Subjective Visual Vertical (SVV)

Explained in simple words

1SVV stands for Subjective Visual Vertical. In simple words, it is a test of whether your body knows which way is straight up.

2Think of a mason holding a plumb line to check whether a wall is straight. Your inner ear does exactly the same job for your body.

3Inside each ear there is a tiny organ, called the otolith organ, that senses gravity. It tells the brain where "up" and "down" are.

4When this organ is damaged on one side, the brain gets a wrong message. The person feels tilted or pulled to one side, even while standing straight.

5Such a person may lean while walking, or feel the floor is sloping, or feel that the room is tilted.

6The SVV test measures this tilt exactly, in degrees, so we know how much the balance system is off.

7The test itself is very easy and completely painless. Nothing is put in the ear, and no needles are used.

8You sit comfortably in a chair. You are shown a straight glowing line in a dark background — either through goggles or on a screen in a dark room.

9The line is deliberately shown tilted. Your only job is to turn the line, using a small knob or remote, until you feel it is perfectly straight up and down.

10You do not need to read anything or answer questions. You simply say "stop" or press a button when it looks vertical to you.

11Because the room is dark, you cannot use walls, doors or furniture to judge. So the answer comes purely from your inner ear.

12This is repeated a few times so that the result is reliable.

13A person with healthy balance organs sets the line almost exactly upright, within about two degrees.

14A person whose inner ear is damaged on one side sets the line tilted, often towards the weak side, by several degrees.

15The bigger the tilt, the more the imbalance in the system.

16This test is especially useful because it checks a part of the balance system that other tests may not show — the part that senses gravity.

17It helps us tell whether the sudden dizziness came from the ear or from the brain, which is a very important difference.

18It is also very useful for following up patients. If the tilt gets smaller over weeks, it means the person is recovering and the brain is compensating well.

19The test takes only about ten to fifteen minutes.

20There are no side effects at all. You may go home immediately and continue your normal work.

21People who cannot read or write can do this test very easily, because it only needs you to look and turn a knob.

22The result is explained to you in simple language along with your other test results, before the treatment is planned.