I found a few people that didn’t know the 4m4s-rule! So we did that once more. While declinating the various brainstem strokes we had on our ward today, we also spoke about the various ways that vestibular disturbances can be found, what the ocular tilt reaction is and how the subjective visual vertical works. To be honest, while I still marvel at the possibility to measure it with a simple bucket contraption (here is how they build them in Pittsburgh and here is how you can even throw your Iphone into the bucket), I find it exceedingly difficult to interpret the test – it should be less affected by peripheral than central disorders (with thresholds around 8-10°), but would you really forgo an MRI if the SVV is only 6° deviated?
BTW: A very short table exemplifying the “use” of the SVV is found in the wonderful article “A bucket of vestibular function”, written by the Brandt/Strupp/Dieterich clan.