation: when the SVV tilts and the canals look normal, you are looking at the graviceptive pathway.
The direction of the tilt is as informative as its magnitude. Lesions from the utricle to the pontomedullary vestibular nuclei produce ipsiversive tilts (toward the lesion); lesions in the rostral midbrain — including the interstitial nucleus of Cajal — produce contraversive tilts[1]. The decussation in the pons is the switch.