What is Subjective Visual Vertical (SVV)?

In humans, the perception of vertical or Subjective Visual Vertical (SVV) depends on many sensory inputs. Our spatial orientation critically depends on accurate reference of the horizontal and vertical. Perception of the vertical is provided by input from sensory pathways, input from the eyes, neck muscles, vestibular cues and various central pathways. 

Disturbance of our eye-head postural control can significantly affect our neurological development of orientation. Subjective Visual Vertical could disturb the interpretation of orientation of numbers and letters. This form of learning difficulty is often interpreted as dyslexia. 

How is Subjective Visual Vertical Tested? 

Evaluation of Subjective Visual Vertical is confirmed through skilled interpretation of a simple bedside test. Testing has advanced from the early 70’s, when the patient manipulates a large rod on a measured scale in a dimly lit room. The angular displacement of the rod from vertical is recorded as Subjective Visual Vertical. 

More recently, computerised and handheld devices have improved practicality, efficiency and accuracy of Subjective Visual Vertical testing. For more information about Subjective Visual Vertical please contact one of our therapist at Brainstorm.

Contact Us
What is Subjective Visual Vertical (SVV)?